[src/trunk]: src/sys/dev/pci Replace the xxx_acquire()/xxx_release() rwlocks ...

[pgoyette <pgoyette%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/d81bbabf1d34
branches:  trunk
changeset: 773728:d81bbabf1d34
user:      pgoyette <pgoyette%NetBSD.org@localhost>
date:      Tue Feb 14 15:08:07 2012 +0000

description:
Replace the xxx_acquire()/xxx_release() rwlocks with mutexes.  There are
only RW_WRITERs for these, and no RW_READERs, so no need to incur the
extra overhead of allowing for both.  As discussed on tech-kern.

For piixpm and ichsmb, the acquire/release protocol needs to be used,
even if the request is I2C_F_POLL'd (or if the device supports only
polled mode).  Otherwise multiple requests can be running at the same
time, and they stomp on each other and create anomolous results.

Part 2 addresses my PR kern/45889

3 ACKs from releng

diffstat:

 sys/dev/pci/amdpm_smbus.c |  12 ++++++------
 sys/dev/pci/amdpmvar.h    |   6 +++---
 sys/dev/pci/ichsmb.c      |  18 +++++++++---------
 sys/dev/pci/nfsmb.c       |  14 +++++++-------
 sys/dev/pci/piixpm.c      |  22 ++++++++++------------
 5 files changed, 35 insertions(+), 37 deletions(-)

diffs (287 lines):

diff -r f203180816d5 -r d81bbabf1d34 sys/dev/pci/amdpm_smbus.c
--- a/sys/dev/pci/amdpm_smbus.c Tue Feb 14 14:33:53 2012 +0000
+++ b/sys/dev/pci/amdpm_smbus.c Tue Feb 14 15:08:07 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: amdpm_smbus.c,v 1.17 2011/11/19 02:39:14 christos Exp $ */
+/*     $NetBSD: amdpm_smbus.c,v 1.18 2012/02/14 15:08:07 pgoyette Exp $ */
 
 /*
  * Copyright (c) 2005 Anil Gopinath (anil_public%yahoo.com@localhost)
@@ -32,14 +32,14 @@
  * AMD-8111 HyperTransport I/O Hub
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: amdpm_smbus.c,v 1.17 2011/11/19 02:39:14 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: amdpm_smbus.c,v 1.18 2012/02/14 15:08:07 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/kernel.h>
 #include <sys/device.h>
 #include <sys/rnd.h>
-#include <sys/rwlock.h>
+#include <sys/mutex.h>
 
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcivar.h>
@@ -83,7 +83,7 @@
        sc->sc_i2c.ic_write_byte = NULL;
        sc->sc_i2c.ic_exec = amdpm_smbus_exec;
 
-       rw_init(&sc->sc_rwlock);
+       mutex_init(&sc->sc_mutex, MUTEX_DEFAULT, IPL_NONE);
 
        iba.iba_tag = &sc->sc_i2c;
        (void)config_found_ia(&sc->sc_dev, "i2cbus", &iba, iicbus_print);
@@ -94,7 +94,7 @@
 {
        struct amdpm_softc *sc = cookie;
 
-       rw_enter(&sc->sc_rwlock, RW_WRITER);
+       mutex_enter(&sc->sc_mutex);
        return 0;
 }
 
@@ -103,7 +103,7 @@
 {
        struct amdpm_softc *sc = cookie;
 
-       rw_exit(&sc->sc_rwlock);
+       mutex_exit(&sc->sc_mutex);
 }
 
 static int
diff -r f203180816d5 -r d81bbabf1d34 sys/dev/pci/amdpmvar.h
--- a/sys/dev/pci/amdpmvar.h    Tue Feb 14 14:33:53 2012 +0000
+++ b/sys/dev/pci/amdpmvar.h    Tue Feb 14 15:08:07 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: amdpmvar.h,v 1.7 2011/11/19 22:51:23 tls Exp $ */
+/*     $NetBSD: amdpmvar.h,v 1.8 2012/02/14 15:08:07 pgoyette Exp $    */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -32,7 +32,7 @@
 #ifndef _DEV_PCI_AMDPMVAR_H_
 #define _DEV_PCI_AMDPMVAR_H_
 
