IB/ipath: Use counters in ipath_poll and cleanup interrupts in ipath_close

ipath_poll() suffered from a couple subtle bugs.  Under the right
conditions we could leave recv interrupts enabled on an ipath user
context on close, thereby taking potentially unwanted interrupts on the
next open -- this is fixed by unconditionally turning off recv
interrupts on close.  Also, we now use counters rather than set/clear
bits which allows us to make sure we catch all interrupts at the cost of
changing the semantics slightly (it's now give me all events since the
last time I called poll() rather than give me all events since I called
_this_ poll routine).  We also added some memory barriers which may help
ensure we get all notifications in a timely manner.

Signed-off-by: Arthur Jones <arthur.jones@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 10 insertions, 23 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c
index 11b361408ae6..61eac8cc0d9f 100644
--- a/drivers/infiniband/hw/ipath/ipath_intr.c
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c
@@ -688,17 +688,9 @@ static int handle_errors(struct ipath_devdata *dd, ipath_err_t errs)
                                         chkerrpkts = 1;
                                 dd->ipath_lastrcvhdrqtails[i] = tl;
                                 pd->port_hdrqfull++;
-                                if (test_bit(IPATH_PORT_WAITING_OVERFLOW,
-                                             &pd->port_flag)) {
-                                        clear_bit(
-                                          IPATH_PORT_WAITING_OVERFLOW,
-                                          &pd->port_flag);
-                                        set_bit(
-                                          IPATH_PORT_WAITING_OVERFLOW,
-                                          &pd->int_flag);
-                                        wake_up_interruptible(
-                                          &pd->port_wait);
-                                }
+                                /* flush hdrqfull so that poll() sees it */
+                                wmb();
+                                wake_up_interruptible(&pd->port_wait);
                         }
                 }
         }
@@ -960,6 +952,8 @@ static void handle_urcv(struct ipath_devdata *dd, u32 istat)
         int i;
         int rcvdint = 0;
 
+        /* test_bit below needs this... */
+        rmb();
         portr = ((istat >> INFINIPATH_I_RCVAVAIL_SHIFT) &
                  dd->ipath_i_rcvavail_mask)
                 | ((istat >> INFINIPATH_I_RCVURG_SHIFT) &
@@ -967,22 +961,15 @@ static void handle_urcv(struct ipath_devdata *dd, u32 istat)
         for (i = 1; i < dd->ipath_cfgports; i++) {
                 struct ipath_portdata *pd = dd->ipath_pd[i];
                 if (portr & (1 << i) && pd && pd->port_cnt) {
-                        if (test_bit(IPATH_PORT_WAITING_RCV,
-                                     &pd->port_flag)) {
-                                clear_bit(IPATH_PORT_WAITING_RCV,
-                                          &pd->port_flag);
-                                set_bit(IPATH_PORT_WAITING_RCV,
-                                        &pd->int_flag);
+                        if (test_and_clear_bit(IPATH_PORT_WAITING_RCV,
+                                               &pd->port_flag)) {
                                 clear_bit(i + INFINIPATH_R_INTRAVAIL_SHIFT,
                                           &dd->ipath_rcvctrl);
                                 wake_up_interruptible(&pd->port_wait);
                                 rcvdint = 1;
-                        } else if (test_bit(IPATH_PORT_WAITING_URG,
-                                            &pd->port_flag)) {
-                                clear_bit(IPATH_PORT_WAITING_URG,
-                                          &pd->port_flag);
-                                set_bit(IPATH_PORT_WAITING_URG,
-                                        &pd->int_flag);
+                        } else if (test_and_clear_bit(IPATH_PORT_WAITING_URG,
+                                                      &pd->port_flag)) {
+                                pd->port_urgent++;
                                 wake_up_interruptible(&pd->port_wait);
                         }
                 }