Gitweb:     
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=e342c119172f87f2d812bccfd0283f62e1bc1c2a
Commit:     e342c119172f87f2d812bccfd0283f62e1bc1c2a
Parent:     9ab4295d1d9ab10a249aea002060685f935a528c
Author:     John Gregor <[EMAIL PROTECTED]>
AuthorDate: Wed Sep 5 01:57:14 2007 -0700
Committer:  Roland Dreier <[EMAIL PROTECTED]>
CommitDate: Fri Jan 25 14:15:27 2008 -0800

    IB/ipath: Fix sendctrl locking
    
    Code review pointed out that the locking around uses of ipath_sendctrl
    and kr_sendctrl were, in several places, incorrect and/or inconsistent.
    
    Signed-off-by: John Gregor <[EMAIL PROTECTED]>
    Signed-off-by: Roland Dreier <[EMAIL PROTECTED]>
---
 drivers/infiniband/hw/ipath/ipath_driver.c    |   40 ++++++++++++++++---------
 drivers/infiniband/hw/ipath/ipath_file_ops.c  |   10 ++++--
 drivers/infiniband/hw/ipath/ipath_init_chip.c |   24 ++++++++++-----
 drivers/infiniband/hw/ipath/ipath_intr.c      |   19 ++++++++++--
 drivers/infiniband/hw/ipath/ipath_kernel.h    |    1 +
 drivers/infiniband/hw/ipath/ipath_ruc.c       |    7 ++++-
 6 files changed, 72 insertions(+), 29 deletions(-)

diff --git a/drivers/infiniband/hw/ipath/ipath_driver.c 
b/drivers/infiniband/hw/ipath/ipath_driver.c
index fc35598..6a48442 100644
--- a/drivers/infiniband/hw/ipath/ipath_driver.c
+++ b/drivers/infiniband/hw/ipath/ipath_driver.c
@@ -803,31 +803,37 @@ void ipath_disarm_piobufs(struct ipath_devdata *dd, 
unsigned first,
                          unsigned cnt)
 {
        unsigned i, last = first + cnt;
-       u64 sendctrl, sendorig;
+       unsigned long flags;
 
        ipath_cdbg(PKT, "disarm %u PIObufs first=%u\n", cnt, first);
-       sendorig = dd->ipath_sendctrl;
        for (i = first; i < last; i++) {
-               sendctrl = sendorig  | INFINIPATH_S_DISARM |
-                       (i << INFINIPATH_S_DISARMPIOBUF_SHIFT);
+               spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+               /*
+                * The disarm-related bits are write-only, so it
+                * is ok to OR them in with our copy of sendctrl
+                * while we hold the lock.
+                */
                ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-                                sendctrl);
+                       dd->ipath_sendctrl | INFINIPATH_S_DISARM |
+                       (i << INFINIPATH_S_DISARMPIOBUF_SHIFT));
+               /* can't disarm bufs back-to-back per iba7220 spec */
+               ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+               spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
        }
 
        /*
-        * Write it again with current value, in case ipath_sendctrl changed
-        * while we were looping; no critical bits that would require
-        * locking.
-        *
-        * disable PIOAVAILUPD, then re-enable, reading scratch in
+        * Disable PIOAVAILUPD, then re-enable, reading scratch in
         * between.  This seems to avoid a chip timing race that causes
-        * pioavail updates to memory to stop.
+        * pioavail updates to memory to stop.  We xor as we don't
+        * know the state of the bit when we're called.
         */
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-                        sendorig & ~INFINIPATH_S_PIOBUFAVAILUPD);
-       sendorig = ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+               dd->ipath_sendctrl ^ INFINIPATH_S_PIOBUFAVAILUPD);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                         dd->ipath_sendctrl);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 }
 
