/* $NetBSD: subr_extent.c,v 1.47 2002/09/04 01:32:42 matt Exp $ */ /*- * Copyright (c) 1996, 1998 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Jason R. Thorpe and Matthias Drochner. * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``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 FOUNDATION OR CONTRIBUTORS * 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. */ /* * General purpose extent manager. */ #include __KERNEL_RCSID(0, "$NetBSD: subr_extent.c,v 1.47 2002/09/04 01:32:42 matt Exp $"); #ifdef _KERNEL #include #include #include #include #include #include #include #include #include #define KMEM_IS_RUNNING (kmem_map != NULL) #elif defined(_EXTENT_TESTING) /* * user-land definitions, so it can fit into a testing harness. */ #include #include #include #include #include #include #include /* * Use multi-line #defines to avoid screwing up the kernel tags file; * without this, ctags produces a tags file where panic() shows up * in subr_extent.c rather than subr_prf.c. */ #define \ malloc(s, t, flags) malloc(s) #define \ free(p, t) free(p) #define \ tsleep(chan, pri, str, timo) (EWOULDBLOCK) #define \ ltsleep(chan,pri,str,timo,lck) (EWOULDBLOCK) #define \ wakeup(chan) ((void)0) #define \ pool_get(pool, flags) malloc((pool)->pr_size,0,0) #define \ pool_put(pool, rp) free(rp,0) #define \ panic(a) printf(a) #define \ splhigh() (1) #define \ splx(s) ((void)(s)) #define \ simple_lock_init(l) ((void)(l)) #define \ simple_lock(l) ((void)(l)) #define \ simple_unlock(l) ((void)(l)) #define KMEM_IS_RUNNING (1) #endif static void extent_insert_and_optimize __P((struct extent *, u_long, u_long, int, struct extent_region *, struct extent_region *)); static struct extent_region *extent_alloc_region_descriptor __P((struct extent *, int)); static void extent_free_region_descriptor __P((struct extent *, struct extent_region *)); static struct pool expool; static struct simplelock expool_init_slock = SIMPLELOCK_INITIALIZER; static int expool_initialized; /* * Macro to align to an arbitrary power-of-two boundary. */ #define EXTENT_ALIGN(_start, _align, _skew) \ (((((_start) - (_skew)) + ((_align) - 1)) & (-(_align))) + (_skew)) /* * Create the extent_region pool. * (This is deferred until one of our callers thinks we can malloc()). */ static __inline void expool_init(void) { simple_lock(&expool_init_slock); if (expool_initialized) { simple_unlock(&expool_init_slock); return; } #if defined(_KERNEL) pool_init(&expool, sizeof(struct extent_region), 0, 0, 0, "extent", NULL); #else expool.pr_size = sizeof(struct extent_region); #endif expool_initialized = 1; simple_unlock(&expool_init_slock); } /* * Allocate and initialize an extent map. */ struct extent * extent_create(name, start, end, mtype, storage, storagesize, flags) const char *name; u_long start, end; int mtype; caddr_t storage; size_t storagesize; int flags; { struct extent *ex; caddr_t cp = storage; size_t sz = storagesize; struct extent_region *rp; int fixed_extent = (storage != NULL); int s; #ifdef DIAGNOSTIC /* Check arguments. */ if (name == NULL) panic("extent_create: name == NULL"); if (end < start) { printf("extent_create: extent `%s', start 0x%lx, end 0x%lx\n", name, start, end); panic("extent_create: end < start"); } if (fixed_extent && (storagesize < sizeof(struct extent_fixed))) panic("extent_create: fixed extent, bad storagesize 0x%lx", (u_long)storagesize); if (fixed_extent == 0 && (storagesize != 0 || storage != NULL)) panic("extent_create: storage provided for non-fixed"); #endif /* Allocate extent descriptor. */ if (fixed_extent) { struct extent_fixed *fex; memset(storage, 0, storagesize); /* * Align all descriptors on "long" boundaries. */ fex = (struct extent_fixed *)cp; ex = (struct extent *)fex; cp += ALIGN(sizeof(struct extent_fixed)); sz -= ALIGN(sizeof(struct extent_fixed)); fex->fex_storage = storage; fex->fex_storagesize = storagesize; /* * In a fixed extent, we have to pre-allocate region * descriptors and place them in the extent's freelist. */ LIST_INIT(&fex->fex_freelist); while (sz >= ALIGN(sizeof(struct extent_region))) { rp = (struct extent_region *)cp; cp += ALIGN(sizeof(struct extent_region)); sz -= ALIGN(sizeof(struct extent_region)); LIST_INSERT_HEAD(&fex->fex_freelist, rp, er_link); } } else { s = splhigh(); if (expool_initialized == 0) expool_init(); splx(s); ex = (struct extent *)malloc(sizeof(struct extent), mtype, (flags & EX_WAITOK) ? M_WAITOK : M_NOWAIT); if (ex == NULL) return (NULL); } /* Fill in the extent descriptor and return it to the caller. */ simple_lock_init(&ex->ex_slock); LIST_INIT(&ex->ex_regions); ex->ex_name = name; ex->ex_start = start; ex->ex_end = end; ex->ex_mtype = mtype; ex->ex_flags = 0; if (fixed_extent) ex->ex_flags |= EXF_FIXED; if (flags & EX_NOCOALESCE) ex->ex_flags |= EXF_NOCOALESCE; return (ex); } /* * Destroy an extent map. * Since we're freeing the data, there can't be any references * so we don't need any locking. */ void extent_destroy(ex) struct extent *ex; { struct extent_region *rp, *orp; #ifdef DIAGNOSTIC /* Check arguments. */ if (ex == NULL) panic("extent_destroy: NULL extent"); #endif /* Free all region descriptors in extent. */ for (rp = LIST_FIRST(&ex->ex_regions); rp != NULL; ) { orp = rp; rp = LIST_NEXT(rp, er_link); LIST_REMOVE(orp, er_link); extent_free_region_descriptor(ex, orp); } /* If we're not a fixed extent, free the extent descriptor itself. */ if ((ex->ex_flags & EXF_FIXED) == 0) free(ex, ex->ex_mtype); } /* * Insert a region descriptor into the sorted region list after the * entry "after" or at the head of the list (if "after" is NULL). * The region descriptor we insert is passed in "rp". We must * allocate the region descriptor before calling this function! * If we don't need the region descriptor, it will be freed here. */ static void extent_insert_and_optimize(ex, start, size, flags, after, rp) struct extent *ex; u_long start, size; int flags; struct extent_region *after, *rp; { struct extent_region *nextr; int appended = 0; if (after == NULL) { /* * We're the first in the region list. If there's * a region after us, attempt to coalesce to save * descriptor overhead. */ if (((ex->ex_flags & EXF_NOCOALESCE) == 0) && (LIST_FIRST(&ex->ex_regions) != NULL) && ((start + size) == LIST_FIRST(&ex->ex_regions)->er_start)) { /* * We can coalesce. Prepend us to the first region. */ LIST_FIRST(&ex->ex_regions)->er_start = start; extent_free_region_descriptor(ex, rp); return; } /* * Can't coalesce. Fill in the region descriptor * in, and insert us at the head of the region list. */ rp->er_start = start; rp->er_end = start + (size - 1); LIST_INSERT_HEAD(&ex->ex_regions, rp, er_link); return; } /* * If EXF_NOCOALESCE is set, coalescing is disallowed. */ if (ex->ex_flags & EXF_NOCOALESCE) goto cant_coalesce; /* * Attempt to coalesce with the region before us. */ if ((after->er_end + 1) == start) { /* * We can coalesce. Append ourselves and make * note of it. */ after->er_end = start + (size - 1); appended = 1; } /* * Attempt to coalesce with the region after us. */ if ((LIST_NEXT(after, er_link) != NULL) && ((start + size) == LIST_NEXT(after, er_link)->er_start)) { /* * We can coalesce. Note that if we appended ourselves * to the previous region, we exactly fit the gap, and * can free the "next" region descriptor. */ if (appended) { /* * Yup, we can free it up. */ after->er_end = LIST_NEXT(after, er_link)->er_end; nextr = LIST_NEXT(after, er_link); LIST_REMOVE(nextr, er_link); extent_free_region_descriptor(ex, nextr); } else { /* * Nope, just prepend us to the next region. */ LIST_NEXT(after, er_link)->er_start = start; } extent_free_region_descriptor(ex, rp); return; } /* * We weren't able to coalesce with the next region, but * we don't need