struct vnode: document the protection required for manipulating v_numoutput

correct sr_rw() and sr_ccb_rw() to properly manipulate v_numoutput under splbio.

ok visa@

diff --git a/sys/dev/softraid.c b/sys/dev/softraid.c
index 735a61e..607989f 100644 (file)
--- a/sys/dev/softraid.c
+++ b/sys/dev/softraid.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: softraid.c,v 1.423 2022/04/06 18:59:27 naddy Exp $ */
+/* $OpenBSD: softraid.c,v 1.424 2022/04/12 14:34:11 semarie Exp $ */
 /*
  * Copyright (c) 2007, 2008, 2009 Marco Peereboom <marco@peereboom.us>
  * Copyright (c) 2008 Chris Kuethe <ckuethe@openbsd.org>
@@ -404,6 +404,7 @@ sr_rw(struct sr_softc *sc, dev_t dev, char *buf, size_t size, daddr_t blkno,
        size_t                  bufsize, dma_bufsize;
        int                     rv = 1;
        char                    *dma_buf;
+       int                     s;
 
        DNPRINTF(SR_D_MISC, "%s: sr_rw(0x%x, %p, %zu, %lld 0x%lx)\n",
            DEVNAME(sc), dev, buf, size, (long long)blkno, flags);
@@ -437,8 +438,11 @@ sr_rw(struct sr_softc *sc, dev_t dev, char *buf, size_t size, daddr_t blkno,
                b.b_resid = bufsize;
                b.b_vp = vp;
 
-               if ((b.b_flags & B_READ) == 0)
+               if ((b.b_flags & B_READ) == 0) {
+                       s = splbio();
                        vp->v_numoutput++;
+                       splx(s);
+               }
 
                LIST_INIT(&b.b_dep);
                VOP_STRATEGY(vp, &b);
@@ -1980,6 +1984,7 @@ sr_ccb_rw(struct sr_discipline *sd, int chunk, daddr_t blkno,
 {
        struct sr_chunk         *sc = sd->sd_vol.sv_chunks[chunk];
        struct sr_ccb           *ccb = NULL;
+       int                     s;
 
        ccb = sr_ccb_get(sd);
        if (ccb == NULL)
@@ -2006,8 +2011,11 @@ sr_ccb_rw(struct sr_discipline *sd, int chunk, daddr_t blkno,
        ccb->ccb_buf.b_vp = sc->src_vn;
        ccb->ccb_buf.b_bq = NULL;
 
-       if (!ISSET(ccb->ccb_buf.b_flags, B_READ))
+       if (!ISSET(ccb->ccb_buf.b_flags, B_READ)) {
+               s = splbio();
                ccb->ccb_buf.b_vp->v_numoutput++;
+               splx(s);
+       }
 
        LIST_INIT(&ccb->ccb_buf.b_dep);
 

diff --git a/sys/sys/vnode.h b/sys/sys/vnode.h
index f7dc8d8..0ba69cd 100644 (file)
--- a/sys/sys/vnode.h
+++ b/sys/sys/vnode.h
@@ -1,4 +1,4 @@
-/*     $OpenBSD: vnode.h,v 1.164 2022/03/27 16:19:39 semarie Exp $     */
+/*     $OpenBSD: vnode.h,v 1.165 2022/04/12 14:34:11 semarie Exp $     */
 /*     $NetBSD: vnode.h,v 1.38 1996/02/29 20:59:05 cgd Exp $   */
 
 /*
@@ -89,6 +89,7 @@ RBT_HEAD(namecache_rb_cache, namecache);
  * Locks used to protect struct members in struct vnode:
  *     a       atomic
  *     V       vnode_mtx
+ *     B       IPL_BIO
  */
 struct uvm_vnode;
 struct vnode {
@@ -113,7 +114,7 @@ struct vnode {
        struct  buf_rb_bufs v_bufs_tree;        /* lookup of all bufs */
        struct  buflists v_cleanblkhd;          /* clean blocklist head */
        struct  buflists v_dirtyblkhd;          /* dirty blocklist head */
-       u_int   v_numoutput;                    /* num of writes in progress */
+       u_int   v_numoutput;            /* [B] num of writes in progress */
        LIST_ENTRY(vnode) v_synclist;           /* vnode with dirty buffers */
        union {
                struct mount    *vu_mountedhere;/* ptr to mounted vfs (VDIR) */