/* $OpenBSD: uvm_swap.c,v 1.92 2009/06/17 00:13:59 oga Exp $ */ /* $NetBSD: uvm_swap.c,v 1.40 2000/11/17 11:39:39 mrg Exp $ */ /* * Copyright (c) 1995, 1996, 1997 Matthew R. Green * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: NetBSD: vm_swap.c,v 1.52 1997/12/02 13:47:37 pk Exp * from: Id: uvm_swap.c,v 1.1.2.42 1998/02/02 20:38:06 chuck Exp */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef UVM_SWAP_ENCRYPT #include #include #endif #include /* * uvm_swap.c: manage configuration and i/o to swap space. */ /* * swap space is managed in the following way: * * each swap partition or file is described by a "swapdev" structure. * each "swapdev" structure contains a "swapent" structure which contains * information that is passed up to the user (via system calls). * * each swap partition is assigned a "priority" (int) which controls * swap partition usage. * * the system maintains a global data structure describing all swap * partitions/files. there is a sorted LIST of "swappri" structures * which describe "swapdev"'s at that priority. this LIST is headed * by the "swap_priority" global var. each "swappri" contains a * CIRCLEQ of "swapdev" structures at that priority. * * locking: * - swap_syscall_lock (sleep lock): this lock serializes the swapctl * system call and prevents the swap priority list from changing * while we are in the middle of a system call (e.g. SWAP_STATS). * - uvm.swap_data_lock (simple_lock): this lock protects all swap data * structures including the priority list, the swapdev structures, * and the swapmap extent. * * each swap device has the following info: * - swap device in use (could be disabled, preventing future use) * - swap enabled (allows new allocations on swap) * - map info in /dev/drum * - vnode pointer * for swap files only: * - block size * - max byte count in buffer * - buffer * - credentials to use when doing i/o to file * * userland controls and configures swap with the swapctl(2) system call. * the sys_swapctl performs the following operations: * [1] SWAP_NSWAP: returns the number of swap devices currently configured * [2] SWAP_STATS: given a pointer to an array of swapent structures * (passed in via "arg") of a size passed in via "misc" ... we load * the current swap config into the array. * [3] SWAP_ON: given a pathname in arg (could be device or file) and a * priority in "misc", start swapping on it. * [4] SWAP_OFF: as SWAP_ON, but stops swapping to a device * [5] SWAP_CTL: changes the priority of a swap device (new priority in * "misc") */ /* * swapdev: describes a single swap partition/file * * note the following should be true: * swd_inuse <= swd_nblks [number of blocks in use is <= total blocks] * swd_nblks <= swd_mapsize [because mapsize includes miniroot+disklabel] */ struct swapdev { struct swapent swd_se; #define swd_dev swd_se.se_dev /* device id */ #define swd_flags swd_se.se_flags /* flags:inuse/enable/fake */ #define swd_priority swd_se.se_priority /* our priority */ #define swd_inuse swd_se.se_inuse /* our priority */ #define swd_nblks swd_se.se_nblks /* our priority */ char *swd_path; /* saved pathname of device */ int swd_pathlen; /* length of pathname */ int swd_npages; /* #pages we can use */ int swd_npginuse; /* #pages in use */ int swd_npgbad; /* #pages bad */ int swd_drumoffset; /* page0 offset in drum */ int swd_drumsize; /* #pages in drum */ struct extent *swd_ex; /* extent for this swapdev */ char swd_exname[12]; /* name of extent above */ struct vnode *swd_vp; /* backing vnode */ CIRCLEQ_ENTRY(swapdev) swd_next; /* priority circleq */ int swd_bsize; /* blocksize (bytes) */ int swd_maxactive; /* max active i/o reqs */ struct buf swd_tab; /* buffer list */ struct ucred *swd_cred; /* cred for file access */ #ifdef UVM_SWAP_ENCRYPT #define SWD_KEY_SHIFT 7 /* One key per 0.5 MByte */ #define SWD_KEY(x,y) &((x)->swd_keys[((y) - (x)->swd_drumoffset) >> SWD_KEY_SHIFT]) #define SWD_KEY_SIZE(x) (((x) + (1 << SWD_KEY_SHIFT) - 1) >> SWD_KEY_SHIFT) #define SWD_DCRYPT_SHIFT 5 #define SWD_DCRYPT_BITS 32 #define SWD_DCRYPT_MASK (SWD_DCRYPT_BITS - 1) #define SWD_DCRYPT_OFF(x) ((x) >> SWD_DCRYPT_SHIFT) #define SWD_DCRYPT_BIT(x) ((x) & SWD_DCRYPT_MASK) #define SWD_DCRYPT_SIZE(x) (SWD_DCRYPT_OFF((x) + SWD_DCRYPT_MASK) * sizeof(u_int32_t)) u_int32_t *swd_decrypt; /* bitmap for decryption */ struct swap_key *swd_keys; /* keys for different parts */ #endif }; /* * swap device priority entry; the list is kept sorted on `spi_priority'. */ struct swappri { int spi_priority; /* priority */ CIRCLEQ_HEAD(spi_swapdev, swapdev) spi_swapdev; /* circleq of swapdevs at this priority */ LIST_ENTRY(swappri) spi_swappri; /* global list of pri's */ }; /* * The following two structures are used to keep track of data transfers * on swap devices associated with regular files. * NOTE: this code is more or less a copy of vnd.c; we use the same * structure names here to ease porting.. */ struct vndxfer { struct buf *vx_bp; /* Pointer to parent buffer */ struct swapdev *vx_sdp; int vx_error; int vx_pending; /* # of pending aux buffers */ int vx_flags; #define VX_BUSY 1 #define VX_DEAD 2 }; struct vndbuf { struct buf vb_buf; struct vndxfer *vb_xfer; }; /* * We keep a of pool vndbuf's and vndxfer structures. */ struct pool vndxfer_pool; struct pool vndbuf_pool; #define getvndxfer(vnx) do { \ int s = splbio(); \ vnx = pool_get(&vndxfer_pool, PR_WAITOK); \ splx(s); \ } while (0) #define putvndxfer(vnx) { \ pool_put(&vndxfer_pool, (void *)(vnx)); \ } #define getvndbuf(vbp) do { \ int s = splbio(); \ vbp = pool_get(&vndbuf_pool, PR_WAITOK); \ splx(s); \ } while (0) #define putvndbuf(vbp) { \ pool_put(&vndbuf_pool, (void *)(vbp)); \ } /* * local variables */ static struct extent *swapmap; /* controls the mapping of /dev/drum */ /* list of all active swap devices [by priority] */ LIST_HEAD(swap_priority, swappri); static struct swap_priority swap_priority; /* locks */ struct rwlock swap_syscall_lock = RWLOCK_INITIALIZER("swplk"); /* * prototypes */ static void swapdrum_add(struct swapdev *, int); static struct swapdev *swapdrum_getsdp(int); static struct swapdev *swaplist_find(struct vnode *, int); static void swaplist_insert(struct swapdev *, struct swappri *, int); static void swaplist_trim(void); static int swap_on(struct proc *, struct swapdev *); static int swap_off(struct proc *, struct swapdev *); static void sw_reg_strategy(struct swapdev *, struct buf *, int); static void sw_reg_iodone(struct buf *); static void sw_reg_start(struct swapdev *); static int uvm_swap_io(struct vm_page **, int, int, int); static void swapmount(void); #ifdef UVM_SWAP_ENCRYPT /* for swap encrypt */ boolean_t uvm_swap_allocpages(struct vm_page **, int); void uvm_swap_markdecrypt(struct swapdev *, int, int, int); boolean_t uvm_swap_needdecrypt(struct swapdev *, int); void uvm_swap_initcrypt(struct swapdev *, int); #endif /* * uvm_swap_init: init the swap system data structures and locks * * => called at boot time from init_main.c after the filesystems * are brought up (which happens after uvm_init()) */ void uvm_swap_init(void) { UVMHIST_FUNC("uvm_swap_init"); UVMHIST_CALLED(pdhist); /* * first, init the swap list, its counter, and its lock. * then get a handle on the vnode for /dev/drum by using * the its dev_t number ("swapdev", from MD conf.c). */ LIST_INIT(&swap_priority); uvmexp.nswapdev = 0; simple_lock_init(&uvm.swap_data_lock); if (!swapdev_vp && bdevvp(swapdev, &swapdev_vp)) panic("uvm_swap_init: can't get vnode for swap device"); /* * create swap block resource map to map /dev/drum. the range * from 1 to INT_MAX allows 2 gigablocks of swap space. note * that block 0 is reserved (used to indicate an allocation * failure, or no allocation). */ swapmap = extent_create("swapmap", 1, INT_MAX, M_VMSWAP, 0, 0, EX_NOWAIT); if (swapmap == 0) panic("uvm_swap_init: extent_create failed"); /* * allocate pools for structures used for swapping to files. */ pool_init(&vndxfer_pool, sizeof(struct vndxfer), 0, 0, 0, "swp vnx", NULL); pool_init(&vndbuf_pool, sizeof(struct vndbuf), 0, 0, 0, "swp vnd", NULL); /* * Setup the initial swap partition */ swapmount(); /* * done! */ UVMHIST_LOG(pdhist, "<- done", 0, 0, 0, 0); } #ifdef UVM_SWAP_ENCRYPT void uvm_swap_initcrypt_all(void) { struct swapdev *sdp; struct swappri *spp; int npages; simple_lock(&uvm.swap_data_lock); LIST_FOREACH(spp, &swap_priority, spi_swappri) { CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) if (sdp->swd_decrypt == NULL) { npages = dbtob((uint64_t)sdp->swd_nblks) >> PAGE_SHIFT; uvm_swap_initcrypt(sdp, npages); } } simple_unlock(&uvm.swap_data_lock); } void uvm_swap_initcrypt(struct swapdev *sdp, int npages) { /* * keep information if a page needs to be decrypted when we get it * from the swap device. * We cannot chance a malloc later, if we are doing ASYNC puts, * we may not call malloc with M_WAITOK. This consumes only * 8KB memory for a 256MB swap partition. */ sdp->swd_decrypt = malloc(SWD_DCRYPT_SIZE(npages), M_VMSWAP, M_WAITOK|M_ZERO); sdp->swd_keys = malloc(SWD_KEY_SIZE(npages) * sizeof(struct swap_key), M_VMSWAP, M_WAITOK|M_ZERO); } boolean_t uvm_swap_allocpages(struct vm_page **pps, int npages) { int i; boolean_t fail; /* Estimate if we will succeed */ uvm_lock_fpageq(); fail = uvmexp.free - npages < uvmexp.reserve_kernel; uvm_unlock_fpageq(); if (fail) return FALSE; /* Get new pages */ for (i = 0; i < npages; i++) { pps[i] = uvm_pagealloc(NULL, 0, NULL, 0); if (pps[i] == NULL) break; } /* On failure free and return */ if (i < npages) { uvm_swap_freepages(pps, i); return FALSE; } return TRUE; } void uvm_swap_freepages(struct vm_page **pps, int npages) { int i; uvm_lock_pageq(); for (i = 0; i < npages; i++) uvm_pagefree(pps[i]); uvm_unlock_pageq(); } /* * Mark pages on the swap device for later decryption */ void uvm_swap_markdecrypt(struct swapdev *sdp, int startslot, int npages, int decrypt) { int pagestart, i; int off, bit; if (!sdp) return; pagestart = startslot - sdp->swd_drumoffset; for (i = 0; i < npages; i++, pagestart++) { off = SWD_DCRYPT_OFF(pagestart); bit = SWD_DCRYPT_BIT(pagestart); if (decrypt) /* pages read need decryption */ sdp->swd_decrypt[off] |= 1 << bit; else /* pages read do not need decryption */ sdp->swd_decrypt[off] &= ~(1 << bit); } } /* * Check if the page that we got from disk needs to be decrypted */ boolean_t uvm_swap_needdecrypt(struct swapdev *sdp, int off) { if (!sdp) return FALSE; off -= sdp->swd_drumoffset; return sdp->swd_decrypt[SWD_DCRYPT_OFF(off)] & (1 << SWD_DCRYPT_BIT(off)) ? TRUE : FALSE; } void uvm_swap_finicrypt_all(void) { struct swapdev *sdp; struct swappri *spp; struct swap_key *key; unsigned int nkeys; simple_lock(&uvm.swap_data_lock); LIST_FOREACH(spp, &swap_priority, spi_swappri) { CIRCLEQ_FOREACH(sdp, &spp->spi_swapdev, swd_next) { if (sdp->swd_decrypt == NULL) continue; nkeys = dbtob((uint64_t)sdp->swd_nblks) >> PAGE_SHIFT; key = sdp->swd_keys + (SWD_KEY_SIZE(nkeys) - 1); do { if (key->refcount != 0) swap_key_delete(key); } while (key-- != sdp->swd_keys); } } simple_unlock(&uvm.swap_data_lock); } #endif /* UVM_SWAP_ENCRYPT */ /* * swaplist functions: functions that operate on the list of swap * devices on the system. */ /* * swaplist_insert: insert swap device "sdp" into the global list * * => caller must hold both swap_syscall_lock and uvm.swap_data_lock * => caller must provide a newly malloc'd swappri structure (we will * FREE it if we don't need it... this it to prevent malloc blocking * here while adding swap) */ static void swaplist_insert(struct swapdev *sdp, struct swappri *newspp, int priority) { struct swappri *spp, *pspp; UVMHIST_FUNC("swaplist_insert"); UVMHIST_CALLED(pdhist); /* * find entry at or after which to insert the new device. */ for (pspp = NULL, spp = LIST_FIRST(&swap_priority); spp != NULL; spp = LIST_NEXT(spp, spi_swappri)) { if (priority <= spp->spi_priority) break; pspp = spp; } /* * new