to allocate a region descriptor if we * appended ourselves to the previous region. */ if (appended) { extent_free_region_descriptor(ex, rp); return; } cant_coalesce: /* * Fill in the region descriptor and insert ourselves * into the region list. */ rp->er_start = start; rp->er_end = start + (size - 1); LIST_INSERT_AFTER(after, rp, er_link); } /* * Allocate a specific region in an extent map. */ int extent_alloc_region(ex, start, size, flags) struct extent *ex; u_long start, size; int flags; { struct extent_region *rp, *last, *myrp; u_long end = start + (size - 1); int error; #ifdef DIAGNOSTIC /* Check arguments. */ if (ex == NULL) panic("extent_alloc_region: NULL extent"); if (size < 1) { printf("extent_alloc_region: extent `%s', size 0x%lx\n", ex->ex_name, size); panic("extent_alloc_region: bad size"); } if (end < start) { printf( "extent_alloc_region: extent `%s', start 0x%lx, size 0x%lx\n", ex->ex_name, start, size); panic("extent_alloc_region: overflow"); } #endif #ifdef LOCKDEBUG if (flags & EX_WAITSPACE) simple_lock_only_held(NULL, "extent_alloc_region(EX_WAITSPACE)"); #endif /* * Make sure the requested region lies within the * extent. * * We don't lock to check the range, because those values * are never modified, and if another thread deletes the * extent, we're screwed anyway. */ if ((start < ex->ex_start) || (end > ex->ex_end)) { #ifdef DIAGNOSTIC printf("extent_alloc_region: extent `%s' (0x%lx - 0x%lx)\n", ex->ex_name, ex->ex_start, ex->ex_end); printf("extent_alloc_region: start 0x%lx, end 0x%lx\n", start, end); panic("extent_alloc_region: region lies outside extent"); #else return (EINVAL); #endif } /* * Allocate the region descriptor. It will be freed later * if we can coalesce with another region. Don't lock before * here! This could block. */ myrp = extent_alloc_region_descriptor(ex, flags); if (myrp == NULL) { #ifdef DIAGNOSTIC printf( "extent_alloc_region: can't allocate region descriptor\n"); #endif return (ENOMEM); } alloc_start: simple_lock(&ex->ex_slock); /* * Attempt to place ourselves in the desired area of the * extent. We save ourselves some work by keeping the list sorted. * In other words, if the start of the current region is greater * than the end of our region, we don't have to search any further. */ /* * Keep a pointer to the last region we looked at so * that we don't have to traverse the list again when * we insert ourselves. If "last" is NULL when we * finally insert ourselves, we go at the head of the * list. See extent_insert_and_optimize() for details. */ last = NULL; LIST_FOREACH(rp, &ex->ex_regions, er_link) { if (rp->er_start > end) { /* * We lie before this region and don't * conflict. */ break; } /* * The current region begins before we end. * Check for a conflict. */ if (rp->er_end >= start) { /* * We conflict. If we can (and want to) wait, * do so. */ if (flags & EX_WAITSPACE) { ex->ex_flags |= EXF_WANTED; error = ltsleep(ex, PNORELOCK | PRIBIO | ((flags & EX_CATCH) ? PCATCH : 0), "extnt", 0, &ex->ex_slock); if (error) return (error); goto alloc_start; } extent_free_region_descriptor(ex, myrp); simple_unlock(&ex->ex_slock); return (EAGAIN); } /* * We don't conflict, but this region lies before * us. Keep a pointer to this region, and keep * trying. */ last = rp; } /* * We don't conflict with any regions. "last" points * to the region we fall after, or is NULL if we belong * at the beginning of the region list. Insert ourselves. */ extent_insert_and_optimize(ex, start, size, flags, last, myrp); simple_unlock(&ex->ex_slock); return (0); } /* * Macro to check (x + y) <= z. This check is designed to fail * if an overflow occurs. */ #define LE_OV(x, y, z) ((((x) + (y)) >= (x)) && (((x) + (y)) <= (z))) /* * Allocate a region in an extent map subregion. * * If EX_FAST is specified, we return the first fit in the map. * Otherwise, we try to minimize