[PATCH] pci_regs: reintroduce PCI_MSIX_FLAGS_BIRMASK

["Michael S. Tsirkin" <mst@redhat.com>]

This partially reverts commit 09a2c73ddfc7f173237fc7209a65b34dd5bcb5ed.
    PCI: Remove unused PCI_MSIX_FLAGS_BIRMASK definition

That commit dropped a symbol from an exported header claiming "no one
uses it". This isn't how Linux normally approaches userspace API though,
and in fact QEMU build fails if trying to use updated headers from linux
3.12 and up.

Sure, userspace can be fixed to use the new symbol, but the cost
of keeping the old one around is fairly low, too.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/uapi/linux/pci_regs.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index efe3443..66644ac 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -319,6 +319,7 @@
 #define PCI_MSIX_PBA		8	/* Pending Bit Array offset */
 #define  PCI_MSIX_PBA_BIR	0x00000007 /* BAR index */
 #define  PCI_MSIX_PBA_OFFSET	0xfffffff8 /* Offset into specified BAR */
+#define  PCI_MSIX_FLAGS_BIRMASK	PCI_MSIX_PBA_BIR /* deprecated */
 #define PCI_CAP_MSIX_SIZEOF	12	/* size of MSIX registers */
 
 /* MSI-X Table entry format */
-- 
MST