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-rw-r--r--arch/s390/include/asm/ccwgroup.h1
-rw-r--r--arch/s390/pci/pci_sysfs.c18
-rw-r--r--drivers/base/core.c50
-rw-r--r--drivers/base/dma-buf.c18
-rw-r--r--drivers/gpu/drm/drm_prime.c2
-rw-r--r--drivers/gpu/drm/exynos/exynos_drm_dmabuf.c2
-rw-r--r--drivers/media/v4l2-core/videobuf2-dma-contig.c2
-rw-r--r--drivers/pci/pci-sysfs.c17
-rw-r--r--drivers/s390/block/dcssblk.c14
-rw-r--r--drivers/s390/cio/ccwgroup.c26
-rw-r--r--drivers/scsi/scsi_sysfs.c15
-rw-r--r--fs/Kconfig1
-rw-r--r--fs/Makefile3
-rw-r--r--fs/kernfs/Kconfig7
-rw-r--r--fs/kernfs/dir.c754
-rw-r--r--fs/kernfs/file.c55
-rw-r--r--fs/kernfs/kernfs-internal.h14
-rw-r--r--fs/kernfs/mount.c37
-rw-r--r--fs/kernfs/symlink.c6
-rw-r--r--fs/sysfs/Kconfig1
-rw-r--r--fs/sysfs/dir.c44
-rw-r--r--fs/sysfs/file.c115
-rw-r--r--fs/sysfs/mount.c2
-rw-r--r--include/linux/device.h13
-rw-r--r--include/linux/kernfs.h108
-rw-r--r--include/linux/sysfs.h23
-rw-r--r--lib/kobject.c2
27 files changed, 847 insertions, 503 deletions
diff --git a/arch/s390/include/asm/ccwgroup.h b/arch/s390/include/asm/ccwgroup.h
index 23723ce5ca7a..6e670f88d125 100644
--- a/arch/s390/include/asm/ccwgroup.h
+++ b/arch/s390/include/asm/ccwgroup.h
@@ -23,6 +23,7 @@ struct ccwgroup_device {
unsigned int count;
struct device dev;
struct ccw_device *cdev[0];
+ struct work_struct ungroup_work;
};
/**
diff --git a/arch/s390/pci/pci_sysfs.c b/arch/s390/pci/pci_sysfs.c
index cf8a12ff733b..ab4a91393005 100644
--- a/arch/s390/pci/pci_sysfs.c
+++ b/arch/s390/pci/pci_sysfs.c
@@ -48,29 +48,27 @@ static ssize_t show_pfgid(struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR(pfgid, S_IRUGO, show_pfgid, NULL);
-static void recover_callback(struct device *dev)
+static ssize_t store_recover(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct zpci_dev *zdev = get_zdev(pdev);
int ret;
+ if (!device_remove_file_self(dev, attr))
+ return count;
+
pci_stop_and_remove_bus_device(pdev);
ret = zpci_disable_device(zdev);
if (ret)
- return;
+ return ret;
ret = zpci_enable_device(zdev);
if (ret)
- return;
+ return ret;
pci_rescan_bus(zdev->bus);
-}
-
-static ssize_t store_recover(struct device *dev, struct device_attribute *attr,
- const char *buf, size_t count)
-{
- int rc = device_schedule_callback(dev, recover_callback);
- return rc ? rc : count;
+ return count;
}
static DEVICE_ATTR(recover, S_IWUSR, NULL, store_recover);
diff --git a/drivers/base/core.c b/drivers/base/core.c
index 2b567177ef78..4195364f9fdd 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -571,6 +571,23 @@ void device_remove_file(struct device *dev,
EXPORT_SYMBOL_GPL(device_remove_file);
/**
+ * device_remove_file_self - remove sysfs attribute file from its own method.
+ * @dev: device.
+ * @attr: device attribute descriptor.
+ *
+ * See kernfs_remove_self() for details.
+ */
+bool device_remove_file_self(struct device *dev,
+ const struct device_attribute *attr)
+{
+ if (dev)
+ return sysfs_remove_file_self(&dev->kobj, &attr->attr);
+ else
+ return false;
+}
+EXPORT_SYMBOL_GPL(device_remove_file_self);
+
+/**
* device_create_bin_file - create sysfs binary attribute file for device.
* @dev: device.
* @attr: device binary attribute descriptor.
@@ -598,39 +615,6 @@ void device_remove_bin_file(struct device *dev,
}
EXPORT_SYMBOL_GPL(device_remove_bin_file);
-/**
- * device_schedule_callback_owner - helper to schedule a callback for a device
- * @dev: device.
- * @func: callback function to invoke later.
- * @owner: module owning the callback routine
- *
- * Attribute methods must not unregister themselves or their parent device
- * (which would amount to the same thing). Attempts to do so will deadlock,
- * since unregistration is mutually exclusive with driver callbacks.
- *
- * Instead methods can call this routine, which will attempt to allocate
- * and schedule a workqueue request to call back @func with @dev as its
- * argument in the workqueue's process context. @dev will be pinned until
- * @func returns.
- *
- * This routine is usually called via the inline device_schedule_callback(),
- * which automatically sets @owner to THIS_MODULE.
- *
- * Returns 0 if the request was submitted, -ENOMEM if storage could not
- * be allocated, -ENODEV if a reference to @owner isn't available.
- *
- * NOTE: This routine won't work if CONFIG_SYSFS isn't set! It uses an
- * underlying sysfs routine (since it is intended for use by attribute
- * methods), and if sysfs isn't available you'll get nothing but -ENOSYS.
- */
-int device_schedule_callback_owner(struct device *dev,
- void (*func)(struct device *), struct module *owner)
-{
- return sysfs_schedule_callback(&dev->kobj,
- (void (*)(void *)) func, dev, owner);
-}
-EXPORT_SYMBOL_GPL(device_schedule_callback_owner);
-
static void klist_children_get(struct klist_node *n)
{
struct device_private *p = to_device_private_parent(n);
diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c
index 1e16cbd61da2..cfe1d8bc7bb8 100644
--- a/drivers/base/dma-buf.c
+++ b/drivers/base/dma-buf.c
@@ -251,9 +251,8 @@ EXPORT_SYMBOL_GPL(dma_buf_put);
* @dmabuf: [in] buffer to attach device to.
* @dev: [in] device to be attached.
*
- * Returns struct dma_buf_attachment * for this attachment; may return negative
- * error codes.
- *
+ * Returns struct dma_buf_attachment * for this attachment; returns ERR_PTR on
+ * error.
*/
struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
struct device *dev)
@@ -319,9 +318,8 @@ EXPORT_SYMBOL_GPL(dma_buf_detach);
* @attach: [in] attachment whose scatterlist is to be returned
* @direction: [in] direction of DMA transfer
*
- * Returns sg_table containing the scatterlist to be returned; may return NULL
- * or ERR_PTR.
- *
+ * Returns sg_table containing the scatterlist to be returned; returns ERR_PTR
+ * on error.
*/
struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
enum dma_data_direction direction)
@@ -334,6 +332,8 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
return ERR_PTR(-EINVAL);
sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
+ if (!sg_table)
+ sg_table = ERR_PTR(-ENOMEM);
return sg_table;
}
@@ -544,6 +544,8 @@ EXPORT_SYMBOL_GPL(dma_buf_mmap);
* These calls are optional in drivers. The intended use for them
* is for mapping objects linear in kernel space for high use objects.
* Please attempt to use kmap/kunmap before thinking about these interfaces.
+ *
+ * Returns NULL on error.
*/
void *dma_buf_vmap(struct dma_buf *dmabuf)
{
@@ -566,7 +568,9 @@ void *dma_buf_vmap(struct dma_buf *dmabuf)
BUG_ON(dmabuf->vmap_ptr);
ptr = dmabuf->ops->vmap(dmabuf);
- if (IS_ERR_OR_NULL(ptr))
+ if (WARN_ON_ONCE(IS_ERR(ptr)))
+ ptr = NULL;
+ if (!ptr)
goto out_unlock;
dmabuf->vmap_ptr = ptr;
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c
index 56805c39c906..bb516fdd195d 100644
--- a/drivers/gpu/drm/drm_prime.c
+++ b/drivers/gpu/drm/drm_prime.c
@@ -471,7 +471,7 @@ struct drm_gem_object *drm_gem_prime_import(struct drm_device *dev,
get_dma_buf(dma_buf);
sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
- if (IS_ERR_OR_NULL(sgt)) {
+ if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
goto fail_detach;
}
diff --git a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
index 59827cc5e770..c786cd4f457b 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dmabuf.c
@@ -224,7 +224,7 @@ struct drm_gem_object *exynos_dmabuf_prime_import(struct drm_device *drm_dev,
get_dma_buf(dma_buf);
sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
- if (IS_ERR_OR_NULL(sgt)) {
+ if (IS_ERR(sgt)) {
ret = PTR_ERR(sgt);
goto err_buf_detach;
}
diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
index 33d3871d1e13..880be0782dd9 100644
--- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
@@ -719,7 +719,7 @@ static int vb2_dc_map_dmabuf(void *mem_priv)
/* get the associated scatterlist for this buffer */
sgt = dma_buf_map_attachment(buf->db_attach, buf->dma_dir);
- if (IS_ERR_OR_NULL(sgt)) {
+ if (IS_ERR(sgt)) {
pr_err("Error getting dmabuf scatterlist\n");
return -EINVAL;
}
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index 276ef9c18802..4e0acefb7565 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -351,28 +351,17 @@ static struct device_attribute dev_rescan_attr = __ATTR(rescan,
(S_IWUSR|S_IWGRP),
NULL, dev_rescan_store);
-static void remove_callback(struct device *dev)
-{
- pci_stop_and_remove_bus_device_locked(to_pci_dev(dev));
-}
-
static ssize_t
-remove_store(struct device *dev, struct device_attribute *dummy,
+remove_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
- int ret = 0;
unsigned long val;
if (kstrtoul(buf, 0, &val) < 0)
return -EINVAL;
- /* An attribute cannot be unregistered by one of its own methods,
- * so we have to use this roundabout approach.
