From 0369559168a0dfc9762155240eca21a5e67cf0fa Mon Sep 17 00:00:00 2001 From: phk Date: Sat, 30 Aug 2003 16:10:28 +0000 Subject: [PATCH] Protect the swapdevice tailq with a mutex. Store the udev_t we will report to userland in the swdevt. --- sys/vm/swap_pager.c | 73 +++++++++++++++++++++++++++++++-------------- 1 file changed, 50 insertions(+), 23 deletions(-) diff --git a/sys/vm/swap_pager.c b/sys/vm/swap_pager.c index 844d6544e41..a3aa6a28150 100644 --- a/sys/vm/swap_pager.c +++ b/sys/vm/swap_pager.c @@ -151,6 +151,7 @@ struct swdevt { int sw_flags; int sw_nblks; int sw_used; + udev_t sw_udev; void *sw_id; swblk_t sw_first; swblk_t sw_end; @@ -169,6 +170,7 @@ struct swblock { daddr_t swb_pages[SWAP_META_PAGES]; }; +static struct mtx sw_dev_mtx; static TAILQ_HEAD(, swdevt) swtailq = TAILQ_HEAD_INITIALIZER(swtailq); static struct swdevt *swdevhd; /* Allocate from here next */ static int nswapdev; /* Number of swap devices */ @@ -351,6 +353,7 @@ swap_pager_init(void) TAILQ_INIT(&swap_pager_object_list[i]); TAILQ_INIT(&swap_pager_un_object_list); mtx_init(&sw_alloc_mtx, "swap_pager list", NULL, MTX_DEF); + mtx_init(&sw_dev_mtx, "swapdev", NULL, MTX_DEF); /* * Device Stripe, in PAGE_SIZE'd blocks @@ -573,6 +576,7 @@ swp_pager_getswapspace(int npages) GIANT_REQUIRED; blk = SWAPBLK_NONE; + mtx_lock(&sw_dev_mtx); sp = swdevhd; for (i = 0; i < nswapdev; i++) { if (sp == NULL) @@ -585,13 +589,15 @@ swp_pager_getswapspace(int npages) sp->sw_used += npages; swp_sizecheck(); swdevhd = TAILQ_NEXT(sp, sw_list); + mtx_unlock(&sw_dev_mtx); return(blk); } } sp = TAILQ_NEXT(sp, sw_list); } + mtx_unlock(&sw_dev_mtx); if (swap_pager_full != 2) { - printf("swap_pager_getswapspace: failed\n"); + printf("swap_pager_getswapspace(%d): failed\n", npages); swap_pager_full = 2; swap_pager_almost_full = 1; } @@ -604,15 +610,14 @@ swp_pager_find_dev(daddr_t blk) { struct swdevt *sp; + mtx_lock(&sw_dev_mtx); TAILQ_FOREACH(sp, &swtailq, sw_list) { - if (blk >= sp->sw_first && blk < sp->sw_end) + if (blk >= sp->sw_first && blk < sp->sw_end) { + mtx_unlock(&sw_dev_mtx); return (sp); + } } - printf("Failed to find swapdev blk %ju\n", (uintmax_t)blk); - TAILQ_FOREACH(sp, &swtailq, sw_list) - printf("has %ju...%ju\n", - (uintmax_t)sp->sw_first, (uintmax_t)sp->sw_end); - return (NULL); + panic("Swapdev not found"); } static void @@ -620,13 +625,15 @@ swp_pager_strategy(struct buf *bp) { struct swdevt *sp; + mtx_lock(&sw_dev_mtx); TAILQ_FOREACH(sp, &swtailq, sw_list) { if (bp->b_blkno >= sp->sw_first && bp->b_blkno < sp->sw_end) { + mtx_unlock(&sw_dev_mtx); sp->sw_strategy(bp, sp); return; } } - KASSERT(0 == 1, ("Swapdev not found")); + panic("Swapdev not found"); } @@ -2094,9 +2101,9 @@ swapon(struct thread *td, struct swapon_args *uap) NDFREE(&nd, NDF_ONLY_PNBUF); vp = nd.ni_vp; - if (vn_isdisk(vp, &error)) + if (vn_isdisk(vp, &error)) { error = swapondev(td, vp); - else if (vp->v_type == VREG && + } else if (vp->v_type == VREG && (vp->v_mount->mnt_vfc->vfc_flags & VFCF_NETWORK) != 0 && (error = VOP_GETATTR(vp, &attr, td->td_ucred, td)) == 0) { /* @@ -2117,13 +2124,14 @@ swapon(struct thread *td, struct swapon_args *uap) } static void -swaponsomething(struct vnode *vp, u_long nblks, sw_strategy_t *strategy) +swaponsomething(void *vp, u_long nblks, sw_strategy_t *strategy, udev_t udev) { struct swdevt *sp; swblk_t dvbase; u_long mblocks; dvbase = 0; + mtx_lock(&sw_dev_mtx); TAILQ_FOREACH(sp, &swtailq, sw_list) { if (sp->sw_end >= dvbase) { /* @@ -2134,6 +2142,7 @@ swaponsomething(struct vnode *vp, u_long nblks, sw_strategy_t *strategy) dvbase = sp->sw_end + 