[ofa-general] [PATCH 15/23] IB/ipath - use counters in ipath_poll and cleanup interrupts in ipath_close
Arthur Jones
arthur.jones at qlogic.com
Tue Oct 9 13:00:32 PDT 2007
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 at qlogic.com>
---
drivers/infiniband/hw/ipath/ipath_file_ops.c | 67 ++++++++++++++++----------
drivers/infiniband/hw/ipath/ipath_intr.c | 33 ++++---------
drivers/infiniband/hw/ipath/ipath_kernel.h | 8 ++-
3 files changed, 57 insertions(+), 51 deletions(-)
diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index 33ab0d6..016e7c4 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -1341,6 +1341,19 @@ bail:
return ret;
}
+static unsigned ipath_poll_hdrqfull(struct ipath_portdata *pd)
+{
+ unsigned pollflag = 0;
+
+ if ((pd->poll_type & IPATH_POLL_TYPE_OVERFLOW) &&
+ pd->port_hdrqfull != pd->port_hdrqfull_poll) {
+ pollflag |= POLLIN | POLLRDNORM;
+ pd->port_hdrqfull_poll = pd->port_hdrqfull;
+ }
+
+ return pollflag;
+}
+
static unsigned int ipath_poll_urgent(struct ipath_portdata *pd,
struct file *fp,
struct poll_table_struct *pt)
@@ -1350,22 +1363,20 @@ static unsigned int ipath_poll_urgent(struct ipath_portdata *pd,
dd = pd->port_dd;
- if (test_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag)) {
- pollflag |= POLLERR;
- clear_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag);
- }
+ /* variable access in ipath_poll_hdrqfull() needs this */
+ rmb();
+ pollflag = ipath_poll_hdrqfull(pd);
- if (test_bit(IPATH_PORT_WAITING_URG, &pd->int_flag)) {
+ if (pd->port_urgent != pd->port_urgent_poll) {
pollflag |= POLLIN | POLLRDNORM;
- clear_bit(IPATH_PORT_WAITING_URG, &pd->int_flag);
+ pd->port_urgent_poll = pd->port_urgent;
}
if (!pollflag) {
+ /* this saves a spin_lock/unlock in interrupt handler... */
set_bit(IPATH_PORT_WAITING_URG, &pd->port_flag);
- if (pd->poll_type & IPATH_POLL_TYPE_OVERFLOW)
- set_bit(IPATH_PORT_WAITING_OVERFLOW,
- &pd->port_flag);
-
+ /* flush waiting flag so don't miss an event... */
+ wmb();
poll_wait(fp, &pd->port_wait, pt);
}
@@ -1376,31 +1387,27 @@ static unsigned int ipath_poll_next(struct ipath_portdata *pd,
struct file *fp,
struct poll_table_struct *pt)
{
- u32 head, tail;
+ u32 head;
+ u32 tail;
unsigned pollflag = 0;
struct ipath_devdata *dd;
dd = pd->port_dd;
+ /* variable access in ipath_poll_hdrqfull() needs this */
+ rmb();
+ pollflag = ipath_poll_hdrqfull(pd);
+
head = ipath_read_ureg32(dd, ur_rcvhdrhead, pd->port_port);
tail = *(volatile u64 *)pd->port_rcvhdrtail_kvaddr;
- if (test_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag)) {
- pollflag |= POLLERR;
- clear_bit(IPATH_PORT_WAITING_OVERFLOW, &pd->int_flag);
- }
-
- if (tail != head ||
- test_bit(IPATH_PORT_WAITING_RCV, &pd->int_flag)) {
+ if (head != tail)
pollflag |= POLLIN | POLLRDNORM;
- clear_bit(IPATH_PORT_WAITING_RCV, &pd->int_flag);
- }
-
- if (!pollflag) {
+ else {
+ /* this saves a spin_lock/unlock in interrupt handler */
set_bit(IPATH_PORT_WAITING_RCV, &pd->port_flag);
- if (pd->poll_type & IPATH_POLL_TYPE_OVERFLOW)
- set_bit(IPATH_PORT_WAITING_OVERFLOW,
- &pd->port_flag);
+ /* flush waiting flag so we don't miss an event */
+ wmb();
set_bit(pd->port_port + INFINIPATH_R_INTRAVAIL_SHIFT,
&dd->ipath_rcvctrl);
@@ -1917,6 +1924,12 @@ static int ipath_do_user_init(struct file *fp,
ipath_cdbg(VERBOSE, "Wrote port%d egrhead %x from tail regs\n",
pd->port_port, head32);
pd->port_tidcursor = 0; /* start at beginning after open */
+
+ /* initialize poll variables... */
+ pd->port_urgent = 0;
+ pd->port_urgent_poll = 0;
+ pd->port_hdrqfull_poll = pd->port_hdrqfull;
+
/*
* now enable the port; the tail registers will be written to memory
* by the chip as soon as it sees the write to
@@ -2039,9 +2052,11 @@ static int ipath_close(struct inode *in, struct file *fp)
if (dd->ipath_kregbase) {
int i;
- /* atomically clear receive enable port. */
+ /* atomically clear receive enable port and intr avail. */
clear_bit(INFINIPATH_R_PORTENABLE_SHIFT + port,
&dd->ipath_rcvctrl);
+ clear_bit(pd->port_port + INFINIPATH_R_INTRAVAIL_SHIFT,
+ &dd->ipath_rcvctrl);
ipath_write_kreg( dd, dd->ipath_kregs->kr_rcvctrl,
dd->ipath_rcvctrl);
/* and read back from chip to be sure that nothing
diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c b/drivers/infiniband/hw/ipath/ipath_intr.c
index 11b3614..61eac8c 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);
}
}
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h b/drivers/infiniband/hw/ipath/ipath_kernel.h
index d983f92..872fb36 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -139,6 +139,12 @@ struct ipath_portdata {
u32 port_pionowait;
/* total number of rcvhdrqfull errors */
u32 port_hdrqfull;
+ /* saved total number of rcvhdrqfull errors for poll edge trigger */
+ u32 port_hdrqfull_poll;
+ /* total number of polled urgent packets */
+ u32 port_urgent;
+ /* saved total number of polled urgent packets for poll edge trigger */
+ u32 port_urgent_poll;
/* pid of process using this port */
pid_t port_pid;
/* same size as task_struct .comm[] */
@@ -757,8 +763,6 @@ int ipath_set_rx_pol_inv(struct ipath_devdata *dd, u8 new_pol_inv);
#define IPATH_PORT_MASTER_UNINIT 4
/* waiting for an urgent packet to arrive */
#define IPATH_PORT_WAITING_URG 5
- /* waiting for a header overflow */
-#define IPATH_PORT_WAITING_OVERFLOW 6
/* free up any allocated data at closes */
void ipath_free_data(struct ipath_portdata *dd);
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