 /**
@@ -2056,6 +2062,8 @@ void ipath_set_led_override(struct ipath_devdata *dd, 
unsigned int val)
  */
 void ipath_shutdown_device(struct ipath_devdata *dd)
 {
+       unsigned long flags;
+
        ipath_dbg("Shutting down the device\n");
 
        dd->ipath_flags |= IPATH_LINKUNK;
@@ -2076,9 +2084,13 @@ void ipath_shutdown_device(struct ipath_devdata *dd)
         * gracefully stop all sends allowing any in progress to trickle out
         * first.
         */
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, 0ULL);
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+       dd->ipath_sendctrl = 0;
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
        /* flush it */
        ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
+
        /*
         * enough for anything that's going to trickle out to have actually
         * done so.
diff --git a/drivers/infiniband/hw/ipath/ipath_file_ops.c 
b/drivers/infiniband/hw/ipath/ipath_file_ops.c
index 5de3243..92dae6f 100644
--- a/drivers/infiniband/hw/ipath/ipath_file_ops.c
+++ b/drivers/infiniband/hw/ipath/ipath_file_ops.c
@@ -2149,11 +2149,15 @@ static int ipath_get_slave_info(struct ipath_portdata 
*pd,
 
 static int ipath_force_pio_avail_update(struct ipath_devdata *dd)
 {
-       u64 reg = dd->ipath_sendctrl;
+       unsigned long flags;
 
-       clear_bit(IPATH_S_PIOBUFAVAILUPD, &reg);
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, reg);
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
+               dd->ipath_sendctrl & ~INFINIPATH_S_PIOBUFAVAILUPD);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 
        return 0;
 }
diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c 
b/drivers/infiniband/hw/ipath/ipath_init_chip.c
index 9e9d6fa..1c65ab9 100644
--- a/drivers/infiniband/hw/ipath/ipath_init_chip.c
+++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c
@@ -345,7 +345,7 @@ static int init_chip_first(struct ipath_devdata *dd,
                       dd->ipath_piobcnt2k, dd->ipath_pio2kbase);
 
        spin_lock_init(&dd->ipath_tid_lock);
-
+       spin_lock_init(&dd->ipath_sendctrl_lock);
        spin_lock_init(&dd->ipath_gpio_lock);
        spin_lock_init(&dd->ipath_eep_st_lock);
        mutex_init(&dd->ipath_eep_lock);
@@ -372,9 +372,9 @@ static int init_chip_reset(struct ipath_devdata *dd,
        *pdp = dd->ipath_pd[0];
        /* ensure chip does no sends or receives while we re-initialize */
        dd->ipath_control = dd->ipath_sendctrl = dd->ipath_rcvctrl = 0U;
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl, 0);
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, 0);
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_control, 0);
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl, dd->ipath_rcvctrl);
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_control, dd->ipath_control);
 
        rtmp = ipath_read_kreg32(dd, dd->ipath_kregs->kr_portcnt);
        if (dd->ipath_portcnt != rtmp)
@@ -487,6 +487,7 @@ static void enable_chip(struct ipath_devdata *dd,
                        struct ipath_portdata *pd, int reinit)
 {
        u32 val;
+       unsigned long flags;
        int i;
 
        if (!reinit)
@@ -495,11 +496,13 @@ static void enable_chip(struct ipath_devdata *dd,
        ipath_write_kreg(dd, dd->ipath_kregs->kr_rcvctrl,
                         dd->ipath_rcvctrl);
 
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
        /* Enable PIO send, and update of PIOavail regs to memory. */
        dd->ipath_sendctrl = INFINIPATH_S_PIOENABLE |
                INFINIPATH_S_PIOBUFAVAILUPD;
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-                        dd->ipath_sendctrl);
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 
        /*
         * enable port 0 receive, and receive interrupt.  other ports
@@ -696,6 +699,7 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
        u64 val;
        struct ipath_portdata *pd = NULL; /* keep gcc4 happy */
        gfp_t gfp_flags = GFP_USER | __GFP_COMP;
+       unsigned long flags;
 
        ret = init_housekeeping(dd, &pd, reinit);
        if (ret)
@@ -827,8 +831,12 @@ int ipath_init_chip(struct ipath_devdata *dd, int reinit)
        ipath_write_kreg(dd, dd->ipath_kregs->kr_hwerrclear,
                         ~0ULL&~INFINIPATH_HWE_MEMBISTFAILED);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_control, 0ULL);
-       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-                        INFINIPATH_S_PIOENABLE);
+
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+       dd->ipath_sendctrl = INFINIPATH_S_PIOENABLE;
+       ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl, dd->ipath_sendctrl);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 
        /*
         * before error clears, since we expect serdes pll errors during
diff --git a/drivers/infiniband/hw/ipath/ipath_intr.c 
b/drivers/infiniband/hw/ipath/ipath_intr.c
index ad41ccc..eac2e9c 100644
--- a/drivers/infiniband/hw/ipath/ipath_intr.c
+++ b/drivers/infiniband/hw/ipath/ipath_intr.c
@@ -795,6 +795,7 @@ void ipath_clear_freeze(struct ipath_devdata *dd)
 {
        int i, im;
        __le64 val;
+       unsigned long flags;
 
