From 70c51da2c4f84317bb13a2b564600afdcebd686f Mon Sep 17 00:00:00 2001 From: Arthur Jones Date: Fri, 14 Sep 2007 12:22:49 -0700 Subject: 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 Signed-off-by: Roland Dreier --- drivers/infiniband/hw/ipath/ipath_file_ops.c | 67 +++++++++++++++++----------- 1 file changed, 41 insertions(+), 26 deletions(-) (limited to 'drivers/infiniband/hw/ipath/ipath_file_ops.c') diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c b/drivers/infiniband/hw/ipath/ipath_file_ops.c index 33ab0d6b80f..016e7c4e366 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 -- cgit v1.2.3