kernel - Make swap, nullfs MPSAFE

* Mark the swap dummy mount as being MPSAFE so strategy operations do not
  acquire the mplock.

* Mark NULLFS mounts as being MPSAFE so operations do not acquire the
  mplock.  If the underlying VFS is not MPSAFE it will still acquire
  the mplock.

diff --git a/sys/kern/vfs_mount.c b/sys/kern/vfs_mount.c
index 47fb214..b47cc61 100644 (file)
--- a/sys/kern/vfs_mount.c
+++ b/sys/kern/vfs_mount.c
@@ -143,6 +143,7 @@ vfs_mount_init(void)
        TAILQ_INIT(&mntvnodescan_list);
        mount_init(&dummymount);
        dummymount.mnt_flag |= MNT_RDONLY;
+       dummymount.mnt_kern_flag |= MNTK_ALL_MPSAFE;
 }
 
 /*

diff --git a/sys/kern/vfs_vopops.c b/sys/kern/vfs_vopops.c
index 05bb93c..a9944f8 100644 (file)
--- a/sys/kern/vfs_vopops.c
+++ b/sys/kern/vfs_vopops.c
@@ -830,7 +830,6 @@ vop_strategy(struct vop_ops *ops, struct vnode *vp, struct bio *bio)
        ap.a_bio = bio;
 
        if (vp->v_mount) {
-
                VFS_MPLOCK_FLAG(vp->v_mount, MNTK_SG_MPSAFE);
                DO_OPS(ops, error, &ap, vop_strategy);
                VFS_MPUNLOCK(vp->v_mount);

diff --git a/sys/vfs/nullfs/null_vfsops.c b/sys/vfs/nullfs/null_vfsops.c
index 57901df..c4b261c 100644 (file)
--- a/sys/vfs/nullfs/null_vfsops.c
+++ b/sys/vfs/nullfs/null_vfsops.c
@@ -195,9 +195,13 @@ nullfs_mount(struct mount *mp, char *path, caddr_t data, struct ucred *cred)
                mp->mnt_stat.f_mntfromname, mp->mnt_stat.f_mntfromname);
 
        /*
-        * So unmount won't complain about namecache refs still existing
+        * Set NCALIASED so unmount won't complain about namecache refs
+        * still existing.
+        *
+        * All NULLFS operations are MPSAFE, though it will be short-lived
+        * if the underlying filesystem is not.
         */
-       mp->mnt_kern_flag |= MNTK_NCALIASED;
+       mp->mnt_kern_flag |= MNTK_NCALIASED | MNTK_ALL_MPSAFE;
        return (0);
 fail2:
        nlookup_done(&nd);