-#include <sys/rwlock.h>
+#include <sys/mutex.h>
 
 struct amdpm_softc {
        struct device sc_dev;
@@ -47,7 +47,7 @@
 
        i2c_addr_t sc_smbus_slaveaddr;          /* address of smbus slave */
        struct i2c_controller sc_i2c;           /* i2c controller info */
-       krwlock_t sc_rwlock;
+       kmutex_t sc_mutex;
 
        void *sc_ih;
 
diff -r f203180816d5 -r d81bbabf1d34 sys/dev/pci/ichsmb.c
--- a/sys/dev/pci/ichsmb.c      Tue Feb 14 14:33:53 2012 +0000
+++ b/sys/dev/pci/ichsmb.c      Tue Feb 14 15:08:07 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: ichsmb.c,v 1.26 2012/01/30 19:41:19 drochner Exp $     */
+/*     $NetBSD: ichsmb.c,v 1.27 2012/02/14 15:08:07 pgoyette Exp $     */
 /*     $OpenBSD: ichiic.c,v 1.18 2007/05/03 09:36:26 dlg Exp $ */
 
 /*
@@ -22,13 +22,13 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ichsmb.c,v 1.26 2012/01/30 19:41:19 drochner Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ichsmb.c,v 1.27 2012/02/14 15:08:07 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
 #include <sys/errno.h>
 #include <sys/kernel.h>
-#include <sys/rwlock.h>
+#include <sys/mutex.h>
 #include <sys/proc.h>
 
 #include <sys/bus.h>
@@ -59,7 +59,7 @@
        int                     sc_poll;
 
        struct i2c_controller   sc_i2c_tag;
-       krwlock_t               sc_i2c_rwlock;
+       kmutex_t                sc_i2c_mutex;
        struct {
                i2c_op_t     op;
                void *       buf;
@@ -166,7 +166,7 @@
        }
 
        /* Attach I2C bus */
-       rw_init(&sc->sc_i2c_rwlock);
+       mutex_init(&sc->sc_i2c_mutex, MUTEX_DEFAULT, IPL_NONE);
        sc->sc_i2c_tag.ic_cookie = sc;
        sc->sc_i2c_tag.ic_acquire_bus = ichsmb_i2c_acquire_bus;
        sc->sc_i2c_tag.ic_release_bus = ichsmb_i2c_release_bus;
@@ -186,10 +186,10 @@
 {
        struct ichsmb_softc *sc = cookie;
 
-       if (cold || sc->sc_poll || (flags & I2C_F_POLL))
+       if (cold)
                return 0;
 
-       rw_enter(&sc->sc_i2c_rwlock, RW_WRITER);
+       mutex_enter(&sc->sc_i2c_mutex);
        return 0;
 }
 
@@ -198,10 +198,10 @@
 {
        struct ichsmb_softc *sc = cookie;
 
-       if (cold || sc->sc_poll || (flags & I2C_F_POLL))
+       if (cold)
                return;
 
-       rw_exit(&sc->sc_i2c_rwlock);
+       mutex_exit(&sc->sc_i2c_mutex);
 }
 
 static int
diff -r f203180816d5 -r d81bbabf1d34 sys/dev/pci/nfsmb.c
--- a/sys/dev/pci/nfsmb.c       Tue Feb 14 14:33:53 2012 +0000
+++ b/sys/dev/pci/nfsmb.c       Tue Feb 14 15:08:07 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: nfsmb.c,v 1.22 2012/01/30 19:41:22 drochner Exp $      */
+/*     $NetBSD: nfsmb.c,v 1.23 2012/02/14 15:08:07 pgoyette Exp $      */
 /*
  * Copyright (c) 2007 KIYOHARA Takashi
  * All rights reserved.
@@ -26,13 +26,13 @@
  *
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: nfsmb.c,v 1.22 2012/01/30 19:41:22 drochner Exp $");
+__KERNEL_RCSID(0, "$NetBSD: nfsmb.c,v 1.23 2012/02/14 15:08:07 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
 #include <sys/errno.h>
 #include <sys/kernel.h>
-#include <sys/rwlock.h>
+#include <sys/mutex.h>
 #include <sys/proc.h>
 
