diff options
Diffstat (limited to 'lib')
-rw-r--r-- | lib/test_xarray.c | 53 | ||||
-rw-r--r-- | lib/xarray.c | 50 |
2 files changed, 103 insertions, 0 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index b5a6b981454d..eaf53f742c72 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -715,6 +715,57 @@ static noinline void check_xa_alloc_2(struct xarray *xa, unsigned int base) xa_destroy(xa); } +static noinline void check_xa_alloc_3(struct xarray *xa, unsigned int base) +{ + struct xa_limit limit = XA_LIMIT(1, 0x3fff); + u32 next = 0; + unsigned int i, id; + unsigned long index; + void *entry; + + XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(1), limit, + &next, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 1); + + next = 0x3ffd; + XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(0x3ffd), limit, + &next, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 0x3ffd); + xa_erase_index(xa, 0x3ffd); + xa_erase_index(xa, 1); + XA_BUG_ON(xa, !xa_empty(xa)); + + for (i = 0x3ffe; i < 0x4003; i++) { + if (i < 0x4000) + entry = xa_mk_index(i); + else + entry = xa_mk_index(i - 0x3fff); + XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, entry, limit, + &next, GFP_KERNEL) != (id == 1)); + XA_BUG_ON(xa, xa_mk_index(id) != entry); + } + + /* Check wrap-around is handled correctly */ + if (base != 0) + xa_erase_index(xa, base); + xa_erase_index(xa, base + 1); + next = UINT_MAX; + XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(UINT_MAX), + xa_limit_32b, &next, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != UINT_MAX); + XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(base), + xa_limit_32b, &next, GFP_KERNEL) != 1); + XA_BUG_ON(xa, id != base); + XA_BUG_ON(xa, xa_alloc_cyclic(xa, &id, xa_mk_index(base + 1), + xa_limit_32b, &next, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != base + 1); + + xa_for_each(xa, index, entry) + xa_erase_index(xa, index); + + XA_BUG_ON(xa, !xa_empty(xa)); +} + static DEFINE_XARRAY_ALLOC(xa0); static DEFINE_XARRAY_ALLOC1(xa1); @@ -724,6 +775,8 @@ static noinline void check_xa_alloc(void) check_xa_alloc_1(&xa1, 1); check_xa_alloc_2(&xa0, 0); check_xa_alloc_2(&xa1, 1); + check_xa_alloc_3(&xa0, 0); + check_xa_alloc_3(&xa1, 1); } static noinline void __check_store_iter(struct xarray *xa, unsigned long start, diff --git a/lib/xarray.c b/lib/xarray.c index c707388fb05e..89e37ac50850 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1657,6 +1657,56 @@ int __xa_alloc(struct xarray *xa, u32 *id, void *entry, EXPORT_SYMBOL(__xa_alloc); /** + * __xa_alloc_cyclic() - Find somewhere to store this entry in the XArray. + * @xa: XArray. + * @id: Pointer to ID. + * @entry: New entry. + * @limit: Range of allocated ID. + * @next: Pointer to next ID to allocate. + * @gfp: Memory allocation flags. + * + * Finds an empty entry in @xa between @limit.min and @limit.max, + * stores the index into the @id pointer, then stores the entry at + * that index. A concurrent lookup will not see an uninitialised @id. + * The search for an empty entry will start at @next and will wrap + * around if necessary. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: 0 if the allocation succeeded without wrapping. 1 if the + * allocation succeeded after wrapping, -ENOMEM if memory could not be + * allocated or -EBUSY if there are no free entries in @limit. + */ +int __xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, u32 *next, gfp_t gfp) +{ + u32 min = limit.min; + int ret; + + limit.min = max(min, *next); + ret = __xa_alloc(xa, id, entry, limit, gfp); + if ((xa->xa_flags & XA_FLAGS_ALLOC_WRAPPED) && ret == 0) { + xa->xa_flags &= ~XA_FLAGS_ALLOC_WRAPPED; + ret = 1; + } + + if (ret < 0 && limit.min > min) { + limit.min = min; + ret = __xa_alloc(xa, id, entry, limit, gfp); + if (ret == 0) + ret = 1; + } + + if (ret >= 0) { + *next = *id + 1; + if (*next == 0) + xa->xa_flags |= XA_FLAGS_ALLOC_WRAPPED; + } + return ret; +} +EXPORT_SYMBOL(__xa_alloc_cyclic); + +/** * __xa_set_mark() - Set this mark on this entry while locked. * @xa: XArray. * @index: Index of entry. |