diff options
Diffstat (limited to 'include/linux/xarray.h')
| -rw-r--r-- | include/linux/xarray.h | 711 |
1 files changed, 559 insertions, 152 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h index f492e21c4aa2..be850174e802 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -9,15 +9,21 @@ * See Documentation/core-api/xarray.rst for how to use the XArray. */ +#include <linux/bitmap.h> #include <linux/bug.h> #include <linux/compiler.h> +#include <linux/err.h> #include <linux/gfp.h> #include <linux/kconfig.h> -#include <linux/kernel.h> +#include <linux/limits.h> +#include <linux/lockdep.h> #include <linux/rcupdate.h> +#include <linux/sched/mm.h> #include <linux/spinlock.h> #include <linux/types.h> +struct list_lru; + /* * The bottom two bits of the entry determine how the XArray interprets * the contents: @@ -32,8 +38,8 @@ * The following internal entries have a special meaning: * * 0-62: Sibling entries - * 256: Zero entry - * 257: Retry entry + * 256: Retry entry + * 257: Zero entry * * Errors are also represented as internal entries, but use the negative * space (-4094 to -2). They're never stored in the slots array; only @@ -131,6 +137,12 @@ static inline unsigned int xa_pointer_tag(void *entry) * xa_mk_internal() - Create an internal entry. * @v: Value to turn into an internal entry. * + * Internal entries are used for a number of purposes. Entries 0-255 are + * used for sibling entries (only 0-62 are used by the current code). 256 + * is used for the retry entry. 257 is used for the reserved / zero entry. + * Negative internal entries are used to represent errnos. Node pointers + * are also tagged as internal entries in some situations. + * * Context: Any context. * Return: An XArray internal entry corresponding to this value. */ @@ -163,6 +175,22 @@ static inline bool xa_is_internal(const void *entry) return ((unsigned long)entry & 3) == 2; } +#define XA_ZERO_ENTRY xa_mk_internal(257) + +/** + * xa_is_zero() - Is the entry a zero entry? + * @entry: Entry retrieved from the XArray + * + * The normal API will return NULL as the contents of a slot containing + * a zero entry. You can only see zero entries by using the advanced API. + * + * Return: %true if the entry is a zero entry. + */ +static inline bool xa_is_zero(const void *entry) +{ + return unlikely(entry == XA_ZERO_ENTRY); +} + /** * xa_is_err() - Report whether an XArray operation returned an error * @entry: Result from calling an XArray function @@ -176,7 +204,8 @@ static inline bool xa_is_internal(const void *entry) */ static inline bool xa_is_err(const void *entry) { - return unlikely(xa_is_internal(entry)); + return unlikely(xa_is_internal(entry) && + entry >= xa_mk_internal(-MAX_ERRNO)); } /** @@ -199,6 +228,29 @@ static inline int xa_err(void *entry) return 0; } +/** + * struct xa_limit - Represents a range of IDs. + * @min: The lowest ID to allocate (inclusive). + * @max: The maximum ID to allocate (inclusive). + * + * This structure is used either directly or via the XA_LIMIT() macro + * to communicate the range of IDs that are valid for allocation. + * Three common ranges are predefined for you: + * * xa_limit_32b - [0 - UINT_MAX] + * * xa_limit_31b - [0 - INT_MAX] + * * xa_limit_16b - [0 - USHRT_MAX] + */ +struct xa_limit { + u32 max; + u32 min; +}; + +#define XA_LIMIT(_min, _max) (struct xa_limit) { .min = _min, .max = _max } + +#define xa_limit_32b XA_LIMIT(0, UINT_MAX) +#define xa_limit_31b XA_LIMIT(0, INT_MAX) +#define xa_limit_16b XA_LIMIT(0, USHRT_MAX) + typedef unsigned __bitwise xa_mark_t; #define XA_MARK_0 ((__force xa_mark_t)0U) #define XA_MARK_1 ((__force xa_mark_t)1U) @@ -219,10 +271,15 @@ enum xa_lock_type { #define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ) #define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH) #define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U) +#define XA_FLAGS_ZERO_BUSY ((__force gfp_t)8U) +#define XA_FLAGS_ALLOC_WRAPPED ((__force gfp_t)16U) +#define XA_FLAGS_ACCOUNT ((__force gfp_t)32U) #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ (__force unsigned)(mark))) +/* ALLOC is for a normal 0-based alloc. ALLOC1 is for an 1-based alloc */ #define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK)) +#define XA_FLAGS_ALLOC1 (XA_FLAGS_TRACK_FREE | XA_FLAGS_ZERO_BUSY) /** * struct xarray - The anchor of the XArray. @@ -278,7 +335,7 @@ struct xarray { #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0) /** - * DEFINE_XARRAY_ALLOC() - Define