- */
- if (val)
- ret = device_schedule_callback(dev, remove_callback);
- if (ret)
- count = ret;
+ if (val && device_remove_file_self(dev, attr))
+ pci_stop_and_remove_bus_device_locked(to_pci_dev(dev));
return count;
}
static struct device_attribute dev_remove_attr = __ATTR(remove,
diff --git a/drivers/s390/block/dcssblk.c b/drivers/s390/block/dcssblk.c
index ebf41e228e55..ee0e85abe1fd 100644
--- a/drivers/s390/block/dcssblk.c
+++ b/drivers/s390/block/dcssblk.c
@@ -304,12 +304,6 @@ dcssblk_load_segment(char *name, struct segment_info **seg_info)
return rc;
}
-static void dcssblk_unregister_callback(struct device *dev)
-{
- device_unregister(dev);
- put_device(dev);
-}
-
/*
* device attribute for switching shared/nonshared (exclusive)
* operation (show + store)
@@ -397,7 +391,13 @@ removeseg:
blk_cleanup_queue(dev_info->dcssblk_queue);
dev_info->gd->queue = NULL;
put_disk(dev_info->gd);
- rc = device_schedule_callback(dev, dcssblk_unregister_callback);
+ up_write(&dcssblk_devices_sem);
+
+ if (device_remove_file_self(dev, attr)) {
+ device_unregister(dev);
+ put_device(dev);
+ }
+ return rc;
out:
up_write(&dcssblk_devices_sem);
return rc;
diff --git a/drivers/s390/cio/ccwgroup.c b/drivers/s390/cio/ccwgroup.c
index fd3367a1dc7a..dfd7bc681c25 100644
--- a/drivers/s390/cio/ccwgroup.c
+++ b/drivers/s390/cio/ccwgroup.c
@@ -168,14 +168,12 @@ static ssize_t ccwgroup_online_show(struct device *dev,
* Provide an 'ungroup' attribute so the user can remove group devices no
* longer needed or accidentially created. Saves memory :)
*/
-static void ccwgroup_ungroup_callback(struct device *dev)
+static void ccwgroup_ungroup(struct ccwgroup_device *gdev)
{
- struct ccwgroup_device *gdev = to_ccwgroupdev(dev);
-
mutex_lock(&gdev->reg_mutex);
if (device_is_registered(&gdev->dev)) {
__ccwgroup_remove_symlinks(gdev);
- device_unregister(dev);
+ device_unregister(&gdev->dev);
__ccwgroup_remove_cdev_refs(gdev);
}
mutex_unlock(&gdev->reg_mutex);
@@ -195,10 +193,9 @@ static ssize_t ccwgroup_ungroup_store(struct device *dev,
rc = -EINVAL;
goto out;
}
- /* Note that we cannot unregister the device from one of its
- * attribute methods, so we have to use this roundabout approach.
- */
- rc = device_schedule_callback(dev, ccwgroup_ungroup_callback);
+
+ if (device_remove_file_self(dev, attr))
+ ccwgroup_ungroup(gdev);
out:
if (rc) {
if (rc != -EAGAIN)
@@ -224,6 +221,14 @@ static const struct attribute_group *ccwgroup_attr_groups[] = {
NULL,
};
+static void ccwgroup_ungroup_workfn(struct work_struct *work)
+{
+ struct ccwgroup_device *gdev =
+ container_of(work, struct ccwgroup_device, ungroup_work);
+
+ ccwgroup_ungroup(gdev);
+}
+
static void ccwgroup_release(struct device *dev)
{
kfree(to_ccwgroupdev(dev));
@@ -323,6 +328,7 @@ int ccwgroup_create_dev(struct device *parent, struct ccwgroup_driver *gdrv,
atomic_set(&gdev->onoff, 0);
mutex_init(&gdev->reg_mutex);
mutex_lock(&gdev->reg_mutex);
+ INIT_WORK(&gdev->ungroup_work, ccwgroup_ungroup_workfn);
gdev->count = num_devices;
gdev->dev.bus = &ccwgroup_bus_type;
gdev->dev.parent = parent;
@@ -404,10 +410,10 @@ EXPORT_SYMBOL(ccwgroup_create_dev);
static int ccwgroup_notifier(struct notifier_block *nb, unsigned long action,
void *data)
{
- struct device *dev = data;
+ struct ccwgroup_device *gdev = to_ccwgroupdev(data);
if (action == BUS_NOTIFY_UNBIND_DRIVER)
- device_schedule_callback(dev, ccwgroup_ungroup_callback);
+ schedule_work(&gdev->ungroup_work);
return NOTIFY_OK;
}
diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
index 9117d0bf408e..8ead24c3453a 100644
--- a/drivers/scsi/scsi_sysfs.c
+++ b/drivers/scsi/scsi_sysfs.c
@@ -649,23 +649,12 @@ store_rescan_field (struct device *dev, struct device_attribute *attr,
}
static DEVICE_ATTR(rescan, S_IWUSR, NULL, store_rescan_field);
-static void sdev_store_delete_callback(struct device *dev)
-{
- scsi_remove_device(to_scsi_device(dev));
-}
-
static ssize_t
sdev_store_delete(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
- int rc;
-
- /* An attribute cannot be unregistered by one of its own methods,
- * so we have to use this roundabout approach.
- */
- rc = device_schedule_callback(dev, sdev_store_delete_callback);
- if (rc)
- count = rc;
+ if (device_remove_file_self(dev, attr))
+ scsi_remove_device(to_scsi_device(dev));
return count;
};
static DEVICE_ATTR(delete, S_IWUSR, NULL, sdev_store_delete);
diff --git a/fs/Kconfig b/fs/Kconfig
index 7385e54be4b9..312393f32948 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -96,6 +96,7 @@ endif # BLOCK
menu "Pseudo filesystems"
source "fs/proc/Kconfig"
+source "fs/kernfs/Kconfig"
source "fs/sysfs/Kconfig"
config TMPFS
diff --git a/fs/Makefile b/fs/Makefile
index 47ac07bb4acc..f9cb9876e466 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -52,7 +52,8 @@ obj-$(CONFIG_FHANDLE) += fhandle.o
obj-y += quota/
obj-$(CONFIG_PROC_FS) += proc/
-obj-$(CONFIG_SYSFS) += sysfs/ kernfs/
+obj-$(CONFIG_KERNFS) += kernfs/
+obj-$(CONFIG_SYSFS) += sysfs/
obj-$(CONFIG_CONFIGFS_FS) += configfs/
obj-y += devpts/
diff --git a/fs/kernfs/Kconfig b/fs/kernfs/Kconfig
new file mode 100644
index 000000000000..397b5f7a7a16
--- /dev/null
+++ b/fs/kernfs/Kconfig
@@ -0,0 +1,7 @@
+#
+# KERNFS should be selected by its users
+#
+
+config KERNFS
+ bool
+ default n
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 5104cf5d25c5..a347792c2e5a 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -8,6 +8,7 @@
* This file is released under the GPLv2.
*/
+#include <linux/sched.h>
#include <linux/fs.h>
#include <linux/namei.h>
#include <linux/idr.h>
@@ -18,9 +19,161 @@
#include "kernfs-internal.h"
DEFINE_MUTEX(kernfs_mutex);
+static DEFINE_SPINLOCK(kernfs_rename_lock); /* kn->parent and ->name */
+static char kernfs_pr_cont_buf[PATH_MAX]; /* protected by rename_lock */
#define rb_to_kn(X) rb_entry((X), struct kernfs_node, rb)
+static bool kernfs_active(struct kernfs_node *kn)
+{
+ lockdep_assert_held(&kernfs_mutex);
+ return atomic_read(&kn->active) >= 0;
+}
+
+static bool kernfs_lockdep(struct kernfs_node *kn)
+{
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+ return kn->flags & KERNFS_LOCKDEP;
+#else
+ return false;
+#endif
+}
+
+static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
+{
+ return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
+}
+
+static char * __must_check kernfs_path_locked(struct kernfs_node *kn, char *buf,
+ size_t buflen)
+{
+ char *p = buf + buflen;
+ int len;
+
+ *--p = '\0';
+
+ do {
+ len = strlen(kn->name);
+ if (p - buf < len + 1) {
+ buf[0] = '\0';
+ p = NULL;
+ break;
+ }
+ p -= len;
+ memcpy(p, kn->name, len);
+ *--p = '/';
+ kn = kn->parent;
+ } while (kn && kn->parent);
+
+ return p;
+}
+
+/**
+ * kernfs_name - obtain the name of a given node
+ * @kn: kernfs_node of interest
+ * @buf: buffer to copy @kn's name into
+ * @buflen: size of @buf
+ *
+ * Copies the name of @kn into @buf of @buflen bytes. The behavior is
+ * similar to strlcpy(). It returns the length of @kn's name and if @buf
+ * isn't long enough, it's filled upto @buflen-1 and nul terminated.
+ *
+ * This function can be called from any context.
+ */
+int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
+{
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+ ret = kernfs_name_locked(kn, buf, buflen);
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+ return ret;
+}
+
+/**
+ * kernfs_path - build full path of a given node
+ * @kn: kernfs_node of interest
+ * @buf: buffer to copy @kn's name into
+ * @buflen: size of @buf
+ *
+ * Builds and returns the full path of @kn in @buf of @buflen bytes. The
+ * path is built from the end of @buf so the returned pointer usually
+ * doesn't match @buf. If @buf isn't long enough, @buf is nul terminated
+ * and %NULL is returned.
