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authorArthur Jones <arthur.jones@qlogic.com>2007-10-17 18:18:29 -0700
committerRoland Dreier <rolandd@cisco.com>2008-01-25 14:15:28 -0800
commit2f01a7001131bbf3ce1e39252bf72aea2da034df (patch)
tree926b215a1da4cd9c6956306b187507ea0c5ae185 /drivers/infiniband/hw
parent6276980138292056aab162f7eb98afe5243b2976 (diff)
IB/ipath: Better comment for rmb() in ipath_intr()
An internal code review found the comment here lacking -- update it with more specifics of how and why the rmb() is there. Signed-off-by: Arthur Jones <arthur.jones@qlogic.com> Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'drivers/infiniband/hw')
-rw-r--r--drivers/infiniband/hw/ipath/ipath_intr.c10
1 files changed, 9 insertions, 1 deletions
diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c
index eac2e9c5528..4795cb895f8 100644
--- a/drivers/infiniband/hw/ipath/ipath_intr.c
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c
@@ -954,7 +954,15 @@ static void handle_urcv(struct ipath_devdata *dd, u32 istat)
int i;
int rcvdint = 0;
- /* test_bit below needs this... */
+ /*
+ * test_and_clear_bit(IPATH_PORT_WAITING_RCV) and
+ * test_and_clear_bit(IPATH_PORT_WAITING_URG) below
+ * would both like timely updates of the bits so that
+ * we don't pass them by unnecessarily. the rmb()
+ * here ensures that we see them promptly -- the
+ * corresponding wmb()'s are in ipath_poll_urgent()
+ * and ipath_poll_next()...
+ */
rmb();
portr = ((istat >> INFINIPATH_I_RCVAVAIL_SHIFT) &
dd->ipath_i_rcvavail_mask)