Messages in this thread | | | Date | Wed, 21 Jan 2015 23:21:53 +0900 | From | Sergey Senozhatsky <> | Subject | Re: [PATCH v1 01/10] zram: avoid calling of zram_meta_free under init_lock |
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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@kernel.org> > --- > 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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