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-rw-r--r--block/genhd.c68
1 files changed, 48 insertions, 20 deletions
diff --git a/block/genhd.c b/block/genhd.c
index 703267865f14..ad6826628e79 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
/*
* gendisk handling
*/
@@ -531,6 +532,18 @@ void blk_free_devt(dev_t devt)
}
}
+/**
+ * We invalidate devt by assigning NULL pointer for devt in idr.
+ */
+void blk_invalidate_devt(dev_t devt)
+{
+ if (MAJOR(devt) == BLOCK_EXT_MAJOR) {
+ spin_lock_bh(&ext_devt_lock);
+ idr_replace(&ext_devt_idr, NULL, blk_mangle_minor(MINOR(devt)));
+ spin_unlock_bh(&ext_devt_lock);
+ }
+}
+
static char *bdevt_str(dev_t devt, char *buf)
{
if (MAJOR(devt) <= 0xff && MINOR(devt) <= 0xff) {
@@ -793,6 +806,13 @@ void del_gendisk(struct gendisk *disk)
if (!(disk->flags & GENHD_FL_HIDDEN))
blk_unregister_region(disk_devt(disk), disk->minors);
+ /*
+ * Remove gendisk pointer from idr so that it cannot be looked up
+ * while RCU period before freeing gendisk is running to prevent
+ * use-after-free issues. Note that the device number stays
+ * "in-use" until we really free the gendisk.
+ */
+ blk_invalidate_devt(disk_devt(disk));
kobject_put(disk->part0.holder_dir);
kobject_put(disk->slave_dir);
@@ -1628,12 +1648,11 @@ static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
/*
* If device-specific poll interval is set, always use it. If
- * the default is being used, poll iff there are events which
- * can't be monitored asynchronously.
+ * the default is being used, poll if the POLL flag is set.
*/
if (ev->poll_msecs >= 0)
intv_msecs = ev->poll_msecs;
- else if (disk->events & ~disk->async_events)
+ else if (disk->event_flags & DISK_EVENT_FLAG_POLL)
intv_msecs = disk_events_dfl_poll_msecs;
return msecs_to_jiffies(intv_msecs);
@@ -1843,11 +1862,13 @@ static void disk_check_events(struct disk_events *ev,
/*
* Tell userland about new events. Only the events listed in
- * @disk->events are reported. Unlisted events are processed the
- * same internally but never get reported to userland.
+ * @disk->events are reported, and only if DISK_EVENT_FLAG_UEVENT
+ * is set. Otherwise, events are processed internally but never
+ * get reported to userland.
*/
for (i = 0; i < ARRAY_SIZE(disk_uevents); i++)
- if (events & disk->events & (1 << i))
+ if ((events & disk->events & (1 << i)) &&
+ (disk->event_flags & DISK_EVENT_FLAG_UEVENT))
envp[nr_events++] = disk_uevents[i];
if (nr_events)
@@ -1860,6 +1881,7 @@ static void disk_check_events(struct disk_events *ev,
*
* events : list of all supported events
* events_async : list of events which can be detected w/o polling
+ * (always empty, only for backwards compatibility)
* events_poll_msecs : polling interval, 0: disable, -1: system default
*/
static ssize_t __disk_events_show(unsigned int events, char *buf)
@@ -1884,15 +1906,16 @@ static ssize_t disk_events_show(struct device *dev,
{
struct gendisk *disk = dev_to_disk(dev);
+ if (!(disk->event_flags & DISK_EVENT_FLAG_UEVENT))
+ return 0;
+
return __disk_events_show(disk->events, buf);
}
static ssize_t disk_events_async_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
- struct gendisk *disk = dev_to_disk(dev);
-
- return __disk_events_show(disk->async_events, buf);
+ return 0;
}
static ssize_t disk_events_poll_msecs_show(struct device *dev,
@@ -1901,6 +1924,9 @@ static ssize_t disk_events_poll_msecs_show(struct device *dev,
{
struct gendisk *disk = dev_to_disk(dev);
+ if (!disk->ev)
+ return sprintf(buf, "-1\n");
+
return sprintf(buf, "%ld\n", disk->ev->poll_msecs);
}
@@ -1917,6 +1943,9 @@ static ssize_t disk_events_poll_msecs_store(struct device *dev,
if (intv < 0 && intv != -1)
return -EINVAL;
+ if (!disk->ev)
+ return -ENODEV;
+
disk_block_events(disk);
disk->ev->poll_msecs = intv;
__disk_unblock_events(disk, true);
@@ -1981,7 +2010,7 @@ static void disk_alloc_events(struct gendisk *disk)
{
struct disk_events *ev;
- if (!disk->fops->check_events)
+ if (!disk->fops->check_events || !disk->events)
return;
ev = kzalloc(sizeof(*ev), GFP_KERNEL);
@@ -2003,14 +2032,14 @@ static void disk_alloc_events(struct gendisk *disk)
static void disk_add_events(struct gendisk *disk)
{
- if (!disk->ev)
- return;
-
/* FIXME: error handling */
if (sysfs_create_files(&disk_to_dev(disk)->kobj, disk_events_attrs) < 0)
pr_warn("%s: failed to create sysfs files for events\n",
disk->disk_name);
+ if (!disk->ev)
+ return;
+
mutex_lock(&disk_events_mutex);
list_add_tail(&disk->ev->node, &disk_events);
mutex_unlock(&disk_events_mutex);
@@ -2024,14 +2053,13 @@ static void disk_add_events(struct gendisk *disk)
static void disk_del_events(struct gendisk *disk)
{
- if (!disk->ev)
- return;
-
- disk_block_events(disk);
+ if (disk->ev) {
+ disk_block_events(disk);
- mutex_lock(&disk_events_mutex);
- list_del_init(&disk->ev->node);
- mutex_unlock(&disk_events_mutex);
+ mutex_lock(&disk_events_mutex);
+ list_del_init(&disk->ev->node);
+ mutex_unlock(&disk_events_mutex);
+ }
sysfs_remove_files(&disk_to_dev(disk)->kobj, disk_events_attrs);
}