priority? */ if (spp == NULL || spp->spi_priority != priority) { spp = newspp; /* use newspp! */ UVMHIST_LOG(pdhist, "created new swappri = %ld", priority, 0, 0, 0); spp->spi_priority = priority; CIRCLEQ_INIT(&spp->spi_swapdev); if (pspp) LIST_INSERT_AFTER(pspp, spp, spi_swappri); else LIST_INSERT_HEAD(&swap_priority, spp, spi_swappri); } else { /* we don't need a new priority structure, free it */ free(newspp, M_VMSWAP); } /* * priority found (or created). now insert on the priority's * circleq list and bump the total number of swapdevs. */ sdp->swd_priority = priority; CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); uvmexp.nswapdev++; } /* * swaplist_find: find and optionally remove a swap device from the * global list. * * => caller must hold both swap_syscall_lock and uvm.swap_data_lock * => we return the swapdev we found (and removed) */ static struct swapdev * swaplist_find(struct vnode *vp, boolean_t remove) { struct swapdev *sdp; struct swappri *spp; /* * search the lists for the requested vp */ for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = LIST_NEXT(spp, spi_swappri)) { for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); sdp != (void *)&spp->spi_swapdev; sdp = CIRCLEQ_NEXT(sdp, swd_next)) if (sdp->swd_vp == vp) { if (remove) { CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); uvmexp.nswapdev--; } return(sdp); } } return (NULL); } /* * swaplist_trim: scan priority list for empty priority entries and kill * them. * * => caller must hold both swap_syscall_lock and uvm.swap_data_lock */ static void swaplist_trim(void) { struct swappri *spp, *nextspp; for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = nextspp) { nextspp = LIST_NEXT(spp, spi_swappri); if (CIRCLEQ_FIRST(&spp->spi_swapdev) != (void *)&spp->spi_swapdev) continue; LIST_REMOVE(spp, spi_swappri); free(spp, M_VMSWAP); } } /* * swapdrum_add: add a "swapdev"'s blocks into /dev/drum's area. * * => caller must hold swap_syscall_lock * => uvm.swap_data_lock should be unlocked (we may sleep) */ static void swapdrum_add(struct swapdev *sdp, int npages) { u_long result; if (extent_alloc(swapmap, npages, EX_NOALIGN, 0, EX_NOBOUNDARY, EX_WAITOK, &result)) panic("swapdrum_add"); sdp->swd_drumoffset = result; sdp->swd_drumsize = npages; } /* * swapdrum_getsdp: given a page offset in /dev/drum, convert it back * to the "swapdev" that maps that section of the drum. * * => each swapdev takes one big contig chunk of the drum * => caller must hold uvm.swap_data_lock */ static struct swapdev * swapdrum_getsdp(int pgno) { struct swapdev *sdp; struct swappri *spp; for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = LIST_NEXT(spp, spi_swappri)) for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); sdp != (void *)&spp->spi_swapdev; sdp = CIRCLEQ_NEXT(sdp, swd_next)) if (pgno >= sdp->swd_drumoffset && pgno < (sdp->swd_drumoffset + sdp->swd_drumsize)) { return sdp; } return NULL; } /* * sys_swapctl: main entry point for swapctl(2) system call * [with two helper functions: swap_on and swap_off] */ int sys_swapctl(struct proc *p, void *v, register_t *retval) { struct sys_swapctl_args /* { syscallarg(int) cmd; syscallarg(void *) arg; syscallarg(int) misc; } */ *uap = (struct sys_swapctl_args *)v; struct vnode *vp; struct nameidata nd; struct swappri *spp; struct swapdev *sdp; struct swapent *sep; char userpath[MAXPATHLEN]; size_t len; int count, error, misc; int priority; UVMHIST_FUNC("sys_swapctl"); UVMHIST_CALLED(pdhist); misc = SCARG(uap, misc); /* * ensure serialized syscall access by grabbing the swap_syscall_lock */ rw_enter_write(&swap_syscall_lock); /* * we handle the non-priv NSWAP and STATS request first. * * SWAP_NSWAP: return number of config'd swap devices * [can also be obtained with uvmexp sysctl] */ if (SCARG(uap, cmd) == SWAP_NSWAP) { UVMHIST_LOG(pdhist, "<- done SWAP_NSWAP=%ld", uvmexp.nswapdev, 0, 0, 0); *retval = uvmexp.nswapdev; error = 0; goto out; } /* * SWAP_STATS: get stats on current # of configured swap devs * * note that the swap_priority list can't change as long * as we are holding the swap_syscall_lock. we don't want * to grab the uvm.swap_data_lock because we may fault&sleep during * copyout() and we don't want to be holding that lock then! */ if (SCARG(uap, cmd) == SWAP_STATS) { sep = (struct swapent *)SCARG(uap, arg); count = 0; for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = LIST_NEXT(spp, spi_swappri)) { for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); sdp != (void *)&spp->spi_swapdev && misc-- > 0; sdp = CIRCLEQ_NEXT(sdp, swd_next)) { sdp->swd_inuse = btodb((u_int64_t)sdp->swd_npginuse << PAGE_SHIFT); error = copyout(&sdp->swd_se, sep, sizeof(struct swapent)); /* now copy out the path if necessary */ if (error == 0) error = copyout(sdp->swd_path, &sep->se_path, sdp->swd_pathlen); if (error) goto out; count++; sep++; } } UVMHIST_LOG(pdhist, "<- done SWAP_STATS", 0, 0, 0, 0); *retval = count; error = 0; goto out; } /* * all other requests require superuser privs. verify. */ if ((error = suser(p, 0))) goto out; /* * at this point we expect a path name in arg. we will * use namei() to gain a vnode reference (vref), and lock * the vnode (VOP_LOCK). * * XXX: a NULL arg means use the root vnode pointer (e.g. for * miniroot) */ if (SCARG(uap, arg) == NULL) { vp = rootvp; /* miniroot */ if (vget(vp, LK_EXCLUSIVE, p)) { error = EBUSY; goto out; } if (SCARG(uap, cmd) == SWAP_ON && copystr("miniroot", userpath, sizeof userpath, &len)) panic("swapctl: miniroot copy failed"); } else { int space; char *where; if (SCARG(uap, cmd) == SWAP_ON) { if ((error = copyinstr(SCARG(uap, arg), userpath, sizeof userpath, &len))) goto out; space = UIO_SYSSPACE; where = userpath; } else { space = UIO_USERSPACE; where = (char *)SCARG(uap, arg); } NDINIT(&nd, LOOKUP, FOLLOW|LOCKLEAF, space, where, p); if ((error = namei(&nd))) goto out; vp = nd.ni_vp; } /* note: "vp" is referenced and locked */ error = 