[src/trunk]: src/sys/dev Make md(4) mp-safe.

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

details:   https://anonhg.NetBSD.org/src/rev/bbdc8cc4aa54
branches:  trunk
changeset: 758992:bbdc8cc4aa54
user:      hannken <hannken%NetBSD.org@localhost>
date:      Tue Nov 23 09:30:43 2010 +0000

description:
Make md(4) mp-safe.

diffstat:

 sys/dev/md.c |  61 ++++++++++++++++++++++++++++++++++++++++++++++-------------
 1 files changed, 47 insertions(+), 14 deletions(-)

diffs (230 lines):

diff -r 3636f6849487 -r bbdc8cc4aa54 sys/dev/md.c
--- a/sys/dev/md.c      Tue Nov 23 08:44:23 2010 +0000
+++ b/sys/dev/md.c      Tue Nov 23 09:30:43 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: md.c,v 1.64 2010/11/22 21:10:10 pooka Exp $    */
+/*     $NetBSD: md.c,v 1.65 2010/11/23 09:30:43 hannken Exp $  */
 
 /*
  * Copyright (c) 1995 Gordon W. Ross, Leo Weppelman.
@@ -40,7 +40,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.64 2010/11/22 21:10:10 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.65 2010/11/23 09:30:43 hannken Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_md.h"
@@ -84,6 +84,8 @@
        device_t sc_dev;        /* Self. */
        struct disk sc_dkdev;   /* hook for generic disk handling */
        struct md_conf sc_md;
+       kmutex_t sc_lock;       /* Protect self. */
+       kcondvar_t sc_cv;       /* Signal work. */
        struct bufq_state *sc_buflist;
 };
 /* shorthand for fields in sc_md: */
@@ -105,7 +107,7 @@
 static dev_type_size(mdsize);
 
 const struct bdevsw md_bdevsw = {
-       mdopen, mdclose, mdstrategy, mdioctl, nodump, mdsize, D_DISK
+       mdopen, mdclose, mdstrategy, mdioctl, nodump, mdsize, D_DISK | D_MPSAFE
 };
 
 const struct cdevsw md_cdevsw = {
@@ -144,6 +146,8 @@
        struct md_softc *sc = device_private(self);
 
        sc->sc_dev = self;
+       mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
+       cv_init(&sc->sc_cv, "mdidle");
        bufq_alloc(&sc->sc_buflist, "fcfs", 0);
 
        /* XXX - Could accept aux info here to set the config. */
@@ -190,6 +194,8 @@
        disk_detach(&sc->sc_dkdev);
        disk_destroy(&sc->sc_dkdev);
        bufq_free(sc->sc_buflist);
+       mutex_destroy(&sc->sc_lock);
+       cv_destroy(&sc->sc_cv);
        return 0;
 }
 
@@ -211,15 +217,20 @@
 mdsize(dev_t dev)
 {
        struct md_softc *sc;
+       int res;
 
        sc = device_lookup_private(&md_cd, MD_UNIT(dev));
        if (sc == NULL)
                return 0;
 
+       mutex_enter(&sc->sc_lock);
        if (sc->sc_type == MD_UNCONFIGURED)
-               return 0;
+               res = 0;
+       else
+               res = sc->sc_size >> DEV_BSHIFT;
+       mutex_exit(&sc->sc_lock);
 
-       return (sc->sc_size >> DEV_BSHIFT);
+       return res;
 }
 
 static int
@@ -373,6 +384,8 @@
 
        sc = device_lookup_private(&md_cd, MD_UNIT(bp->b_dev));
 
+       mutex_enter(&sc->sc_lock);
+
        if (sc == NULL || sc->sc_type == MD_UNCONFIGURED) {
                bp->b_error = ENXIO;
                goto done;
@@ -383,7 +396,8 @@
        case MD_UMEM_SERVER:
                /* Just add this job to the server's queue. */
                bufq_put(sc->sc_buflist, bp);
-               wakeup((void *)sc);
+               cv_signal(&sc->sc_cv);
+               mutex_exit(&sc->sc_lock);
                /* see md_server_loop() */
                /* no biodone in this case */
                return;
@@ -421,6 +435,8 @@
        }
  done:
        biodone(bp);
+
+       mutex_exit(&sc->sc_lock);
 }
 
 static int
@@ -430,15 +446,18 @@
        struct md_conf *umd;
        struct disklabel *lp;
        struct partinfo *pp;
+       int error;
 
        if ((sc = device_lookup_private(&md_cd, MD_UNIT(dev))) == NULL)
                return ENXIO;
 
