IB/qib: Fix a possible data corruption when receiving packets

Prevent a receive data corruption by ensuring that the write to update
the rcvhdrheadn register to generate an interrupt is at the very end
of the receive processing.

Signed-off-by: Ramkrishna Vepa <ram.vepa@qlogic.com>
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@qlogic.com>
Cc: <stable@kernel.org>
Signed-off-by: Roland Dreier <roland@purestorage.com>

3 files changed, 10 insertions, 4 deletions

diff --git a/drivers/infiniband/hw/qib/qib_iba6120.c b/drivers/infiniband/hw/qib/qib_iba6120.c
index 781a802a321f..4f18e2d332df 100644
--- a/drivers/infiniband/hw/qib/qib_iba6120.c
+++ b/drivers/infiniband/hw/qib/qib_iba6120.c
@@ -2076,9 +2076,11 @@ static void qib_6120_config_ctxts(struct qib_devdata *dd)
 static void qib_update_6120_usrhead(struct qib_ctxtdata *rcd, u64 hd,
                                     u32 updegr, u32 egrhd, u32 npkts)
 {
-        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
         if (updegr)
                 qib_write_ureg(rcd->dd, ur_rcvegrindexhead, egrhd, rcd->ctxt);
+        mmiowb();
+        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
+        mmiowb();
 }
 
 static u32 qib_6120_hdrqempty(struct qib_ctxtdata *rcd)
diff --git a/drivers/infiniband/hw/qib/qib_iba7220.c b/drivers/infiniband/hw/qib/qib_iba7220.c
index 9dd886cc633a..3c722f79d6f6 100644
--- a/drivers/infiniband/hw/qib/qib_iba7220.c
+++ b/drivers/infiniband/hw/qib/qib_iba7220.c
@@ -2725,9 +2725,11 @@ static int qib_7220_set_loopback(struct qib_pportdata *ppd, const char *what)
 static void qib_update_7220_usrhead(struct qib_ctxtdata *rcd, u64 hd,
                                     u32 updegr, u32 egrhd, u32 npkts)
 {
-        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
         if (updegr)
                 qib_write_ureg(rcd->dd, ur_rcvegrindexhead, egrhd, rcd->ctxt);
+        mmiowb();
+        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
+        mmiowb();
 }
 
 static u32 qib_7220_hdrqempty(struct qib_ctxtdata *rcd)
diff --git a/drivers/infiniband/hw/qib/qib_iba7322.c b/drivers/infiniband/hw/qib/qib_iba7322.c
index abd218d429fe..e22735402649 100644
--- a/drivers/infiniband/hw/qib/qib_iba7322.c
+++ b/drivers/infiniband/hw/qib/qib_iba7322.c
@@ -4083,10 +4083,12 @@ static void qib_update_7322_usrhead(struct qib_ctxtdata *rcd, u64 hd,
          */
         if (hd >> IBA7322_HDRHEAD_PKTINT_SHIFT)
                 adjust_rcv_timeout(rcd, npkts);
-        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
-        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
         if (updegr)
                 qib_write_ureg(rcd->dd, ur_rcvegrindexhead, egrhd, rcd->ctxt);
+        mmiowb();
+        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
+        qib_write_ureg(rcd->dd, ur_rcvhdrhead, hd, rcd->ctxt);
+        mmiowb();
 }
 
 static u32 qib_7322_hdrqempty(struct qib_ctxtdata *rcd)