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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-11 20:06:18 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-11 20:06:18 -0700 |
commit | ea295481b6e313b4ea3ca2720ffcafd6005b5643 (patch) | |
tree | 85cade73987615fb5d86acdf2c7eac0a0378e255 /lib | |
parent | f3124ccf025caf25b764d900d1f9c49731673e49 (diff) | |
parent | 4a5c8d898948d1ac876522cdd62f07a78104bfe9 (diff) | |
download | linux-ea295481b6e313b4ea3ca2720ffcafd6005b5643.tar.bz2 |
Merge tag 'xarray-5.1-rc1' of git://git.infradead.org/users/willy/linux-dax
Pull XArray updates from Matthew Wilcox:
"This pull request changes the xa_alloc() API. I'm only aware of one
subsystem that has started trying to use it, and we agree on the fixup
as part of the merge.
The xa_insert() error code also changed to match xa_alloc() (EEXIST to
EBUSY), and I added xa_alloc_cyclic(). Beyond that, the usual
bugfixes, optimisations and tweaking.
I now have a git tree with all users of the radix tree and IDR
converted over to the XArray that I'll be feeding to maintainers over
the next few weeks"
* tag 'xarray-5.1-rc1' of git://git.infradead.org/users/willy/linux-dax:
XArray: Fix xa_reserve for 2-byte aligned entries
XArray: Fix xa_erase of 2-byte aligned entries
XArray: Use xa_cmpxchg to implement xa_reserve
XArray: Fix xa_release in allocating arrays
XArray: Mark xa_insert and xa_reserve as must_check
XArray: Add cyclic allocation
XArray: Redesign xa_alloc API
XArray: Add support for 1s-based allocation
XArray: Change xa_insert to return -EBUSY
XArray: Update xa_erase family descriptions
XArray tests: RCU lock prohibits GFP_KERNEL
Diffstat (limited to 'lib')
-rw-r--r-- | lib/test_xarray.c | 288 | ||||
-rw-r--r-- | lib/xarray.c | 163 |
2 files changed, 324 insertions, 127 deletions
diff --git a/lib/test_xarray.c b/lib/test_xarray.c index c596a957f764..5d4bad8bd96a 100644 --- a/lib/test_xarray.c +++ b/lib/test_xarray.c @@ -40,9 +40,9 @@ static void *xa_store_index(struct xarray *xa, unsigned long index, gfp_t gfp) static void xa_alloc_index(struct xarray *xa, unsigned long index, gfp_t gfp) { - u32 id = 0; + u32 id; - XA_BUG_ON(xa, xa_alloc(xa, &id, UINT_MAX, xa_mk_index(index), + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(index), xa_limit_32b, gfp) != 0); XA_BUG_ON(xa, id != index); } @@ -107,8 +107,11 @@ static noinline void check_xas_retry(struct xarray *xa) XA_BUG_ON(xa, xas.xa_node != XAS_RESTART); XA_BUG_ON(xa, xas_next_entry(&xas, ULONG_MAX) != xa_mk_value(0)); XA_BUG_ON(xa, xas.xa_node != NULL); + rcu_read_unlock(); XA_BUG_ON(xa, xa_store_index(xa, 1, GFP_KERNEL) != NULL); + + rcu_read_lock(); XA_BUG_ON(xa, !xa_is_internal(xas_reload(&xas))); xas.xa_node = XAS_RESTART; XA_BUG_ON(xa, xas_next_entry(&xas, ULONG_MAX) != xa_mk_value(0)); @@ -343,7 +346,7 @@ static noinline void check_cmpxchg(struct xarray *xa) XA_BUG_ON(xa, !xa_empty(xa)); XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_KERNEL) != NULL); - XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EEXIST); + XA_BUG_ON(xa, xa_insert(xa, 12345678, xa, GFP_KERNEL) != -EBUSY); XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, SIX, FIVE, GFP_KERNEL) != LOTS); XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, LOTS, FIVE, GFP_KERNEL) != LOTS); XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, FIVE, LOTS, GFP_KERNEL) != FIVE); @@ -358,46 +361,65 @@ static noinline void check_reserve(struct xarray *xa) { void *entry; unsigned long index; + int count; /* An array with a reserved entry is not empty */ XA_BUG_ON(xa, !xa_empty(xa)); - xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0); XA_BUG_ON(xa, xa_empty(xa)); XA_BUG_ON(xa, xa_load(xa, 12345678)); xa_release(xa, 12345678); XA_BUG_ON(xa, !xa_empty(xa)); /* Releasing a used entry does nothing */ - xa_reserve(xa, 12345678, GFP_KERNEL); + XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0); XA_BUG_ON(xa, xa_store_index(xa, 12345678, GFP_NOWAIT) != NULL); xa_release(xa, 12345678); xa_erase_index(xa, 12345678); XA_BUG_ON(xa, !xa_empty(xa)); - /* cmpxchg sees a reserved entry as NULL */ - xa_reserve(xa, 12345678, GFP_KERNEL); - XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, NULL, xa_mk_value(12345678), - GFP_NOWAIT) != NULL); + /* cmpxchg sees a reserved entry as ZERO */ + XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0); + XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, XA_ZERO_ENTRY, + xa_mk_value(12345678), GFP_NOWAIT) != NULL); xa_release(xa, 12345678); xa_erase_index(xa, 12345678); XA_BUG_ON(xa, !xa_empty(xa)); - /* But xa_insert does not */ - xa_reserve(xa, 12345678, GFP_KERNEL); + /* xa_insert treats it as busy */ + XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0); XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) != - -EEXIST); + -EBUSY); XA_BUG_ON(xa, xa_empty(xa)); XA_BUG_ON(xa, xa_erase(xa, 12345678) != NULL); XA_BUG_ON(xa, !xa_empty(xa)); /* Can iterate through a reserved entry */ xa_store_index(xa, 5, GFP_KERNEL); - xa_reserve(xa, 6, GFP_KERNEL); + XA_BUG_ON(xa, xa_reserve(xa, 6, GFP_KERNEL) != 0); xa_store_index(xa, 7, GFP_KERNEL); + count = 0; xa_for_each(xa, index, entry) { XA_BUG_ON(xa, index != 5 && index != 7); + count++; + } + XA_BUG_ON(xa, count != 2); + + /* If we free a reserved entry, we should be able to allocate it */ + if (xa->xa_flags & XA_FLAGS_ALLOC) { + u32 id; + + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(8), + XA_LIMIT(5, 10), GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 8); + + xa_release(xa, 6); + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_value(6), + XA_LIMIT(5, 10), GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 6); } + xa_destroy(xa); } @@ -586,64 +608,194 @@ static noinline void check_multi_store(struct xarray *xa) #endif } -static DEFINE_XARRAY_ALLOC(xa0); - -static noinline void check_xa_alloc(void) +static noinline void check_xa_alloc_1(struct xarray *xa, unsigned int base) { int i; u32 id; - /* An empty array should assign 0 to the first alloc */ - xa_alloc_index(&xa0, 0, GFP_KERNEL); + XA_BUG_ON(xa, !xa_empty(xa)); + /* An empty array should assign %base to the first alloc */ + xa_alloc_index(xa, base, GFP_KERNEL); /* Erasing it should make the array empty again */ - xa_erase_index(&xa0, 0); - XA_BUG_ON(&xa0, !xa_empty(&xa0)); + xa_erase_index(xa, base); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* And it should assign %base again */ + xa_alloc_index(xa, base, GFP_KERNEL); + + /* Allocating and then erasing a lot should not lose base */ + for (i = base + 1; i < 2 * XA_CHUNK_SIZE; i++) + xa_alloc_index(xa, i, GFP_KERNEL); + for (i = base; i < 2 * XA_CHUNK_SIZE; i++) + xa_erase_index(xa, i); + xa_alloc_index(xa, base, GFP_KERNEL); - /* And it should assign 0 again */ - xa_alloc_index(&xa0, 