diff options
Diffstat (limited to 'freebsd/sys/kern/subr_rman.c')
| -rw-r--r-- | freebsd/sys/kern/subr_rman.c | 163 |
1 files changed, 163 insertions, 0 deletions
diff --git a/freebsd/sys/kern/subr_rman.c b/freebsd/sys/kern/subr_rman.c index c3c87e44..a1982daf 100644 --- a/freebsd/sys/kern/subr_rman.c +++ b/freebsd/sys/kern/subr_rman.c @@ -140,6 +140,8 @@ rman_init(struct rman *rm) mtx_init(&rman_mtx, "rman head", NULL, MTX_DEF); } + if (rm->rm_start == 0 && rm->rm_end == 0) + rm->rm_end = ~0ul; if (rm->rm_type == RMAN_UNINIT) panic("rman_init"); if (rm->rm_type == RMAN_GAUGE) @@ -164,6 +166,8 @@ rman_manage_region(struct rman *rm, u_long start, u_long end) DPRINTF(("rman_manage_region: <%s> request: start %#lx, end %#lx\n", rm->rm_descr, start, end)); + if (start < rm->rm_start || end > rm->rm_end) + return EINVAL; r = int_alloc_resource(M_NOWAIT); if (r == NULL) return ENOMEM; @@ -270,6 +274,164 @@ rman_fini(struct rman *rm) return 0; } +int +rman_first_free_region(struct rman *rm, u_long *start, u_long *end) +{ + struct resource_i *r; + + mtx_lock(rm->rm_mtx); + TAILQ_FOREACH(r, &rm->rm_list, r_link) { + if (!(r->r_flags & RF_ALLOCATED)) { + *start = r->r_start; + *end = r->r_end; + mtx_unlock(rm->rm_mtx); + return (0); + } + } + mtx_unlock(rm->rm_mtx); + return (ENOENT); +} + +int +rman_last_free_region(struct rman *rm, u_long *start, u_long *end) +{ + struct resource_i *r; + + mtx_lock(rm->rm_mtx); + TAILQ_FOREACH_REVERSE(r, &rm->rm_list, resource_head, r_link) { + if (!(r->r_flags & RF_ALLOCATED)) { + *start = r->r_start; + *end = r->r_end; + mtx_unlock(rm->rm_mtx); + return (0); + } + } + mtx_unlock(rm->rm_mtx); + return (ENOENT); +} + +/* Shrink or extend one or both ends of an allocated resource. */ +int +rman_adjust_resource(struct resource *rr, u_long start, u_long end) +{ + struct resource_i *r, *s, *t, *new; + struct rman *rm; + + /* Not supported for shared resources. */ + r = rr->__r_i; + if (r->r_flags & (RF_TIMESHARE | RF_SHAREABLE)) + return (EINVAL); + + /* + * This does not support wholesale moving of a resource. At + * least part of the desired new range must overlap with the + * existing resource. + */ + if (end < r->r_start || r->r_end < start) + return (EINVAL); + + /* + * Find the two resource regions immediately adjacent to the + * allocated resource. + */ + rm = r->r_rm; + mtx_lock(rm->rm_mtx); +#ifdef INVARIANTS + TAILQ_FOREACH(s, &rm->rm_list, r_link) { + if (s == r) + break; + } + if (s == NULL) + panic("resource not in list"); +#endif + s = TAILQ_PREV(r, resource_head, r_link); + t = TAILQ_NEXT(r, r_link); + KASSERT(s == NULL || s->r_end + 1 == r->r_start, + ("prev resource mismatch")); + KASSERT(t == NULL || r->r_end + 1 == t->r_start, + ("next resource mismatch")); + + /* + * See if the changes are permitted. Shrinking is always allowed, + * but growing requires sufficient room in the adjacent region. + */ + if (start < r->r_start && (s == NULL || (s->r_flags & RF_ALLOCATED) || + s->r_start > start)) { + mtx_unlock(rm->rm_mtx); + return (EBUSY); + } + if (end > r->r_end && (t == NULL || (t->r_flags & RF_ALLOCATED) || + t->r_end < end)) { + mtx_unlock(rm->rm_mtx); + return (EBUSY); + } + + /* + * While holding the lock, grow either end of the resource as + * needed and shrink either end if the shrinking does not require + * allocating a new resource. We can safely drop the lock and then + * insert a new range to handle the shrinking case afterwards. + */ + if (start < r->r_start || + (start > r->r_start && s != NULL && !(s->r_flags & RF_ALLOCATED))) { + KASSERT(s->r_flags == 0, ("prev is busy")); + r->r_start = start; + if (s->r_start == start) { + TAILQ_REMOVE(&rm->rm_list, s, r_link); + free(s, M_RMAN); + } else + s->r_end = start - 1; + } + if (end > r->r_end || + (end < r->r_end && t != NULL && !(t->r_flags & RF_ALLOCATED))) { + KASSERT(t->r_flags == 0, ("next is busy")); + r->r_end = end; + if (t->r_end == end) { + TAILQ_REMOVE(&rm->rm_list, t, r_link); + free(t, M_RMAN); + } else + t->r_start = end + 1; + } + mtx_unlock(rm->rm_mtx); + + /* + * Handle the shrinking cases that require allocating a new + * resource to hold the newly-free region. We have to recheck + * if we still need this new region after acquiring the lock. + */ + if (start > r->r_start) { + new = int_alloc_resource(M_WAITOK); + new->r_start = r->r_start; + new->r_end = start - 1; + new->r_rm = rm; + mtx_lock(rm->rm_mtx); + r->r_start = start; + s = TAILQ_PREV(r, resource_head, r_link); + if (s != NULL && !(s->r_flags & RF_ALLOCATED)) { + s->r_end = start - 1; + free(new, M_RMAN); + } else + TAILQ_INSERT_BEFORE(r, new, r_link); + mtx_unlock(rm->rm_mtx); + } + if (end < r->r_end) { + new = int_alloc_resource(M_WAITOK); + new->r_start = end + 1; + new->r_end = r->r_end; + new->r_rm = rm; + mtx_lock(rm->rm_mtx); + r->r_end = end; + t = TAILQ_NEXT(r, r_link); + if (t != NULL && !(t->r_flags & RF_ALLOCATED)) { + t->r_start = end + 1; + free(new, M_RMAN); + } else + TAILQ_INSERT_AFTER(&rm->rm_list, r, new, r_link); + mtx_unlock(rm->rm_mtx); + } + return (0); +} + struct resource * rman_reserve_resource_bound(struct rman *rm, u_long start, u_long end, u_long count, u_long bound, u_int flags, @@ -679,6 +841,7 @@ int_rman_release_resource(struct rman *rm, struct resource_i *r) * without freeing anything. */ r->r_flags &= ~RF_ALLOCATED; + r->r_dev = NULL; return 0; } |