+ */
+char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
+{
+ unsigned long flags;
+ char *p;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+ p = kernfs_path_locked(kn, buf, buflen);
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+ return p;
+}
+
+/**
+ * pr_cont_kernfs_name - pr_cont name of a kernfs_node
+ * @kn: kernfs_node of interest
+ *
+ * This function can be called from any context.
+ */
+void pr_cont_kernfs_name(struct kernfs_node *kn)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+
+ kernfs_name_locked(kn, kernfs_pr_cont_buf, sizeof(kernfs_pr_cont_buf));
+ pr_cont("%s", kernfs_pr_cont_buf);
+
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+}
+
+/**
+ * pr_cont_kernfs_path - pr_cont path of a kernfs_node
+ * @kn: kernfs_node of interest
+ *
+ * This function can be called from any context.
+ */
+void pr_cont_kernfs_path(struct kernfs_node *kn)
+{
+ unsigned long flags;
+ char *p;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+
+ p = kernfs_path_locked(kn, kernfs_pr_cont_buf,
+ sizeof(kernfs_pr_cont_buf));
+ if (p)
+ pr_cont("%s", p);
+ else
+ pr_cont("<name too long>");
+
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+}
+
+/**
+ * kernfs_get_parent - determine the parent node and pin it
+ * @kn: kernfs_node of interest
+ *
+ * Determines @kn's parent, pins and returns it. This function can be
+ * called from any context.
+ */
+struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
+{
+ struct kernfs_node *parent;
+ unsigned long flags;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+ parent = kn->parent;
+ kernfs_get(parent);
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+
+ return parent;
+}
+
/**
* kernfs_name_hash
* @name: Null terminated string to hash
@@ -105,18 +258,24 @@ static int kernfs_link_sibling(struct kernfs_node *kn)
* kernfs_unlink_sibling - unlink kernfs_node from sibling rbtree
* @kn: kernfs_node of interest
*
- * Unlink @kn from its sibling rbtree which starts from
- * kn->parent->dir.children.
+ * Try to unlink @kn from its sibling rbtree which starts from
+ * kn->parent->dir.children. Returns %true if @kn was actually
+ * removed, %false if @kn wasn't on the rbtree.
*
* Locking:
* mutex_lock(kernfs_mutex)
*/
-static void kernfs_unlink_sibling(struct kernfs_node *kn)
+static bool kernfs_unlink_sibling(struct kernfs_node *kn)
{
+ if (RB_EMPTY_NODE(&kn->rb))
+ return false;
+
if (kernfs_type(kn) == KERNFS_DIR)
kn->parent->dir.subdirs--;
rb_erase(&kn->rb, &kn->parent->dir.children);
+ RB_CLEAR_NODE(&kn->rb);
+ return true;
}
/**
@@ -137,7 +296,7 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
if (!atomic_inc_unless_negative(&kn->active))
return NULL;
- if (kn->flags & KERNFS_LOCKDEP)
+ if (kernfs_lockdep(kn))
rwsem_acquire_read(&kn->dep_map, 0, 1, _RET_IP_);
return kn;
}
@@ -151,55 +310,57 @@ struct kernfs_node *kernfs_get_active(struct kernfs_node *kn)
*/
void kernfs_put_active(struct kernfs_node *kn)
{
+ struct kernfs_root *root = kernfs_root(kn);
int v;
if (unlikely(!kn))
return;
- if (kn->flags & KERNFS_LOCKDEP)
+ if (kernfs_lockdep(kn))
rwsem_release(&kn->dep_map, 1, _RET_IP_);
v = atomic_dec_return(&kn->active);
if (likely(v != KN_DEACTIVATED_BIAS))
return;
- /*
- * atomic_dec_return() is a mb(), we'll always see the updated
- * kn->u.completion.
- */
- complete(kn->u.completion);
+ wake_up_all(&root->deactivate_waitq);
}
/**
- * kernfs_deactivate - deactivate kernfs_node
- * @kn: kernfs_node to deactivate
+ * kernfs_drain - drain kernfs_node
+ * @kn: kernfs_node to drain
*
- * Deny new active references and drain existing ones.
+ * Drain existing usages and nuke all existing mmaps of @kn. Mutiple
+ * removers may invoke this function concurrently on @kn and all will
+ * return after draining is complete.
*/
-static void kernfs_deactivate(struct kernfs_node *kn)
+static void kernfs_drain(struct kernfs_node *kn)
+ __releases(&kernfs_mutex) __acquires(&kernfs_mutex)
{
- DECLARE_COMPLETION_ONSTACK(wait);
- int v;
+ struct kernfs_root *root = kernfs_root(kn);
- BUG_ON(!(kn->flags & KERNFS_REMOVED));
+ lockdep_assert_held(&kernfs_mutex);
+ WARN_ON_ONCE(kernfs_active(kn));
- if (!(kernfs_type(kn) & KERNFS_ACTIVE_REF))
- return;
+ mutex_unlock(&kernfs_mutex);
- kn->u.completion = (void *)&wait;
+ if (kernfs_lockdep(kn)) {
+ rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
+ if (atomic_read(&kn->active) != KN_DEACTIVATED_BIAS)
+ lock_contended(&kn->dep_map, _RET_IP_);
+ }
- rwsem_acquire(&kn->dep_map, 0, 0, _RET_IP_);
- /* atomic_add_return() is a mb(), put_active() will always see
- * the updated kn->u.completion.
- */
- v = atomic_add_return(KN_DEACTIVATED_BIAS, &kn->active);
+ /* but everyone should wait for draining */
+ wait_event(root->deactivate_waitq,
+ atomic_read(&kn->active) == KN_DEACTIVATED_BIAS);
- if (v != KN_DEACTIVATED_BIAS) {
- lock_contended(&kn->dep_map, _RET_IP_);
- wait_for_completion(&wait);
+ if (kernfs_lockdep(kn)) {
+ lock_acquired(&kn->dep_map, _RET_IP_);
+ rwsem_release(&kn->dep_map, 1, _RET_IP_);
}
- lock_acquired(&kn->dep_map, _RET_IP_);
- rwsem_release(&kn->dep_map, 1, _RET_IP_);
+ kernfs_unmap_bin_file(kn);
+
+ mutex_lock(&kernfs_mutex);
}
/**
@@ -230,13 +391,15 @@ void kernfs_put(struct kernfs_node *kn)
return;
root = kernfs_root(kn);
repeat:
- /* Moving/renaming is always done while holding reference.
+ /*
+ * Moving/renaming is always done while holding reference.
* kn->parent won't change beneath us.
*/
parent = kn->parent;
- WARN(!(kn->flags & KERNFS_REMOVED), "kernfs: free using entry: %s/%s\n",
- parent ? parent->name : "", kn->name);
+ WARN_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS,
+ "kernfs_put: %s/%s: released with incorrect active_ref %d\n",
+ parent ? parent->name : "", kn->name, atomic_read(&kn->active));
if (kernfs_type(kn) == KERNFS_LINK)
kernfs_put(kn->symlink.target_kn);
@@ -278,8 +441,8 @@ static int kernfs_dop_revalidate(struct dentry *dentry, unsigned int flags)
kn = dentry->d_fsdata;
mutex_lock(&kernfs_mutex);
- /* The kernfs node has been deleted */
- if (kn->flags & KERNFS_REMOVED)
+ /* The kernfs node has been deactivated */
+ if (!kernfs_active(kn))
goto out_bad;
/* The kernfs node has been moved? */
@@ -324,6 +487,24 @@ const struct dentry_operations kernfs_dops = {
.d_release = kernfs_dop_release,
};
+/**
+ * kernfs_node_from_dentry - determine kernfs_node associated with a dentry
+ * @dentry: the dentry in question
+ *
+ * Return the kernfs_node associated with @dentry. If @dentry is not a
+ * kernfs one, %NULL is returned.
+ *
+ * While the returned kernfs_node will stay accessible as long as @dentry
+ * is accessible, the returned node can be in any state and the caller is
+ * fully responsible for determining what's accessible.
+ */
+struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
+{
+ if (dentry->d_op == &kernfs_dops)
+ return dentry->d_fsdata;
+ return NULL;
+}
+
static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
const char *name, umode_t mode,
unsigned flags)
@@ -348,11 +529,12 @@ static struct kernfs_node *__kernfs_new_node(struct kernfs_root *root,
kn->ino = ret;
atomic_set(&kn->count, 1);
- atomic_set(&kn->active, 0);
+ atomic_set(&kn->active, KN_DEACTIVATED_BIAS);
+ RB_CLEAR_NODE(&kn->rb);
kn->name = name;
kn->mode = mode;
- kn->flags = flags | KERNFS_REMOVED;
+ kn->flags = flags;
return kn;
@@ -378,69 +560,44 @@ struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
}
/**
- * kernfs_addrm_start - prepare for kernfs_node add/remove
- * @acxt: pointer to kernfs_addrm_cxt to be used
- *
- * This function is called when the caller is about to add or remove
- * kernfs_node. This function acquires kernfs_mutex. @acxt is used
- * to keep and pass context to other addrm functions.
- *
- * LOCKING:
- * Kernel thread context (may sleep). kernfs_mutex is locked on
- * return.
- */
-void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt)
- __acquires(kernfs_mutex)
-{
- memset(acxt, 0, sizeof(*acxt));
-
- mutex_lock(&kernfs_mutex);
-}
-
-/**
* kernfs_add_one - add kernfs_node to parent without warning
- * @acxt: addrm context to use
* @kn: kernfs_node to be added
*
* The caller must already have initialized @kn->parent. This
* function increments nlink of the parent's inode if @kn is a
* directory and link into the children list of the parent.
*
- * This function should be called between calls to
- * kernfs_addrm_start() and kernfs_addrm_finish() and should be passed
- * the same @acxt as passed to kernfs_addrm_start().
