| From | Ben Hutchings <> | Date | Mon, 21 Oct 2013 09:46:28 +0100 | Subject | [PATCH 3.2 128/149] Revert "zram: use zram->lock to protect zram_free_page() in swap free notify path" |
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3.2.52-rc1 review patch. If anyone has any objections, please let me know.
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From: Ben Hutchings <ben@decadent.org.uk>
This reverts commit 9e443904906ca2b5b3ae71f34ac4a4fa6905623e, which was commit 57ab048532c0d975538cebd4456491b5c34248f4 upstream.
Taking the semaphore here leads to sleeping in atomic context. This was fixed in mainline commit a0c516cbfc74 ("zram: don't grab mutex in zram_slot_free_noity") but that is too difficult to backport.
Signed-off-by: Ben Hutchings <ben@decadent.org.uk> --- --- a/drivers/staging/zram/zram_drv.c +++ b/drivers/staging/zram/zram_drv.c @@ -709,9 +709,7 @@ static void zram_slot_free_notify(struct struct zram *zram; zram = bdev->bd_disk->private_data; - down_write(&zram->lock); zram_free_page(zram, index); - up_write(&zram->lock); zram_stat64_inc(zram, &zram->stats.notify_free); } --- a/drivers/staging/zram/zram_drv.h +++ b/drivers/staging/zram/zram_drv.h @@ -107,9 +107,8 @@ struct zram { void *compress_buffer; struct table *table; spinlock_t stat64_lock; /* protect 64-bit stats */ - struct rw_semaphore lock; /* protect compression buffers, table, - * 32bit stat counters against concurrent - * notifications, reads and writes */ + struct rw_semaphore lock; /* protect compression buffers and table + * against concurrent read and writes */ struct request_queue *queue; struct gendisk *disk; int init_done;
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