fragmentation by finding the * smallest gap that will hold the request. * * The allocated region is aligned to "alignment", which must be * a power of 2. */ int extent_alloc_subregion1(ex, substart, subend, size, alignment, skew, boundary, flags, result) struct extent *ex; u_long substart, subend, size, alignment, skew, boundary; int flags; u_long *result; { struct extent_region *rp, *myrp, *last, *bestlast; u_long newstart, newend, exend, beststart, bestovh, ovh; u_long dontcross; int error; #ifdef DIAGNOSTIC /* * Check arguments. * * We don't lock to check these, because these values * are never modified, and if another thread deletes the * extent, we're screwed anyway. */ if (ex == NULL) panic("extent_alloc_subregion: NULL extent"); if (result == NULL) panic("extent_alloc_subregion: NULL result pointer"); if ((substart < ex->ex_start) || (substart > ex->ex_end) || (subend > ex->ex_end) || (subend < ex->ex_start)) { printf("extent_alloc_subregion: extent `%s', ex_start 0x%lx, ex_end 0x%lx\n", ex->ex_name, ex->ex_start, ex->ex_end); printf("extent_alloc_subregion: substart 0x%lx, subend 0x%lx\n", substart, subend); panic("extent_alloc_subregion: bad subregion"); } if ((size < 1) || ((size - 1) > (subend - substart))) { printf("extent_alloc_subregion: extent `%s', size 0x%lx\n", ex->ex_name, size); panic("extent_alloc_subregion: bad size"); } if (alignment == 0) panic("extent_alloc_subregion: bad alignment"); if (boundary && (boundary < size)) { printf( "extent_alloc_subregion: extent `%s', size 0x%lx, " "boundary 0x%lx\n", ex->ex_name, size, boundary); panic("extent_alloc_subregion: bad boundary"); } #endif #ifdef LOCKDEBUG if (flags & EX_WAITSPACE) simple_lock_only_held(NULL, "extent_alloc_subregion1(EX_WAITSPACE)"); #endif /* * Allocate the region descriptor. It will be freed later * if we can coalesce with another region. Don't lock before * here! This could block. */ myrp = extent_alloc_region_descriptor(ex, flags); if (myrp == NULL) { #ifdef DIAGNOSTIC printf( "extent_alloc_subregion: can't allocate region descriptor\n"); #endif return (ENOMEM); } alloc_start: simple_lock(&ex->ex_slock); /* * Keep a pointer to the last region we looked at so * that we don't have to traverse the list again when * we insert ourselves. If "last" is NULL when we * finally insert ourselves, we go at the head of the * list. See extent_insert_and_optimize() for deatails. */ last = NULL; /* * Keep track of size and location of the smallest * chunk we fit in. * * Since the extent can be as large as the numeric range * of the CPU (0 - 0xffffffff for 32-bit systems), the * best overhead value can be the maximum unsigned integer. * Thus, we initialize "bestovh" to 0, since we insert ourselves * into the region list immediately on an exact match (which * is the only case where "bestovh" would be set to 0). */ bestovh = 0; beststart = 0; bestlast = NULL; /* * Keep track of end of free region. This is either the end of extent * or the start of a region past the subend. */ exend = ex->ex_end; /* * For N allocated regions, we must make (N + 1) * checks for unallocated space. The first chunk we * check is the area from the beginning of the subregion * to the first allocated region after that point. */ newstart = EXTENT_ALIGN(substart, alignment, skew); if (newstart < ex->ex_start) { #ifdef DIAGNOSTIC printf( "extent_alloc_subregion: extent `%s' (0x%lx - 0x%lx), alignment 0x%lx\n", ex->ex_name, ex->ex_start, ex->ex_end, alignment); simple_unlock(&ex->ex_slock); panic("extent_alloc_subregion: overflow after alignment"); #else extent_free_region_descriptor(ex, myrp); simple_unlock(&ex->ex_slock); return (EINVAL); #endif } /* * Find the first allocated region that begins on or after * the subregion start, advancing the "last" pointer along * the way. */ LIST_FOREACH(rp, &ex->ex_regions, er_link) { if (rp->er_start >= newstart) break; last = rp; } /* * Relocate the start of our candidate region to the end of * the last allocated region (if there was one overlapping * our subrange). */ if (last != NULL && last->er_end >= newstart) newstart = EXTENT_ALIGN((last->er_end + 1), alignment, skew); for (; rp != NULL; rp = LIST_NEXT(rp, er_link)) { /* * If the region pasts the subend, bail out and see * if we fit against the subend. */ if (rp->er_start >= subend) { exend = rp->er_start; break; } /* * Check the chunk before "rp". Note that our * comparison is safe from overflow conditions. */ if (LE_OV(newstart, size, rp->er_start)) { /* * Do a boundary check, if necessary. Note * that a region may *begin* on the boundary, * but it must end before the boundary. */ if (boundary) { newend = newstart + (size - 1); /* * Calculate the next boundary after the start * of this region. */ dontcross = EXTENT_ALIGN(newstart+1, boundary, (flags & EX_BOUNDZERO) ? 0 : ex->ex_start) - 1; #if 0 printf("newstart=%lx newend=%lx ex_start=%lx ex_end=%lx boundary=%lx dontcross=%lx\n", newstart, newend, ex->ex_start, ex->ex_end, boundary, dontcross); #endif /* Check for overflow */ if (dontcross < ex->ex_start) dontcross = ex->ex_end; else if (newend > dontcross) { /* * Candidate region crosses boundary. * Throw away the leading part and see * if we still fit. */ newstart = dontcross + 1; newend = newstart + (size - 1); dontcross += boundary; if (!LE_OV(newstart, size, rp->er_start)) goto skip; } /* * If we run past the end of * the extent or the boundary * overflows, then the request * can't fit. */ if (newstart + size - 1 > ex->ex_end || dontcross < newstart) goto fail; } /* * We would fit into this space. Calculate * the overhead (wasted space). If we exactly * fit, or we're taking the first fit, insert * ourselves into the region list. */ ovh = rp->er_start - newstart - size; if ((flags & EX_FAST) || (ovh == 0)) goto found; /* * Don't exactly fit, but check to see * if we're better than any current choice. */ if ((bestovh == 0) || (ovh < bestovh)) { bestovh = ovh; beststart = newstart; bestlast = last; } } skip: /* * Skip past the current region and check again. */ newstart = EXTENT_ALIGN((rp->er_end + 1), alignment, skew); if (newstart < rp->er_end) { /* * Overflow condition. Don't error out, since * we might have a chunk of space that we can * use. */ goto fail; } last = rp; } /* * The final check is from the current starting point to the * end of the subregion. If there were no allocated regions, * "newstart" is set to the beginning of the subregion, or * just past the end of the last allocated region, adjusted * for alignment in either case. */ if (LE_OV(newstart, (size - 1), subend)) { /* * Do a boundary check, if necessary. Note * that a region may *begin* on the boundary, * but it must end before the boundary. */ if (boundary) { newend = newstart + (size - 1); /* * Calculate the next boundary after the start * of this region. */ dontcross = EXTENT_ALIGN(newstart+1, boundary, (flags & EX_BOUNDZERO) ? 0 : ex->ex_start) - 1; #if 0 printf("newstart=%lx newend=%lx ex_start=%lx ex_end=%lx boundary=%lx dontcross=%lx\n", newstart, newend, ex->ex_start, ex->ex_end, boundary, dontcross); #endif /* Check for overflow */ if (dontcross < ex->ex_start) dontcross = ex->ex_end; else if (newend > dontcross) { /* * Candidate region crosses boundary. * Throw away the leading part and see * if we still fit. */ newstart = dontcross + 1; newend = newstart + (size - 1); dontcross += boundary; if (!LE_OV(newstart, (size - 1), subend)) goto fail; } /* * If we run past the end of * the extent or the boundary * overflows, then the request * can't fit. */ if (newstart + size - 1 > ex->ex_end || dontcross < newstart) goto fail; } /* * We would fit into this space. Calculate * the overhead (wasted space). If we exactly * fit, or we're taking the first fit, insert * ourselves