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| author | Roger Pau Monne | 2012-12-07 19:00:31 +0100 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk | 2012-12-18 03:56:03 +0100 |
| commit | d62f691858252333ff1ddb920e6774d9020734aa (patch) | |
| tree | d3f54da525e07849c3825d19d6d10e96ffaf1cdf /drivers/block/xen-blkfront.c | |
| parent | llist/xen-blkfront: implement safe version of llist_for_each_entry (diff) | |
| download | kernel-qcow2-linux-d62f691858252333ff1ddb920e6774d9020734aa.tar.gz kernel-qcow2-linux-d62f691858252333ff1ddb920e6774d9020734aa.tar.xz kernel-qcow2-linux-d62f691858252333ff1ddb920e6774d9020734aa.zip | |
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/xen-blkfront.c')
| -rw-r--r-- | drivers/block/xen-blkfront.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c index cfdb033c7107..11043c18ac5a 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 */ |