Move a locking function that was spread throughout disk device drivers into

the disk structure.

The locking was mostly used in disk device drivers to prevent multiple
disklabel operations from going on simultaneously against the device.

Added disk_construct(), a constructor for the disk structure, that
initializes the lock structure in disk. It is called by default in
disk_attach() if it hasn't been called yet.

Added disk_lock and disk_unlock

1 files changed, 39 insertions, 1 deletions

diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c
index 5d8f8fda806..a166a72c4a1 100644
--- a/sys/kern/subr_disk.c
+++ b/sys/kern/subr_disk.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: subr_disk.c,v 1.17 1999/11/17 04:31:22 d Exp $	*/
+/*	$OpenBSD: subr_disk.c,v 1.18 2000/04/09 19:26:35 csapuntz Exp $	*/
 /*	$NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $	*/
 
 /*
@@ -53,9 +53,11 @@
 #include <sys/time.h>
 #include <sys/disklabel.h>
 #include <sys/conf.h>
+#include <sys/lock.h>
 #include <sys/disk.h>
 #include <sys/dkio.h>
 #include <sys/dkstat.h>		/* XXX */
+#include <sys/proc.h>
 
 #include <dev/rndvar.h>
 
@@ -266,6 +268,19 @@ disk_find(name)
 	return (NULL);
 }
 
+int
+disk_construct(diskp, lockname)
+	struct disk *diskp;
+	char *lockname;
+{
+	lockinit(&diskp->dk_lock, PRIBIO | PCATCH, lockname,
+		 0, LK_CANRECURSE);
+	
+	diskp->dk_flags |= DKF_CONSTRUCTED;
+	    
+	return (0);
+}
+
 /*
  * Attach a disk.
  */
@@ -275,6 +290,9 @@ disk_attach(diskp)
 {
 	int s;
 
+	if (!diskp->dk_flags & DKF_CONSTRUCTED)
+		disk_construct(diskp, diskp->dk_name);
+
 	/*
 	 * Allocate and initialize the disklabel structures.  Note that
 	 * it's not safe to sleep here, since we're probably going to be
@@ -378,6 +396,26 @@ disk_unbusy(diskp, bcount)
 	add_disk_randomness(bcount ^ diff_time.tv_usec);
 }
 
+
+int
+disk_lock(dk)
+	struct disk *dk;
+{
+	int error;
+
+	error = lockmgr(&dk->dk_lock, LK_EXCLUSIVE, 0, curproc);
+
+	return (error);
+}
+
+void
+disk_unlock(dk)
+	struct disk *dk;
+{
+	lockmgr(&dk->dk_lock, LK_RELEASE, 0, curproc);
+}
+
+
 /*
  * Reset the metrics counters on the given disk.  Note that we cannot
  * reset the busy counter, as it may case a panic in disk_unbusy().