into the region list. */ ovh = exend - newstart - (size - 1); if ((flags & EX_FAST) || (ovh == 0)) goto found; /* * Don't exactly fit, but check to see * if we're better than any current choice. */ if ((bestovh == 0) || (ovh < bestovh)) { bestovh = ovh; beststart = newstart; bestlast = last; } } fail: /* * One of the following two conditions have * occurred: * * There is no chunk large enough to hold the request. * * If EX_FAST was not specified, there is not an * exact match for the request. * * Note that if we reach this point and EX_FAST is * set, then we know there is no space in the extent for * the request. */ if (((flags & EX_FAST) == 0) && (bestovh != 0)) { /* * We have a match that's "good enough". */ newstart = beststart; last = bestlast; goto found; } /* * No space currently available. Wait for it to free up, * if possible. */ if (flags & EX_WAITSPACE) { ex->ex_flags |= EXF_WANTED; error = ltsleep(ex, PNORELOCK | PRIBIO | ((flags & EX_CATCH) ? PCATCH : 0), "extnt", 0, &ex->ex_slock); if (error) return (error); goto alloc_start; } extent_free_region_descriptor(ex, myrp); simple_unlock(&ex->ex_slock); return (EAGAIN); found: /* * Insert ourselves into the region list. */ extent_insert_and_optimize(ex, newstart, size, flags, last, myrp); simple_unlock(&ex->ex_slock); *result = newstart; return (0); } int extent_free(ex, start, size, flags) struct extent *ex; u_long start, size; int flags; { struct extent_region *rp, *nrp = NULL; u_long end = start + (size - 1); int exflags; #ifdef DIAGNOSTIC /* * Check arguments. * * We don't lock to check these, because these values * are never modified, and if another thread deletes the * extent, we're screwed anyway. */ if (ex == NULL) panic("extent_free: NULL extent"); if ((start < ex->ex_start) || (start > ex->ex_end)) { extent_print(ex); printf("extent_free: extent `%s', start 0x%lx, size 0x%lx\n", ex->ex_name, start, size); panic("extent_free: extent `%s', region not within extent", ex->ex_name); } /* Check for an overflow. */ if (end < start) { extent_print(ex); printf("extent_free: extent `%s', start 0x%lx, size 0x%lx\n", ex->ex_name, start, size); panic("extent_free: overflow"); } #endif /* * If we're allowing coalescing, we must allocate a region * descriptor now, since it might block. * * XXX Make a static, create-time flags word, so we don't * XXX have to lock to read it! */ simple_lock(&ex->ex_slock); exflags = ex->ex_flags; simple_unlock(&ex->ex_slock); if ((exflags & EXF_NOCOALESCE) == 0) { /* Allocate a region descriptor. */ nrp = extent_alloc_region_descriptor(ex, flags); if (nrp == NULL) return (ENOMEM); } simple_lock(&ex->ex_slock); /* * Find region and deallocate. Several possibilities: * * 1. (start == er_start) && (end == er_end): * Free descriptor. * * 2. (start == er_start) && (end < er_end): * Adjust er_start. * * 3. (start > er_start) && (end == er_end): * Adjust er_end. * * 4. (start > er_start) && (end < er_end): * Fragment region. Requires descriptor alloc. * * Cases 2, 3, and 4 require that the EXF_NOCOALESCE flag * is not set. */ LIST_FOREACH(rp, &ex->ex_regions, er_link) { /* * Save ourselves some comparisons; does the current * region end before chunk to be freed begins? If so, * then we haven't found the appropriate region descriptor. */ if (rp->er_end < start) continue; /* * Save ourselves some traversal; does the current * region begin after the chunk to be freed ends? If so, * then we've already passed any possible region descriptors * that might have contained the chunk to be freed. */ if (rp->er_start > end) break; /* Case 1. */ if ((start == rp->er_start) && (end == rp->er_end)) { LIST_REMOVE(rp, er_link); extent_free_region_descriptor(ex, rp); goto done; } /* * The following cases all require that EXF_NOCOALESCE * is not set. */ if (ex->ex_flags & EXF_NOCOALESCE) continue; /* Case 2. */ if ((start == rp->er_start) && (end < rp->er_end)) { rp->er_start = (end + 1); goto done; } /* Case 3. */ if ((start > rp->er_start) && (end == rp->er_end)) { rp->er_end = (start - 1); goto done; } /* Case 4. */ if ((start > rp->er_start) && (end < rp->er_end)) { /* Fill in new descriptor. */ nrp->er_start = end + 1; nrp->er_end = rp->er_end; /* Adjust current descriptor. */ rp->er_end = start - 1; /* Insert new descriptor after current. */ LIST_INSERT_AFTER(rp, nrp, er_link); /* We used the new descriptor, so don't free it below */ nrp = NULL; goto done; } } /* Region not found, or request otherwise invalid. */ simple_unlock(&ex->ex_slock); extent_print(ex); printf("extent_free: start 0x%lx, end 0x%lx\n", start, end); panic("extent_free: region not found"); done: if (nrp != NULL) extent_free_region_descriptor(ex, nrp); if (ex->ex_flags & EXF_WANTED) { ex->ex_flags &= ~EXF_WANTED; wakeup(ex); } simple_unlock(&ex->ex_slock); return (0); } /* * Allocate an extent region descriptor. EXTENT MUST NOT BE LOCKED, * AS THIS FUNCTION MAY BLOCK! We will handle any locking we may need. */ static struct extent_region * extent_alloc_region_descriptor(ex, flags) struct extent *ex; int flags; { struct extent_region *rp; int exflags; int s; /* * If the kernel memory allocator is not yet running, we can't * use it (obviously). */ if (KMEM_IS_RUNNING == 0) flags &= ~EX_MALLOCOK; /* * XXX Make a static, create-time flags word, so we don't * XXX have to lock to read it! */ simple_lock(&ex->ex_slock); exflags = ex->ex_flags; simple_unlock(&ex->ex_slock); if (exflags & EXF_FIXED) { struct extent_fixed *fex = (struct extent_fixed *)ex; for (;;) { simple_lock(&ex->ex_slock); if ((rp = LIST_FIRST(&fex->fex_freelist)) != NULL) { /* * Don't muck with flags after pulling it off * the freelist; it may have been dynamically * allocated, and kindly given to us. We * need to remember that information. */ LIST_REMOVE(rp, er_link); simple_unlock(&ex->ex_slock); return (rp); } if (flags & EX_MALLOCOK) { simple_unlock(&ex->ex_slock); goto alloc; } if ((flags & EX_WAITOK) == 0) { simple_unlock(&ex->ex_slock); return (NULL); } ex->ex_flags |= EXF_FLWANTED; if (ltsleep(&fex->fex_freelist, PNORELOCK| PRIBIO | ((flags & EX_CATCH) ? PCATCH : 0), "extnt", 0, &ex->ex_slock)) return (NULL); } } alloc: s = splhigh(); if (expool_initialized == 0) expool_init(); rp = pool_get(&expool, (flags & EX_WAITOK) ? PR_WAITOK : 0); splx(s); if (rp != NULL) rp->er_flags = ER_ALLOC; return (rp); } /* * Free an extent region descriptor. EXTENT _MUST_ BE LOCKED! This * is safe as we do not block here. */ static void extent_free_region_descriptor(ex, rp) struct extent *ex; struct extent_region *rp; { int s; if (ex->ex_flags & EXF_FIXED) { struct extent_fixed *fex = (struct extent_fixed *)ex; /* * If someone's waiting for a region descriptor, * be nice and give them this one, rather than * just free'ing it back to the system. */ if (rp->er_flags & ER_ALLOC) { if (ex->ex_flags & EXF_FLWANTED) { /* Clear all but ER_ALLOC flag. */ rp->er_flags = ER_ALLOC; LIST_INSERT_HEAD(&fex->fex_freelist, rp, er_link); goto wake_em_up; } else { s = splhigh(); pool_put(&expool, rp); splx(s); } } else { /* Clear all flags. */ rp->er_flags = 0; LIST_INSERT_HEAD(&fex->fex_freelist, rp, er_link); } if (ex->ex_flags & EXF_FLWANTED) { wake_em_up: ex->ex_flags &= ~EXF_FLWANTED; wakeup(&fex->fex_freelist); } return; } /* * We know it's dynamically allocated if we get here. */ s = splhigh(); pool_put(&expool, rp); splx(s); } void extent_print(ex) struct extent *ex; { struct extent_region *rp; if (ex == NULL) panic("extent_print: NULL extent"); simple_lock(&ex->ex_slock); printf("extent `%s' (0x%lx - 0x%lx), flags = 0x%x\n", ex->ex_name, ex->ex_start, ex->ex_end, ex->ex_flags); LIST_FOREACH(rp, &ex->ex_regions, er_link) printf(" 0x%lx - 0x%lx\n", rp->er_start, rp->er_end); simple_unlock(&ex->ex_slock); }