1; } } + mtx_unlock(&sw_dev_mtx); /* * If we go beyond this, we get overflows in the radix @@ -2156,6 +2165,7 @@ swaponsomething(struct vnode *vp, u_long nblks, sw_strategy_t *strategy) sp = malloc(sizeof *sp, M_VMPGDATA, M_WAITOK | M_ZERO); sp->sw_id = vp; + sp->sw_udev = udev; sp->sw_flags = 0; sp->sw_nblks = nblks; sp->sw_used = 0; @@ -2170,7 +2180,9 @@ swaponsomething(struct vnode *vp, u_long nblks, sw_strategy_t *strategy) */ blist_free(sp->sw_blist, 2, nblks - 2); + mtx_lock(&sw_dev_mtx); TAILQ_INSERT_TAIL(&swtailq, sp, sw_list); + mtx_unlock(&sw_dev_mtx); nswapdev++; swap_pager_avail += nblks; swap_pager_full = 0; @@ -2185,9 +2197,14 @@ swapondev(struct thread *td, struct vnode *vp) off_t mediasize; u_long nblks; - TAILQ_FOREACH(sp, &swtailq, sw_list) - if (sp->sw_id == vp) + mtx_lock(&sw_dev_mtx); + TAILQ_FOREACH(sp, &swtailq, sw_list) { + if (sp->sw_id == vp) { + mtx_unlock(&sw_dev_mtx); return (EBUSY); + } + } + mtx_unlock(&sw_dev_mtx); (void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); #ifdef MAC @@ -2213,7 +2230,7 @@ swapondev(struct thread *td, struct vnode *vp) * XXX: it should be a power of two, no larger than the page size. */ - swaponsomething(vp, nblks, swapdev_devstrategy); + swaponsomething(vp, nblks, swapdev_devstrategy, dev2udev(vp->v_rdev)); return (0); } @@ -2226,9 +2243,14 @@ swaponvp(struct thread *td, struct vnode *vp, u_long nblks) if (nblks == 0) return (ENXIO); - TAILQ_FOREACH(sp, &swtailq, sw_list) - if (sp->sw_id == vp) + mtx_lock(&sw_dev_mtx); + TAILQ_FOREACH(sp, &swtailq, sw_list) { + if (sp->sw_id == vp) { + mtx_unlock(&sw_dev_mtx); return (EBUSY); + } + } + mtx_unlock(&sw_dev_mtx); (void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); #ifdef MAC @@ -2240,7 +2262,7 @@ swaponvp(struct thread *td, struct vnode *vp, u_long nblks) if (error) return (error); - swaponsomething(vp, nblks, swapdev_strategy); + swaponsomething(vp, nblks, swapdev_strategy, NOUDEV); return (0); } @@ -2285,13 +2307,16 @@ swapoff(struct thread *td, struct swapoff_args *uap) NDFREE(&nd, NDF_ONLY_PNBUF); vp = nd.ni_vp; + mtx_lock(&sw_dev_mtx); TAILQ_FOREACH(sp, &swtailq, sw_list) { if (sp->sw_id == vp) goto found; } + mtx_unlock(&sw_dev_mtx); error = EINVAL; goto done; found: + mtx_unlock(&sw_dev_mtx); #ifdef MAC (void) vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td); error = mac_check_system_swapoff(td->td_ucred, vp); @@ -2334,7 +2359,9 @@ swapoff(struct thread *td, struct swapoff_args *uap) VOP_CLOSE(vp, FREAD | FWRITE, td->td_ucred, td); vrele(vp); sp->sw_id = NULL; + mtx_lock(&sw_dev_mtx); TAILQ_REMOVE(&swtailq, sp, sw_list); + mtx_unlock(&sw_dev_mtx); if (swdevhd == sp) swdevhd = NULL; nswapdev--; @@ -2356,10 +2383,12 @@ swap_pager_status(int *total, int *used) *total = 0; *used = 0; + mtx_lock(&sw_dev_mtx); TAILQ_FOREACH(sp, &swtailq, sw_list) { *total += sp->sw_nblks; *used += sp->sw_used; } + mtx_unlock(&sw_dev_mtx); } static int @@ -2369,20 +2398,17 @@ sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS) int error, n; struct xswdev xs; struct swdevt *sp; - struct vnode *vp; if (arg2 != 1) /* name length */ return (EINVAL); n = 0; + mtx_lock(&sw_dev_mtx); TAILQ_FOREACH(sp, &swtailq, sw_list) { if (n == *name) { + mtx_unlock(&sw_dev_mtx); xs.xsw_version = XSWDEV_VERSION; - vp = sp->sw_id; - if (vp->v_rdev != NULL) - xs.xsw_dev = dev2udev(vp->v_rdev); - else - xs.xsw_dev = NOUDEV; + xs.xsw_dev = sp->sw_udev; xs.xsw_flags = sp->sw_flags; xs.xsw_nblks = sp->sw_nblks; xs.xsw_used = sp->sw_used; @@ -2392,6 +2418,7 @@ sysctl_vm_swap_info(SYSCTL_HANDLER_ARGS) } n++; } + mtx_unlock(&sw_dev_mtx); return (ENOENT); } -- 2.45.2