- *
- * LOCKING:
- * Determined by kernfs_addrm_start().
- *
* RETURNS:
* 0 on success, -EEXIST if entry with the given name already
* exists.
*/
-int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
+int kernfs_add_one(struct kernfs_node *kn)
{
struct kernfs_node *parent = kn->parent;
- bool has_ns = kernfs_ns_enabled(parent);
struct kernfs_iattrs *ps_iattr;
+ bool has_ns;
int ret;
- if (has_ns != (bool)kn->ns) {
- WARN(1, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
- has_ns ? "required" : "invalid", parent->name, kn->name);
- return -EINVAL;
- }
+ mutex_lock(&kernfs_mutex);
+
+ ret = -EINVAL;
+ has_ns = kernfs_ns_enabled(parent);
+ if (WARN(has_ns != (bool)kn->ns, KERN_WARNING "kernfs: ns %s in '%s' for '%s'\n",
+ has_ns ? "required" : "invalid", parent->name, kn->name))
+ goto out_unlock;
if (kernfs_type(parent) != KERNFS_DIR)
- return -EINVAL;
+ goto out_unlock;
- if (parent->flags & KERNFS_REMOVED)
- return -ENOENT;
+ ret = -ENOENT;
+ if ((parent->flags & KERNFS_ACTIVATED) && !kernfs_active(parent))
+ goto out_unlock;
kn->hash = kernfs_name_hash(kn->name, kn->ns);
ret = kernfs_link_sibling(kn);
if (ret)
- return ret;
+ goto out_unlock;
/* Update timestamps on the parent */
ps_iattr = parent->iattr;
@@ -449,82 +606,22 @@ int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn)
ps_iattrs->ia_ctime = ps_iattrs->ia_mtime = CURRENT_TIME;
}
- /* Mark the entry added into directory tree */
- kn->flags &= ~KERNFS_REMOVED;
-
- return 0;
-}
-
-/**
- * kernfs_remove_one - remove kernfs_node from parent
- * @acxt: addrm context to use
- * @kn: kernfs_node to be removed
- *
- * Mark @kn removed and drop nlink of parent inode if @kn is a
- * directory. @kn is unlinked from the children list.
- *
- * This function should be called between calls to
- * kernfs_addrm_start() and kernfs_addrm_finish() and should be
- * passed the same @acxt as passed to kernfs_addrm_start().
- *
- * LOCKING:
- * Determined by kernfs_addrm_start().
- */
-static void kernfs_remove_one(struct kernfs_addrm_cxt *acxt,
- struct kernfs_node *kn)
-{
- struct kernfs_iattrs *ps_iattr;
+ mutex_unlock(&kernfs_mutex);
/*
- * Removal can be called multiple times on the same node. Only the
- * first invocation is effective and puts the base ref.
+ * Activate the new node unless CREATE_DEACTIVATED is requested.
+ * If not activated here, the kernfs user is responsible for
+ * activating the node with kernfs_activate(). A node which hasn't
+ * been activated is not visible to userland and its removal won't
+ * trigger deactivation.
*/
- if (kn->flags & KERNFS_REMOVED)
- return;
-
- if (kn->parent) {
- kernfs_unlink_sibling(kn);
-
- /* Update timestamps on the parent */
- ps_iattr = kn->parent->iattr;
- if (ps_iattr) {
- ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
- ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
- }
- }
-
- kn->flags |= KERNFS_REMOVED;
- kn->u.removed_list = acxt->removed;
- acxt->removed = kn;
-}
+ if (!(kernfs_root(kn)->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
+ kernfs_activate(kn);
+ return 0;
-/**
- * kernfs_addrm_finish - finish up kernfs_node add/remove
- * @acxt: addrm context to finish up
- *
- * Finish up kernfs_node add/remove. Resources acquired by
- * kernfs_addrm_start() are released and removed kernfs_nodes are
- * cleaned up.
- *
- * LOCKING:
- * kernfs_mutex is released.
- */
-void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt)
- __releases(kernfs_mutex)
-{
- /* release resources acquired by kernfs_addrm_start() */
+out_unlock:
mutex_unlock(&kernfs_mutex);
-
- /* kill removed kernfs_nodes */
- while (acxt->removed) {
- struct kernfs_node *kn = acxt->removed;
-
- acxt->removed = kn->u.removed_list;
-
- kernfs_deactivate(kn);
- kernfs_unmap_bin_file(kn);
- kernfs_put(kn);
- }
+ return ret;
}
/**
@@ -595,13 +692,15 @@ EXPORT_SYMBOL_GPL(kernfs_find_and_get_ns);
/**
* kernfs_create_root - create a new kernfs hierarchy
- * @kdops: optional directory syscall operations for the hierarchy
+ * @scops: optional syscall operations for the hierarchy
+ * @flags: KERNFS_ROOT_* flags
* @priv: opaque data associated with the new directory
*
* Returns the root of the new hierarchy on success, ERR_PTR() value on
* failure.
*/
-struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
+struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
+ unsigned int flags, void *priv)
{
struct kernfs_root *root;
struct kernfs_node *kn;
@@ -620,12 +719,16 @@ struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
return ERR_PTR(-ENOMEM);
}
- kn->flags &= ~KERNFS_REMOVED;
kn->priv = priv;
kn->dir.root = root;
- root->dir_ops = kdops;
+ root->syscall_ops = scops;
+ root->flags = flags;
root->kn = kn;
+ init_waitqueue_head(&root->deactivate_waitq);
+
+ if (!(root->flags & KERNFS_ROOT_CREATE_DEACTIVATED))
+ kernfs_activate(kn);
return root;
}
@@ -656,7 +759,6 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
const char *name, umode_t mode,
void *priv, const void *ns)
{
- struct kernfs_addrm_cxt acxt;
struct kernfs_node *kn;
int rc;
@@ -670,10 +772,7 @@ struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
kn->priv = priv;
/* link in */
- kernfs_addrm_start(&acxt);
- rc = kernfs_add_one(&acxt, kn);
- kernfs_addrm_finish(&acxt);
-
+ rc = kernfs_add_one(kn);
if (!rc)
return kn;
@@ -699,7 +798,7 @@ static struct dentry *kernfs_iop_lookup(struct inode *dir,
kn = kernfs_find_ns(parent, dentry->d_name.name, ns);
/* no such entry */
- if (!kn) {
+ if (!kn || !kernfs_active(kn)) {
ret = NULL;
goto out_unlock;
}
@@ -724,23 +823,37 @@ static int kernfs_iop_mkdir(struct inode *dir, struct dentry *dentry,
umode_t mode)
{
struct kernfs_node *parent = dir->i_private;
- struct kernfs_dir_ops *kdops = kernfs_root(parent)->dir_ops;
+ struct kernfs_syscall_ops *scops = kernfs_root(parent)->syscall_ops;
+ int ret;
- if (!kdops || !kdops->mkdir)
+ if (!scops || !scops->mkdir)
return -EPERM;
- return kdops->mkdir(parent, dentry->d_name.name, mode);
+ if (!kernfs_get_active(parent))
+ return -ENODEV;
+
+ ret = scops->mkdir(parent, dentry->d_name.name, mode);
+
+ kernfs_put_active(parent);
+ return ret;
}
static int kernfs_iop_rmdir(struct inode *dir, struct dentry *dentry)
{
struct kernfs_node *kn = dentry->d_fsdata;
- struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
+ struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
+ int ret;
- if (!kdops || !kdops->rmdir)
+ if (!scops || !scops->rmdir)
return -EPERM;
- return kdops->rmdir(kn);
+ if (!kernfs_get_active(kn))
+ return -ENODEV;
+
+ ret = scops->rmdir(kn);
+
+ kernfs_put_active(kn);
+ return ret;
}
static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
@@ -748,12 +861,25 @@ static int kernfs_iop_rename(struct inode *old_dir, struct dentry *old_dentry,
{
struct kernfs_node *kn = old_dentry->d_fsdata;
struct kernfs_node *new_parent = new_dir->i_private;
- struct kernfs_dir_ops *kdops = kernfs_root(kn)->dir_ops;
+ struct kernfs_syscall_ops *scops = kernfs_root(kn)->syscall_ops;
+ int ret;
- if (!kdops || !kdops->rename)
+ if (!scops || !scops->rename)
return -EPERM;
- return kdops->rename(kn, new_parent, new_dentry->d_name.name);
+ if (!kernfs_get_active(kn))
+ return -ENODEV;
+
+ if (!kernfs_get_active(new_parent)) {
+ kernfs_put_active(kn);
+ return -ENODEV;
+ }
+
+ ret = scops->rename(kn, new_parent, new_dentry->d_name.name);
+
+ kernfs_put_active(new_parent);
+ kernfs_put_active(kn);
+ return ret;
}
const struct inode_operations kernfs_dir_iops = {
@@ -826,23 +952,104 @@ static struct kernfs_node *kernfs_next_descendant_post(struct kernfs_node *pos,
return pos->parent;
}
-static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
- struct kernfs_node *kn)
+/**
+ * kernfs_activate - activate a node which started deactivated
+ * @kn: kernfs_node whose subtree is to be activated
+ *
+ * If the root has KERNFS_ROOT_CREATE_DEACTIVATED set, a newly created node
+ * needs to be explicitly activated. A node which hasn't been activated
+ * isn't visible to userland and deactivation is skipped during its
+ * removal. This is useful to construct atomic init sequences where
+ * creation of multiple nodes should either succeed or fail atomically.
+ *
+ * The caller is responsible for ensuring that this function is not called
+ * after kernfs_remove*() is invoked on @kn.
