From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Matthew Wilcox To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Matthew Wilcox , Jan Kara , Jeff Layton , Lukas Czerner , Ross Zwisler , Christoph Hellwig , Goldwyn Rodrigues , Nicholas Piggin , Ryusuke Konishi , linux-nilfs@vger.kernel.org, Jaegeuk Kim , Chao Yu , linux-f2fs-devel@lists.sourceforge.net Subject: [PATCH v13 16/72] xarray: Add xas_for_each_conflict Date: Mon, 11 Jun 2018 07:05:43 -0700 Message-Id: <20180611140639.17215-17-willy@infradead.org> In-Reply-To: <20180611140639.17215-1-willy@infradead.org> References: <20180611140639.17215-1-willy@infradead.org> Sender: owner-linux-mm@kvack.org List-ID: From: Matthew Wilcox This iterator iterates over each entry that is stored in the index or indices specified by the xa_state. This is intended for use for a conditional store of a multiindex entry, or to allow entries which are about to be removed from the xarray to be disposed of properly. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 17 +++++++ lib/xarray.c | 61 +++++++++++++++++++++++++ tools/testing/radix-tree/xarray-test.c | 63 ++++++++++++++++++++++++++ 3 files changed, 141 insertions(+) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index dd941454bb5b..6a61aab11038 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -750,6 +750,7 @@ static inline bool xas_retry(struct xa_state *xas, const void *entry) void *xas_load(struct xa_state *); void *xas_store(struct xa_state *, void *entry); void *xas_find(struct xa_state *, unsigned long max); +void *xas_next_conflict(struct xa_state *); bool xas_get_tag(const struct xa_state *, xa_tag_t); void xas_set_tag(const struct xa_state *, xa_tag_t); @@ -964,6 +965,22 @@ enum { for (entry = xas_find_tagged(xas, max, tag); entry; \ entry = xas_next_tagged(xas, max, tag)) +/** + * xas_for_each_conflict() - Iterate over a range of an XArray. + * @xas: XArray operation state. + * @entry: Entry retrieved from the array. + * + * The loop body will be executed for each entry in the XArray that lies + * within the range specified by @xas. If the loop completes successfully, + * any entries that lie in this range will be replaced by @entry. The caller + * may break out of the loop; if they do so, the contents of the XArray will + * be unchanged. The operation may fail due to an out of memory condition. + * The caller may also call xa_set_err() to exit the loop while setting an + * error to record the reason. + */ +#define xas_for_each_conflict(xas, entry) \ + while ((entry = xas_next_conflict(xas))) + void *__xas_next(struct xa_state *); void *__xas_prev(struct xa_state *); diff --git a/lib/xarray.c b/lib/xarray.c index 3b2c2f2240bf..d76db0ff17cf 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1100,6 +1100,67 @@ void *xas_find_tagged(struct xa_state *xas, unsigned long max, xa_tag_t tag) } EXPORT_SYMBOL_GPL(xas_find_tagged); +/** + * xas_next_conflict() - Step for xas_for_each_conflict(). + * @xas: XArray operation state. + * + * This function does the work for xas_for_each_conflict(). + * + * Context: Any context. Expects xa_lock to be held. + * Return: The next entry in the range covered by @xas or %NULL. + */ +void *xas_next_conflict(struct xa_state *xas) +{ + void *curr; + + if (xas_error(xas)) + return NULL; + + if (!xas->xa_node) + return NULL; + + if (xas_top(xas->xa_node)) { + curr = xas_start(xas); + if (!curr) + return NULL; + while (xa_is_node(curr)) { + struct xa_node *node = xa_to_node(curr); + curr = xas_descend(xas, node); + } + if (curr) + return curr; + } + + if (xas->xa_node->shift > xas->xa_shift) + return NULL; + + for (;;) { + if (xas->xa_node->shift == xas->xa_shift) { + if ((xas->xa_offset & xas->xa_sibs) == xas->xa_sibs) + break; + } else if (xas->xa_offset == XA_CHUNK_MASK) { + xas->xa_offset = xas->xa_node->offset; + xas->xa_node = xas->xa_node->parent; + if (!xas->xa_node) + break; + continue; + } + curr = xa_entry_locked(xas->xa, xas->xa_node, ++xas->xa_offset); + if (xa_is_sibling(curr)) + continue; + while (xa_is_node(curr)) { + xas->xa_node = xa_to_node(curr); + xas->xa_offset = 0; + curr = xa_entry_locked(xas->xa, xas->xa_node, 0); + } + if (curr) + return curr; + } + xas->xa_offset -= xas->xa_sibs; + return NULL; +} +EXPORT_SYMBOL_GPL(xas_next_conflict); + /** * xa_init_flags() - Initialise an empty XArray with flags. * @xa: XArray. diff --git a/tools/testing/radix-tree/xarray-test.c b/tools/testing/radix-tree/xarray-test.c index eeafbf8c948c..296ace77c4f4 100644 --- a/tools/testing/radix-tree/xarray-test.c +++ b/tools/testing/radix-tree/xarray-test.c @@ -315,6 +315,68 @@ void check_multi_store(struct xarray *xa) BUG_ON(!xa_empty(xa)); } +void __check_store_iter(struct xarray *xa, unsigned long start, + unsigned int order, unsigned int present) +{ + XA_STATE_ORDER(xas, xa, start, order); + void *entry; + unsigned int count = 0; + +retry: + xas_for_each_conflict(&xas, entry) { + BUG_ON(!xa_is_value(entry)); + BUG_ON(entry < xa_mk_value(start)); + BUG_ON(entry > xa_mk_value(start + (1UL << order) - 1)); + count++; + } + xas_store(&xas, xa_mk_value(start)); + if (xas_nomem(&xas, GFP_KERNEL)) { + count = 0; + goto retry; + } + BUG_ON(xas_error(&xas)); + BUG_ON(count != present); + BUG_ON(xa_load(xa, start) != xa_mk_value(start)); + BUG_ON(xa_load(xa, start + (1UL << order) - 1) != xa_mk_value(start)); + xa_store(xa, start, NULL, 0); +} + +void check_store_iter(struct xarray *xa) +{ + unsigned int i, j; + + for (i = 0; i < 20; i++) { + unsigned int min = 1 << i; + unsigned int max = (2 << i) - 1; + __check_store_iter(xa, 0, i, 0); + BUG_ON(!xa_empty(xa)); + __check_store_iter(xa, min, i, 0); + BUG_ON(!xa_empty(xa)); + + xa_store(xa, min, xa_mk_value(min), GFP_KERNEL); + __check_store_iter(xa, min, i, 1); + BUG_ON(!xa_empty(xa)); + xa_store(xa, max, xa_mk_value(max), GFP_KERNEL); + __check_store_iter(xa, min, i, 1); + BUG_ON(!xa_empty(xa)); + + for (j = 0; j < min; j++) + xa_store(xa, j, xa_mk_value(j), GFP_KERNEL); + __check_store_iter(xa, 0, i, min); + BUG_ON(!xa_empty(xa)); + for (j = 0; j < min; j++) + xa_store(xa, min + j, xa_mk_value(min + j), GFP_KERNEL); + __check_store_iter(xa, min, i, min); + BUG_ON(!xa_empty(xa)); + } + xa_store(xa, 63, xa_mk_value(63), GFP_KERNEL); + xa_store(xa, 65, xa_mk_value(65), GFP_KERNEL); + __check_store_iter(xa, 64, 2, 1); + BUG_ON(xa_load(xa, 63) != xa_mk_value(63)); + xa_store(xa, 63, NULL, 0); + BUG_ON(!xa_empty(xa)); +} + void check_multi_find(struct xarray *xa) { unsigned long index; @@ -537,6 +599,7 @@ void xarray_checks(void) check_cmpxchg(&array); check_multi_store(&array); item_kill_tree(&array); + check_store_iter(&array); check_find(&array); check_xas_delete(&array); -- 2.17.1