From c5beb07e7a06b24f4f27304f6282b5dbd929543b Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 31 Oct 2018 14:39:28 -0400 Subject: [PATCH] XArray: Unify xa_cmpxchg and __xa_cmpxchg xa_cmpxchg() was one of the largest functions in the xarray implementation. By turning it into a wrapper and having the callers take the lock (like several other functions), we save 160 bytes on a tinyconfig build and reduce the duplication in xarray.c. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 113 +++++++++++++++++++++++++---------------- lib/xarray.c | 41 --------------- 2 files changed, 69 insertions(+), 85 deletions(-) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index c2cb0426c60c..8e59d4fbd55e 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -289,8 +289,6 @@ struct xarray { void xa_init_flags(struct xarray *, gfp_t flags); void *xa_load(struct xarray *, unsigned long index); void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); -void *xa_cmpxchg(struct xarray *, unsigned long index, - void *old, void *entry, gfp_t); void *xa_store_range(struct xarray *, unsigned long first, unsigned long last, void *entry, gfp_t); bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); @@ -359,48 +357,6 @@ static inline void *xa_erase(struct xarray *xa, unsigned long index) return xa_store(xa, index, NULL, 0); } -/** - * xa_insert() - Store this entry in the XArray unless another entry is - * already present. - * @xa: XArray. - * @index: Index into array. - * @entry: New entry. - * @gfp: Memory allocation flags. - * - * If you would rather see the existing entry in the array, use xa_cmpxchg(). - * This function is for users who don't care what the entry is, only that - * one is present. - * - * Context: Process context. Takes and releases the xa_lock. - * May sleep if the @gfp flags permit. - * Return: 0 if the store succeeded. -EEXIST if another entry was present. - * -ENOMEM if memory could not be allocated. - */ -static inline int xa_insert(struct xarray *xa, unsigned long index, - void *entry, gfp_t gfp) -{ - void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp); - if (!curr) - return 0; - if (xa_is_err(curr)) - return xa_err(curr); - return -EEXIST; -} - -/** - * xa_release() - Release a reserved entry. - * @xa: XArray. - * @index: Index of entry. - * - * After calling xa_reserve(), you can call this function to release the - * reservation. If the entry at @index has been stored to, this function - * will do nothing. - */ -static inline void xa_release(struct xarray *xa, unsigned long index) -{ - xa_cmpxchg(xa, index, NULL, NULL, 0); -} - /** * xa_for_each() - Iterate over a portion of an XArray. * @xa: XArray. @@ -534,6 +490,61 @@ static inline void *xa_erase_irq(struct xarray *xa, unsigned long index) return entry; } +/** + * xa_cmpxchg() - Conditionally replace an entry in the XArray. + * @xa: XArray. + * @index: Index into array. + * @old: Old value to test against. + * @entry: New value to place in array. + * @gfp: Memory allocation flags. + * + * If the entry at @index is the same as @old, replace it with @entry. + * If the return value is equal to @old, then the exchange was successful. + * + * Context: Any context. Takes and releases the xa_lock. May sleep + * if the @gfp flags permit. + * Return: The old value at this index or xa_err() if an error happened. + */ +static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index, + void *old, void *entry, gfp_t gfp) +{ + void *curr; + + xa_lock(xa); + curr = __xa_cmpxchg(xa, index, old, entry, gfp); + xa_unlock(xa); + + return curr; +} + +/** + * xa_insert() - Store this entry in the XArray unless another entry is + * already present. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * If you would rather see the existing entry in the array, use xa_cmpxchg(). + * This function is for users who don't care what the entry is, only that + * one is present. + * + * Context: Process context. Takes and releases the xa_lock. + * May sleep if the @gfp flags permit. + * Return: 0 if the store succeeded. -EEXIST if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +static inline int xa_insert(struct xarray *xa, unsigned long index, + void *entry, gfp_t gfp) +{ + void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp); + if (!curr) + return 0; + if (xa_is_err(curr)) + return xa_err(curr); + return -EEXIST; +} + /** * xa_alloc() - Find somewhere to store this entry in the XArray. * @xa: XArray. @@ -699,6 +710,20 @@ int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) return ret; } +/** + * xa_release() - Release a reserved entry. + * @xa: XArray. + * @index: Index of entry. + * + * After calling xa_reserve(), you can call this function to release the + * reservation. If the entry at @index has been stored to, this function + * will do nothing. + */ +static inline void xa_release(struct xarray *xa, unsigned long index) +{ + xa_cmpxchg(xa, index, NULL, NULL, 0); +} + /* Everything below here is the Advanced API. Proceed with caution. */ /* diff --git a/lib/xarray.c b/lib/xarray.c index 9cab8cfef8a8..77671d4a7910 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1406,47 +1406,6 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) } EXPORT_SYMBOL(__xa_store); -/** - * xa_cmpxchg() - Conditionally replace an entry in the XArray. - * @xa: XArray. - * @index: Index into array. - * @old: Old value to test against. - * @entry: New value to place in array. - * @gfp: Memory allocation flags. - * - * If the entry at @index is the same as @old, replace it with @entry. - * If the return value is equal to @old, then the exchange was successful. - * - * Context: Process context. Takes and releases the xa_lock. May sleep - * if the @gfp flags permit. - * Return: The old value at this index or xa_err() if an error happened. - */ -void *xa_cmpxchg(struct xarray *xa, unsigned long index, - void *old, void *entry, gfp_t gfp) -{ - XA_STATE(xas, xa, index); - void *curr; - - if (WARN_ON_ONCE(xa_is_internal(entry))) - return XA_ERROR(-EINVAL); - - do { - xas_lock(&xas); - curr = xas_load(&xas); - if (curr == XA_ZERO_ENTRY) - curr = NULL; - if (curr == old) { - xas_store(&xas, entry); - if (xa_track_free(xa) && entry) - xas_clear_mark(&xas, XA_FREE_MARK); - } - xas_unlock(&xas); - } while (xas_nomem(&xas, gfp)); - - return xas_result(&xas, curr); -} -EXPORT_SYMBOL(xa_cmpxchg); - /** * __xa_cmpxchg() - Store this entry in the XArray. * @xa: XArray.