+ */
+void kernfs_activate(struct kernfs_node *kn)
{
- struct kernfs_node *pos, *next;
+ struct kernfs_node *pos;
- if (!kn)
+ mutex_lock(&kernfs_mutex);
+
+ pos = NULL;
+ while ((pos = kernfs_next_descendant_post(pos, kn))) {
+ if (!pos || (pos->flags & KERNFS_ACTIVATED))
+ continue;
+
+ WARN_ON_ONCE(pos->parent && RB_EMPTY_NODE(&pos->rb));
+ WARN_ON_ONCE(atomic_read(&pos->active) != KN_DEACTIVATED_BIAS);
+
+ atomic_sub(KN_DEACTIVATED_BIAS, &pos->active);
+ pos->flags |= KERNFS_ACTIVATED;
+ }
+
+ mutex_unlock(&kernfs_mutex);
+}
+
+static void __kernfs_remove(struct kernfs_node *kn)
+{
+ struct kernfs_node *pos;
+
+ lockdep_assert_held(&kernfs_mutex);
+
+ /*
+ * Short-circuit if non-root @kn has already finished removal.
+ * This is for kernfs_remove_self() which plays with active ref
+ * after removal.
+ */
+ if (!kn || (kn->parent && RB_EMPTY_NODE(&kn->rb)))
return;
pr_debug("kernfs %s: removing\n", kn->name);
- next = NULL;
+ /* prevent any new usage under @kn by deactivating all nodes */
+ pos = NULL;
+ while ((pos = kernfs_next_descendant_post(pos, kn)))
+ if (kernfs_active(pos))
+ atomic_add(KN_DEACTIVATED_BIAS, &pos->active);
+
+ /* deactivate and unlink the subtree node-by-node */
do {
- pos = next;
- next = kernfs_next_descendant_post(pos, kn);
- if (pos)
- kernfs_remove_one(acxt, pos);
- } while (next);
+ pos = kernfs_leftmost_descendant(kn);
+
+ /*
+ * kernfs_drain() drops kernfs_mutex temporarily and @pos's
+ * base ref could have been put by someone else by the time
+ * the function returns. Make sure it doesn't go away
+ * underneath us.
+ */
+ kernfs_get(pos);
+
+ /*
+ * Drain iff @kn was activated. This avoids draining and
+ * its lockdep annotations for nodes which have never been
+ * activated and allows embedding kernfs_remove() in create
+ * error paths without worrying about draining.
+ */
+ if (kn->flags & KERNFS_ACTIVATED)
+ kernfs_drain(pos);
+ else
+ WARN_ON_ONCE(atomic_read(&kn->active) != KN_DEACTIVATED_BIAS);
+
+ /*
+ * kernfs_unlink_sibling() succeeds once per node. Use it
+ * to decide who's responsible for cleanups.
+ */
+ if (!pos->parent || kernfs_unlink_sibling(pos)) {
+ struct kernfs_iattrs *ps_iattr =
+ pos->parent ? pos->parent->iattr : NULL;
+
+ /* update timestamps on the parent */
+ if (ps_iattr) {
+ ps_iattr->ia_iattr.ia_ctime = CURRENT_TIME;
+ ps_iattr->ia_iattr.ia_mtime = CURRENT_TIME;
+ }
+
+ kernfs_put(pos);
+ }
+
+ kernfs_put(pos);
+ } while (pos != kn);
}
/**
@@ -853,11 +1060,140 @@ static void __kernfs_remove(struct kernfs_addrm_cxt *acxt,
*/
void kernfs_remove(struct kernfs_node *kn)
{
- struct kernfs_addrm_cxt acxt;
+ mutex_lock(&kernfs_mutex);
+ __kernfs_remove(kn);
+ mutex_unlock(&kernfs_mutex);
+}
- kernfs_addrm_start(&acxt);
- __kernfs_remove(&acxt, kn);
- kernfs_addrm_finish(&acxt);
+/**
+ * kernfs_break_active_protection - break out of active protection
+ * @kn: the self kernfs_node
+ *
+ * The caller must be running off of a kernfs operation which is invoked
+ * with an active reference - e.g. one of kernfs_ops. Each invocation of
+ * this function must also be matched with an invocation of
+ * kernfs_unbreak_active_protection().
+ *
+ * This function releases the active reference of @kn the caller is
+ * holding. Once this function is called, @kn may be removed at any point
+ * and the caller is solely responsible for ensuring that the objects it
+ * dereferences are accessible.
+ */
+void kernfs_break_active_protection(struct kernfs_node *kn)
+{
+ /*
+ * Take out ourself out of the active ref dependency chain. If
+ * we're called without an active ref, lockdep will complain.
+ */
+ kernfs_put_active(kn);
+}
+
+/**
+ * kernfs_unbreak_active_protection - undo kernfs_break_active_protection()
+ * @kn: the self kernfs_node
+ *
+ * If kernfs_break_active_protection() was called, this function must be
+ * invoked before finishing the kernfs operation. Note that while this
+ * function restores the active reference, it doesn't and can't actually
+ * restore the active protection - @kn may already or be in the process of
+ * being removed. Once kernfs_break_active_protection() is invoked, that
+ * protection is irreversibly gone for the kernfs operation instance.
+ *
+ * While this function may be called at any point after
+ * kernfs_break_active_protection() is invoked, its most useful location
+ * would be right before the enclosing kernfs operation returns.
+ */
+void kernfs_unbreak_active_protection(struct kernfs_node *kn)
+{
+ /*
+ * @kn->active could be in any state; however, the increment we do
+ * here will be undone as soon as the enclosing kernfs operation
+ * finishes and this temporary bump can't break anything. If @kn
+ * is alive, nothing changes. If @kn is being deactivated, the
+ * soon-to-follow put will either finish deactivation or restore
+ * deactivated state. If @kn is already removed, the temporary
+ * bump is guaranteed to be gone before @kn is released.
+ */
+ atomic_inc(&kn->active);
+ if (kernfs_lockdep(kn))
+ rwsem_acquire(&kn->dep_map, 0, 1, _RET_IP_);
+}
+
+/**
+ * kernfs_remove_self - remove a kernfs_node from its own method
+ * @kn: the self kernfs_node to remove
+ *
+ * The caller must be running off of a kernfs operation which is invoked
+ * with an active reference - e.g. one of kernfs_ops. This can be used to
+ * implement a file operation which deletes itself.
+ *
+ * For example, the "delete" file for a sysfs device directory can be
+ * implemented by invoking kernfs_remove_self() on the "delete" file
+ * itself. This function breaks the circular dependency of trying to
+ * deactivate self while holding an active ref itself. It isn't necessary
+ * to modify the usual removal path to use kernfs_remove_self(). The
+ * "delete" implementation can simply invoke kernfs_remove_self() on self
+ * before proceeding with the usual removal path. kernfs will ignore later
+ * kernfs_remove() on self.
+ *
+ * kernfs_remove_self() can be called multiple times concurrently on the
+ * same kernfs_node. Only the first one actually performs removal and
+ * returns %true. All others will wait until the kernfs operation which
+ * won self-removal finishes and return %false. Note that the losers wait
+ * for the completion of not only the winning kernfs_remove_self() but also
+ * the whole kernfs_ops which won the arbitration. This can be used to
+ * guarantee, for example, all concurrent writes to a "delete" file to
+ * finish only after the whole operation is complete.
+ */
+bool kernfs_remove_self(struct kernfs_node *kn)
+{
+ bool ret;
+
+ mutex_lock(&kernfs_mutex);
+ kernfs_break_active_protection(kn);
+
+ /*
+ * SUICIDAL is used to arbitrate among competing invocations. Only
+ * the first one will actually perform removal. When the removal
+ * is complete, SUICIDED is set and the active ref is restored
+ * while holding kernfs_mutex. The ones which lost arbitration
+ * waits for SUICDED && drained which can happen only after the
+ * enclosing kernfs operation which executed the winning instance
+ * of kernfs_remove_self() finished.
+ */
+ if (!(kn->flags & KERNFS_SUICIDAL)) {
+ kn->flags |= KERNFS_SUICIDAL;
+ __kernfs_remove(kn);
+ kn->flags |= KERNFS_SUICIDED;
+ ret = true;
+ } else {
+ wait_queue_head_t *waitq = &kernfs_root(kn)->deactivate_waitq;
+ DEFINE_WAIT(wait);
+
+ while (true) {
+ prepare_to_wait(waitq, &wait, TASK_UNINTERRUPTIBLE);
+
+ if ((kn->flags & KERNFS_SUICIDED) &&
+ atomic_read(&kn->active) == KN_DEACTIVATED_BIAS)
+ break;
+
+ mutex_unlock(&kernfs_mutex);
+ schedule();
+ mutex_lock(&kernfs_mutex);
+ }
+ finish_wait(waitq, &wait);
+ WARN_ON_ONCE(!RB_EMPTY_NODE(&kn->rb));
+ ret = false;
+ }
+
+ /*
+ * This must be done while holding kernfs_mutex; otherwise, waiting
+ * for SUICIDED && deactivated could finish prematurely.