an XArray which can allocate IDs. + * DEFINE_XARRAY_ALLOC() - Define an XArray which allocates IDs starting at 0. * @name: A string that names your XArray. * * This is intended for file scope definitions of allocating XArrays. @@ -286,7 +343,15 @@ struct xarray { */ #define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC) -void xa_init_flags(struct xarray *, gfp_t flags); +/** + * DEFINE_XARRAY_ALLOC1() - Define an XArray which allocates IDs starting at 1. + * @name: A string that names your XArray. + * + * This is intended for file scope definitions of allocating XArrays. + * See also DEFINE_XARRAY(). + */ +#define DEFINE_XARRAY_ALLOC1(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC1) + void *xa_load(struct xarray *, unsigned long index); void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); void *xa_erase(struct xarray *, unsigned long index); @@ -304,6 +369,24 @@ unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, void xa_destroy(struct xarray *); /** + * xa_init_flags() - Initialise an empty XArray with flags. + * @xa: XArray. + * @flags: XA_FLAG values. + * + * If you need to initialise an XArray with special flags (eg you need + * to take the lock from interrupt context), use this function instead + * of xa_init(). + * + * Context: Any context. + */ +static inline void xa_init_flags(struct xarray *xa, gfp_t flags) +{ + spin_lock_init(&xa->xa_lock); + xa->xa_flags = flags; + xa->xa_head = NULL; +} + +/** * xa_init() - Initialise an empty XArray. * @xa: XArray. * @@ -342,20 +425,72 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) } /** - * xa_for_each() - Iterate over a portion of an XArray. + * xa_for_each_range() - Iterate over a portion of an XArray. * @xa: XArray. + * @index: Index of @entry. * @entry: Entry retrieved from array. + * @start: First index to retrieve from array. + * @last: Last index to retrieve from array. + * + * During the iteration, @entry will have the value of the entry stored + * in @xa at @index. You may modify @index during the iteration if you + * want to skip or reprocess indices. It is safe to modify the array + * during the iteration. At the end of the iteration, @entry will be set + * to NULL and @index will have a value less than or equal to max. + * + * xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have + * to handle your own locking with xas_for_each(), and if you have to unlock + * after each iteration, it will also end up being O(n.log(n)). + * xa_for_each_range() will spin if it hits a retry entry; if you intend to + * see retry entries, you should use the xas_for_each() iterator instead. + * The xas_for_each() iterator will expand into more inline code than + * xa_for_each_range(). + * + * Context: Any context. Takes and releases the RCU lock. + */ +#define xa_for_each_range(xa, index, entry, start, last) \ + for (index = start, \ + entry = xa_find(xa, &index, last, XA_PRESENT); \ + entry; \ + entry = xa_find_after(xa, &index, last, XA_PRESENT)) + +/** + * xa_for_each_start() - Iterate over a portion of an XArray. + * @xa: XArray. * @index: Index of @entry. - * @max: Maximum index to retrieve from array. - * @filter: Selection criterion. + * @entry: Entry retrieved from array. + * @start: First index to retrieve from array. + * + * During the iteration, @entry will have the value of the entry stored + * in @xa at @index. You may modify @index during the iteration if you + * want to skip or reprocess indices. It is safe to modify the array + * during the iteration. At the end of the iteration, @entry will be set + * to NULL and @index will have a value less than or equal to max. * - * Initialise @index to the lowest index you want to retrieve from the - * array. During the iteration, @entry will have the value of the entry - * stored in @xa at @index. The iteration will skip all entries in the - * array which do not match @filter. You may modify @index during the - * iteration if you want to skip or reprocess indices. It is safe to modify - * the array during the iteration. At the end of the iteration, @entry will - * be set to NULL and @index will have a value less than or equal to max. + * xa_for_each_start() is O(n.log(n)) while xas_for_each() is O(n). You have + * to handle your own locking with xas_for_each(), and if you have to unlock + * after each iteration, it will also end up being O(n.log(n)). + * xa_for_each_start() will spin if it hits a retry