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authorChristoph Hellwig <hch@lst.de>2015-09-27 22:01:50 +0300
committerJens Axboe <axboe@fb.com>2015-10-01 11:10:55 +0300
commitf4829a9b7a61e159367350008a608b062c4f6840 (patch)
treea2f488a95324e0c0b558273f48b18413ab2fa221 /drivers/block/xen-blkfront.c
parent60de074ba1e8f327db19bc33d8530131ac01695d (diff)
downloadlinux-f4829a9b7a61e159367350008a608b062c4f6840.tar.xz
blk-mq: fix racy updates of rq->errors
blk_mq_complete_request may be a no-op if the request has already been completed by others means (e.g. a timeout or cancellation), but currently drivers have to set rq->errors before calling blk_mq_complete_request, which might leave us with the wrong error value. Add an error parameter to blk_mq_complete_request so that we can defer setting rq->errors until we known we won the race to complete the request. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Sagi Grimberg <sagig@mellanox.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'drivers/block/xen-blkfront.c')
-rw-r--r--drivers/block/xen-blkfront.c19
1 files changed, 10 insertions, 9 deletions
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 0823a96902f8..611170896b8c 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -1142,6 +1142,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
RING_IDX i, rp;
unsigned long flags;
struct blkfront_info *info = (struct blkfront_info *)dev_id;
+ int error;
spin_lock_irqsave(&info->io_lock, flags);
@@ -1182,37 +1183,37 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
continue;
}
- req->errors = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
+ error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
switch (bret->operation) {
case BLKIF_OP_DISCARD:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
struct request_queue *rq = info->rq;
printk(KERN_WARNING "blkfront: %s: %s op failed\n",
info->gd->disk_name, op_name(bret->operation));
- req->errors = -EOPNOTSUPP;
+ error = -EOPNOTSUPP;
info->feature_discard = 0;
info->feature_secdiscard = 0;
queue_flag_clear(QUEUE_FLAG_DISCARD, rq);
queue_flag_clear(QUEUE_FLAG_SECDISCARD, rq);
}
- blk_mq_complete_request(req);
+ blk_mq_complete_request(req, error);
break;
case BLKIF_OP_FLUSH_DISKCACHE:
case BLKIF_OP_WRITE_BARRIER:
if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
printk(KERN_WARNING "blkfront: %s: %s op failed\n",
info->gd->disk_name, op_name(bret->operation));
- req->errors = -EOPNOTSUPP;
+ error = -EOPNOTSUPP;
}
if (unlikely(bret->status == BLKIF_RSP_ERROR &&
info->shadow[id].req.u.rw.nr_segments == 0)) {
printk(KERN_WARNING "blkfront: %s: empty %s op failed\n",
info->gd->disk_name, op_name(bret->operation));
- req->errors = -EOPNOTSUPP;
+ error = -EOPNOTSUPP;
}
- if (unlikely(req->errors)) {
- if (req->errors == -EOPNOTSUPP)
- req->errors = 0;
+ if (unlikely(error)) {
+ if (error == -EOPNOTSUPP)
+ error = 0;
info->feature_flush = 0;
xlvbd_flush(info);
}
@@ -1223,7 +1224,7 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
dev_dbg(&info->xbdev->dev, "Bad return from blkdev data "
"request: %x\n", bret->status);
- blk_mq_complete_request(req);
+ blk_mq_complete_request(req, error);
break;
default:
BUG();