0; /* assume no error */ switch(SCARG(uap, cmd)) { case SWAP_DUMPDEV: if (vp->v_type != VBLK) { error = ENOTBLK; break; } dumpdev = vp->v_rdev; break; case SWAP_CTL: /* * get new priority, remove old entry (if any) and then * reinsert it in the correct place. finally, prune out * any empty priority structures. */ priority = SCARG(uap, misc); spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); simple_lock(&uvm.swap_data_lock); if ((sdp = swaplist_find(vp, 1)) == NULL) { error = ENOENT; } else { swaplist_insert(sdp, spp, priority); swaplist_trim(); } simple_unlock(&uvm.swap_data_lock); if (error) free(spp, M_VMSWAP); break; case SWAP_ON: /* * check for duplicates. if none found, then insert a * dummy entry on the list to prevent someone else from * trying to enable this device while we are working on * it. */ priority = SCARG(uap, misc); simple_lock(&uvm.swap_data_lock); if ((sdp = swaplist_find(vp, 0)) != NULL) { error = EBUSY; simple_unlock(&uvm.swap_data_lock); break; } sdp = malloc(sizeof *sdp, M_VMSWAP, M_WAITOK|M_ZERO); spp = malloc(sizeof *spp, M_VMSWAP, M_WAITOK); sdp->swd_flags = SWF_FAKE; /* placeholder only */ sdp->swd_vp = vp; sdp->swd_dev = (vp->v_type == VBLK) ? vp->v_rdev : NODEV; /* * XXX Is NFS elaboration necessary? */ if (vp->v_type == VREG) { sdp->swd_cred = crdup(p->p_ucred); } swaplist_insert(sdp, spp, priority); simple_unlock(&uvm.swap_data_lock); sdp->swd_pathlen = len; sdp->swd_path = malloc(sdp->swd_pathlen, M_VMSWAP, M_WAITOK); if (copystr(userpath, sdp->swd_path, sdp->swd_pathlen, 0) != 0) panic("swapctl: copystr"); /* * we've now got a FAKE placeholder in the swap list. * now attempt to enable swap on it. if we fail, undo * what we've done and kill the fake entry we just inserted. * if swap_on is a success, it will clear the SWF_FAKE flag */ if ((error = swap_on(p, sdp)) != 0) { simple_lock(&uvm.swap_data_lock); (void) swaplist_find(vp, 1); /* kill fake entry */ swaplist_trim(); simple_unlock(&uvm.swap_data_lock); if (vp->v_type == VREG) { crfree(sdp->swd_cred); } free(sdp->swd_path, M_VMSWAP); free(sdp, M_VMSWAP); break; } break; case SWAP_OFF: simple_lock(&uvm.swap_data_lock); if ((sdp = swaplist_find(vp, 0)) == NULL) { simple_unlock(&uvm.swap_data_lock); error = ENXIO; break; } /* * If a device isn't in use or enabled, we * can't stop swapping from it (again). */ if ((sdp->swd_flags & (SWF_INUSE|SWF_ENABLE)) == 0) { simple_unlock(&uvm.swap_data_lock); error = EBUSY; break; } /* * do the real work. */ error = swap_off(p, sdp); break; default: error = EINVAL; } /* * done! release the ref gained by namei() and unlock. */ vput(vp); out: rw_exit_write(&swap_syscall_lock); UVMHIST_LOG(pdhist, "<- done! error=%ld", error, 0, 0, 0); return (error); } /* * swap_on: attempt to enable a swapdev for swapping. note that the * swapdev is already on the global list, but disabled (marked * SWF_FAKE). * * => we avoid the start of the disk (to protect disk labels) * => we also avoid the miniroot, if we are swapping to root. * => caller should leave uvm.swap_data_lock unlocked, we may lock it * if needed. */ static int swap_on(struct proc *p, struct swapdev *sdp) { static int count = 0; /* static */ struct vnode *vp; int error, npages, nblocks, size; long addr; struct vattr va; #if defined(NFSCLIENT) extern int (**nfsv2_vnodeop_p)(void *); #endif /* defined(NFSCLIENT) */ dev_t dev; UVMHIST_FUNC("swap_on"); UVMHIST_CALLED(pdhist); /* * we want to enable swapping on sdp. the swd_vp contains * the vnode we want (locked and ref'd), and the swd_dev * contains the dev_t of the file, if it a block device. */ vp = sdp->swd_vp; dev = sdp->swd_dev; /* * open the swap file (mostly useful for block device files to * let device driver know what is up). * * we skip the open/close for root on swap because the root * has already been opened when root was mounted (mountroot). */ if (vp != rootvp) { if ((error = VOP_OPEN(vp, FREAD|FWRITE, p->p_ucred, p))) return (error); } /* XXX this only works for block devices */ UVMHIST_LOG(pdhist, " dev=%ld, major(dev)=%ld", dev, major(dev), 0,0); /* * we now need to determine the size of the swap area. for * block specials we can call the d_psize function. * for normal files, we must stat [get attrs]. * * we put the result in nblks. * for normal files, we also want the filesystem block size * (which we get with statfs). */ switch (vp->v_type) { case VBLK: if (bdevsw[major(dev)].d_psize == 0 || (nblocks = (*bdevsw[major(dev)].d_psize)(dev)) == -1) { error = ENXIO; goto bad; } break; case VREG: if ((error = VOP_GETATTR(vp, &va, p->p_ucred, p))) goto bad; nblocks = (int)btodb(va.va_size); if ((error = VFS_STATFS(vp->v_mount, &vp->v_mount->mnt_stat, p)) != 0) goto bad; sdp->swd_bsize = vp->v_mount->mnt_stat.f_iosize; /* * limit the max # of outstanding I/O requests we issue * at any one time. take it easy on NFS servers. */ #if defined(NFSCLIENT) if (vp->v_op == nfsv2_vnodeop_p) sdp->swd_maxactive = 2; /* XXX */ else #endif /* defined(NFSCLIENT) */ sdp->swd_maxactive = 8; /* XXX */ break; default: error = ENXIO; goto bad; } /* * save nblocks in a safe place and convert to pages. */ sdp->swd_nblks = nblocks; npages = dbtob((u_int64_t)nblocks) >> PAGE_SHIFT; /* * for block special files, we want to make sure that leave * the disklabel and bootblocks alone, so we arrange to skip * over them (arbitrarily choosing to skip PAGE_SIZE bytes). * note that because of this the "size" can be less than the * actual number of blocks on the device. */ if (vp->v_type == VBLK) { /* we use pages 1 to (size - 1) [inclusive] */ size = npages - 1; addr = 1; } else { /* we use pages 0 to (size - 1) [inclusive] */ size = npages; addr = 0; } /* * make sure we have enough blocks for a reasonable sized swap * area. we want at least one page. */ if (size < 1) { UVMHIST_LOG(pdhist, " size <= 1!!", 0, 0, 0, 0); error = EINVAL; goto bad; } UVMHIST_LOG(pdhist, " dev=%lx: size=%ld addr=0x%lx\n", dev, size, addr, 0); /* * now