+ */
+ kernfs_unbreak_active_protection(kn);
+
+ mutex_unlock(&kernfs_mutex);
+ return ret;
}
/**
@@ -872,7 +1208,6 @@ void kernfs_remove(struct kernfs_node *kn)
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
const void *ns)
{
- struct kernfs_addrm_cxt acxt;
struct kernfs_node *kn;
if (!parent) {
@@ -881,13 +1216,13 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
return -ENOENT;
}
- kernfs_addrm_start(&acxt);
+ mutex_lock(&kernfs_mutex);
kn = kernfs_find_ns(parent, name, ns);
if (kn)
- __kernfs_remove(&acxt, kn);
+ __kernfs_remove(kn);
- kernfs_addrm_finish(&acxt);
+ mutex_unlock(&kernfs_mutex);
if (kn)
return 0;
@@ -905,12 +1240,18 @@ int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
const char *new_name, const void *new_ns)
{
+ struct kernfs_node *old_parent;
+ const char *old_name = NULL;
int error;
+ /* can't move or rename root */
+ if (!kn->parent)
+ return -EINVAL;
+
mutex_lock(&kernfs_mutex);
error = -ENOENT;
- if ((kn->flags | new_parent->flags) & KERNFS_REMOVED)
+ if (!kernfs_active(kn) || !kernfs_active(new_parent))
goto out;
error = 0;
@@ -928,13 +1269,8 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
new_name = kstrdup(new_name, GFP_KERNEL);
if (!new_name)
goto out;
-
- if (kn->flags & KERNFS_STATIC_NAME)
- kn->flags &= ~KERNFS_STATIC_NAME;
- else
- kfree(kn->name);
-
- kn->name = new_name;
+ } else {
+ new_name = NULL;
}
/*
@@ -942,12 +1278,29 @@ int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
*/
kernfs_unlink_sibling(kn);
kernfs_get(new_parent);
- kernfs_put(kn->parent);
- kn->ns = new_ns;
- kn->hash = kernfs_name_hash(kn->name, kn->ns);
+
+ /* rename_lock protects ->parent and ->name accessors */
+ spin_lock_irq(&kernfs_rename_lock);
+
+ old_parent = kn->parent;
kn->parent = new_parent;
+
+ kn->ns = new_ns;
+ if (new_name) {
+ if (!(kn->flags & KERNFS_STATIC_NAME))
+ old_name = kn->name;
+ kn->flags &= ~KERNFS_STATIC_NAME;
+ kn->name = new_name;
+ }
+
+ spin_unlock_irq(&kernfs_rename_lock);
+
+ kn->hash = kernfs_name_hash(new_name, new_ns);
kernfs_link_sibling(kn);
+ kernfs_put(old_parent);
+ kfree(old_name);
+
error = 0;
out:
mutex_unlock(&kernfs_mutex);
@@ -970,7 +1323,7 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns,
struct kernfs_node *parent, loff_t hash, struct kernfs_node *pos)
{
if (pos) {
- int valid = !(pos->flags & KERNFS_REMOVED) &&
+ int valid = kernfs_active(pos) &&
pos->parent == parent && hash == pos->hash;
kernfs_put(pos);
if (!valid)
@@ -989,8 +1342,8 @@ static struct kernfs_node *kernfs_dir_pos(const void *ns,
break;
}
}
- /* Skip over entries in the wrong namespace */
- while (pos && pos->ns != ns) {
+ /* Skip over entries which are dying/dead or in the wrong namespace */
+ while (pos && (!kernfs_active(pos) || pos->ns != ns)) {
struct rb_node *node = rb_next(&pos->rb);
if (!node)
pos = NULL;
@@ -1004,14 +1357,15 @@ static struct kernfs_node *kernfs_dir_next_pos(const void *ns,
struct kernfs_node *parent, ino_t ino, struct kernfs_node *pos)
{
pos = kernfs_dir_pos(ns, parent, ino, pos);
- if (pos)
+ if (pos) {
do {
struct rb_node *node = rb_next(&pos->rb);
if (!node)
pos = NULL;
else
pos = rb_to_kn(node);
- } while (pos && pos->ns != ns);
+ } while (pos && (!kernfs_active(pos) || pos->ns != ns));
+ }
return pos;
}
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c
index dbf397bfdff2..ddcb471b9cc9 100644
--- a/fs/kernfs/file.c
+++ b/fs/kernfs/file.c
@@ -252,19 +252,9 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
size_t count, loff_t *ppos)
{
struct kernfs_open_file *of = kernfs_of(file);
- ssize_t len = min_t(size_t, count, PAGE_SIZE);
const struct kernfs_ops *ops;
- char *buf;
-
- buf = kmalloc(len + 1, GFP_KERNEL);
- if (!buf)
- return -ENOMEM;
-
- if (copy_from_user(buf, user_buf, len)) {
- len = -EFAULT;
- goto out_free;
- }
- buf[len] = '\0'; /* guarantee string termination */
+ char *buf = NULL;
+ ssize_t len;
/*
* @of->mutex nests outside active ref and is just to ensure that
@@ -273,22 +263,45 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf,
mutex_lock(&of->mutex);
if (!kernfs_get_active(of->kn)) {
mutex_unlock(&of->mutex);
- len = -ENODEV;
- goto out_free;
+ return -ENODEV;
}
ops = kernfs_ops(of->kn);
- if (ops->write)
- len = ops->write(of, buf, len, *ppos);
- else
+ if (!ops->write) {
len = -EINVAL;
+ goto out_unlock;
+ }
+ if (ops->atomic_write_len) {
+ len = count;
+ if (len > ops->atomic_write_len) {
+ len = -E2BIG;
+ goto out_unlock;
+ }
+ } else {
+ len = min_t(size_t, count, PAGE_SIZE);
+ }
+
+ buf = kmalloc(len + 1, GFP_KERNEL);
+ if (!buf) {
+ len = -ENOMEM;
+ goto out_unlock;
+ }
+
+ if (copy_from_user(buf, user_buf, len)) {
+ len = -EFAULT;
+ goto out_unlock;
+ }
+ buf[len] = '\0'; /* guarantee string termination */
+
+ len = ops->write(of, buf, len, *ppos);
+out_unlock:
kernfs_put_active(of->kn);
mutex_unlock(&of->mutex);
if (len > 0)
*ppos += len;
-out_free:
+
kfree(buf);
return len;
}
@@ -820,7 +833,6 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
bool name_is_static,
struct lock_class_key *key)
{
- struct kernfs_addrm_cxt acxt;
struct kernfs_node *kn;
unsigned flags;
int rc;
@@ -855,10 +867,7 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
if (ops->mmap)
kn->flags |= KERNFS_HAS_MMAP;
- kernfs_addrm_start(&acxt);
- rc = kernfs_add_one(&acxt, kn);
- kernfs_addrm_finish(&acxt);
-
+ rc = kernfs_add_one(kn);
if (rc) {
kernfs_put(kn);
return ERR_PTR(rc);
diff --git a/fs/kernfs/kernfs-internal.h b/fs/kernfs/kernfs-internal.h
index eb536b76374a..a91d7a1113d9 100644
--- a/fs/kernfs/kernfs-internal.h
+++ b/fs/kernfs/kernfs-internal.h
@@ -26,7 +26,8 @@ struct kernfs_iattrs {
struct simple_xattrs xattrs;
};
-#define KN_DEACTIVATED_BIAS INT_MIN
+/* +1 to avoid triggering overflow warning when negating it */
+#define KN_DEACTIVATED_BIAS (INT_MIN + 1)
/* KERNFS_TYPE_MASK and types are defined in include/linux/kernfs.h */
@@ -45,13 +46,6 @@ static inline struct kernfs_root *kernfs_root(struct kernfs_node *kn)
}
/*
- * Context structure to be used while adding/removing nodes.
- */
-struct kernfs_addrm_cxt {
- struct kernfs_node *removed;
-};
-
-/*
* mount.c
*/
struct kernfs_super_info {
@@ -100,9 +94,7 @@ extern const struct inode_operations kernfs_dir_iops;
struct kernfs_node *kernfs_get_active(struct kernfs_node *kn);
void kernfs_put_active(struct kernfs_node *kn);
-void kernfs_addrm_start(struct kernfs_addrm_cxt *acxt);
-int kernfs_add_one(struct kernfs_addrm_cxt *acxt, struct kernfs_node *kn);
-void kernfs_addrm_finish(struct kernfs_addrm_cxt *acxt);
+int kernfs_add_one(struct kernfs_node *kn);
struct kernfs_node *kernfs_new_node(struct kernfs_node *parent,
const char *name, umode_t mode,
unsigned flags);
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 0d6ce895a9ee..e5b28b0ebc37 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -19,12 +19,49 @@
struct kmem_cache *kernfs_node_cache;
+static int kernfs_sop_remount_fs(struct super_block *sb, int *flags, char *data)
+{
+ struct kernfs_root *root = kernfs_info(sb)->root;
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->remount_fs)
+ return scops->remount_fs(root, flags, data);
+ return 0;
+}
+
+static int kernfs_sop_show_options(struct seq_file *sf, struct dentry *dentry)
+{
+ struct kernfs_root *root = kernfs_root(dentry->d_fsdata);
+ struct kernfs_syscall_ops *scops = root->syscall_ops;
+
+ if (scops && scops->show_options)
+ return scops->show_options(sf, root);
+ return 0;
+}
+
static const struct super_operations kernfs_sops = {
.statfs = simple_statfs,
.drop_inode = generic_delete_inode,
.evict_inode = kernfs_evict_inode,
+
+ .remount_fs = kernfs_sop_remount_fs,
+ .show_options = kernfs_sop_show_options,
};
+/**
+ * kernfs_root_from_sb - determine kernfs_root associated with a super_block
+ * @sb: the super_block in question
+ *
+ * Return the kernfs_root associated with @sb. If @sb is not a kernfs one,
+ * %NULL is returned.
