From: "Bryan O'Sullivan" <bos@pathscale.com>

The mb() prevents the compiler from reordering on this function, with some
versions of gcc and -Os optimization.  The result is random failures in the
EEPROM read without this change.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Bryan O'Sullivan <bryan.osullivan@qlogic.com>
Cc: "Michael S. Tsirkin" <mst@mellanox.co.il>
Cc: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---

 drivers/infiniband/hw/ipath/ipath_eeprom.c |    1 +
 1 files changed, 1 insertion(+)

diff -puN drivers/infiniband/hw/ipath/ipath_eeprom.c~ib-ipath-fixes-a-bug-where-our-delay-for-eeprom-no drivers/infiniband/hw/ipath/ipath_eeprom.c
--- a/drivers/infiniband/hw/ipath/ipath_eeprom.c~ib-ipath-fixes-a-bug-where-our-delay-for-eeprom-no
+++ a/drivers/infiniband/hw/ipath/ipath_eeprom.c
@@ -186,6 +186,7 @@ bail:
  */
 static void i2c_wait_for_writes(struct ipath_devdata *dd)
 {
+	mb();
 	(void)ipath_read_kreg32(dd, dd->ipath_kregs->kr_scratch);
 }
 
_