we need to allocate an extent to manage this swap device */ snprintf(sdp->swd_exname, sizeof(sdp->swd_exname), "swap0x%04x", count++); /* note that extent_create's 3rd arg is inclusive, thus "- 1" */ sdp->swd_ex = extent_create(sdp->swd_exname, 0, npages - 1, M_VMSWAP, 0, 0, EX_WAITOK); /* allocate the `saved' region from the extent so it won't be used */ if (addr) { if (extent_alloc_region(sdp->swd_ex, 0, addr, EX_WAITOK)) panic("disklabel region"); } /* * if the vnode we are swapping to is the root vnode * (i.e. we are swapping to the miniroot) then we want * to make sure we don't overwrite it. do a statfs to * find its size and skip over it. */ if (vp == rootvp) { struct mount *mp; struct statfs *sp; int rootblocks, rootpages; mp = rootvnode->v_mount; sp = &mp->mnt_stat; rootblocks = sp->f_blocks * btodb(sp->f_bsize); rootpages = round_page(dbtob((u_int64_t)rootblocks)) >> PAGE_SHIFT; if (rootpages >= size) panic("swap_on: miniroot larger than swap?"); if (extent_alloc_region(sdp->swd_ex, addr, rootpages, EX_WAITOK)) panic("swap_on: unable to preserve miniroot"); size -= rootpages; printf("Preserved %d pages of miniroot ", rootpages); printf("leaving %d pages of swap\n", size); } /* * add a ref to vp to reflect usage as a swap device. */ vref(vp); #ifdef UVM_SWAP_ENCRYPT if (uvm_doswapencrypt) uvm_swap_initcrypt(sdp, npages); #endif /* * now add the new swapdev to the drum and enable. */ simple_lock(&uvm.swap_data_lock); swapdrum_add(sdp, npages); sdp->swd_npages = size; sdp->swd_flags &= ~SWF_FAKE; /* going live */ sdp->swd_flags |= (SWF_INUSE|SWF_ENABLE); uvmexp.swpages += size; simple_unlock(&uvm.swap_data_lock); return (0); bad: /* * failure: close device if necessary and return error. */ if (vp != rootvp) (void)VOP_CLOSE(vp, FREAD|FWRITE, p->p_ucred, p); return (error); } /* * swap_off: stop swapping on swapdev * * => swap data should be locked, we will unlock. */ static int swap_off(struct proc *p, struct swapdev *sdp) { int error = 0; UVMHIST_FUNC("swap_off"); UVMHIST_CALLED(pdhist); UVMHIST_LOG(pdhist, " dev=%lx", sdp->swd_dev,0,0,0); /* disable the swap area being removed */ sdp->swd_flags &= ~SWF_ENABLE; simple_unlock(&uvm.swap_data_lock); /* * the idea is to find all the pages that are paged out to this * device, and page them all in. in uvm, swap-backed pageable * memory can take two forms: aobjs and anons. call the * swapoff hook for each subsystem to bring in pages. */ if (uao_swap_off(sdp->swd_drumoffset, sdp->swd_drumoffset + sdp->swd_drumsize) || amap_swap_off(sdp->swd_drumoffset, sdp->swd_drumoffset + sdp->swd_drumsize)) { error = ENOMEM; } else if (sdp->swd_npginuse > sdp->swd_npgbad) { error = EBUSY; } if (error) { simple_lock(&uvm.swap_data_lock); sdp->swd_flags |= SWF_ENABLE; simple_unlock(&uvm.swap_data_lock); return (error); } /* * done with the vnode and saved creds. * drop our ref on the vnode before calling VOP_CLOSE() * so that spec_close() can tell if this is the last close. */ if (sdp->swd_vp->v_type == VREG) { crfree(sdp->swd_cred); } vrele(sdp->swd_vp); if (sdp->swd_vp != rootvp) { (void) VOP_CLOSE(sdp->swd_vp, FREAD|FWRITE, p->p_ucred, p); } simple_lock(&uvm.swap_data_lock); uvmexp.swpages -= sdp->swd_npages; if (swaplist_find(sdp->swd_vp, 1) == NULL) panic("swap_off: swapdev not in list"); swaplist_trim(); /* * free all resources! */ extent_free(swapmap, sdp->swd_drumoffset, sdp->swd_drumsize, EX_WAITOK); extent_destroy(sdp->swd_ex); free(sdp, M_VMSWAP); simple_unlock(&uvm.swap_data_lock); return (0); } /* * /dev/drum interface and i/o functions */ /* * swstrategy: perform I/O on the drum * * => we must map the i/o request from the drum to the correct swapdev. */ void swstrategy(struct buf *bp) { struct swapdev *sdp; int s, pageno, bn; UVMHIST_FUNC("swstrategy"); UVMHIST_CALLED(pdhist); /* * convert block number to swapdev. note that swapdev can't * be yanked out from under us because we are holding resources * in it (i.e. the blocks we are doing I/O on). */ pageno = dbtob((u_int64_t)bp->b_blkno) >> PAGE_SHIFT; simple_lock(&uvm.swap_data_lock); sdp = swapdrum_getsdp(pageno); simple_unlock(&uvm.swap_data_lock); if (sdp == NULL) { bp->b_error = EINVAL; bp->b_flags |= B_ERROR; s = splbio(); biodone(bp); splx(s); UVMHIST_LOG(pdhist, " failed to get swap device", 0, 0, 0, 0); return; } /* * convert drum page number to block number on this swapdev. */ pageno -= sdp->swd_drumoffset; /* page # on swapdev */ bn = btodb((u_int64_t)pageno << PAGE_SHIFT); /* convert to diskblock */ UVMHIST_LOG(pdhist, " %s: mapoff=%lx bn=0x%lx bcount=%ld", ((bp->b_flags & B_READ) == 0) ? "write" : "read", sdp->swd_drumoffset, bn, bp->b_bcount); /* * for block devices we finish up here. * for regular files we have to do more work which we delegate * to sw_reg_strategy(). */ switch (sdp->swd_vp->v_type) { default: panic("swstrategy: vnode type 0x%x", sdp->swd_vp->v_type); case VBLK: /* * must convert "bp" from an I/O on /dev/drum to an I/O * on the swapdev (sdp). */ s = splbio(); buf_replacevnode(bp, sdp->swd_vp); bp->b_blkno = bn; splx(s); VOP_STRATEGY(bp); return; case VREG: /* * delegate to sw_reg_strategy function. */ sw_reg_strategy(sdp, bp, bn); return; } /* NOTREACHED */ } /* * sw_reg_strategy: handle swap i/o to regular files */ static void sw_reg_strategy(struct swapdev *sdp, struct buf *bp, int bn) { struct vnode *vp; struct vndxfer *vnx; daddr64_t nbn; caddr_t addr; off_t byteoff; int s, off, nra, error, sz, resid; UVMHIST_FUNC("sw_reg_strategy"); UVMHIST_CALLED(pdhist); /* * allocate a vndxfer head for this transfer and point it to * our buffer. */ getvndxfer(vnx); vnx->vx_flags = VX_BUSY; vnx->vx_error = 0; vnx->vx_pending = 0; vnx->vx_bp = bp; vnx->vx_sdp = sdp; /* * setup for main loop where we read filesystem blocks into * our buffer. */ error = 0; bp->b_resid = bp->b_bcount; /* nothing transferred yet! */ addr = bp->b_data; /* current position in buffer */ byteoff = dbtob((u_int64_t)bn); for (resid = bp->b_resid; resid; resid -= sz) { struct vndbuf *nbp; /* * translate byteoffset into block number. return values: * vp = vnode of underlying device * nbn = new block number (on underlying vnode dev) * nra = num blocks we can read-ahead (excludes requested * block) */ nra = 0; error = VOP_BMAP(sdp->swd_vp, byteoff / sdp->swd_bsize, &vp, &nbn, &nra); if (error == 0 && nbn == (daddr64_t)-1) { /* * this used to just set error, but that doesn't * do the right thing. Instead, it causes random * memory errors. The panic() should remain until * this condition doesn't destabilize the system. */ #if 1 panic("sw_reg_strategy: swap to sparse file"); #else error = EIO; /* failure */ #endif } /* * punt if there was an error or a hole in the file. * we must wait for any i/o ops we have already started * to finish before returning. * * XXX we could deal with holes here but it would be * a hassle (in the write case). */ if (error) { s = splbio(); vnx->vx_error = error; /* pass error up */ goto out; } /* * compute the size ("sz") of this transfer (in bytes). */ off = byteoff % sdp->swd_bsize; sz = (1 + nra) * sdp->swd_bsize - off; if (sz > resid) sz = resid; UVMHIST_LOG(pdhist, "sw_reg_strategy: " "vp %p/%p offset 0x%lx/0x%llx", sdp->swd_vp, vp, (u_long)byteoff, nbn); /* * now get a buf structure. note that the vb_buf is * at the front of the nbp structure so that you can * cast pointers between the two structure easily. */ getvndbuf(nbp); nbp->vb_buf.b_flags = bp->b_flags | B_CALL; nbp->vb_buf.b_bcount = sz; nbp->vb_buf.b_bufsize = sz; nbp->vb_buf.b_error = 0; nbp->vb_buf.b_data = addr; nbp->vb_buf.b_blkno = nbn + btodb(off); nbp->vb_buf.b_proc = bp->b_proc; nbp->vb_buf.b_iodone = sw_reg_iodone; nbp->vb_buf.b_vp = NULLVP; nbp->vb_buf.b_vnbufs.le_next = NOLIST; LIST_INIT(&nbp->vb_buf.b_dep); /* * set b_dirtyoff/end and b_validoff/end. this is * required by the NFS client code (otherwise it will * just discard our I/O request). */ if (bp->b_dirtyend == 0) { nbp->vb_buf.b_dirtyoff = 0; nbp->vb_buf.b_dirtyend = sz; } else { nbp->vb_buf.b_dirtyoff = max(0, bp->b_dirtyoff - (bp->b_bcount-resid)); nbp->vb_buf.b_dirtyend = min(sz, max(0, bp->b_dirtyend - (bp->b_bcount-resid))); } if (bp->b_validend == 0) { nbp->vb_buf.b_validoff = 0; nbp->vb_buf.b_validend = sz; } else { nbp->vb_buf.b_validoff = max(0, bp->b_validoff - (bp->b_bcount-resid)); nbp->vb_buf.b_validend = min(sz, max(0, bp->b_validend - (bp->b_bcount-resid))); } nbp->vb_xfer = vnx; /* patch it back in to vnx */ /* * Just sort by block number */ nbp->vb_buf.b_cylinder = nbp->vb_buf.b_blkno; s = splbio(); if (vnx->vx_error != 0) { putvndbuf(nbp); goto out; } vnx->vx_pending++; /* assoc new buffer with underlying vnode */ bgetvp(vp, &nbp->vb_buf); /* sort it in and start I/O if we are not over our limit */ disksort(&sdp->swd_tab, &nbp->vb_buf); sw_reg_start(sdp); splx(s); /* * advance to the next I/O */ byteoff += sz; addr += sz; } s = splbio(); out: /* Arrive here at splbio */ vnx->vx_flags &= ~VX_BUSY; if (vnx->vx_pending == 0) { if (vnx->vx_error != 0) { bp->b_error = vnx->vx_error; bp->b_flags |= B_ERROR; } putvndxfer(vnx); biodone(bp); } splx(s); } /* * sw_reg_start: start an I/O request on the requested swapdev * * => reqs are sorted by disksort (above) */ static void sw_reg_start(struct swapdev *sdp) { struct buf *bp; UVMHIST_FUNC("sw_reg_start"); UVMHIST_CALLED(pdhist); /* recursion control */ if ((sdp->swd_flags & SWF_BUSY) != 0) return; sdp->swd_flags |= SWF_BUSY; while (sdp->swd_tab.b_active < sdp->swd_maxactive) { bp = sdp->swd_tab.b_actf; if (bp == NULL) break; sdp->swd_tab.b_actf = bp->b_actf; sdp->swd_tab.b_active++; UVMHIST_LOG(pdhist, "sw_reg_start: bp %p vp %p blkno 0x%lx cnt 0x%lx", bp, bp->b_vp, bp->b_blkno, bp->b_bcount); if ((bp->b_flags & B_READ) == 0) bp->b_vp->v_numoutput++; VOP_STRATEGY(bp); } sdp->swd_flags &= ~SWF_BUSY; } /* * sw_reg_iodone: one of our i/o's has completed and needs post-i/o cleanup * * => note that we can recover the vndbuf struct by casting the buf ptr */ static void sw_reg_iodone(struct buf *bp) { struct vndbuf *vbp = (struct vndbuf *) bp; struct vndxfer *vnx = vbp->vb_xfer; struct buf *pbp = vnx->vx_bp; /* parent buffer */ struct swapdev *sdp = vnx->vx_sdp; int resid; UVMHIST_FUNC("sw_reg_iodone"); UVMHIST_CALLED(pdhist); UVMHIST_LOG(pdhist, " vbp=%p vp=%p blkno=0x%lx addr=%p", vbp, vbp->vb_buf.b_vp, vbp->vb_buf.b_blkno, vbp->vb_buf.b_data); UVMHIST_LOG(pdhist, " cnt=%lx resid=%lx", vbp->vb_buf.b_bcount, vbp->vb_buf.b_resid, 0, 0); splassert(IPL_BIO); resid = vbp->vb_buf.b_bcount - vbp->vb_buf.b_resid; pbp->b_resid -= resid; vnx->vx_pending--; if (vbp->vb_buf.b_error) { UVMHIST_LOG(pdhist, " got error=%ld !", vbp->vb_buf.b_error, 0, 0, 0); /* pass error upward */ vnx->vx_error = vbp->vb_buf.b_error; } /* * disassociate this buffer from the vnode (if any). */ if (vbp->vb_buf.b_vp != NULL) { brelvp(&vbp->vb_buf); } /* * kill vbp structure */ putvndbuf(vbp); /* * wrap up this transaction if it has run to completion or, in * case of an error, when all auxiliary buffers have returned. */ if (vnx->vx_error != 0) { /* pass error upward */ pbp->b_flags |= B_ERROR; pbp->b_error = vnx->vx_error; if ((vnx->vx_flags & VX_BUSY) == 0 && vnx->vx_pending == 0) { putvndxfer(vnx); biodone(pbp); } } else if (pbp->b_resid == 0) { KASSERT(vnx->vx_pending == 0); if ((vnx->vx_flags & VX_BUSY) == 0) { UVMHIST_LOG(pdhist, " iodone error=%ld !", pbp, vnx->vx_error, 0, 0); putvndxfer(vnx); biodone(pbp); } } /* * done! start next swapdev I/O if one is pending */ sdp->swd_tab.b_active--; sw_reg_start(sdp); } /* * uvm_swap_alloc: allocate space on swap * * => allocation is done "round robin" down the priority list, as we * allocate in a priority we "rotate" the circle queue. * => space can be freed with uvm_swap_free * => we return the page slot number in /dev/drum (0 == invalid slot) * => we lock uvm.swap_data_lock * => XXXMRG: "LESSOK" INTERFACE NEEDED TO EXTENT