 #include <sys/bus.h>
@@ -73,7 +73,7 @@
        bus_space_handle_t sc_ioh;
 
        struct i2c_controller sc_i2c;   /* i2c controller info */
-       krwlock_t sc_rwlock;
+       kmutex_t sc_mutex;
 };
 
 
@@ -237,7 +237,7 @@
        sc->sc_i2c.ic_write_byte = NULL;
        sc->sc_i2c.ic_exec = nfsmb_exec;
 
-       rw_init(&sc->sc_rwlock);
+       mutex_init(&sc->sc_mutex, MUTEX_DEFAULT, IPL_NONE);
 
        if (bus_space_map(sc->sc_iot, nfsmbcap->nfsmb_addr, NFORCE_SMBSIZE, 0,
            &sc->sc_ioh) != 0) {
@@ -261,7 +261,7 @@
 {
        struct nfsmb_softc *sc = cookie;
 
-       rw_enter(&sc->sc_rwlock, RW_WRITER);
+       mutex_enter(&sc->sc_mutex);
        return 0;
 }
 
@@ -270,7 +270,7 @@
 {
        struct nfsmb_softc *sc = cookie;
 
-       rw_exit(&sc->sc_rwlock);
+       mutex_exit(&sc->sc_mutex);
 }
 
 static int
diff -r f203180816d5 -r d81bbabf1d34 sys/dev/pci/piixpm.c
--- a/sys/dev/pci/piixpm.c      Tue Feb 14 14:33:53 2012 +0000
+++ b/sys/dev/pci/piixpm.c      Tue Feb 14 15:08:07 2012 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: piixpm.c,v 1.39 2012/01/30 19:41:22 drochner Exp $ */
+/* $NetBSD: piixpm.c,v 1.40 2012/02/14 15:08:07 pgoyette Exp $ */
 /*     $OpenBSD: piixpm.c,v 1.20 2006/02/27 08:25:02 grange Exp $      */
 
 /*
@@ -22,13 +22,13 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: piixpm.c,v 1.39 2012/01/30 19:41:22 drochner Exp $");
+__KERNEL_RCSID(0, "$NetBSD: piixpm.c,v 1.40 2012/02/14 15:08:07 pgoyette Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/device.h>
 #include <sys/kernel.h>
-#include <sys/rwlock.h>
+#include <sys/mutex.h>
 #include <sys/proc.h>
 
 #include <sys/bus.h>
@@ -82,7 +82,7 @@
        pcireg_t                sc_id;
 
        struct i2c_controller   sc_i2c_tag;
-       krwlock_t               sc_i2c_rwlock;
+       kmutex_t                sc_i2c_mutex;
        struct {
                i2c_op_t     op;
                void *      buf;
@@ -251,7 +251,7 @@
 
 attach_i2c:
        /* Attach I2C bus */
-       rw_init(&sc->sc_i2c_rwlock);
+       mutex_init(&sc->sc_i2c_mutex, MUTEX_DEFAULT, IPL_NONE);
        sc->sc_i2c_tag.ic_cookie = sc;
        sc->sc_i2c_tag.ic_acquire_bus = piixpm_i2c_acquire_bus;
        sc->sc_i2c_tag.ic_release_bus = piixpm_i2c_release_bus;
@@ -331,6 +331,7 @@
                aprint_error_dev(sc->sc_dev, "can't map smbus I/O space\n");
                return EBUSY;
        }
+       aprint_normal_dev(sc->sc_dev, "polling (SB800)\n");
        sc->sc_poll = 1;
 
        return 0;
@@ -362,10 +363,9 @@
 {
        struct piixpm_softc *sc = cookie;
 
-       if (cold || sc->sc_poll || (flags & I2C_F_POLL))
-               return (0);
+       if (!cold)
+               mutex_enter(&sc->sc_i2c_mutex);
 
-       rw_enter(&sc->sc_i2c_rwlock, RW_WRITER);
        return 0;
 }
 
@@ -374,10 +374,8 @@
 {
        struct piixpm_softc *sc = cookie;
 
-       if (cold || sc->sc_poll || (flags & I2C_F_POLL))
-               return;
-
-       rw_exit(&sc->sc_i2c_rwlock);
+       if (!cold)
+               mutex_exit(&sc->sc_i2c_mutex);
 }
 
 static int