[SCSI] hpsa: fixup MSI-X registration

Commit 254f796b updated
the driver to use 16 MSI-X vectors, despite the fact that
older controllers would provide only 4.
This was causing MSI-X registration to drop down to INTx
mode. But as the controller support performant mode, the
initialisation will become confused and cause the machine
to stall during boot.

This patch fixes up the MSI-X registration to re-issue
the pci_enable_msix() call with the correct number of
MSI-X vectors. With that the hpsa driver continues to
works on older controllers like the P200.
Signed-off-by: Hannes Reinecke <hare@suse.de>
Acked-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

drivers/scsi/hpsa.c

@@ -598,7 +598,7 @@ static void set_performant_mode(struct ctlr_info *h, struct CommandList *c)
 {
 	if (likely(h->transMethod & CFGTBL_Trans_Performant)) {
 		c->busaddr |= 1 | (h->blockFetchTable[c->Header.SGList] << 1);
-		if (likely(h->msix_vector))
+		if (likely(h->msix_vector > 0))
 			c->Header.ReplyQueue =
 				raw_smp_processor_id() % h->nreply_queues;
 	}
@@ -4169,21 +4169,24 @@ static void hpsa_interrupt_mode(struct ctlr_info *h)
 		goto default_int_mode;
 	if (pci_find_capability(h->pdev, PCI_CAP_ID_MSIX)) {
 		dev_info(&h->pdev->dev, "MSIX\n");
+		h->msix_vector = MAX_REPLY_QUEUES;
 		err = pci_enable_msix(h->pdev, hpsa_msix_entries,
-						MAX_REPLY_QUEUES);
-		if (!err) {
-			for (i = 0; i < MAX_REPLY_QUEUES; i++)
-				h->intr[i] = hpsa_msix_entries[i].vector;
-			h->msix_vector = 1;
-			return;
-		}
+				      h->msix_vector);
 		if (err > 0) {
 			dev_warn(&h->pdev->dev, "only %d MSI-X vectors "
 			       "available\n", err);
-			goto default_int_mode;
+			h->msix_vector = err;
+			err = pci_enable_msix(h->pdev, hpsa_msix_entries,
+					      h->msix_vector);
+		}
+		if (!err) {
+			for (i = 0; i < h->msix_vector; i++)
+				h->intr[i] = hpsa_msix_entries[i].vector;
+			return;
 		} else {
 			dev_warn(&h->pdev->dev, "MSI-X init failed %d\n",
 			       err);
+			h->msix_vector = 0;
 			goto default_int_mode;
 		}
 	}
@@ -4597,15 +4600,15 @@ static int hpsa_request_irq(struct ctlr_info *h,
 	for (i = 0; i < MAX_REPLY_QUEUES; i++)
 		h->q[i] = (u8) i;
 
-	if (h->intr_mode == PERF_MODE_INT && h->msix_vector) {
+	if (h->intr_mode == PERF_MODE_INT && h->msix_vector > 0) {
 		/* If performant mode and MSI-X, use multiple reply queues */
-		for (i = 0; i < MAX_REPLY_QUEUES; i++)
+		for (i = 0; i < h->msix_vector; i++)
 			rc = request_irq(h->intr[i], msixhandler,
 					0, h->devname,
 					&h->q[i]);
 	} else {
 		/* Use single reply pool */
-		if (h->msix_vector || h->msi_vector) {
+		if (h->msix_vector > 0 || h->msi_vector) {
 			rc = request_irq(h->intr[h->intr_mode],
 				msixhandler, 0, h->devname,
 				&h->q[h->intr_mode]);
@@ -4658,7 +4661,7 @@ static void free_irqs(struct ctlr_info *h)
 		return;
 	}
 
-	for (i = 0; i < MAX_REPLY_QUEUES; i++)
+	for (i = 0; i < h->msix_vector; i++)
 		free_irq(h->intr[i], &h->q[i]);
 }
 
@@ -5178,7 +5181,7 @@ static void hpsa_put_ctlr_into_performant_mode(struct ctlr_info *h)
 	if (!(trans_support & PERFORMANT_MODE))
 		return;
 
-	h->nreply_queues = h->msix_vector ? MAX_REPLY_QUEUES : 1;
+	h->nreply_queues = h->msix_vector > 0 ? h->msix_vector : 1;
 	hpsa_get_max_perf_mode_cmds(h);
 	/* Performant mode ring buffer and supporting data structures */
 	h->reply_pool_size = h->max_commands * sizeof(u64) * h->nreply_queues;