diff options
| author | Mark Kettenis <kettenis@cvs.openbsd.org> | 2019-09-11 12:30:36 +0000 |
|---|---|---|
| committer | Mark Kettenis <kettenis@cvs.openbsd.org> | 2019-09-11 12:30:36 +0000 |
| commit | dfb478e4e59ce9fb3c42672d334998fe15660625 (patch) | |
| tree | 1efd5d3d0186087ed2b4b7d3acd09643264dc809 /sys | |
| parent | 8f0069afd498f879698c6d0055bf290dec6cf6fc (diff) | |
Make it possible to free overlapping regions (effectively allowing
freeing parts of regions that are already free) when the EX_CONFLICTOK
flag is passed to extent_free.
ok jmatthew@
Diffstat (limited to 'sys')
| -rw-r--r-- | sys/kern/subr_extent.c | 31 |
1 files changed, 26 insertions, 5 deletions
diff --git a/sys/kern/subr_extent.c b/sys/kern/subr_extent.c index 09132e69dd5..43e4aa20357 100644 --- a/sys/kern/subr_extent.c +++ b/sys/kern/subr_extent.c @@ -1,4 +1,4 @@ -/* $OpenBSD: subr_extent.c,v 1.61 2019/08/28 22:22:43 kettenis Exp $ */ +/* $OpenBSD: subr_extent.c,v 1.62 2019/09/11 12:30:34 kettenis Exp $ */ /* $NetBSD: subr_extent.c,v 1.7 1996/11/21 18:46:34 cgd Exp $ */ /*- @@ -962,6 +962,7 @@ int extent_free(struct extent *ex, u_long start, u_long size, int flags) { struct extent_region *rp, *nrp = NULL; + struct extent_region *tmp; u_long end = start + (size - 1); int exflags; int error = 0; @@ -1019,8 +1020,12 @@ extent_free(struct extent *ex, u_long start, u_long size, int flags) * * Cases 2, 3, and 4 require that the EXF_NOCOALESCE flag * is not set. + * + * If the EX_CONFLICTOK flag is set, partially overlapping + * regions are allowed. This is handled in cases 1a, 2a and + * 3a below. */ - LIST_FOREACH(rp, &ex->ex_regions, er_link) { + LIST_FOREACH_SAFE(rp, &ex->ex_regions, er_link, tmp) { /* * Save ourselves some comparisons; does the current * region end before chunk to be freed begins? If so, @@ -1080,12 +1085,28 @@ extent_free(struct extent *ex, u_long start, u_long size, int flags) nrp = NULL; goto done; } + + if ((flags & EX_CONFLICTOK) == 0) + continue; + + /* Case 1a. */ + if ((start <= rp->er_start && end >= rp->er_end)) { + LIST_REMOVE(rp, er_link); + extent_free_region_descriptor(ex, rp); + continue; + } + + /* Case 2a. */ + if ((start <= rp->er_start) && (end >= rp->er_start)) + rp->er_start = (end + 1); + + /* Case 3a. */ + if ((start <= rp->er_end) && (end >= rp->er_end)) + rp->er_end = (start - 1); } - if (flags & EX_CONFLICTOK) { - error = EINVAL; + if (flags & EX_CONFLICTOK) goto done; - } /* Region not found, or request otherwise invalid. */ #if defined(DIAGNOSTIC) || defined(DDB) |