+       mutex_enter(&sc->sc_lock);
        if (sc->sc_type != MD_UNCONFIGURED) {
                switch (cmd) {
                case DIOCGDINFO:
                        lp = (struct disklabel *)data;
                        *lp = *sc->sc_dkdev.dk_label;
+                       mutex_exit(&sc->sc_lock);
                        return 0;
 
                case DIOCGPART:
@@ -446,19 +465,24 @@
                        pp->disklab = sc->sc_dkdev.dk_label;
                        pp->part =
                            &sc->sc_dkdev.dk_label->d_partitions[DISKPART(dev)];
+                       mutex_exit(&sc->sc_lock);
                        return 0;
                }
        }
 
        /* If this is not the raw partition, punt! */
-       if (DISKPART(dev) != RAW_PART)
+       if (DISKPART(dev) != RAW_PART) {
+               mutex_exit(&sc->sc_lock);
                return ENOTTY;
+       }
 
        umd = (struct md_conf *)data;
+       error = EINVAL;
        switch (cmd) {
        case MD_GETCONF:
                *umd = sc->sc_md;
-               return 0;
+               error = 0;
+               break;
 
        case MD_SETCONF:
                /* Can only set it once. */
@@ -466,17 +490,20 @@
                        break;
                switch (umd->md_type) {
                case MD_KMEM_ALLOCATED:
-                       return md_ioctl_kalloc(sc, umd, l);
+                       error = md_ioctl_kalloc(sc, umd, l);
+                       break;
 #if MEMORY_DISK_SERVER
                case MD_UMEM_SERVER:
-                       return md_ioctl_server(sc, umd, l);
+                       error = md_ioctl_server(sc, umd, l);
+                       break;
 #endif /* MEMORY_DISK_SERVER */
                default:
                        break;
                }
                break;
        }
-       return EINVAL;
+       mutex_exit(&sc->sc_lock);
+       return error;
 }
 
 static void
@@ -534,6 +561,8 @@
        vaddr_t addr;
        vsize_t size;
 
+       KASSERT(mutex_owned(&sc->sc_lock));
+
        /* Sanity check the size. */
        size = umd->md_size;
        addr = uvm_km_alloc(kernel_map, size, 0, UVM_KMF_WIRED|UVM_KMF_ZERO);
@@ -561,6 +590,8 @@
        vaddr_t end;
        int error;
 
+       KASSERT(mutex_owned(&sc->sc_lock));
+
        /* Sanity check addr, size. */
        end = (vaddr_t) ((char *)umd->md_addr + umd->md_size);
 
@@ -585,8 +616,6 @@
        return (error);
 }
 
-static int md_sleep_pri = PWAIT | PCATCH;
-
 static int
 md_server_loop(struct md_softc *sc)
 {
@@ -597,15 +626,18 @@
        int error;
        bool is_read;
 
+       KASSERT(mutex_owned(&sc->sc_lock));
+
        for (;;) {
                /* Wait for some work to arrive. */
                while ((bp = bufq_get(sc->sc_buflist)) == NULL) {
-                       error = tsleep((void *)sc, md_sleep_pri, "md_idle", 0);
+                       error = cv_wait_sig(&sc->sc_cv, &sc->sc_lock);
                        if (error)
                                return error;
                }
 
                /* Do the transfer to/from user space. */
+               mutex_exit(&sc->sc_lock);
                error = 0;
                is_read = ((bp->b_flags & B_READ) == B_READ);
                bp->b_resid = bp->b_bcount;
@@ -634,6 +666,7 @@
                        bp->b_error = error;
                }
                biodone(bp);
+               mutex_enter(&sc->sc_lock);
        }
 }
 #endif /* MEMORY_DISK_SERVER */