[src/trunk]: src/sys/dev - Don't detach configured devices on last close.

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

details:   https://anonhg.NetBSD.org/src/rev/ea738bacf579
branches:  trunk
changeset: 759028:ea738bacf579
user:      hannken <hannken%NetBSD.org@localhost>
date:      Thu Nov 25 08:53:30 2010 +0000

description:
- Don't detach configured devices on last close.
- No kmem allocation and biodone() under lock (from rmind%netbsd.org@localhost).

diffstat:

 sys/dev/md.c |  25 ++++++++++++++++++-------
 1 files changed, 18 insertions(+), 7 deletions(-)

diffs (83 lines):

diff -r 01d316759aef -r ea738bacf579 sys/dev/md.c
--- a/sys/dev/md.c      Thu Nov 25 08:18:33 2010 +0000
+++ b/sys/dev/md.c      Thu Nov 25 08:53:30 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: md.c,v 1.65 2010/11/23 09:30:43 hannken Exp $  */
+/*     $NetBSD: md.c,v 1.66 2010/11/25 08:53:30 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 1.65 2010/11/23 09:30:43 hannken Exp $");
+__KERNEL_RCSID(0, "$NetBSD: md.c,v 1.66 2010/11/25 08:53:30 hannken Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_md.h"
@@ -85,7 +85,7 @@
        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. */
+       kcondvar_t sc_cv;       /* Wait here for work. */
        struct bufq_state *sc_buflist;
 };
 /* shorthand for fields in sc_md: */
@@ -146,6 +146,7 @@
        struct md_softc *sc = device_private(self);
 
        sc->sc_dev = self;
+       sc->sc_type = MD_UNCONFIGURED;
        mutex_init(&sc->sc_lock, MUTEX_DEFAULT, IPL_NONE);
        cv_init(&sc->sc_cv, "mdidle");
        bufq_alloc(&sc->sc_buflist, "fcfs", 0);
@@ -181,7 +182,7 @@
 
        rc = 0;
        mutex_enter(&sc->sc_dkdev.dk_openlock);
-       if (sc->sc_dkdev.dk_openmask == 0)
+       if (sc->sc_dkdev.dk_openmask == 0 && sc->sc_type == MD_UNCONFIGURED)
                ;       /* nothing to do */
        else if ((flags & DETACH_FORCE) == 0)
                rc = EBUSY;
@@ -433,10 +434,11 @@
                bp->b_error = EIO;
                break;
        }
+
  done:
+       mutex_exit(&sc->sc_lock);
+
        biodone(bp);
-
-       mutex_exit(&sc->sc_lock);
 }
 
 static int
@@ -561,14 +563,23 @@
        vaddr_t addr;
        vsize_t size;
 
-       KASSERT(mutex_owned(&sc->sc_lock));
+       mutex_exit(&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);
+
+       mutex_enter(&sc->sc_lock);
+
        if (!addr)
                return ENOMEM;
 
+       /* If another thread beat us to configure this unit:  fail. */
+       if (sc->sc_type != MD_UNCONFIGURED) {
+               uvm_km_free(kernel_map, addr, size, UVM_KMF_WIRED);
+               return EINVAL;
+       }
+
        /* This unit is now configured. */
        sc->sc_addr = (void *)addr;     /* kernel space */
        sc->sc_size = (size_t)size;