+ */
+struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
+{
+ if (sb->s_op == &kernfs_sops)
+ return kernfs_info(sb)->root;
+ return NULL;
+}
+
static int kernfs_fill_super(struct super_block *sb)
{
struct kernfs_super_info *info = kernfs_info(sb);
diff --git a/fs/kernfs/symlink.c b/fs/kernfs/symlink.c
index 4d457055acb9..8a198898e39a 100644
--- a/fs/kernfs/symlink.c
+++ b/fs/kernfs/symlink.c
@@ -27,7 +27,6 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
struct kernfs_node *target)
{
struct kernfs_node *kn;
- struct kernfs_addrm_cxt acxt;
int error;
kn = kernfs_new_node(parent, name, S_IFLNK|S_IRWXUGO, KERNFS_LINK);
@@ -39,10 +38,7 @@ struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
kn->symlink.target_kn = target;
kernfs_get(target); /* ref owned by symlink */
- kernfs_addrm_start(&acxt);
- error = kernfs_add_one(&acxt, kn);
- kernfs_addrm_finish(&acxt);
-
+ error = kernfs_add_one(kn);
if (!error)
return kn;
diff --git a/fs/sysfs/Kconfig b/fs/sysfs/Kconfig
index 8c41feacbac5..b2756014508c 100644
--- a/fs/sysfs/Kconfig
+++ b/fs/sysfs/Kconfig
@@ -1,6 +1,7 @@
config SYSFS
bool "sysfs file system support" if EXPERT
default y
+ select KERNFS
help
The sysfs filesystem is a virtual filesystem that the kernel uses to
export internal kernel objects, their attributes, and their
diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index ee0d761c3179..0b45ff42f374 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -19,39 +19,18 @@
DEFINE_SPINLOCK(sysfs_symlink_target_lock);
-/**
- * sysfs_pathname - return full path to sysfs dirent
- * @kn: kernfs_node whose path we want
- * @path: caller allocated buffer of size PATH_MAX
- *
- * Gives the name "/" to the sysfs_root entry; any path returned
- * is relative to wherever sysfs is mounted.
- */
-static char *sysfs_pathname(struct kernfs_node *kn, char *path)
-{
- if (kn->parent) {
- sysfs_pathname(kn->parent, path);
- strlcat(path, "/", PATH_MAX);
- }
- strlcat(path, kn->name, PATH_MAX);
- return path;
-}
-
void sysfs_warn_dup(struct kernfs_node *parent, const char *name)
{
- char *path;
+ char *buf, *path = NULL;
- path = kzalloc(PATH_MAX, GFP_KERNEL);
- if (path) {
- sysfs_pathname(parent, path);
- strlcat(path, "/", PATH_MAX);
- strlcat(path, name, PATH_MAX);
- }
+ buf = kzalloc(PATH_MAX, GFP_KERNEL);
+ if (buf)
+ path = kernfs_path(parent, buf, PATH_MAX);
- WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s'\n",
- path ? path : name);
+ WARN(1, KERN_WARNING "sysfs: cannot create duplicate filename '%s/%s'\n",
+ path, name);
- kfree(path);
+ kfree(buf);
}
/**
@@ -122,9 +101,13 @@ void sysfs_remove_dir(struct kobject *kobj)
int sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
const void *new_ns)
{
- struct kernfs_node *parent = kobj->sd->parent;
+ struct kernfs_node *parent;
+ int ret;
- return kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
+ parent = kernfs_get_parent(kobj->sd);
+ ret = kernfs_rename_ns(kobj->sd, parent, new_name, new_ns);
+ kernfs_put(parent);
+ return ret;
}
int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
@@ -133,7 +116,6 @@ int sysfs_move_dir_ns(struct kobject *kobj, struct kobject *new_parent_kobj,
struct kernfs_node *kn = kobj->sd;
struct kernfs_node *new_parent;
- BUG_ON(!kn->parent);
new_parent = new_parent_kobj && new_parent_kobj->sd ?
new_parent_kobj->sd : sysfs_root_kn;
diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 810cf6e613e5..28cc1acd5439 100644
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -372,6 +372,29 @@ void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
}
EXPORT_SYMBOL_GPL(sysfs_remove_file_ns);
+/**
+ * sysfs_remove_file_self - remove an object attribute from its own method
+ * @kobj: object we're acting for
+ * @attr: attribute descriptor
+ *
+ * See kernfs_remove_self() for details.
+ */
+bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr)
+{
+ struct kernfs_node *parent = kobj->sd;
+ struct kernfs_node *kn;
+ bool ret;
+
+ kn = kernfs_find_and_get(parent, attr->name);
+ if (WARN_ON_ONCE(!kn))
+ return false;
+
+ ret = kernfs_remove_self(kn);
+
+ kernfs_put(kn);
+ return ret;
+}
+
void sysfs_remove_files(struct kobject *kobj, const struct attribute **ptr)
{
int i;
@@ -430,95 +453,3 @@ void sysfs_remove_bin_file(struct kobject *kobj,
kernfs_remove_by_name(kobj->sd, attr->attr.name);
}
EXPORT_SYMBOL_GPL(sysfs_remove_bin_file);
-
-struct sysfs_schedule_callback_struct {
- struct list_head workq_list;
- struct kobject *kobj;
- void (*func)(void *);
- void *data;
- struct module *owner;
- struct work_struct work;
-};
-
-static struct workqueue_struct *sysfs_workqueue;
-static DEFINE_MUTEX(sysfs_workq_mutex);
-static LIST_HEAD(sysfs_workq);
-static void sysfs_schedule_callback_work(struct work_struct *work)
-{
- struct sysfs_schedule_callback_struct *ss = container_of(work,
- struct sysfs_schedule_callback_struct, work);
-
- (ss->func)(ss->data);
- kobject_put(ss->kobj);
- module_put(ss->owner);
- mutex_lock(&sysfs_workq_mutex);
- list_del(&ss->workq_list);
- mutex_unlock(&sysfs_workq_mutex);
- kfree(ss);
-}
-
-/**
- * sysfs_schedule_callback - helper to schedule a callback for a kobject
- * @kobj: object we're acting for.
- * @func: callback function to invoke later.
- * @data: argument to pass to @func.
- * @owner: module owning the callback code
- *
- * sysfs attribute methods must not unregister themselves or their parent
- * kobject (which would amount to the same thing). Attempts to do so will
- * deadlock, since unregistration is mutually exclusive with driver
- * callbacks.
- *
- * Instead methods can call this routine, which will attempt to allocate
- * and schedule a workqueue request to call back @func with @data as its
- * argument in the workqueue's process context. @kobj will be pinned
- * until @func returns.
- *
- * Returns 0 if the request was submitted, -ENOMEM if storage could not
- * be allocated, -ENODEV if a reference to @owner isn't available,
- * -EAGAIN if a callback has already been scheduled for @kobj.
- */
-int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
- void *data, struct module *owner)
-{
- struct sysfs_schedule_callback_struct *ss, *tmp;
-
- if (!try_module_get(owner))
- return -ENODEV;
-
- mutex_lock(&sysfs_workq_mutex);
- list_for_each_entry_safe(ss, tmp, &sysfs_workq, workq_list)
- if (ss->kobj == kobj) {
- module_put(owner);
- mutex_unlock(&sysfs_workq_mutex);
- return -EAGAIN;
- }
- mutex_unlock(&sysfs_workq_mutex);
-
- if (sysfs_workqueue == NULL) {
- sysfs_workqueue = create_singlethread_workqueue("sysfsd");
- if (sysfs_workqueue == NULL) {
- module_put(owner);
- return -ENOMEM;
- }
- }
-
- ss = kmalloc(sizeof(*ss), GFP_KERNEL);
- if (!ss) {
- module_put(owner);
- return -ENOMEM;
- }
- kobject_get(kobj);
- ss->kobj = kobj;
- ss->func = func;
- ss->data = data;
- ss->owner = owner;
- INIT_WORK(&ss->work, sysfs_schedule_callback_work);
- INIT_LIST_HEAD(&ss->workq_list);
- mutex_lock(&sysfs_workq_mutex);
- list_add_tail(&ss->workq_list, &sysfs_workq);
- mutex_unlock(&sysfs_workq_mutex);
- queue_work(sysfs_workqueue, &ss->work);
- return 0;
-}
-EXPORT_SYMBOL_GPL(sysfs_schedule_callback);
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 6211230814fd..5c7fdd9c6811 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -62,7 +62,7 @@ int __init sysfs_init(void)
{
int err;
- sysfs_root = kernfs_create_root(NULL, NULL);
+ sysfs_root = kernfs_create_root(NULL, 0, NULL);
if (IS_ERR(sysfs_root))
return PTR_ERR(sysfs_root);
diff --git a/include/linux/device.h b/include/linux/device.h
index 952b01033c32..fb1ba13f7665 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -560,16 +560,12 @@ extern int device_create_file(struct device *device,
const struct device_attribute *entry);
extern void device_remove_file(struct device *dev,
const struct device_attribute *attr);
+extern bool device_remove_file_self(struct device *dev,
+ const struct device_attribute *attr);
extern int __must_check device_create_bin_file(struct device *dev,
const struct bin_attribute *attr);
extern void device_remove_bin_file(struct device *dev,
const struct bin_attribute *attr);
-extern int device_schedule_callback_owner(struct device *dev,
- void (*func)(struct device *dev), struct module *owner);
-
-/* This is a macro to avoid include problems with THIS_MODULE */
-#define device_schedule_callback(dev, func) \
- device_schedule_callback_owner(dev, func, THIS_MODULE)
/* device resource management */
typedef void (*dr_release_t)(struct device *dev, void *res);
@@ -929,10 +925,7 @@ extern int device_online(struct device *dev);
extern struct device *__root_device_register(const char *name,
struct module *owner);
-/*
- * This is a macro to avoid include problems with THIS_MODULE,
- * just as per what is done for device_schedule_callback() above.
