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 15/72] xarray: Add xas_next and xas_prev Date: Mon, 11 Jun 2018 07:05:42 -0700 Message-Id: <20180611140639.17215-16-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 These two functions move the xas index by one position, and adjust the rest of the iterator state to match it. This is more efficient than calling xas_set() as it keeps the iterator at the leaves of the tree instead of walking the iterator from the root each time. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 67 +++++++ lib/xarray.c | 74 +++++++ tools/testing/radix-tree/xarray-test.c | 261 ++++++++++++++++++++++++- 3 files changed, 401 insertions(+), 1 deletion(-) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index 6273dd222fda..dd941454bb5b 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -700,6 +700,12 @@ static inline bool xas_not_node(struct xa_node *node) return ((unsigned long)node & 3) || !node; } +/* True if the node represents RESTART or an error */ +static inline bool xas_frozen(struct xa_node *node) +{ + return (unsigned long)node & 2; +} + /* True if the node represents head-of-tree, RESTART or BOUNDS */ static inline bool xas_top(struct xa_node *node) { @@ -958,6 +964,67 @@ enum { for (entry = xas_find_tagged(xas, max, tag); entry; \ entry = xas_next_tagged(xas, max, tag)) +void *__xas_next(struct xa_state *); +void *__xas_prev(struct xa_state *); + +/** + * xas_prev() - Move iterator to previous index. + * @xas: XArray operation state. + * + * If the @xas was in an error state, it will remain in an error state + * and this function will return %NULL. If the @xas has never been walked, + * it will have the effect of calling xas_load(). Otherwise one will be + * subtracted from the index and the state will be walked to the correct + * location in the array for the next operation. + * + * If the iterator was referencing index 0, this function wraps + * around to %ULONG_MAX. + * + * Return: The entry at the new index. This may be %NULL or an internal + * entry. + */ +static inline void *xas_prev(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset == 0)) + return __xas_prev(xas); + + xas->xa_index--; + xas->xa_offset--; + return xa_entry(xas->xa, node, xas->xa_offset); +} + +/** + * xas_next() - Move state to next index. + * @xas: XArray operation state. + * + * If the @xas was in an error state, it will remain in an error state + * and this function will return %NULL. If the @xas has never been walked, + * it will have the effect of calling xas_load(). Otherwise one will be + * added to the index and the state will be walked to the correct + * location in the array for the next operation. + * + * If the iterator was referencing index %ULONG_MAX, this function wraps + * around to 0. + * + * Return: The entry at the new index. This may be %NULL or an internal + * entry. + */ +static inline void *xas_next(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset == XA_CHUNK_MASK)) + return __xas_next(xas); + + xas->xa_index++; + xas->xa_offset++; + return xa_entry(xas->xa, node, xas->xa_offset); +} + /* Internal functions, mostly shared between radix-tree.c, xarray.c and idr.c */ void xas_destroy(struct xa_state *); diff --git a/lib/xarray.c b/lib/xarray.c index c505084ad43a..3b2c2f2240bf 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -877,6 +877,80 @@ void xas_pause(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_pause); +/* + * __xas_prev() - Find the previous entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_prev() which handles all the complex cases + * out of line. + */ +void *__xas_prev(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index--; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset--; + + while (xas->xa_offset == 255) { + xas->xa_offset = xas->xa_node->offset - 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } +} +EXPORT_SYMBOL_GPL(__xas_prev); + +/* + * __xas_next() - Find the next entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_next() which handles all the complex cases + * out of line. + */ +void *__xas_next(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index++; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset++; + + while (xas->xa_offset == XA_CHUNK_SIZE) { + xas->xa_offset = xas->xa_node->offset + 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas_set_offset(xas); + } +} +EXPORT_SYMBOL_GPL(__xas_next); + /** * xas_find() - Find the next present entry in the XArray. * @xas: XArray operation state. diff --git a/tools/testing/radix-tree/xarray-test.c b/tools/testing/radix-tree/xarray-test.c index 24eb1bda4a79..eeafbf8c948c 100644 --- a/tools/testing/radix-tree/xarray-test.c +++ b/tools/testing/radix-tree/xarray-test.c @@ -53,6 +53,147 @@ void check_xa_tag(struct xarray *xa) xa_store(xa, 0, NULL, 0); } +/* Check that putting the xas into an error state works correctly */ +void check_xas_error(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + + assert(xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL) == 0); + assert(xa_load(xa, 1) == xa_mk_value(1)); + + assert(xas_error(&xas) == 0); + + xas_set_err(&xas, -ENOTTY); + assert(xas_error(&xas) == -ENOTTY); + + xas_set_err(&xas, -ENOSPC); + assert(xas_error(&xas) == -ENOSPC); + + xas_set_err(&xas, -ENOMEM); + assert(xas_error(&xas) == -ENOMEM); + + assert(xas_load(&xas) == NULL); + assert(xas_store(&xas, &xas) == NULL); + assert(xas_load(&xas) == NULL); + + assert(xas.xa_index == 0); + assert(xas_next(&xas) == NULL); + assert(xas.xa_index == 0); + + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == 0); + + xas_retry(&xas, XA_RETRY_ENTRY); + assert(xas_error(&xas) == 0); + + assert(xas_find(&xas, ULONG_MAX) == xa_mk_value(1)); + assert(xas.xa_index == 1); + assert(xas_error(&xas) == 0); + + assert(xas_find(&xas, ULONG_MAX) == NULL); + assert(xas.xa_index > 1); + assert(xas_error(&xas) == 0); + assert(xas.xa_node == XAS_BOUNDS); +} + +void check_xas_pause(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + void *entry; + unsigned int seen; + + xa_store(xa, 0, xa_mk_value(0), GFP_KERNEL); + xa_set_tag(xa, 0, XA_TAG_0); + + seen = 0; + rcu_read_lock(); + xas_for_each_tagged(&xas, entry, ULONG_MAX, XA_TAG_0) { + if (!seen++) { + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + xa_set_tag(xa, 1, XA_TAG_0); + } + } + rcu_read_unlock(); + /* We don't see an entry that was added after we started */ + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each_tagged(&xas, entry, ULONG_MAX, XA_TAG_0) { + if (!seen++) + xa_erase(xa, 1); + } + rcu_read_unlock(); + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!seen++) + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + } + rcu_read_unlock(); + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!seen++) + xa_erase(xa, 1); + } + rcu_read_unlock(); + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + for (entry = xas_load(&xas); entry; entry = xas_next(&xas)) { + if (!seen++) + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + } + rcu_read_unlock(); + assert(seen == 2); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + for (entry = xas_load(&xas); entry; entry = xas_next(&xas)) { + if (!seen++) + xa_erase(xa, 1); + } + rcu_read_unlock(); + assert(seen == 1); + + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + seen = 0; + xas_set(&xas, 0); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!seen++) + xas_pause(&xas); + } + assert(seen == 2); + + seen = 0; + xas_set(&xas, 0); + for (entry = xas_load(&xas); entry; entry = xas_next(&xas)) { + if (!seen++) + xas_pause(&xas); + } + assert(seen == 2); + + seen = 0; + xas_set(&xas, 0); + xa_set_tag(xa, 1, XA_TAG_0); + xas_for_each_tagged(&xas, entry, ULONG_MAX, XA_TAG_0) { + if (!seen++) + xas_pause(&xas); + } + assert(seen == 2); +} + void check_xas_retry(struct xarray *xa) { XA_STATE(xas, xa, 0); @@ -65,7 +206,7 @@ void check_xas_retry(struct xarray *xa) assert(xa_is_retry(xas_reload(&xas))); assert(!xas_retry(&xas, NULL)); assert(!xas_retry(&xas, xa_mk_value(0))); - assert(xas_retry(&xas, XA_RETRY_ENTRY)); + xas_reset(&xas); assert(xas.xa_node == XAS_RESTART); assert(xas_next_entry(&xas, ULONG_MAX) == xa_mk_value(0)); assert(xas.xa_node == NULL); @@ -269,9 +410,108 @@ void check_xas_delete(struct xarray *xa) } } +void check_move_small(struct xarray *xa, unsigned long idx) +{ + XA_STATE(xas, xa, 0); + unsigned long i; + + xa_store(xa, 0, xa_mk_value(0), GFP_KERNEL); + xa_store(xa, idx, xa_mk_value(idx), GFP_KERNEL); + + for (i = 0; i < idx * 4; i++) { + void *entry = xas_next(&xas); + if (i <= idx) + assert(xas.xa_node != XAS_RESTART); + assert(xas.xa_index == i); + if (i == 0 || i == idx) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + } + xas_next(&xas); + assert(xas.xa_index == i); + + do { + void *entry = xas_prev(&xas); + i--; + if (i <= idx) + assert(xas.xa_node != XAS_RESTART); + assert(xas.xa_index == i); + if (i == 0 || i == idx) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + } while (i > 0); + + xas_set(&xas, ULONG_MAX); + assert(xas_next(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); + assert(xas_next(&xas) == xa_mk_value(0)); + assert(xas.xa_index == 0); + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); +} + +void check_move(struct xarray *xa) +{ + XA_STATE(xas, xa, (1 << 16) - 1); + unsigned long i; + + for (i = 0; i < (1 << 16); i++) { + xa_store(xa, i, xa_mk_value(i), GFP_KERNEL); + } + + do { + void *entry = xas_prev(&xas); + i--; + assert(entry == xa_mk_value(i)); + assert(i == xas.xa_index); + } while (i != 0); + + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); + + do { + void *entry = xas_next(&xas); + assert(entry == xa_mk_value(i)); + assert(i == xas.xa_index); + i++; + } while (i < (1 << 16)); + + for (i = (1 << 8); i < (1 << 15); i++) { + xa_erase(xa, i); + } + + i = xas.xa_index; + + do { + void *entry = xas_prev(&xas); + i--; + if ((i < (1 << 8)) || (i >= (1 << 15))) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + assert(i == xas.xa_index); + } while (i != 0); + + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); + + do { + void *entry = xas_next(&xas); + if ((i < (1 << 8)) || (i >= (1 << 15))) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + assert(i == xas.xa_index); + i++; + } while (i < (1 << 16)); +} + void xarray_checks(void) { DEFINE_XARRAY(array); + unsigned long i; check_xa_err(&array); item_kill_tree(&array); @@ -279,9 +519,15 @@ void xarray_checks(void) check_xa_tag(&array); item_kill_tree(&array); + check_xas_error(&array); + item_kill_tree(&array); + check_xas_retry(&array); item_kill_tree(&array); + check_xas_pause(&array); + item_kill_tree(&array); + check_xa_load(&array); item_kill_tree(&array); @@ -295,6 +541,19 @@ void xarray_checks(void) check_find(&array); check_xas_delete(&array); item_kill_tree(&array); + + for (i = 0; i < 16; i++) { + check_move_small(&array, 1UL << i); + item_kill_tree(&array); + } + + for (i = 2; i < 16; i++) { + check_move_small(&array, (1UL << i) - 1); + item_kill_tree(&array); + } + + check_move(&array); + item_kill_tree(&array); } int __weak main(void) -- 2.17.1