        /* disable error interrupts, to avoid confusion */
        ipath_write_kreg(dd, dd->ipath_kregs->kr_errormask, 0ULL);
@@ -813,11 +814,14 @@ void ipath_clear_freeze(struct ipath_devdata *dd)
                         dd->ipath_control);
 
        /* ensure pio avail updates continue */
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                 dd->ipath_sendctrl & ~INFINIPATH_S_PIOBUFAVAILUPD);
        ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
-                dd->ipath_sendctrl);
+                        dd->ipath_sendctrl);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 
        /*
         * We just enabled pioavailupdate, so dma copy is almost certainly
@@ -922,6 +926,7 @@ static noinline void ipath_bad_regread(struct ipath_devdata 
*dd)
 
 static void handle_layer_pioavail(struct ipath_devdata *dd)
 {
+       unsigned long flags;
        int ret;
 
        ret = ipath_ib_piobufavail(dd->verbs_dev);
@@ -930,9 +935,12 @@ static void handle_layer_pioavail(struct ipath_devdata *dd)
 
        return;
 set:
-       set_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+       dd->ipath_sendctrl |= INFINIPATH_S_PIOINTBUFAVAIL;
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                         dd->ipath_sendctrl);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 }
 
 /*
@@ -1168,9 +1176,14 @@ irqreturn_t ipath_intr(int irq, void *data)
                handle_urcv(dd, istat);
 
        if (istat & INFINIPATH_I_SPIOBUFAVAIL) {
-               clear_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
+               unsigned long flags;
+
+               spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+               dd->ipath_sendctrl &= ~INFINIPATH_S_PIOINTBUFAVAIL;
                ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                                 dd->ipath_sendctrl);
+               ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+               spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 
                handle_layer_pioavail(dd);
        }
diff --git a/drivers/infiniband/hw/ipath/ipath_kernel.h 
b/drivers/infiniband/hw/ipath/ipath_kernel.h
index 65f7c7f..81759c2 100644
--- a/drivers/infiniband/hw/ipath/ipath_kernel.h
+++ b/drivers/infiniband/hw/ipath/ipath_kernel.h
@@ -376,6 +376,7 @@ struct ipath_devdata {
        dma_addr_t *ipath_physshadow;
        /* lock to workaround chip bug 9437 */
        spinlock_t ipath_tid_lock;
+       spinlock_t ipath_sendctrl_lock;
 
        /*
         * IPATH_STATUS_*,
diff --git a/drivers/infiniband/hw/ipath/ipath_ruc.c 
b/drivers/infiniband/hw/ipath/ipath_ruc.c
index 54c61a9..1b4f7e1 100644
--- a/drivers/infiniband/hw/ipath/ipath_ruc.c
+++ b/drivers/infiniband/hw/ipath/ipath_ruc.c
@@ -479,9 +479,14 @@ done:
 
 static void want_buffer(struct ipath_devdata *dd)
 {
-       set_bit(IPATH_S_PIOINTBUFAVAIL, &dd->ipath_sendctrl);
+       unsigned long flags;
+
+       spin_lock_irqsave(&dd->ipath_sendctrl_lock, flags);
+       dd->ipath_sendctrl |= INFINIPATH_S_PIOINTBUFAVAIL;
        ipath_write_kreg(dd, dd->ipath_kregs->kr_sendctrl,
                         dd->ipath_sendctrl);
+       ipath_read_kreg64(dd, dd->ipath_kregs->kr_scratch);
+       spin_unlock_irqrestore(&dd->ipath_sendctrl_lock, flags);
 }
 
 /**
-
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