1 files changed, 98 insertions, 40 deletions

diff --git a/drivers/block/xen-blkfront.c b/drivers/block/xen-blkfront.c
index e1f71debdbba..1e44b7880200 100644
--- a/drivers/block/xen-blkfront.c
+++ b/drivers/block/xen-blkfront.c
@@ -64,6 +64,7 @@ enum blkif_state {
 	BLKIF_STATE_DISCONNECTED,
 	BLKIF_STATE_CONNECTED,
 	BLKIF_STATE_SUSPENDED,
+	BLKIF_STATE_ERROR,
 };
 
 struct grant {
@@ -79,6 +80,7 @@ struct blk_shadow {
 	struct grant **indirect_grants;
 	struct scatterlist *sg;
 	unsigned int num_sg;
+	bool inflight;
 };
 
 struct split_bio {
@@ -456,16 +458,31 @@ static int blkif_ioctl(struct block_device *bdev, fmode_t mode,
 	return 0;
 }
 
+static unsigned long blkif_ring_get_request(struct blkfront_info *info,
+					    struct request *req,
+					    struct blkif_request **ring_req)
+{
+	unsigned long id;
+
+	*ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
+	info->ring.req_prod_pvt++;
+
+	id = get_id_from_freelist(info);
+	info->shadow[id].request = req;
+	info->shadow[id].req.u.rw.id = id;
+
+	return id;
+}
+
 static int blkif_queue_discard_req(struct request *req)
 {
 	struct blkfront_info *info = req->rq_disk->private_data;
-	struct blkif_request *ring_req;
+	struct blkif_request *ring_req, *final_ring_req;
 	unsigned long id;
 
 	/* Fill out a communications ring structure. */
-	ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
-	id = get_id_from_freelist(info);
-	info->shadow[id].request = req;
+	id = blkif_ring_get_request(info, req, &final_ring_req);
+	ring_req = &info->shadow[id].req;
 
 	ring_req->operation = BLKIF_OP_DISCARD;
 	ring_req->u.discard.nr_sectors = blk_rq_sectors(req);
@@ -478,8 +495,9 @@ static int blkif_queue_discard_req(struct request *req)
 
 	info->ring.req_prod_pvt++;
 
-	/* Keep a private copy so we can reissue requests when recovering. */
-	info->shadow[id].req = *ring_req;
+	/* Copy the request to the ring page. */
+	*final_ring_req = *ring_req;
+	info->shadow[id].inflight = true;
 
 	return 0;
 }
@@ -569,7 +587,7 @@ static void blkif_setup_rw_req_grant(unsigned long gfn, unsigned int offset,
 static int blkif_queue_rw_req(struct request *req)
 {
 	struct blkfront_info *info = req->rq_disk->private_data;
-	struct blkif_request *ring_req;
+	struct blkif_request *ring_req, *final_ring_req;
 	unsigned long id;
 	int i;
 	struct setup_rw_req setup = {
@@ -613,9 +631,8 @@ static int blkif_queue_rw_req(struct request *req)
 		new_persistent_gnts = 0;
 
 	/* Fill out a communications ring structure. */
-	ring_req = RING_GET_REQUEST(&info->ring, info->ring.req_prod_pvt);
-	id = get_id_from_freelist(info);
-	info->shadow[id].request = req;
+	id = blkif_ring_get_request(info, req, &final_ring_req);
+	ring_req = &info->shadow[id].req;
 
 	BUG_ON(info->max_indirect_segments == 0 &&
 	       GREFS(req->nr_phys_segments) > BLKIF_MAX_SEGMENTS_PER_REQUEST);
@@ -696,8 +713,9 @@ static int blkif_queue_rw_req(struct request *req)
 
 	info->ring.req_prod_pvt++;
 
-	/* Keep a private copy so we can reissue requests when recovering. */
-	info->shadow[id].req = *ring_req;
+	/* Copy request(s) to the ring page. */
+	*final_ring_req = *ring_req;
+	info->shadow[id].inflight = true;
 
 	if (new_persistent_gnts)
 		gnttab_free_grant_references(setup.gref_head);
@@ -1296,58 +1314,84 @@ static void blkif_completion(struct blk_shadow *s, struct blkfront_info *info,
 static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 {
 	struct request *req;
-	struct blkif_response *bret;
+	struct blkif_response bret;
 	RING_IDX i, rp;
 	unsigned long flags;
 	struct blkfront_info *info = (struct blkfront_info *)dev_id;
 	int error;
+	unsigned int eoiflag = XEN_EOI_FLAG_SPURIOUS;
 
 	spin_lock_irqsave(&info->io_lock, flags);
 
 	if (unlikely(info->connected != BLKIF_STATE_CONNECTED)) {
 		spin_unlock_irqrestore(&info->io_lock, flags);
+		xen_irq_lateeoi(irq, XEN_EOI_FLAG_SPURIOUS);
 		return IRQ_HANDLED;
 	}
 
  again:
-	rp = info->ring.sring->rsp_prod;
+	rp = READ_ONCE(info->ring.sring->rsp_prod);
 	rmb(); /* Ensure we see queued responses up to 'rp'. */
+	if (RING_RESPONSE_PROD_OVERFLOW(&info->ring, rp)) {
+		pr_alert("%s: illegal number of responses %u\n",
+			 info->gd->disk_name, rp - info->ring.rsp_cons);
+		goto err;
+	}
 
 	for (i = info->ring.rsp_cons; i != rp; i++) {
 		unsigned long id;
+		unsigned int op;
+
+		eoiflag = 0;
+
+		RING_COPY_RESPONSE(&info->ring, i, &bret);
+		id   = bret.id;
 
