Messages in this thread Patch in this message | | | Date | Mon, 14 Jul 2008 15:06:08 +0900 | From | Tejun Heo <> | Subject | [PATCH] block: fix block_class iteration locking |
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genhd.c used block_class_lock when it wants to iterate over block_class.devices list. This is incorrect as block_class_lock has nothing to do with synchronization around block_class.devices list, so there's a window, albeit small, where the list can change while it's being iterated over. Fix it by using block_class.sem instead.
Signed-off-by: Tejun Heo <tj@kernel.org> --- block/genhd.c | 16 ++++++++-------- 1 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/block/genhd.c b/block/genhd.c index b922d48..b646e7e 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -234,7 +234,7 @@ void __init printk_all_partitions(void) char buf[BDEVNAME_SIZE]; int n; - mutex_lock(&block_class_lock); + down(&block_class.sem); /* For each block device... */ list_for_each_entry(dev, &block_class.devices, node) { if (dev->type != &disk_type) @@ -275,7 +275,7 @@ void __init printk_all_partitions(void) } } - mutex_unlock(&block_class_lock); + up(&block_class.sem); } #ifdef CONFIG_PROC_FS @@ -285,7 +285,7 @@ static void *part_start(struct seq_file *part, loff_t *pos) loff_t k = *pos; struct device *dev; - mutex_lock(&block_class_lock); + down(&block_class.sem); list_for_each_entry(dev, &block_class.devices, node) { if (dev->type != &disk_type) continue; @@ -311,7 +311,7 @@ static void *part_next(struct seq_file *part, void *v, loff_t *pos) static void part_stop(struct seq_file *part, void *v) { - mutex_unlock(&block_class_lock); + up(&block_class.sem); } static int show_partition(struct seq_file *part, void *v) @@ -533,7 +533,7 @@ static void *diskstats_start(struct seq_file *part, loff_t *pos) loff_t k = *pos; struct device *dev; - mutex_lock(&block_class_lock); + down(&block_class.sem); list_for_each_entry(dev, &block_class.devices, node) { if (dev->type != &disk_type) continue; @@ -560,7 +560,7 @@ static void *diskstats_next(struct seq_file *part, void *v, loff_t *pos) static void diskstats_stop(struct seq_file *part, void *v) { - mutex_unlock(&block_class_lock); + up(&block_class.sem); } static int diskstats_show(struct seq_file *s, void *v) @@ -658,7 +658,7 @@ dev_t blk_lookup_devt(const char *name, int part) struct device *dev; dev_t devt = MKDEV(0, 0); - mutex_lock(&block_class_lock); + down(&block_class.sem); list_for_each_entry(dev, &block_class.devices, node) { if (dev->type != &disk_type) continue; @@ -671,7 +671,7 @@ dev_t blk_lookup_devt(const char *name, int part) break; } } - mutex_unlock(&block_class_lock); + up(&block_class.sem); return devt; } -- 1.5.4.5
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