SYSTEM */ int uvm_swap_alloc(int *nslots, boolean_t lessok) { struct swapdev *sdp; struct swappri *spp; u_long result; UVMHIST_FUNC("uvm_swap_alloc"); UVMHIST_CALLED(pdhist); /* * no swap devices configured yet? definite failure. */ if (uvmexp.nswapdev < 1) return 0; /* * lock data lock, convert slots into blocks, and enter loop */ simple_lock(&uvm.swap_data_lock); ReTry: /* XXXMRG */ for (spp = LIST_FIRST(&swap_priority); spp != NULL; spp = LIST_NEXT(spp, spi_swappri)) { for (sdp = CIRCLEQ_FIRST(&spp->spi_swapdev); sdp != (void *)&spp->spi_swapdev; sdp = CIRCLEQ_NEXT(sdp,swd_next)) { /* if it's not enabled, then we can't swap from it */ if ((sdp->swd_flags & SWF_ENABLE) == 0) continue; if (sdp->swd_npginuse + *nslots > sdp->swd_npages) continue; if (extent_alloc(sdp->swd_ex, *nslots, EX_NOALIGN, 0, EX_NOBOUNDARY, EX_MALLOCOK|EX_NOWAIT, &result) != 0) { continue; } /* * successful allocation! now rotate the circleq. */ CIRCLEQ_REMOVE(&spp->spi_swapdev, sdp, swd_next); CIRCLEQ_INSERT_TAIL(&spp->spi_swapdev, sdp, swd_next); sdp->swd_npginuse += *nslots; uvmexp.swpginuse += *nslots; simple_unlock(&uvm.swap_data_lock); /* done! return drum slot number */ UVMHIST_LOG(pdhist, "success! returning %ld slots starting at %ld", *nslots, result + sdp->swd_drumoffset, 0, 0); return(result + sdp->swd_drumoffset); } } /* XXXMRG: BEGIN HACK */ if (*nslots > 1 && lessok) { *nslots = 1; goto ReTry; /* XXXMRG: ugh! extent should support this for us */ } /* XXXMRG: END HACK */ simple_unlock(&uvm.swap_data_lock); return 0; /* failed */ } /* * uvm_swap_markbad: keep track of swap ranges where we've had i/o errors * * => we lock uvm.swap_data_lock */ void uvm_swap_markbad(int startslot, int nslots) { struct swapdev *sdp; UVMHIST_FUNC("uvm_swap_markbad"); UVMHIST_CALLED(pdhist); simple_lock(&uvm.swap_data_lock); sdp = swapdrum_getsdp(startslot); if (sdp != NULL) { /* * we just keep track of how many pages have been marked bad * in this device, to make everything add up in swap_off(). * we assume here that the range of slots will all be within * one swap device. */ sdp->swd_npgbad += nslots; UVMHIST_LOG(pdhist, "now %ld bad", sdp->swd_npgbad, 0,0,0); } simple_unlock(&uvm.swap_data_lock); } /* * uvm_swap_free: free swap slots * * => this can be all or part of an allocation made by uvm_swap_alloc * => we lock uvm.swap_data_lock */ void uvm_swap_free(int startslot, int nslots) { struct swapdev *sdp; UVMHIST_FUNC("uvm_swap_free"); UVMHIST_CALLED(pdhist); UVMHIST_LOG(pdhist, "freeing %ld slots starting at %ld", nslots, startslot, 0, 0); /* * ignore attempts to free the "bad" slot. */ if (startslot == SWSLOT_BAD) { return; } /* * convert drum slot offset back to sdp, free the blocks * in the extent, and return. must hold pri lock to do * lookup and access the extent. */ simple_lock(&uvm.swap_data_lock); sdp = swapdrum_getsdp(startslot); KASSERT(uvmexp.nswapdev >= 1); KASSERT(sdp != NULL); KASSERT(sdp->swd_npginuse >= nslots); if (extent_free(sdp->swd_ex, startslot - sdp->swd_drumoffset, nslots, EX_MALLOCOK|EX_NOWAIT) != 0) { printf("warning: resource shortage: %d pages of swap lost\n", nslots); } sdp->swd_npginuse -= nslots; uvmexp.swpginuse -= nslots; #ifdef UVM_SWAP_ENCRYPT { int i; if (swap_encrypt_initialized) { /* Dereference keys */ for (i = 0; i < nslots; i++) if (uvm_swap_needdecrypt(sdp, startslot + i)) { struct swap_key *key; key = SWD_KEY(sdp, startslot + i); if (key->refcount != 0) SWAP_KEY_PUT(sdp, key); } /* Mark range as not decrypt */ uvm_swap_markdecrypt(sdp, startslot, nslots, 0); } } #endif /* UVM_SWAP_ENCRYPT */ simple_unlock(&uvm.swap_data_lock); } /* * uvm_swap_put: put any number of pages into a contig place on swap * * => can be sync or async * => XXXMRG: consider making it an inline or macro */ int uvm_swap_put(int swslot, struct vm_page **ppsp, int npages, int flags) { int result; result = uvm_swap_io(ppsp, swslot, npages, B_WRITE | ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); return (result); } /* * uvm_swap_get: get a single page from swap * * => usually a sync op (from fault) * => XXXMRG: consider making it an inline or macro */ int uvm_swap_get(struct vm_page *page, int swslot, int flags) { int result; uvmexp.nswget++; KASSERT(flags & PGO_SYNCIO); if (swslot == SWSLOT_BAD) { return VM_PAGER_ERROR; } /* * this page is (about to be) no longer only in swap. */ simple_lock(&uvm.swap_data_lock); uvmexp.swpgonly--; simple_unlock(&uvm.swap_data_lock); result = uvm_swap_io(&page, swslot, 1, B_READ | ((flags & PGO_SYNCIO) ? 0 : B_ASYNC)); if (result != VM_PAGER_OK && result != VM_PAGER_PEND) { /* * oops, the read failed so it really is still only in swap. */ simple_lock(&uvm.swap_data_lock); uvmexp.swpgonly++; simple_unlock(&uvm.swap_data_lock); } return (result); } /* * uvm_swap_io: do an i/o operation to swap */ static int uvm_swap_io(struct vm_page **pps, int startslot, int npages, int flags) { daddr64_t startblk; struct buf *bp; vaddr_t kva; int result, s, mapinflags, pflag; boolean_t write, async; #ifdef UVM_SWAP_ENCRYPT vaddr_t dstkva; struct vm_page *tpps[MAXBSIZE >> PAGE_SHIFT]; struct swapdev *sdp; int encrypt = 0; #endif UVMHIST_FUNC("uvm_swap_io"); UVMHIST_CALLED(pdhist); UVMHIST_LOG(pdhist, "<- called, startslot=%ld, npages=%ld, flags=%ld", startslot, npages, flags, 0); write = (flags & B_READ) == 0; async = (flags & B_ASYNC) != 0; /* * convert starting drum slot to block number */ startblk = btodb((u_int64_t)startslot << PAGE_SHIFT); /* * first, map the pages into the kernel (XXX: currently required * by buffer system). */ mapinflags = !write ? UVMPAGER_MAPIN_READ : UVMPAGER_MAPIN_WRITE; if (!async) mapinflags |= UVMPAGER_MAPIN_WAITOK; kva = uvm_pagermapin(pps, npages, mapinflags); if (kva == 0) return (VM_PAGER_AGAIN); #ifdef UVM_SWAP_ENCRYPT if (write) { /* * Check if we need to do swap encryption on old pages. * Later we need a different scheme, that swap encrypts * all pages of a process that had at least