Thread (146 messages) 146 messages, 18 authors, 2013-10-15

Re: [PATCH RFC 54/77] ntb: Ensure number of MSIs on SNB is enough for the link interrupt

From: Jon Mason <hidden>
Date: 2013-10-07 16:51:07
Also in: linux-ide, linux-mips, linux-nvme, linux-pci, linux-rdma, linux-s390, linux-scsi, linuxppc-dev, lkml, stable

On Sat, Oct 05, 2013 at 11:43:04PM +0200, Alexander Gordeev wrote:
On Wed, Oct 02, 2013 at 05:48:05PM -0700, Jon Mason wrote:
quoted
On Wed, Oct 02, 2013 at 12:49:10PM +0200, Alexander Gordeev wrote:
quoted
Signed-off-by: Alexander Gordeev <redacted>
---
 drivers/ntb/ntb_hw.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/drivers/ntb/ntb_hw.c b/drivers/ntb/ntb_hw.c
index de2062c..eccd5e5 100644
--- a/drivers/ntb/ntb_hw.c
+++ b/drivers/ntb/ntb_hw.c
@@ -1066,7 +1066,7 @@ static int ntb_setup_msix(struct ntb_device *ndev)
 		/* On SNB, the link interrupt is always tied to 4th vector.  If
 		 * we can't get all 4, then we can't use MSI-X.
 		 */
-		if (ndev->hw_type != BWD_HW) {
+		if ((rc < SNB_MSIX_CNT) && (ndev->hw_type != BWD_HW)) {
Nack, this check is unnecessary.
If SNB can do more than SNB_MSIX_CNT MSI-Xs then this check is needed
to enable less than maximum MSI-Xs in case the maximum was not allocated.
Otherwise SNB will fallback to single MSI instead of multiple MSI-Xs.
Per the comment in the code snippet above, "If we can't get all 4,
then we can't use MSI-X".  There is already a check to see if more
than 4 were acquired.  So it's not possible to hit this.  Even if it
was, don't use SNB_MSIX_CNT here (limits.msix_cnt is the preferred
variable).  Also, the "()" are unnecessary.

Thanks,
Jon
-- 
Regards,
Alexander Gordeev
agordeev@redhat.com
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