On Sun, Mar 27, 2022 at 03:36:20PM +0200, Sebastien Marie wrote:
> v_numoutput is a struct member of vnode which is used to keep track the
> number
> of writes in progress.
>
> in several function comments, it is marked as "Manipulates v_numoutput. Must
> be
> called at splbio()".
>
> So I added a "[B]" mark in the comment to properly document the need of
> IPL_BIO
> protection.
>
> Next, I audited the tree for usage. I found 2 occurrences of v_numoutput
> (modification) without the required protection, inside dev/softraid.c. I
> added
> them.
>
> Comments or OK ?
Please move the declarations of `s' next to the other variable
declarations at the starts of the functions. With that, OK visa@
> Index: dev/softraid.c
> ===================================================================
> RCS file: /cvs/src/sys/dev/softraid.c,v
> retrieving revision 1.422
> diff -u -p -r1.422 softraid.c
> --- dev/softraid.c 20 Mar 2022 13:14:02 -0000 1.422
> +++ dev/softraid.c 27 Mar 2022 13:28:55 -0000
> @@ -437,8 +437,12 @@ sr_rw(struct sr_softc *sc, dev_t dev, ch
> b.b_resid = bufsize;
> b.b_vp = vp;
>
> - if ((b.b_flags & B_READ) == 0)
> + if ((b.b_flags & B_READ) == 0) {
> + int s;
> + s = splbio();
> vp->v_numoutput++;
> + splx(s);
> + }
>
> LIST_INIT(&b.b_dep);
> VOP_STRATEGY(vp, &b);
> @@ -2006,8 +2010,12 @@ sr_ccb_rw(struct sr_discipline *sd, int
> 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)) {
> + int s;
> + s = splbio();
> ccb->ccb_buf.b_vp->v_numoutput++;
> + splx(s);
> + }
>
> LIST_INIT(&ccb->ccb_buf.b_dep);
>
> Index: sys/vnode.h
> ===================================================================
> RCS file: /cvs/src/sys/sys/vnode.h,v
> retrieving revision 1.163
> diff -u -p -r1.163 vnode.h
> --- sys/vnode.h 12 Dec 2021 09:14:59 -0000 1.163
> +++ sys/vnode.h 27 Mar 2022 13:28:56 -0000
> @@ -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) */
>
