diff options
Diffstat (limited to 'block/genhd.c')
| -rw-r--r-- | block/genhd.c | 68 |
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); } |