---
V2:
- use READ_ONCE() for reading the producer index
- check validity of producer index only after memory barrier (Jan Beulich)
- use virt_rmb() as barrier (Jan Beulich)
---
drivers/block/xen-blkfront.c | 66 ++++++++++++++++++++++++++----------
1 file changed, 49 insertions(+), 17 deletions(-)
diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index 80701860870a..ecdbb0381b4c 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -80,6 +80,7 @@ enum blkif_state {
BLKIF_STATE_DISCONNECTED,
BLKIF_STATE_CONNECTED,
BLKIF_STATE_SUSPENDED,
+ BLKIF_STATE_ERROR,
};
struct grant {
@@ -89,6 +90,7 @@ struct grant {
};
enum blk_req_status {
+ REQ_PROCESSING,
REQ_WAITING,
REQ_DONE,
REQ_ERROR,
@@ -543,7 +545,7 @@ static unsigned long blkif_ring_get_request(struct
blkfront_ring_info *rinfo,
id = get_id_from_freelist(rinfo);
rinfo->shadow[id].request = req;
- rinfo->shadow[id].status = REQ_WAITING;
+ rinfo->shadow[id].status = REQ_PROCESSING;
rinfo->shadow[id].associated_id = NO_ASSOCIATED_ID;
rinfo->shadow[id].req.u.rw.id = id;
@@ -572,6 +574,7 @@ static int blkif_queue_discard_req(struct request *req,
struct blkfront_ring_inf
/* Copy the request to the ring page. */
*final_ring_req = *ring_req;
+ rinfo->shadow[id].status = REQ_WAITING;
return 0;
}
@@ -847,8 +850,11 @@ static int blkif_queue_rw_req(struct request *req, struct
blkfront_ring_info *ri
/* Copy request(s) to the ring page. */
*final_ring_req = *ring_req;
- if (unlikely(require_extra_req))
+ rinfo->shadow[id].status = REQ_WAITING;
+ if (unlikely(require_extra_req)) {
*final_extra_ring_req = *extra_ring_req;
+ rinfo->shadow[extra_id].status = REQ_WAITING;
+ }
if (new_persistent_gnts)
gnttab_free_grant_references(setup.gref_head);
@@ -1402,8 +1408,8 @@ static enum blk_req_status blkif_rsp_to_req_status(int
rsp)
static int blkif_get_final_status(enum blk_req_status s1,
enum blk_req_status s2)
{
- BUG_ON(s1 == REQ_WAITING);
- BUG_ON(s2 == REQ_WAITING);
+ BUG_ON(s1 < REQ_DONE);
+ BUG_ON(s2 < REQ_DONE);
if (s1 == REQ_ERROR || s2 == REQ_ERROR)
return BLKIF_RSP_ERROR;
@@ -1436,7 +1442,7 @@ static bool blkif_completion(unsigned long *id,
s->status = blkif_rsp_to_req_status(bret->status);
/* Wait the second response if not yet here. */
- if (s2->status == REQ_WAITING)
+ if (s2->status < REQ_DONE)
return false;
bret->status = blkif_get_final_status(s->status,
@@ -1555,11 +1561,17 @@ static irqreturn_t blkif_interrupt(int irq, void
*dev_id)
spin_lock_irqsave(&rinfo->ring_lock, flags);
again:
- rp = rinfo->ring.sring->rsp_prod;
- rmb(); /* Ensure we see queued responses up to 'rp'. */
+ rp = READ_ONCE(rinfo->ring.sring->rsp_prod);
+ virt_rmb(); /* Ensure we see queued responses up to 'rp'. */
+ if (RING_RESPONSE_PROD_OVERFLOW(&rinfo->ring, rp)) {
+ pr_alert("%s: illegal number of responses %u\n",
+ info->gd->disk_name, rp - rinfo->ring.rsp_cons);
+ goto err;
+ }
for (i = rinfo->ring.rsp_cons; i != rp; i++) {
unsigned long id;
+ unsigned int op;
RING_COPY_RESPONSE(&rinfo->ring, i, &bret);
id = bret.id;
@@ -1570,14 +1582,28 @@ static irqreturn_t blkif_interrupt(int irq, void
*dev_id)
* look in get_id_from_freelist.
*/
if (id >= BLK_RING_SIZE(info)) {
- WARN(1, "%s: response to %s has incorrect id (%ld)\n",
- info->gd->disk_name, op_name(bret.operation), id);
- /* We can't safely get the 'struct request' as
- * the id is busted. */
- continue;
+ pr_alert("%s: response has incorrect id (%ld)\n",
+ info->gd->disk_name, id);
+ goto err;
}
+ if (rinfo->shadow[id].status != REQ_WAITING) {
+ pr_alert("%s: response references no pending request\n",
+ info->gd->disk_name);
+ goto err;
+ }
+
+ rinfo->shadow[id].status = REQ_PROCESSING;
req = rinfo->shadow[id].request;
+ op = rinfo->shadow[id].req.operation;
+ if (op == BLKIF_OP_INDIRECT)
+ op = rinfo->shadow[id].req.u.indirect.indirect_op;
+ if (bret.operation != op) {
+ pr_alert("%s: response has wrong operation (%u instead of
%u)\n",
+ info->gd->disk_name, bret.operation, op);
+ goto err;
+ }
+
if (bret.operation != BLKIF_OP_DISCARD) {
/*
* We may need to wait for an extra response if the
@@ -1602,7 +1628,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
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",
+
+ pr_warn_ratelimited("blkfront: %s: %s op
failed\n",
info->gd->disk_name,
op_name(bret.operation));
blkif_req(req)->error = BLK_STS_NOTSUPP;
info->feature_discard = 0;
@@ -1614,13 +1641,13 @@ static irqreturn_t blkif_interrupt(int irq, void
*dev_id)
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",
+ pr_warn_ratelimited("blkfront: %s: %s op
failed\n",
info->gd->disk_name,
op_name(bret.operation));
blkif_req(req)->error = BLK_STS_NOTSUPP;
}
if (unlikely(bret.status == BLKIF_RSP_ERROR &&
rinfo->shadow[id].req.u.rw.nr_segments ==
0)) {
- printk(KERN_WARNING "blkfront: %s: empty %s op
failed\n",
+ pr_warn_ratelimited("blkfront: %s: empty %s op
failed\n",
info->gd->disk_name,
op_name(bret.operation));
blkif_req(req)->error = BLK_STS_NOTSUPP;
}
@@ -1635,8 +1662,8 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
case BLKIF_OP_READ:
case BLKIF_OP_WRITE:
if (unlikely(bret.status != BLKIF_RSP_OKAY))
- dev_dbg(&info->xbdev->dev, "Bad return from blkdev
data "
- "request: %x\n", bret.status);
+ dev_dbg_ratelimited(&info->xbdev->dev,
+ "Bad return from blkdev data request:
%x\n", bret.status);
break;
default:
@@ -1662,6 +1689,11 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
spin_unlock_irqrestore(&rinfo->ring_lock, flags);
return IRQ_HANDLED;
+
+ err:
+ info->connected = BLKIF_STATE_ERROR;
+ pr_alert("%s disabled for further use\n", info->gd->disk_name);
+ return IRQ_HANDLED;
}