one page swap * encrypted. Then we might not need to copy all pages * in the cluster, and avoid the memory overheard in * swapping. */ if (uvm_doswapencrypt) encrypt = 1; } if (swap_encrypt_initialized || encrypt) { /* * we need to know the swap device that we are swapping to/from * to see if the pages need to be marked for decryption or * actually need to be decrypted. * XXX - does this information stay the same over the whole * execution of this function? */ simple_lock(&uvm.swap_data_lock); sdp = swapdrum_getsdp(startslot); simple_unlock(&uvm.swap_data_lock); } /* * encrypt to swap */ if (write && encrypt) { int i, opages; caddr_t src, dst; struct swap_key *key; u_int64_t block; int swmapflags; /* We always need write access. */ swmapflags = UVMPAGER_MAPIN_READ; if (!async) swmapflags |= UVMPAGER_MAPIN_WAITOK; if (!uvm_swap_allocpages(tpps, npages)) { uvm_pagermapout(kva, npages); return (VM_PAGER_AGAIN); } dstkva = uvm_pagermapin(tpps, npages, swmapflags); if (dstkva == 0) { uvm_pagermapout(kva, npages); uvm_swap_freepages(tpps, npages); return (VM_PAGER_AGAIN); } src = (caddr_t) kva; dst = (caddr_t) dstkva; block = startblk; for (i = 0; i < npages; i++) { key = SWD_KEY(sdp, startslot + i); SWAP_KEY_GET(sdp, key); /* add reference */ /* mark for async writes */ atomic_setbits_int(&tpps[i]->pg_flags, PQ_ENCRYPT); swap_encrypt(key, src, dst, block, 1 << PAGE_SHIFT); src += 1 << PAGE_SHIFT; dst += 1 << PAGE_SHIFT; block += btodb(1 << PAGE_SHIFT); } uvm_pagermapout(kva, npages); /* dispose of pages we dont use anymore */ opages = npages; uvm_pager_dropcluster(NULL, NULL, pps, &opages, PGO_PDFREECLUST); kva = dstkva; } #endif /* UVM_SWAP_ENCRYPT */ /* * now allocate a buf for the i/o. * [make sure we don't put the pagedaemon to sleep...] */ s = splbio(); pflag = (async || curproc == uvm.pagedaemon_proc) ? 0 : PR_WAITOK; bp = pool_get(&bufpool, pflag); splx(s); /* * if we failed to get a swapbuf, return "try again" */ if (bp == NULL) { #ifdef UVM_SWAP_ENCRYPT if (write && encrypt) { int i; /* swap encrypt needs cleanup */ for (i = 0; i < npages; i++) SWAP_KEY_PUT(sdp, SWD_KEY(sdp, startslot + i)); uvm_pagermapout(kva, npages); uvm_swap_freepages(tpps, npages); } #endif return (VM_PAGER_AGAIN); } #ifdef UVM_SWAP_ENCRYPT /* * prevent ASYNC reads. * uvm_swap_io is only called from uvm_swap_get, uvm_swap_get * assumes that all gets are SYNCIO. Just make sure here. * XXXARTUBC - might not be true anymore. */ if (!write) { flags &= ~B_ASYNC; async = 0; } #endif /* * fill in the bp. we currently route our i/o through * /dev/drum's vnode [swapdev_vp]. */ bp->b_flags = B_BUSY | B_NOCACHE | B_RAW | (flags & (B_READ|B_ASYNC)); bp->b_proc = &proc0; /* XXX */ bp->b_vnbufs.le_next = NOLIST; bp->b_data = (caddr_t)kva; bp->b_blkno = startblk; LIST_INIT(&bp->b_dep); s = splbio(); bp->b_vp = NULL; buf_replacevnode(bp, swapdev_vp); splx(s); bp->b_bufsize = bp->b_bcount = npages << PAGE_SHIFT; /* * for pageouts we must set "dirtyoff" [NFS client code needs it]. * and we bump v_numoutput (counter of number of active outputs). */ if (write) { bp->b_dirtyoff = 0; bp->b_dirtyend = npages << PAGE_SHIFT; #ifdef UVM_SWAP_ENCRYPT /* mark the pages in the drum for decryption */ if (swap_encrypt_initialized) uvm_swap_markdecrypt(sdp, startslot, npages, encrypt); #endif s = splbio(); swapdev_vp->v_numoutput++; splx(s); } /* * for async ops we must set up the iodone handler. */ if (async) { bp->b_flags |= B_CALL | (curproc == uvm.pagedaemon_proc ? B_PDAEMON : 0); bp->b_iodone = uvm_aio_biodone; UVMHIST_LOG(pdhist, "doing async!", 0, 0, 0, 0); } UVMHIST_LOG(pdhist, "about to start io: data = %p blkno = 0x%lx, bcount = %ld", bp->b_data, bp->b_blkno, bp->b_bcount, 0); /* * now we start the I/O, and if async, return. */ VOP_STRATEGY(bp); if (async) return (VM_PAGER_PEND); /* * must be sync i/o. wait for it to finish */ (void) biowait(bp); result = (bp->b_flags & B_ERROR) ? VM_PAGER_ERROR : VM_PAGER_OK; #ifdef UVM_SWAP_ENCRYPT /* * decrypt swap */ if (swap_encrypt_initialized && (bp->b_flags & B_READ) && !(bp->b_flags & B_ERROR)) { int i; caddr_t data = bp->b_data; u_int64_t block = startblk; struct swap_key *key; for (i = 0; i < npages; i++) { /* Check if we need to decrypt */ if (uvm_swap_needdecrypt(sdp, startslot + i)) { key = SWD_KEY(sdp, startslot + i); if (key->refcount == 0) { result = VM_PAGER_ERROR; break; } swap_decrypt(key, data, data, block, 1 << PAGE_SHIFT); } data += 1 << PAGE_SHIFT; block += btodb(1 << PAGE_SHIFT); } } #endif /* * kill the pager mapping */ uvm_pagermapout(kva, npages); #ifdef UVM_SWAP_ENCRYPT /* * Not anymore needed, free after encryption */ if ((bp->b_flags & B_READ) == 0 && encrypt) uvm_swap_freepages(tpps, npages); #endif /* * now dispose of the buf */ s = splbio(); if (bp->b_vp) brelvp(bp); if (write && bp->b_vp) vwakeup(bp->b_vp); pool_put(&bufpool, bp); splx(s); /* * finally return. */ UVMHIST_LOG(pdhist, "<- done (sync) result=%ld", result, 0, 0, 0); return (result); } static void swapmount(void) { struct swapdev *sdp; struct swappri *spp; struct vnode *vp; dev_t swap_dev = swdevt[0].sw_dev; /* * No locking here since we happen to know that we will just be called * once before any other process has forked. */ if (swap_dev == NODEV) { printf("swapmount: no device\n"); return; } if (bdevvp(swap_dev, &vp)) { printf("swapmount: no device 2\n"); return; } sdp = malloc(sizeof(*sdp), M_VMSWAP, M_WAITOK|M_ZERO); spp = malloc(sizeof(*spp), M_VMSWAP, M_WAITOK); sdp->swd_flags = SWF_FAKE; sdp->swd_dev = swap_dev; sdp->swd_vp = vp; swaplist_insert(sdp, spp, 0); sdp->swd_pathlen = strlen("swap_device") + 1; sdp->swd_path = malloc(sdp->swd_pathlen, M_VMSWAP, M_WAITOK); if (copystr("swap_device", sdp->swd_path, sdp->swd_pathlen, 0)) panic("swapmount: copystr"); if (swap_on(curproc, sdp)) { swaplist_find(vp, 1); swaplist_trim(); vput(sdp->swd_vp); free(sdp->swd_path, M_VMSWAP); free(sdp, M_VMSWAP); return; } VOP_UNLOCK(vp, 0, curproc); }