- */
+/* This is a macro to avoid include problems with THIS_MODULE */
#define root_device_register(name) \
__root_device_register(name, THIS_MODULE)
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 5be9f0228a3b..649497a56a95 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -15,7 +15,7 @@
#include <linux/lockdep.h>
#include <linux/rbtree.h>
#include <linux/atomic.h>
-#include <linux/completion.h>
+#include <linux/wait.h>
struct file;
struct dentry;
@@ -35,16 +35,22 @@ enum kernfs_node_type {
};
#define KERNFS_TYPE_MASK 0x000f
-#define KERNFS_ACTIVE_REF KERNFS_FILE
#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK
enum kernfs_node_flag {
- KERNFS_REMOVED = 0x0010,
+ KERNFS_ACTIVATED = 0x0010,
KERNFS_NS = 0x0020,
KERNFS_HAS_SEQ_SHOW = 0x0040,
KERNFS_HAS_MMAP = 0x0080,
KERNFS_LOCKDEP = 0x0100,
KERNFS_STATIC_NAME = 0x0200,
+ KERNFS_SUICIDAL = 0x0400,
+ KERNFS_SUICIDED = 0x0800,
+};
+
+/* @flags for kernfs_create_root() */
+enum kernfs_root_flag {
+ KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
};
/* type-specific structures for kernfs_node union members */
@@ -85,17 +91,17 @@ struct kernfs_node {
#ifdef CONFIG_DEBUG_LOCK_ALLOC
struct lockdep_map dep_map;
#endif
- /* the following two fields are published */
+ /*
+ * Use kernfs_get_parent() and kernfs_name/path() instead of
+ * accessing the following two fields directly. If the node is
+ * never moved to a different parent, it is safe to access the
+ * parent directly.
+ */
struct kernfs_node *parent;
const char *name;
struct rb_node rb;
- union {
- struct completion *completion;
- struct kernfs_node *removed_list;
- } u;
-
const void *ns; /* namespace tag */
unsigned int hash; /* ns + name hash */
union {
@@ -113,12 +119,16 @@ struct kernfs_node {
};
/*
- * kernfs_dir_ops may be specified on kernfs_create_root() to support
- * directory manipulation syscalls. These optional callbacks are invoked
- * on the matching syscalls and can perform any kernfs operations which
- * don't necessarily have to be the exact operation requested.
+ * kernfs_syscall_ops may be specified on kernfs_create_root() to support
+ * syscalls. These optional callbacks are invoked on the matching syscalls
+ * and can perform any kernfs operations which don't necessarily have to be
+ * the exact operation requested. An active reference is held for each
+ * kernfs_node parameter.
*/
-struct kernfs_dir_ops {
+struct kernfs_syscall_ops {
+ int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
+ int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
+
int (*mkdir)(struct kernfs_node *parent, const char *name,
umode_t mode);
int (*rmdir)(struct kernfs_node *kn);
@@ -129,16 +139,19 @@ struct kernfs_dir_ops {
struct kernfs_root {
/* published fields */
struct kernfs_node *kn;
+ unsigned int flags; /* KERNFS_ROOT_* flags */
/* private fields, do not use outside kernfs proper */
struct ida ino_ida;
- struct kernfs_dir_ops *dir_ops;
+ struct kernfs_syscall_ops *syscall_ops;
+ wait_queue_head_t deactivate_waitq;
};
struct kernfs_open_file {
/* published fields */
struct kernfs_node *kn;
struct file *file;
+ void *priv;
/* private fields, do not use outside kernfs proper */
struct mutex mutex;
@@ -171,9 +184,13 @@ struct kernfs_ops {
loff_t off);
/*
- * write() is bounced through kernel buffer and a write larger than
- * PAGE_SIZE results in partial operation of PAGE_SIZE.
+ * write() is bounced through kernel buffer. If atomic_write_len
+ * is not set, a write larger than PAGE_SIZE results in partial
+ * operations of PAGE_SIZE chunks. If atomic_write_len is set,
+ * writes upto the specified size are executed atomically but
+ * larger ones are rejected with -E2BIG.
*/
+ size_t atomic_write_len;
ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes,
loff_t off);
@@ -184,7 +201,7 @@ struct kernfs_ops {
#endif
};
-#ifdef CONFIG_SYSFS
+#ifdef CONFIG_KERNFS
static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
{
@@ -217,13 +234,22 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
return kn->flags & KERNFS_NS;
}
+int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
+char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
+ size_t buflen);
+void pr_cont_kernfs_name(struct kernfs_node *kn);
+void pr_cont_kernfs_path(struct kernfs_node *kn);
+struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
const char *name, const void *ns);
void kernfs_get(struct kernfs_node *kn);
void kernfs_put(struct kernfs_node *kn);
-struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops,
- void *priv);
+struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry);
+struct kernfs_root *kernfs_root_from_sb(struct super_block *sb);
+
+struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
+ unsigned int flags, void *priv);
void kernfs_destroy_root(struct kernfs_root *root);
struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
@@ -239,7 +265,11 @@ struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
const char *name,
struct kernfs_node *target);
+void kernfs_activate(struct kernfs_node *kn);
void kernfs_remove(struct kernfs_node *kn);
+void kernfs_break_active_protection(struct kernfs_node *kn);
+void kernfs_unbreak_active_protection(struct kernfs_node *kn);
+bool kernfs_remove_self(struct kernfs_node *kn);
int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
const void *ns);
int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
@@ -254,7 +284,7 @@ void kernfs_kill_sb(struct super_block *sb);
void kernfs_init(void);
-#else /* CONFIG_SYSFS */
+#else /* CONFIG_KERNFS */
static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
{ return 0; } /* whatever */
@@ -264,6 +294,19 @@ static inline void kernfs_enable_ns(struct kernfs_node *kn) { }
static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
{ return false; }
+static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
+{ return -ENOSYS; }
+
+static inline char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
+ size_t buflen)
+{ return NULL; }
+
+static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
+static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { }
+
+static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
+{ return NULL; }
+
static inline struct kernfs_node *
kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
const void *ns)
@@ -272,8 +315,15 @@ kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
static inline void kernfs_get(struct kernfs_node *kn) { }
static inline void kernfs_put(struct kernfs_node *kn) { }
+static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
+{ return NULL; }
+
+static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
+{ return NULL; }
+
static inline struct kernfs_root *
-kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv)
+kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags,
+ void *priv)
{ return ERR_PTR(-ENOSYS); }
static inline void kernfs_destroy_root(struct kernfs_root *root) { }
@@ -295,8 +345,13 @@ kernfs_create_link(struct kernfs_node *parent, const char *name,
struct kernfs_node *target)
{ return ERR_PTR(-ENOSYS); }
+static inline void kernfs_activate(struct kernfs_node *kn) { }
+
static inline void kernfs_remove(struct kernfs_node *kn) { }
+static inline bool kernfs_remove_self(struct kernfs_node *kn)
+{ return false; }
+
static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
const char *name, const void *ns)
{ return -ENOSYS; }
@@ -324,7 +379,7 @@ static inline void kernfs_kill_sb(struct super_block *sb) { }
static inline void kernfs_init(void) { }
-#endif /* CONFIG_SYSFS */
+#endif /* CONFIG_KERNFS */
static inline struct kernfs_node *
kernfs_find_and_get(struct kernfs_node *kn, const char *name)
@@ -366,6 +421,13 @@ static inline int kernfs_remove_by_name(struct kernfs_node *parent,
return kernfs_remove_by_name_ns(parent, name, NULL);
}
+static inline int kernfs_rename(struct kernfs_node *kn,
+ struct kernfs_node *new_parent,
+ const char *new_name)
+{
+ return kernfs_rename_ns(kn, new_parent, new_name, NULL);
+}
+
static inline struct dentry *
kernfs_mount(struct file_system_type *fs_type, int flags,
struct kernfs_root *root)
diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h
index 30b2ebee6439..fdaa0c6fc7a2 100644
--- a/include/linux/sysfs.h
+++ b/include/linux/sysfs.h
@@ -178,9 +178,6 @@ struct sysfs_ops {
#ifdef CONFIG_SYSFS
-int sysfs_schedule_callback(struct kobject *kobj, void (*func)(void *),
- void *data, struct module *owner);
-
int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns);
void sysfs_remove_dir(struct kobject *kobj);
int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
@@ -198,6 +195,7 @@ int __must_check sysfs_chmod_file(struct kobject *kobj,
const struct attribute *attr, umode_t mode);
void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
const void *ns);
+bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr);
void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr);
int __must_check sysfs_create_bin_file(struct kobject *kobj,
@@ -246,14 +244,13 @@ void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
int __must_check sysfs_init(void);
-#else /* CONFIG_SYSFS */
-
-static inline int sysfs_schedule_callback(struct kobject *kobj,
- void (*func)(void *), void *data, struct module *owner)
+static inline void sysfs_enable_ns(struct kernfs_node *kn)
{
- return -ENOSYS;
+ return kernfs_enable_ns(kn);
}
+#else /* CONFIG_SYSFS */
+
static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
{
return 0;
@@ -301,6 +298,12 @@ static inline void sysfs_remove_file_ns(struct kobject *kobj,
{
}
+static inline bool sysfs_remove_file_self(struct kobject *kobj,
+ const struct attribute *attr)
+{
+ return false;
+}
+
static inline void sysfs_remove_files(struct kobject *kobj,
const struct attribute **attr)
{
@@ -418,6 +421,10 @@ static inline int __must_check sysfs_init(void)
return 0;
}
+static inline void sysfs_enable_ns(struct kernfs_node *kn)
+{
+}
+
#endif /* CONFIG_SYSFS */
static inline int __must_check sysfs_create_file(struct kobject *kobj,
diff --git a/lib/kobject.c b/lib/kobject.c
index cb14aeac4cca..58751bb80a7c 100644
--- a/lib/kobject.c
+++ b/lib/kobject.c
@@ -94,7 +94,7 @@ static int create_dir(struct kobject *kobj)
BUG_ON(ops->type >= KOBJ_NS_TYPES);
BUG_ON(!kobj_ns_type_registered(ops->type));
- kernfs_enable_ns(kobj->sd);
+ sysfs_enable_ns(kobj->sd);
}
return 0;
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-24 20:40:22 +0000