aboutsummaryrefslogtreecommitdiff
path: root/drivers/block
diff options
context:
space:
mode:
authorRoger Pau Monne <roger.pau@citrix.com>2012-12-07 19:00:31 +0100
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2012-12-17 21:56:03 -0500
commitd62f691858252333ff1ddb920e6774d9020734aa (patch)
treed3f54da525e07849c3825d19d6d10e96ffaf1cdf /drivers/block
parentebb351cf78ee6bf3262e6b4b6906f456c05e6d5e (diff)
downloadlinaro-lsk-d62f691858252333ff1ddb920e6774d9020734aa.tar.gz
xen-blkfront: handle bvecs with partial data
Currently blkfront fails to handle cases in blkif_completion like the following: 1st loop in rq_for_each_segment * bv_offset: 3584 * bv_len: 512 * offset += bv_len * i: 0 2nd loop: * bv_offset: 0 * bv_len: 512 * i: 0 In the second loop i should be 1, since we assume we only wanted to read a part of the previous page. This patches fixes this cases where only a part of the shared page is read, and blkif_completion assumes that if the bv_offset of a bvec is less than the previous bv_offset plus the bv_size we have to switch to the next shared page. Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Cc: linux-kernel@vger.kernel.org Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Diffstat (limited to 'drivers/block')
-rw-r--r--drivers/block/xen-blkfront.c7
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index cfdb033c710..11043c18ac5 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -836,7 +836,7 @@ static void blkif_free(struct blkfront_info *info, int suspend)
static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
struct blkif_response *bret)
{
- int i;
+ int i = 0;
struct bio_vec *bvec;
struct req_iterator iter;
unsigned long flags;
@@ -853,7 +853,8 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
*/
rq_for_each_segment(bvec, s->request, iter) {
BUG_ON((bvec->bv_offset + bvec->bv_len) > PAGE_SIZE);
- i = offset >> PAGE_SHIFT;
+ if (bvec->bv_offset < offset)
+ i++;
BUG_ON(i >= s->req.u.rw.nr_segments);
shared_data = kmap_atomic(
pfn_to_page(s->grants_used[i]->pfn));
@@ -862,7 +863,7 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
bvec->bv_len);
bvec_kunmap_irq(bvec_data, &flags);
kunmap_atomic(shared_data);
- offset += bvec->bv_len;
+ offset = bvec->bv_offset + bvec->bv_len;
}
}
/* Add the persistent grant into the list of free grants */