[PATCH 4.12 96/99] ntb: transport shouldnt disable link due to bogus values in SPADs

Greg Kroah-Hartman
2017-08-28T08:09:53Z

From: Dave Jiang <dave.jiang@intel.com>

commit f3fd2afed8eee91620d05b69ab94c14793c849d7 upstream.

It seems that under certain scenarios the SPAD can have bogus values caused
by an agent (i.e. BIOS or other software) that is not the kernel driver, and
that causes memory window setup failure. This should not cause the link to
be disabled because if we do that, the driver will never recover again. We
have verified in testing that this issue happens and prevents proper link
recovery.

Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Acked-by: Allen Hubbe <Allen.Hubbe@dell.com>
Signed-off-by: Jon Mason <jdmason@kudzu.us>
Fixes: 84f766855f61 ("ntb: stop link work when we do not have memory")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/ntb/ntb_transport.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

--- a/drivers/ntb/ntb_transport.c
+++ b/drivers/ntb/ntb_transport.c
@@ -920,10 +920,8 @@ out1:
ntb_free_mw(nt, i);

/* if there's an actual failure, we should just bail */
- if (rc < 0) {
- ntb_link_disable(ndev);
+ if (rc < 0)
return;
- }

out:
if (ntb_link_is_up(ndev, NULL, NULL) == 1)