Rework disklabel reading taskq to plug holes pointed out by jsing@.

Diff from dlg@.

ok jsing@

diff --git a/sys/kern/subr_disk.c b/sys/kern/subr_disk.c
index 75a4cde..80dbc2e 100644 (file)
--- a/sys/kern/subr_disk.c
+++ b/sys/kern/subr_disk.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: subr_disk.c,v 1.178 2014/12/28 18:32:12 krw Exp $     */
+/*     $OpenBSD: subr_disk.c,v 1.179 2014/12/30 04:00:33 krw Exp $     */
 /*     $NetBSD: subr_disk.c,v 1.17 1996/03/16 23:17:08 christos Exp $  */
 
 /*
@@ -89,13 +89,16 @@ int disk_change;            /* set if a disk has been attached/detached
 u_char bootduid[8];            /* DUID of boot disk. */
 u_char rootduid[8];            /* DUID of root disk. */
 
-struct task disktask;
-
 /* softraid callback, do not use! */
 void (*softraid_disk_attach)(struct disk *, int);
 
 void sr_map_root(void);
 
+struct disk_attach_task {
+       struct task task;
+       struct disk *dk;
+};
+
 void disk_attach_callback(void *, void *);
 
 /*
@@ -1036,7 +1039,6 @@ disk_init(void)
 
        TAILQ_INIT(&disklist);
        disk_count = disk_change = 0;
-       task_set(&disktask, disk_attach_callback, NULL, NULL);
 }
 
 int
@@ -1093,46 +1095,50 @@ disk_attach(struct device *dv, struct disk *diskp)
                if (majdev >= 0)
                        diskp->dk_devno =
                            MAKEDISKDEV(majdev, dv->dv_unit, RAW_PART);
+
+               if (diskp->dk_devno != NODEV) {
+                       struct disk_attach_task *dat;
+
+                       dat = malloc(sizeof(*dat), M_TEMP, M_WAITOK);
+
+                       /* XXX: Assumes dk is part of the device softc. */
+                       device_ref(dv);
+                       dat->dk = diskp;
+
+                       task_set(&dat->task, disk_attach_callback, dat, NULL);
+                       task_add(systq, &dat->task);
+               }
        }
-       if (diskp->dk_devno != NODEV)
-               task_add(systq, &disktask);
 
        if (softraid_disk_attach)
                softraid_disk_attach(diskp, 1);
 }
 
 void
-disk_attach_callback(void *arg1, void *arg2)
+disk_attach_callback(void *xdat, void *null)
 {
+       struct disk_attach_task *dat = xdat;
+       struct disk *dk = dat->dk;
        char errbuf[100];
        struct disklabel dl;
-       struct disk *dk;
        dev_t dev;
 
-       /* Read disklabel(s) for newly-attached disk(s) */
-       TAILQ_FOREACH(dk, &disklist, dk_link) {
-
-               if (dk->dk_devno == NODEV)
-                       continue;
-
-               /* XXX: Assumes dk is part of the device softc. */
-               device_ref(dk->dk_device);
+       free(dat, M_TEMP, sizeof(*dat));
 
-               if (dk->dk_flags & (DKF_OPENED | DKF_NOLABELREAD))
-                       goto done;
+       if (dk->dk_flags & (DKF_OPENED | DKF_NOLABELREAD))
+               goto done;
 
-               /* Read disklabel. */
-               dev = dk->dk_devno;
-               if (disk_readlabel(&dl, dev, errbuf, sizeof(errbuf)) == NULL) {
-                       add_timer_randomness(dl.d_checksum);
-                       dk->dk_flags |= DKF_LABELVALID;
-               }
+       /* Read disklabel. */
+       dev = dk->dk_devno;
+       if (disk_readlabel(&dl, dk->dk_devno, errbuf, sizeof(errbuf)) == NULL) {
+               add_timer_randomness(dl.d_checksum);
+               dk->dk_flags |= DKF_LABELVALID;
+       }
 
 done:
-               dk->dk_flags |= DKF_OPENED;
-               device_unref(dk->dk_device);
-               wakeup(dk);
-       }
+       dk->dk_flags |= DKF_OPENED;
+       device_unref(dk->dk_device);
+       wakeup(dk);
 }
 
 /*