@@ -76,6 +76,7 @@ struct blk_shadow {
struct request *request;
unsigned long frame[BLKIF_MAX_SEGMENTS_PER_REQUEST];
struct grant *grants_used[BLKIF_MAX_SEGMENTS_PER_REQUEST];
+ struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
};
static DEFINE_MUTEX(blkfront_mutex);
@@ -99,7 +100,6 @@ struct blkfront_info
enum blkif_state connected;
int ring_ref;
struct blkif_front_ring ring;
- struct scatterlist sg[BLKIF_MAX_SEGMENTS_PER_REQUEST];
unsigned int evtchn, irq;
struct request_queue *rq;
struct work_struct work;
@@ -362,11 +362,11 @@ static int blkif_queue_request(struct request *req)
ring_req->u.discard.flag = 0;
} else {
ring_req->u.rw.nr_segments = blk_rq_map_sg(req->q, req,
- info->sg);
+ info->shadow[id].sg);
BUG_ON(ring_req->u.rw.nr_segments >
BLKIF_MAX_SEGMENTS_PER_REQUEST);
- for_each_sg(info->sg, sg, ring_req->u.rw.nr_segments, i) {
+ for_each_sg(info->shadow[id].sg, sg, ring_req->u.rw.nr_segments, i) {
fsect = sg->offset >> 9;
lsect = fsect + (sg->length >> 9) - 1;
@@ -839,12 +839,12 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
struct blkif_response *bret)
{
int i = 0;
- struct bio_vec *bvec;
- struct req_iterator iter;
- unsigned long flags;
+ struct scatterlist *sg;
char *bvec_data;
void *shared_data;
- unsigned int offset = 0;
+ int nseg;
+
+ nseg = s->req.u.rw.nr_segments;
if (bret->operation == BLKIF_OP_READ) {
/*
@@ -853,19 +853,16 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
* than PAGE_SIZE, we have to keep track of the current offset,
* to be sure we are copying the data from the right shared page.
*/
- rq_for_each_segment(bvec, s->request, iter) {
- BUG_ON((bvec->bv_offset + bvec->bv_len) > PAGE_SIZE);
- if (bvec->bv_offset < offset)
- i++;
- BUG_ON(i >= s->req.u.rw.nr_segments);
+ for_each_sg(s->sg, sg, nseg, i) {
+ BUG_ON(sg->offset + sg->length > PAGE_SIZE);
shared_data = kmap_atomic(
pfn_to_page(s->grants_used[i]->pfn));
- bvec_data = bvec_kmap_irq(bvec, &flags);
- memcpy(bvec_data, shared_data + bvec->bv_offset,
- bvec->bv_len);
- bvec_kunmap_irq(bvec_data, &flags);
+ bvec_data = kmap_atomic(sg_page(sg));
+ memcpy(bvec_data + sg->offset,
+ shared_data + sg->offset,
+ sg->length);
+ kunmap_atomic(bvec_data);
kunmap_atomic(shared_data);
- offset = bvec->bv_offset + bvec->bv_len;
}
}
/* Add the persistent grant into the list of free grants */
@@ -994,7 +991,7 @@ static int setup_blkring(struct xenbus_device *dev,
struct blkfront_info *info)
{
struct blkif_sring *sring;
- int err;
+ int err, i;
info->ring_ref = GRANT_INVALID_REF;
@@ -1006,7 +1003,8 @@ static int setup_blkring(struct xenbus_device *dev,
SHARED_RING_INIT(sring);
FRONT_RING_INIT(&info->ring, sring, PAGE_SIZE);
- sg_init_table(info->sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
+ for (i = 0; i < BLK_RING_SIZE; i++)
+ sg_init_table(info->shadow[i].sg, BLKIF_MAX_SEGMENTS_PER_REQUEST);
err = xenbus_grant_ring(dev, virt_to_mfn(info->ring.sring));
if (err < 0) {
This is a note to let you know that I have just added a patch titled xen-blkfront: use a different scatterlist for each request to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue This patch is scheduled to be released in version 3.8.13.12. If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.8.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Kamal ------ From 3901878b563fbdcbb21ac63cfd096b8d1df0b08b Mon Sep 17 00:00:00 2001 From: Roger Pau Monne <roger.pau@citrix.com> Date: Thu, 2 May 2013 10:58:50 +0200 Subject: xen-blkfront: use a different scatterlist for each request MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit commit b7649158a0d241f8d53d13ff7441858539e16656 upstream. In blkif_queue_request blkfront iterates over the scatterlist in order to set the segments of the request, and in blkif_completion blkfront iterates over the raw request, which makes it hard to know the exact position of the source and destination memory positions. This can be solved by allocating a scatterlist for each request, that will be keep until the request is finished, allowing us to copy the data back to the original memory without having to iterate over the raw request. Oracle-Bug: 16660413 - LARGE ASYNCHRONOUS READS APPEAR BROKEN ON 2.6.39-400 Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reported-and-Tested-by: Anne Milicia <anne.milicia@oracle.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Joseph Salisbury <joseph.salisbury@canonical.com> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- drivers/block/xen-blkfront.c | 36 +++++++++++++++++------------------- 1 file changed, 17 insertions(+), 19 deletions(-) -- 1.8.1.2