diff options
| -rw-r--r-- | fs/kernfs/file.c | 45 | ||||
| -rw-r--r-- | fs/sysfs/file.c | 31 | ||||
| -rw-r--r-- | include/linux/kernfs.h | 8 | ||||
| -rw-r--r-- | include/linux/sysfs.h | 9 |
4 files changed, 71 insertions, 22 deletions
diff --git a/fs/kernfs/file.c b/fs/kernfs/file.c index 4429d6d9217f..70186e2e692a 100644 --- a/fs/kernfs/file.c +++ b/fs/kernfs/file.c @@ -106,7 +106,7 @@ static void *kernfs_seq_start(struct seq_file *sf, loff_t *ppos) const struct kernfs_ops *ops; /* - * @of->mutex nests outside active ref and is just to ensure that + * @of->mutex nests outside active ref and is primarily to ensure that * the ops aren't called concurrently for the same open file. */ mutex_lock(&of->mutex); @@ -194,7 +194,7 @@ static ssize_t kernfs_file_direct_read(struct kernfs_open_file *of, return -ENOMEM; /* - * @of->mutex nests outside active ref and is just to ensure that + * @of->mutex nests outside active ref and is primarily to ensure that * the ops aren't called concurrently for the same open file. */ mutex_lock(&of->mutex); @@ -278,19 +278,16 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, len = min_t(size_t, count, PAGE_SIZE); } - buf = kmalloc(len + 1, GFP_KERNEL); + buf = of->prealloc_buf; + if (!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 */ - /* - * @of->mutex nests outside active ref and is just to ensure that - * the ops aren't called concurrently for the same open file. + * @of->mutex nests outside active ref and is used both to ensure that + * the ops aren't called concurrently for the same open file, and + * to provide exclusive access to ->prealloc_buf (when that exists). */ mutex_lock(&of->mutex); if (!kernfs_get_active(of->kn)) { @@ -299,19 +296,27 @@ static ssize_t kernfs_fop_write(struct file *file, const char __user *user_buf, goto out_free; } + if (copy_from_user(buf, user_buf, len)) { + len = -EFAULT; + goto out_unlock; + } + buf[len] = '\0'; /* guarantee string termination */ + ops = kernfs_ops(of->kn); if (ops->write) len = ops->write(of, buf, len, *ppos); else len = -EINVAL; - kernfs_put_active(of->kn); - mutex_unlock(&of->mutex); - if (len > 0) *ppos += len; + +out_unlock: + kernfs_put_active(of->kn); + mutex_unlock(&of->mutex); out_free: - kfree(buf); + if (buf != of->prealloc_buf) + kfree(buf); return len; } @@ -685,6 +690,14 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) */ of->atomic_write_len = ops->atomic_write_len; + if (ops->prealloc) { + int len = of->atomic_write_len ?: PAGE_SIZE; + of->prealloc_buf = kmalloc(len + 1, GFP_KERNEL); + error = -ENOMEM; + if (!of->prealloc_buf) + goto err_free; + } + /* * Always instantiate seq_file even if read access doesn't use * seq_file or is not requested. This unifies private data access @@ -715,6 +728,7 @@ static int kernfs_fop_open(struct inode *inode, struct file *file) err_close: seq_release(inode, file); err_free: + kfree(of->prealloc_buf); kfree(of); err_out: kernfs_put_active(kn); @@ -728,6 +742,7 @@ static int kernfs_fop_release(struct inode *inode, struct file *filp) kernfs_put_open_node(kn, of); seq_release(inode, filp); + kfree(of->prealloc_buf); kfree(of); return 0; diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c index 589abee16a39..4ad3721a991c 100644 --- a/fs/sysfs/file.c +++ b/fs/sysfs/file.c @@ -184,6 +184,17 @@ static const struct kernfs_ops sysfs_file_kfops_rw = { .write = sysfs_kf_write, }; +static const struct kernfs_ops sysfs_prealloc_kfops_wo = { + .write = sysfs_kf_write, + .prealloc = true, +}; + +static const struct kernfs_ops sysfs_prealloc_kfops_rw = { + .seq_show = sysfs_kf_seq_show, + .write = sysfs_kf_write, + .prealloc = true, +}; + static const struct kernfs_ops sysfs_bin_kfops_ro = { .read = sysfs_kf_bin_read, }; @@ -222,13 +233,19 @@ int sysfs_add_file_mode_ns(struct kernfs_node *parent, kobject_name(kobj))) return -EINVAL; - if (sysfs_ops->show && sysfs_ops->store) - ops = &sysfs_file_kfops_rw; - else if (sysfs_ops->show) + if (sysfs_ops->show && sysfs_ops->store) { + if (mode & SYSFS_PREALLOC) + ops = &sysfs_prealloc_kfops_rw; + else + ops = &sysfs_file_kfops_rw; + } else if (sysfs_ops->show) ops = &sysfs_file_kfops_ro; - else if (sysfs_ops->store) - ops = &sysfs_file_kfops_wo; - else + else if (sysfs_ops->store) { + if (mode & SYSFS_PREALLOC) + ops = &sysfs_prealloc_kfops_wo; + else + ops = &sysfs_file_kfops_wo; + } else ops = &sysfs_file_kfops_empty; size = PAGE_SIZE; @@ -253,7 +270,7 @@ int sysfs_add_file_mode_ns(struct kernfs_node *parent, if (!attr->ignore_lockdep) key = attr->key ?: (struct lock_class_key *)&attr->skey; #endif - kn = __kernfs_create_file(parent, attr->name, mode, size, ops, + kn = __kernfs_create_file(parent, attr->name, mode & 0777, size, ops, (void *)attr, ns, true, key); if (IS_ERR(kn)) { if (PTR_ERR(kn) == -EEXIST) diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h index 30faf797c2c3..d4e01b358341 100644 --- a/include/linux/kernfs.h +++ b/include/linux/kernfs.h @@ -179,6 +179,7 @@ struct kernfs_open_file { struct mutex mutex; int event; struct list_head list; + char *prealloc_buf; size_t atomic_write_len; bool mmapped; @@ -214,6 +215,13 @@ struct kernfs_ops { * larger ones are rejected with -E2BIG. */ size_t atomic_write_len; + /* + * "prealloc" causes a buffer to be allocated at open for + * all read/write requests. As ->seq_show uses seq_read() + * which does its own allocation, it is incompatible with + * ->prealloc. Provide ->read and ->write with ->prealloc. + */ + bool prealloc; ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, loff_t off); diff --git a/include/linux/sysfs.h b/include/linux/sysfs.h index f97d0dbb59fa..ddad16148bd6 100644 --- a/include/linux/sysfs.h +++ b/include/linux/sysfs.h @@ -70,6 +70,8 @@ struct attribute_group { * for examples.. */ +#define SYSFS_PREALLOC 010000 + #define __ATTR(_name, _mode, _show, _store) { \ .attr = {.name = __stringify(_name), \ .mode = VERIFY_OCTAL_PERMISSIONS(_mode) }, \ @@ -77,6 +79,13 @@ struct attribute_group { .store = _store, \ } +#define __ATTR_PREALLOC(_name, _mode, _show, _store) { \ + .attr = {.name = __stringify(_name), \ + .mode = SYSFS_PREALLOC | VERIFY_OCTAL_PERMISSIONS(_mode) },\ + .show = _show, \ + .store = _store, \ +} + #define __ATTR_RO(_name) { \ .attr = { .name = __stringify(_name), .mode = S_IRUGO }, \ .show = _name##_show, \ |