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Commit 70c51da2 authored by Arthur Jones's avatar Arthur Jones Committed by Roland Dreier
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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: default avatarArthur Jones <arthur.jones@qlogic.com>
Signed-off-by: default avatarRoland Dreier <rolandd@cisco.com>
parent 542869a1

drivers/infiniband/hw/ipath/ipath_file_ops.c

+41 −26
Original line number Diff line number Diff line
@@ -1341,6 +1341,19 @@ static int ipath_mmap(struct file *fp, struct vm_area_struct *vma) 
	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

drivers/infiniband/hw/ipath/ipath_intr.c

+10 −23
Original line number Diff line number Diff line
@@ -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,

			if (test_and_clear_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);

				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,

			} else if (test_and_clear_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);

				pd->port_urgent++;

				wake_up_interruptible(&pd->port_wait);

			}

		}

drivers/infiniband/hw/ipath/ipath_kernel.h

+6 −2
Original line number Diff line number Diff line
@@ -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);