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Commit 0a1f127a authored by Peter Horton's avatar Peter Horton Committed by Linus Torvalds
Browse files

aoe: prevent cache aliases 



Prevent the AoE block driver from creating cache aliases of page cache
pages on machines with virtually indexed caches.

Building kernels on an AT91SAM9G20 board without this patch fails with
segmentation faults after a couple of passes.

Signed-off-by: default avatarPeter Horton <zero@colonel-panic.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ca029701

drivers/block/aoe/aoecmd.c

+21 −2
Original line number Diff line number Diff line
@@ -735,6 +735,21 @@ diskstats(struct gendisk *disk, struct bio *bio, ulong duration, sector_t sector 
	part_stat_unlock();

}



/*

 * Ensure we don't create aliases in VI caches

 */

static inline void

killalias(struct bio *bio)

{

	struct bio_vec *bv;

	int i;



	if (bio_data_dir(bio) == READ)

		__bio_for_each_segment(bv, bio, i, 0) {

			flush_dcache_page(bv->bv_page);

		}

}



void

aoecmd_ata_rsp(struct sk_buff *skb)

{
@@ -853,8 +868,12 @@ aoecmd_ata_rsp(struct sk_buff *skb) 


	if (buf && --buf->nframesout == 0 && buf->resid == 0) {

		diskstats(d->gd, buf->bio, jiffies - buf->stime, buf->sector);

		n = (buf->flags & BUFFL_FAIL) ? -EIO : 0;

		bio_endio(buf->bio, n);

		if (buf->flags & BUFFL_FAIL)

			bio_endio(buf->bio, -EIO);

		else {

			killalias(buf->bio);

			bio_endio(buf->bio, 0);

		}

		mempool_free(buf, d->bufpool);

	}