0, GFP_KERNEL); + /* Destroying the array should do the same as erasing */ + xa_destroy(xa); + + /* And it should assign %base again */ + xa_alloc_index(xa, base, GFP_KERNEL); - /* The next assigned ID should be 1 */ - xa_alloc_index(&xa0, 1, GFP_KERNEL); - xa_erase_index(&xa0, 1); + /* The next assigned ID should be base+1 */ + xa_alloc_index(xa, base + 1, GFP_KERNEL); + xa_erase_index(xa, base + 1); /* Storing a value should mark it used */ - xa_store_index(&xa0, 1, GFP_KERNEL); - xa_alloc_index(&xa0, 2, GFP_KERNEL); + xa_store_index(xa, base + 1, GFP_KERNEL); + xa_alloc_index(xa, base + 2, GFP_KERNEL); - /* If we then erase 0, it should be free */ - xa_erase_index(&xa0, 0); - xa_alloc_index(&xa0, 0, GFP_KERNEL); + /* If we then erase base, it should be free */ + xa_erase_index(xa, base); + xa_alloc_index(xa, base, GFP_KERNEL); - xa_erase_index(&xa0, 1); - xa_erase_index(&xa0, 2); + xa_erase_index(xa, base + 1); + xa_erase_index(xa, base + 2); for (i = 1; i < 5000; i++) { - xa_alloc_index(&xa0, i, GFP_KERNEL); + xa_alloc_index(xa, base + i, GFP_KERNEL); } - xa_destroy(&xa0); + xa_destroy(xa); - id = 0xfffffffeU; - XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, UINT_MAX, xa_mk_index(id), + /* Check that we fail properly at the limit of allocation */ + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(UINT_MAX - 1), + XA_LIMIT(UINT_MAX - 1, UINT_MAX), GFP_KERNEL) != 0); - XA_BUG_ON(&xa0, id != 0xfffffffeU); - XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, UINT_MAX, xa_mk_index(id), + XA_BUG_ON(xa, id != 0xfffffffeU); + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(UINT_MAX), + XA_LIMIT(UINT_MAX - 1, UINT_MAX), GFP_KERNEL) != 0); - XA_BUG_ON(&xa0, id != 0xffffffffU); - XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, UINT_MAX, xa_mk_index(id), - GFP_KERNEL) != -ENOSPC); - XA_BUG_ON(&xa0, id != 0xffffffffU); - xa_destroy(&xa0); - - id = 10; - XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, 5, xa_mk_index(id), - GFP_KERNEL) != -ENOSPC); - XA_BUG_ON(&xa0, xa_store_index(&xa0, 3, GFP_KERNEL) != 0); - XA_BUG_ON(&xa0, xa_alloc(&xa0, &id, 5, xa_mk_index(id), - GFP_KERNEL) != -ENOSPC); - xa_erase_index(&xa0, 3); - XA_BUG_ON(&xa0, !xa_empty(&xa0)); + XA_BUG_ON(xa, id != 0xffffffffU); + id = 3; + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(0), + XA_LIMIT(UINT_MAX - 1, UINT_MAX), + GFP_KERNEL) != -EBUSY); + XA_BUG_ON(xa, id != 3); + xa_destroy(xa); + + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(10), XA_LIMIT(10, 5), + GFP_KERNEL) != -EBUSY); + XA_BUG_ON(xa, xa_store_index(xa, 3, GFP_KERNEL) != 0); + XA_BUG_ON(xa, xa_alloc(xa, &id, xa_mk_index(10), XA_LIMIT(10, 5), + GFP_KERNEL) != -EBUSY); + xa_erase_index(xa, 3); + XA_BUG_ON(xa, !xa_empty(xa)); +} + +static noinline void check_xa_alloc_2(struct xarray *xa, unsigned int base) +{ + unsigned int i, id; + unsigned long index; + void *entry; + + /* Allocate and free a NULL and check xa_empty() behaves */ + XA_BUG_ON(xa, !xa_empty(xa)); + XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != base); + XA_BUG_ON(xa, xa_empty(xa)); + XA_BUG_ON(xa, xa_erase(xa, id) != NULL); + XA_BUG_ON(xa, !xa_empty(xa)); + + /* Ditto, but check destroy instead of erase */ + XA_BUG_ON(xa, !xa_empty(xa)); + XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != base); + XA_BUG_ON(xa, xa_empty(xa)); + xa_destroy(xa); + XA_BUG_ON(xa, !xa_empty(xa)); + + for (i = base; i < base + 10; i++) { + XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, + GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != i); + } + + XA_BUG_ON(xa, xa_store(xa, 3, xa_mk_index(3), GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_store(xa, 4, xa_mk_index(4), GFP_KERNEL) != NULL); + XA_BUG_ON(xa, xa_store(xa, 4, NULL, GFP_KERNEL) != xa_mk_index(4)); + XA_BUG_ON(xa, xa_erase(xa, 5) != NULL); + XA_BUG_ON(xa, xa_alloc(xa, &id, NULL, xa_limit_32b, GFP_KERNEL) != 0); + XA_BUG_ON(xa, id != 5); + + xa_for_each(xa, index, entry) { + xa_erase_index(xa, index); + } + + for (i = base; i < base + 9; i++) { + XA_BUG_ON(xa, xa_erase(xa, i) != NULL); + XA_BUG_ON(xa, xa_empty(xa)); + } + XA_BUG_ON(xa, xa_erase(xa, 8) != NULL); + XA_BUG_ON(xa, xa_empty(xa)); + XA_BUG_ON(xa, xa_erase(xa, base + 9) != NULL); + XA_BUG_ON(xa, !xa_empty(xa)); + + 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); + +static noinline void check_xa_alloc(void) +{ + check_xa_alloc_1(&xa0, 0); + 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, @@ -1194,9 +1346,8 @@ static void check_align_1(struct xarray *xa, char *name) void *entry; for (i = 0; i < 8; i++) { - id = 0; - XA_BUG_ON(xa, xa_alloc(xa, &id, UINT_MAX, name + i, GFP_KERNEL) - != 0); + XA_BUG_ON(xa, xa_alloc(xa, &id, name + i, xa_limit_32b, + GFP_KERNEL) != 0); XA_BUG_ON(xa, id != i); } xa_for_each(xa, index, entry) @@ -1204,6 +1355,30 @@ static void check_align_1(struct xarray *xa, char *name) xa_destroy(xa); } +/* + * We should always be able to store without allocating memory after + * reserving a slot. + */ +static void check_align_2(struct xarray *xa, char *name) +{ + int i; + + XA_BUG_ON(xa, !xa_empty(xa)); + + for (i = 0; i < 8; i++) { + XA_BUG_ON(xa, xa_store(xa, 0, name + i, GFP_KERNEL) != NULL); + xa_erase(xa, 0); + } + + for (i = 0; i < 8; i++) { + XA_BUG_ON(xa, xa_reserve(xa, 0, GFP_KERNEL) != 0); + XA_BUG_ON(xa, xa_store(xa, 0, name + i, 0) != NULL); + xa_erase(xa, 0); + } + + XA_BUG_ON(xa, !xa_empty(xa)); +} + static noinline void check_align(struct xarray *xa) { char name[] = "Motorola 68000"; @@ -1212,7 +1387,7 @@ static noinline void check_align(struct xarray *xa) check_align_1(xa, name + 1); check_align_1(xa, name + 2); check_align_1(xa, name + 3); -// check_align_2(xa, name); + check_align_2(xa, name); } static LIST_HEAD(shadow_nodes); @@ -1354,6 +1529,7 @@ static int xarray_checks(void) check_xas_erase(&array); check_cmpxchg(&array); check_reserve(&array); + check_reserve(&xa0); check_multi_store(&array); check_xa_alloc(); check_find(&array); diff --git a/lib/xarray.c b/lib/xarray.c index 81c3171ddde9..6be3acbb861f 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -57,6 +57,11 @@ static inline bool xa_track_free(const struct xarray *xa) return xa->xa_flags & XA_FLAGS_TRACK_FREE; } +static inline bool xa_zero_busy(const struct xarray *xa) +{ + return xa->xa_flags & XA_FLAGS_ZERO_BUSY; +} + static inline void xa_mark_set(struct xarray *xa, xa_mark_t mark) { if (!