3.15-stable review patch. If anyone has any objections, please let me know.
------------------ From: Minchan Kim <minc...@kernel.org> commit b4c5c60920e3b0c4598f43e7317559f6aec51531 upstream. Sasha reported lockdep warning [1] introduced by [2]. It could be fixed by doing disk revalidation out of the init_lock. It's okay because disk capacity change is protected by init_lock so that revalidate_disk always sees up-to-date value so there is no race. [1] https://lkml.org/lkml/2014/7/3/735 [2] zram: revalidate disk after capacity change Fixes 2e32baea46ce ("zram: revalidate disk after capacity change"). Signed-off-by: Minchan Kim <minc...@kernel.org> Reported-by: Sasha Levin <sasha.le...@oracle.com> Cc: "Alexander E. Patrakov" <patra...@gmail.com> Cc: Nitin Gupta <ngu...@vflare.org> Cc: Jerome Marchand <jmarc...@redhat.com> Cc: Sergey Senozhatsky <sergey.senozhat...@gmail.com> Signed-off-by: Andrew Morton <a...@linux-foundation.org> Signed-off-by: Linus Torvalds <torva...@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- drivers/block/zram/zram_drv.c | 22 ++++++++++++++++++---- 1 file changed, 18 insertions(+), 4 deletions(-) --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -622,11 +622,18 @@ static void zram_reset_device(struct zra memset(&zram->stats, 0, sizeof(zram->stats)); zram->disksize = 0; - if (reset_capacity) { + if (reset_capacity) set_capacity(zram->disk, 0); - revalidate_disk(zram->disk); - } + up_write(&zram->init_lock); + + /* + * Revalidate disk out of the init_lock to avoid lockdep splat. + * It's okay because disk's capacity is protected by init_lock + * so that revalidate_disk always sees up-to-date capacity. + */ + if (reset_capacity) + revalidate_disk(zram->disk); } static ssize_t disksize_store(struct device *dev, @@ -666,8 +673,15 @@ static ssize_t disksize_store(struct dev zram->comp = comp; zram->disksize = disksize; set_capacity(zram->disk, zram->disksize >> SECTOR_SHIFT); - revalidate_disk(zram->disk); up_write(&zram->init_lock); + + /* + * Revalidate disk out of the init_lock to avoid lockdep splat. + * It's okay because disk's capacity is protected by init_lock + * so that revalidate_disk always sees up-to-date capacity. + */ + revalidate_disk(zram->disk); + return len; out_destroy_comp: -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