-		bret = RING_GET_RESPONSE(&info->ring, i);
-		id   = bret->id;
 		/*
 		 * The backend has messed up and given us an id that we would
 		 * never have given to it (we stamp it up to BLK_RING_SIZE -
 		 * 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 (!info->shadow[id].inflight) {
+			pr_alert("%s: response references no pending request\n",
+				 info->gd->disk_name);
+			goto err;
+		}
+
+		info->shadow[id].inflight = false;
 		req  = info->shadow[id].request;
 
-		if (bret->operation != BLKIF_OP_DISCARD)
-			blkif_completion(&info->shadow[id], info, bret);
+		op = info->shadow[id].req.operation;
+		if (op == BLKIF_OP_INDIRECT)
+			op = info->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)
+			blkif_completion(&info->shadow[id], info, &bret);
 
 		if (add_id_to_freelist(info, id)) {
 			WARN(1, "%s: response to %s (id %ld) couldn't be recycled!\n",
-			     info->gd->disk_name, op_name(bret->operation), id);
+			     info->gd->disk_name, op_name(bret.operation), id);
 			continue;
 		}
 
-		error = (bret->status == BLKIF_RSP_OKAY) ? 0 : -EIO;
-		switch (bret->operation) {
+		error = (bret.status == BLKIF_RSP_OKAY) ? 0 : -EIO;
+		switch (bret.operation) {
 		case BLKIF_OP_DISCARD:
-			if (unlikely(bret->status == BLKIF_RSP_EOPNOTSUPP)) {
+			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));
+
+				pr_warn_ratelimited("blkfront: %s: %s op failed\n",
+					   info->gd->disk_name, op_name(bret.operation));
 				error = -EOPNOTSUPP;
 				info->feature_discard = 0;
 				info->feature_secdiscard = 0;
@@ -1358,15 +1402,15 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 			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));
+			if (unlikely(bret.status == BLKIF_RSP_EOPNOTSUPP)) {
+				pr_warn_ratelimited("blkfront: %s: %s op failed\n",
+				       info->gd->disk_name, op_name(bret.operation));
 				error = -EOPNOTSUPP;
 			}
-			if (unlikely(bret->status == BLKIF_RSP_ERROR &&
+			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));
+				pr_warn_ratelimited("blkfront: %s: empty %s op failed\n",
+				       info->gd->disk_name, op_name(bret.operation));
 				error = -EOPNOTSUPP;
 			}
 			if (unlikely(error)) {
@@ -1378,9 +1422,10 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 			/* fall through */
 		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);
+			if (unlikely(bret.status != BLKIF_RSP_OKAY))
+				dev_dbg_ratelimited(&info->xbdev->dev,
+					"Bad return from blkdev data request: %x\n",
+					bret.status);
 
 			blk_mq_complete_request(req, error);
 			break;
@@ -1403,6 +1448,18 @@ static irqreturn_t blkif_interrupt(int irq, void *dev_id)
 
 	spin_unlock_irqrestore(&info->io_lock, flags);
 
+	xen_irq_lateeoi(irq, eoiflag);
+
+	return IRQ_HANDLED;
+
+ err:
+	info->connected = BLKIF_STATE_ERROR;
+
+	spin_unlock_irqrestore(&info->io_lock, flags);
+
+	/* No EOI in order to avoid further interrupts. */
+
+	pr_alert("%s disabled for further use\n", info->gd->disk_name);
 	return IRQ_HANDLED;
 }
 
@@ -1440,8 +1497,8 @@ static int setup_blkring(struct xenbus_device *dev,
 	if (err)
 		goto fail;
 
-	err = bind_evtchn_to_irqhandler(info->evtchn, blkif_interrupt, 0,
-					"blkif", info);
+	err = bind_evtchn_to_irqhandler_lateeoi(info->evtchn, blkif_interrupt,
+						0, "blkif", info);
 	if (err <= 0) {
 		xenbus_dev_fatal(dev, err,
 				 "bind_evtchn_to_irqhandler failed");
@@ -1913,6 +1970,7 @@ out_of_memory:
 		info->shadow[i].sg = NULL;
 		kfree(info->shadow[i].indirect_grants);
 		info->shadow[i].indirect_grants = NULL;
+		info->shadow[i].inflight = false;
 	}
 	if (!list_empty(&info->indirect_pages)) {
 		struct page *indirect_page, *n;