(xa->xa_flags & XA_FLAGS_MARK(mark))) @@ -432,6 +437,8 @@ static void xas_shrink(struct xa_state *xas) break; if (!xa_is_node(entry) && node->shift) break; + if (xa_is_zero(entry) && xa_zero_busy(xa)) + entry = NULL; xas->xa_node = XAS_BOUNDS; RCU_INIT_POINTER(xa->xa_head, entry); @@ -628,6 +635,8 @@ static void *xas_create(struct xa_state *xas, bool allow_root) if (xas_top(node)) { entry = xa_head_locked(xa); xas->xa_node = NULL; + if (!entry && xa_zero_busy(xa)) + entry = XA_ZERO_ENTRY; shift = xas_expand(xas, entry); if (shift < 0) return NULL; @@ -758,10 +767,12 @@ void *xas_store(struct xa_state *xas, void *entry) void *first, *next; bool value = xa_is_value(entry); - if (entry) - first = xas_create(xas, !xa_is_node(entry)); - else + if (entry) { + bool allow_root = !xa_is_node(entry) && !xa_is_zero(entry); + first = xas_create(xas, allow_root); + } else { first = xas_load(xas); + } if (xas_invalid(xas)) return first; @@ -791,7 +802,7 @@ void *xas_store(struct xa_state *xas, void *entry) * entry is set to NULL. */ rcu_assign_pointer(*slot, entry); - if (xa_is_node(next)) + if (xa_is_node(next) && (!node || node->shift)) xas_free_nodes(xas, xa_to_node(next)); if (!node) break; @@ -1294,13 +1305,12 @@ static void *xas_result(struct xa_state *xas, void *curr) * @xa: XArray. * @index: Index into array. * - * If the entry at this index is a multi-index entry then all indices will - * be erased, and the entry will no longer be a multi-index entry. - * This function expects the xa_lock to be held on entry. + * After this function returns, loading from @index will return %NULL. + * If the index is part of a multi-index entry, all indices will be erased + * and none of the entries will be part of a multi-index entry. * - * Context: Any context. Expects xa_lock to be held on entry. May - * release and reacquire xa_lock if @gfp flags permit. - * Return: The old entry at this index. + * Context: Any context. Expects xa_lock to be held on entry. + * Return: The entry which used to be at this index. */ void *__xa_erase(struct xarray *xa, unsigned long index) { @@ -1314,9 +1324,9 @@ EXPORT_SYMBOL(__xa_erase); * @xa: XArray. * @index: Index of entry. * - * This function is the equivalent of calling xa_store() with %NULL as - * the third argument. The XArray does not need to allocate memory, so - * the user does not need to provide GFP flags. + * After this function returns, loading from @index will return %NULL. + * If the index is part of a multi-index entry, all indices will be erased + * and none of the entries will be part of a multi-index entry. * * Context: Any context. Takes and releases the xa_lock. * Return: The entry which used to be at this index. @@ -1421,16 +1431,12 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, if (WARN_ON_ONCE(xa_is_advanced(entry))) return XA_ERROR(-EINVAL); - if (xa_track_free(xa) && !entry) - entry = XA_ZERO_ENTRY; do { curr = xas_load(&xas); - if (curr == XA_ZERO_ENTRY) - curr = NULL; if (curr == old) { xas_store(&xas, entry); - if (xa_track_free(xa)) + if (xa_track_free(xa) && entry && !curr) xas_clear_mark(&xas, XA_FREE_MARK); } } while (__xas_nomem(&xas, gfp)); @@ -1452,7 +1458,7 @@ EXPORT_SYMBOL(__xa_cmpxchg); * * 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 store succeeded. -EEXIST if another entry was present. + * Return: 0 if the store succeeded. -EBUSY if another entry was present. * -ENOMEM if memory could not be allocated. */ int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) @@ -1472,7 +1478,7 @@ int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) if (xa_track_free(xa)) xas_clear_mark(&xas, XA_FREE_MARK); } else { - xas_set_err(&xas, -EEXIST); + xas_set_err(&xas, -EBUSY); } } while (__xas_nomem(&xas, gfp)); @@ -1480,42 +1486,6 @@ int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) } EXPORT_SYMBOL(__xa_insert); -/** - * __xa_reserve() - Reserve this index in the XArray. - * @xa: XArray. - * @index: Index into array. - * @gfp: Memory allocation flags. - * - * Ensures there is somewhere to store an entry at @index in the array. - * If there is already something stored at @index, this function does - * nothing. If there was nothing there, the entry is marked as reserved. - * Loading from a reserved entry returns a %NULL pointer. - * - * If you do not use the entry that you have reserved, call xa_release() - * or xa_erase() to free any unnecessary memory. - * - * Context: Any context. Expects the xa_lock to be held on entry. May - * release the lock, sleep and reacquire the lock if the @gfp flags permit. - * Return: 0 if the reservation succeeded or -ENOMEM if it failed. - */ -int __xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) -{ - XA_STATE(xas, xa, index); - void *curr; - - do { - curr = xas_load(&xas); - if (!curr) { - xas_store(&xas, XA_ZERO_ENTRY); - if (xa_track_free(xa)) - xas_clear_mark(&xas, XA_FREE_MARK); - } - } while (__xas_nomem(&xas, gfp)); - - return xas_error(&xas); -} -EXPORT_SYMBOL(__xa_reserve); - #ifdef CONFIG_XARRAY_MULTI static void xas_set_range(struct xa_state *xas, unsigned long first, unsigned long last) @@ -1607,23 +1577,23 @@ EXPORT_SYMBOL(xa_store_range); * __xa_alloc() - Find somewhere to store this entry in the XArray. * @xa: XArray. * @id: Pointer to ID. - * @max: Maximum ID to allocate (inclusive). + * @limit: Range for allocated ID. * @entry: New entry. * @gfp: Memory allocation flags. * - * Allocates an unused ID in the range specified by @id and @max. - * Updates the @id pointer with the index, then stores the entry at that - * index. A concurrent lookup will not see an uninitialised @id. + * 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. * * Context: Any context. Expects xa_lock to be held on entry. May * release and reacquire xa_lock if @gfp flags permit. - * Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if - * there is no more space in the XArray. + * Return: 0 on success, -ENOMEM if memory could not be allocated or + * -EBUSY if there are no free entries in @limit. */ -int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) +int __xa_alloc(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, gfp_t gfp) { XA_STATE(xas, xa, 0); - int err; if (WARN_ON_ONCE(xa_is_advanced(entry))) return -EINVAL; @@ -1634,22 +1604,71 @@ int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) entry = XA_ZERO_ENTRY; do { - xas.xa_index = *id; - xas_find_marked(&xas, max, XA_FREE_MARK); + xas.xa_index = limit.min; + xas_find_marked(&xas, limit.max, XA_FREE_MARK); if (xas.xa_node == XAS_RESTART) - xas_set_err(&xas, -ENOSPC); + xas_set_err(&xas, -EBUSY); + else + *id = xas.xa_index; xas_store(&xas, entry); xas_clear_mark(&xas, XA_FREE_MARK); } while (__xas_nomem(&xas, gfp)); - err = xas_error(&xas); - if (!err) - *id = xas.xa_index; - return err; + return xas_error(&xas); } 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. @@ -1943,6 +1962,8 @@ void xa_destroy(struct xarray *xa) entry = xa_head_locked(xa); RCU_INIT_POINTER(xa->xa_head, NULL); xas_init_marks(&xas); + if (xa_zero_busy(xa)) + xa_mark_clear(xa, XA_FREE_MARK); /* lockdep checks we're still holding the lock in xas_free_nodes() */ if (xa_is_node(entry)) xas_free_nodes(&xas, xa_to_node(entry)); |