git » linux-kernel » commit 0a1f127

aoe: prevent cache aliases

author Peter Horton
2009-12-01 21:17:46 UTC
committer Linus Torvalds
2009-12-02 00:32:20 UTC
parent ca0297015d4f117005718e01aa368875abcccbc5
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: Peter Horton <zero@colonel-panic.org>
Cc: "Ed L. Cashin" <ecashin@coraid.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
drivers/block/aoe/aoecmd.c +21 -2 
diff --git a/drivers/block/aoe/aoecmd.c b/drivers/block/aoe/aoecmd.c
index 965ece2c7e4..13bb69d2abb 100644
--- a/drivers/block/aoe/aoecmd.c
+++ b/drivers/block/aoe/aoecmd.c
@@ -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);
 	}