On (01/21/15 15:14), Minchan Kim wrote:
> We don't need to call zram_meta_free under init_lock.
> What we need to prevent race is setting NULL into zram->meta
> (ie, init_done). This patch does it.
>
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> ---
> drivers/block/zram/zram_drv.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
> index 9250b3f..7e03d86 100644
> --- a/drivers/block/zram/zram_drv.c
> +++ b/drivers/block/zram/zram_drv.c
> @@ -719,6 +719,8 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
> }
>
> meta = zram->meta;
> + zram->meta = NULL;
> +
> /* Free all pages that are still in this zram device */
> for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
> unsigned long handle = meta->table[index].handle;
> @@ -731,8 +733,6 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
> zcomp_destroy(zram->comp);
> zram->max_comp_streams = 1;
>
> - zram_meta_free(zram->meta);
> - zram->meta = NULL;
> /* Reset stats */
> memset(&zram->stats, 0, sizeof(zram->stats));
>
> @@ -741,6 +741,7 @@ static void zram_reset_device(struct zram *zram, bool reset_capacity)
> set_capacity(zram->disk, 0);
>
> up_write(&zram->init_lock);
> + zram_meta_free(meta);
Hello,
since we detached ->meta from zram, this one doesn't really need
->init_lock protection:
/* Free all pages that are still in this zram device */
for (index = 0; index < zram->disksize >> PAGE_SHIFT; index++) {
unsigned long handle = meta->table[index].handle;
if (!handle)
continue;
zs_free(meta->mem_pool, handle);
}
-ss
> /*
> * Revalidate disk out of the init_lock to avoid lockdep splat.
> --
> 1.9.3
>
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