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authorJens Axboe <axboe@kernel.dk>2017-07-25 15:30:21 -0600
committerJens Axboe <axboe@kernel.dk>2017-07-25 15:30:21 -0600
commite9193da00fb5624348b420717af798f01f0bfd64 (patch)
tree900d620faaa4d6dc0a5513a5dca7d574903fb677 /drivers
parent7a362ea96d0df873397be04f4556e92f7e37c5ec (diff)
parentbd912ef3e46b6edb51bb8af4b73fd2be7817e305 (diff)
Merge branch 'stable/for-jens-4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen into for-linus
Pull xen-blkfront fixes from Konrad for 4.13.
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/xen-blkfront.c21
1 files changed, 12 insertions, 9 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 1799bba74390..98e34e4c62b8 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -708,6 +708,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
* existing persistent grants, or if we have to get new grants,
* as there are not sufficiently many free.
*/
+ bool new_persistent_gnts = false;
struct scatterlist *sg;
int num_sg, max_grefs, num_grant;
@@ -719,19 +720,21 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
*/
max_grefs += INDIRECT_GREFS(max_grefs);
- /*
- * We have to reserve 'max_grefs' grants because persistent
- * grants are shared by all rings.
- */
- if (max_grefs > 0)
- if (gnttab_alloc_grant_references(max_grefs, &setup.gref_head) < 0) {
+ /* Check if we have enough persistent grants to allocate a requests */
+ if (rinfo->persistent_gnts_c < max_grefs) {
+ new_persistent_gnts = true;
+
+ if (gnttab_alloc_grant_references(
+ max_grefs - rinfo->persistent_gnts_c,
+ &setup.gref_head) < 0) {
gnttab_request_free_callback(
&rinfo->callback,
blkif_restart_queue_callback,
rinfo,
- max_grefs);
+ max_grefs - rinfo->persistent_gnts_c);
return 1;
}
+ }
/* Fill out a communications ring structure. */
id = blkif_ring_get_request(rinfo, req, &ring_req);
@@ -832,7 +835,7 @@ static int blkif_queue_rw_req(struct request *req, struct blkfront_ring_info *ri
if (unlikely(require_extra_req))
rinfo->shadow[extra_id].req = *extra_ring_req;
- if (max_grefs > 0)
+ if (new_persistent_gnts)
gnttab_free_grant_references(setup.gref_head);
return 0;
@@ -906,8 +909,8 @@ out_err:
return BLK_STS_IOERR;
out_busy:
- spin_unlock_irqrestore(&rinfo->ring_lock, flags);
blk_mq_stop_hw_queue(hctx);
+ spin_unlock_irqrestore(&rinfo->ring_lock, flags);
return BLK_STS_RESOURCE;
}