Patch "xen/pciback: Save the number of MSI-X entries to be copied later." has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

xen/pciback: Save the number of MSI-X entries to be copied later.

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xen-pciback-save-the-number-of-msi-x-entries-to-be-copied-later.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Konrad Rzeszutek Wilk <[email protected]>
Date: Thu, 11 Feb 2016 16:10:24 -0500
Subject: xen/pciback: Save the number of MSI-X entries to be copied later.

From: Konrad Rzeszutek Wilk <[email protected]>

commit d159457b84395927b5a52adb72f748dd089ad5e5 upstream.

Commit 8135cf8b092723dbfcc611fe6fdcb3a36c9951c5 (xen/pciback: Save xen_pci_op commands before processing it) broke enabling MSI-X because it would never copy the resulting vectors into the response. The number of vectors requested was being overwritten by the return value (typically zero for success).

Save the number of vectors before processing the op, so the correct number of vectors are copied afterwards.

---
 drivers/xen/xen-pciback/pciback_ops.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

@@ -333,6 +333,9 @@ void xen_pcibk_do_op(struct work_struct
 	struct xen_pcibk_dev_data *dev_data = NULL;
 	struct xen_pci_op *op = &pdev->op;
 	int test_intx = 0;
+#ifdef CONFIG_PCI_MSI
+	unsigned int nr = 0;
+#endif
 
 	*op = pdev->sh_info->op;
 	barrier();

@@ -361,6 +364,7 @@ void xen_pcibk_do_op(struct work_struct
 			op->err = xen_pcibk_disable_msi(pdev, dev, op);
 			break;
 		case XEN_PCI_OP_enable_msix:
+			nr = op->value;
 			op->err = xen_pcibk_enable_msix(pdev, dev, op);
 			break;
 		case XEN_PCI_OP_disable_msix:

@@ -383,7 +387,7 @@ void xen_pcibk_do_op(struct work_struct
 	if (op->cmd == XEN_PCI_OP_enable_msix && op->err == 0) {
 		unsigned int i;
 
-		for (i = 0; i < op->value; i++)
+		for (i = 0; i < nr; i++)
 			pdev->sh_info->op.msix_entries[i].vector =
 				op->msix_entries[i].vector;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/xen-pciback-save-the-number-of-msi-x-entries-to-be-copied-later.patch queue-4.4/xen-pciback-check-pf-instead-of-vf-for-pci_command_memory.patch queue-4.4/xen-pcifront-fix-mysterious-crashes-when-numa-locality-information-was-extracted.patch