entry; if you intend to + * see retry entries, you should use the xas_for_each() iterator instead. + * The xas_for_each() iterator will expand into more inline code than + * xa_for_each_start(). + * + * Context: Any context. Takes and releases the RCU lock. + */ +#define xa_for_each_start(xa, index, entry, start) \ + xa_for_each_range(xa, index, entry, start, ULONG_MAX) + +/** + * xa_for_each() - Iterate over present entries in an XArray. + * @xa: XArray. + * @index: Index of @entry. + * @entry: Entry retrieved from array. + * + * During the iteration, @entry will have the value of the entry stored + * in @xa at @index. You may modify @index during the iteration if you want + * to skip or reprocess indices. It is safe to modify the array during the + * iteration. At the end of the iteration, @entry will be set to NULL and + * @index will have a value less than or equal to max. * * xa_for_each() is O(n.log(n)) while xas_for_each() is O(n). You have * to handle your own locking with xas_for_each(), and if you have to unlock @@ -366,9 +501,36 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) * * Context: Any context. Takes and releases the RCU lock. */ -#define xa_for_each(xa, entry, index, max, filter) \ - for (entry = xa_find(xa, &index, max, filter); entry; \ - entry = xa_find_after(xa, &index, max, filter)) +#define xa_for_each(xa, index, entry) \ + xa_for_each_start(xa, index, entry, 0) + +/** + * xa_for_each_marked() - Iterate over marked entries in an XArray. + * @xa: XArray. + * @index: Index of @entry. + * @entry: Entry retrieved from array. + * @filter: Selection criterion. + * + * During the iteration, @entry will have the value of the entry stored + * in @xa at @index. The iteration will skip all entries in the array + * which do not match @filter. You may modify @index during the iteration + * if you want to skip or reprocess indices. It is safe to modify the array + * during the iteration. At the end of the iteration, @entry will be set to + * NULL and @index will have a value less than or equal to max. + * + * xa_for_each_marked() is O(n.log(n)) while xas_for_each_marked() is O(n). + * You have to handle your own locking with xas_for_each(), and if you have + * to unlock after each iteration, it will also end up being O(n.log(n)). + * xa_for_each_marked() will spin if it hits a retry entry; if you intend to + * see retry entries, you should use the xas_for_each_marked() iterator + * instead. The xas_for_each_marked() iterator will expand into more inline + * code than xa_for_each_marked(). + * + * Context: Any context. Takes and releases the RCU lock. + */ +#define xa_for_each_marked(xa, index, entry, filter) \ + for (index = 0, entry = xa_find(xa, &index, ULONG_MAX, filter); \ + entry; entry = xa_find_after(xa, &index, ULONG_MAX, filter)) #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) #define xa_lock(xa) spin_lock(&(xa)->xa_lock) @@ -381,6 +543,14 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) spin_lock_irqsave(&(xa)->xa_lock, flags) #define xa_unlock_irqrestore(xa, flags) \ spin_unlock_irqrestore(&(xa)->xa_lock, flags) +#define xa_lock_nested(xa, subclass) \ + spin_lock_nested(&(xa)->xa_lock, subclass) +#define xa_lock_bh_nested(xa, subclass) \ + spin_lock_bh_nested(&(xa)->xa_lock, subclass) +#define xa_lock_irq_nested(xa, subclass) \ + spin_lock_irq_nested(&(xa)->xa_lock, subclass) +#define xa_lock_irqsave_nested(xa, flags, subclass) \ + spin_lock_irqsave_nested(&(xa)->xa_lock, flags, subclass) /* * Versions of the normal API which require the caller to hold the @@ -393,40 +563,16 @@ void *__xa_erase(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); -int __xa_alloc(struct xarray *, u32 *id, u32 max, void *entry, gfp_t); -int __xa_reserve(struct xarray *, unsigned long index, gfp_t); +int __must_check __xa_insert(struct xarray *, unsigned long index, + void *entry, gfp_t); +int __must_check __xa_alloc(struct xarray *, u32 *id, void *entry, + struct xa_limit, gfp_t); +int __must_check __xa_alloc_cyclic(struct xarray *, u32 *id, void *entry, + struct xa_limit, u32 *next, gfp_t); void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); /** - * __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: Any context. Expects xa_lock to be held on entry. May - * release and reacquire xa_lock 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_store_bh() - Store this entry in the XArray. * @xa: XArray. * @index: Index into array. @@ -438,13 +584,14 @@ static inline int __xa_insert(struct xarray *xa, unsigned long index, * * Context: Any context. Takes and releases the xa_lock while * disabling softirqs. - * Return: The entry which used to be at this index. + * Return: The old entry at this index or xa_err() if an error happened. */ static inline void *xa_store_bh(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) { void *curr; + might_alloc(gfp); xa_lock_bh(xa); curr = __xa_store(xa, index, entry, gfp); xa_unlock_bh(xa); @@ -453,7 +600,7 @@ static inline void *xa_store_bh(struct xarray *xa, unsigned long index, } /** - * xa_store_irq() - Erase this entry from the XArray. + * xa_store_irq() - Store this entry in the XArray. * @xa: XArray. * @index: Index into array. * @entry: New entry. @@ -464,13 +611,14 @@ static inline void *xa_store_bh(struct xarray *xa, unsigned long index, * * Context: Process context. Takes and releases the xa_lock while * disabling interrupts. - * Return: The entry which used to be at this index. + * Return: The old entry at this index or xa_err() if an error happened. */ static inline void *xa_store_irq(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) { void *curr; + might_alloc(gfp); xa_lock_irq(xa); curr = __xa_store(xa, index, entry, gfp); xa_unlock_irq(xa); @@ -483,9 +631,9 @@ static inline void *xa_store_irq(struct xarray *xa, unsigned long index, * @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 while * disabling softirqs. @@ -507,9 +655,9 @@ static inline void *xa_erase_bh(struct xarray *xa, unsigned long index) * @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: Process context. Takes and releases the xa_lock while * disabling interrupts. @@ -546,6 +694,7 @@ static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index, { void *curr; + might_alloc(gfp); xa_lock(xa); curr = __xa_cmpxchg(xa, index, old, entry, gfp); xa_unlock(xa); @@ -573,6 +722,7 @@ static inline void *xa_cmpxchg_bh(struct xarray *xa, unsigned long index, { void *curr; + might_alloc(gfp); xa_lock_bh(xa); curr = __xa_cmpxchg(xa, index, old, entry, gfp); xa_unlock_bh(xa); @@ -600,6 +750,7 @@ static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, { void *curr; + might_alloc(gfp); xa_lock_irq(xa); curr = __xa_cmpxchg(xa, index, old, entry, gfp); xa_unlock_irq(xa); @@ -615,50 +766,116 @@ static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, * @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. + * Inserting a NULL entry will store a reserved entry (like xa_reserve()) + * if no entry is present. Inserting will fail if a reserved entry is + * present, even though loading from this index will return NULL. * - * 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. + * Context: Any context. Takes and releases the xa_lock. May sleep if + * the @gfp flags permit. + * Return: 0 if the store succeeded. -EBUSY 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) +static inline int __must_check xa_insert(struct xarray *xa, + unsigned long index, void *entry, gfp_t gfp) +{ + int err; + + might_alloc(gfp); + xa_lock(xa); + err = __xa_insert(xa, index, entry, gfp); + xa_unlock(xa); + + return err; +} + +/** + * xa_insert_bh() - 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. + * + * Inserting a NULL entry will store a reserved entry (like xa_reserve()) + * if no entry is present. Inserting will fail if a reserved entry is + * present, even though loading from this index will return NULL. + * + * Context: Any context. Takes and releases the xa_lock while + * disabling softirqs. May sleep if the @gfp flags permit. + * Return: 0 if the store succeeded. -EBUSY if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +static inline int __must_check xa_insert_bh(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; + int err; + + might_alloc(gfp); + xa_lock_bh(xa); + err = __xa_insert(xa, index, entry, gfp); + xa_unlock_bh(xa); + + return err; +} + +/** + * xa_insert_irq() - 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. + * + * Inserting a NULL entry will store a reserved entry (like xa_reserve()) + * if no entry is present. Inserting will fail if a reserved entry is + * present, even though loading from this index will return NULL. + * + * Context: Process context. Takes and releases the xa_lock while + * disabling interrupts. May sleep if the @gfp flags permit. + * Return: 0 if the store succeeded. -EBUSY if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +static inline int __must_check xa_insert_irq(struct xarray *xa, + unsigned long index, void *entry, gfp_t gfp) +{ + int err; + + might_alloc(gfp); + xa_lock_irq(xa); + err = __xa_insert(xa, index, entry, gfp); + xa_unlock_irq(xa); + + return err; } /** * xa_alloc() - Find somewhere to store this entry in the XArray. * @xa: XArray. * @id: Pointer to ID. - * @max: Maximum ID to allocate (inclusive). * @entry: New entry. + * @limit: Range of ID to allocate. * @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. + * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). * - * Context: Process context. Takes and releases the xa_lock. May sleep if + * Context: Any context. Takes and releases the xa_lock. May sleep if * the @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. */ -static inline int xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, - gfp_t gfp) +static inline __must_check int xa_alloc(struct xarray *xa, u32 *id, + void *entry, struct xa_limit limit, gfp_t gfp) { int err; + might_alloc(gfp); xa_lock(xa); - err = __xa_alloc(xa, id, max, entry, gfp); + err = __xa_alloc(xa, id, entry, limit, gfp); xa_unlock(xa); return err; @@ -668,26 +885,30 @@ static inline int xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, * xa_alloc_bh() - Find somewhere to store this entry in the XArray. * @xa: XArray. * @id: Pointer to ID. - * @max: Maximum ID to allocate (inclusive). * @entry: New entry. + * @limit: Range of ID to allocate. * @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. + * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). * * Context: Any context. Takes and releases the xa_lock while * disabling softirqs. May sleep if the @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. */ -static inline int xa_alloc_bh(struct xarray *xa, u32 *id, u32 max, void *entry, - gfp_t gfp) +static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id, + void *entry, struct xa_limit limit, gfp_t gfp) { int err; + might_alloc(gfp); xa_lock_bh(xa); - err = __xa_alloc(xa, id, max, entry, gfp); + err = __xa_alloc(xa, id, entry, limit, gfp); xa_unlock_bh(xa); return err; @@ -697,32 +918,153 @@ static inline int xa_alloc_bh(struct xarray *xa, u32 *id, u32 max, void *entry, * xa_alloc_irq() - Find somewhere to store this entry in the XArray. * @xa: XArray. * @id: Pointer to ID. - * @max: Maximum ID to allocate (inclusive). * @entry: New entry. + * @limit: Range of ID to allocate. * @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. + * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). * * Context: Process context. Takes and releases the xa_lock while * disabling interrupts. May sleep if the @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. */ -static inline int xa_alloc_irq(struct xarray *xa, u32 *id, u32 max, void *entry, - gfp_t gfp) +static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id, + void *entry, struct xa_limit limit, gfp_t gfp) { int err; + might_alloc(gfp); xa_lock_irq(xa); - err = __xa_alloc(xa, id, max, entry, gfp); + err = __xa_alloc(xa, id, entry, limit, gfp); xa_unlock_irq(xa); return err; } /** + * 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. + * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * + * Note that callers interested in whether wrapping has occurred should + * use __xa_alloc_cyclic() instead. + * + * Context: Any context. Takes and releases the xa_lock. May sleep if + * the @gfp flags permit. + * Return: 0 if the allocation succeeded, -ENOMEM if memory could not be + * allocated or -EBUSY if there are no free entries in @limit. + */ +static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, u32 *next, gfp_t gfp) +{ + int err; + + might_alloc(gfp); + xa_lock(xa); + err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); + xa_unlock(xa); + + return err < 0 ? err : 0; +} + +/** + * xa_alloc_cyclic_bh() - 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. + * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * + * Note that callers interested in whether wrapping has occurred should + * use __xa_alloc_cyclic() instead. + * + * Context: Any context. Takes and releases the xa_lock while + * disabling softirqs. May sleep if the @gfp flags permit. + * Return: 0 if the allocation succeeded, -ENOMEM if memory could not be + * allocated or -EBUSY if there are no free entries in @limit. + */ +static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, u32 *next, gfp_t gfp) +{ + int err; + + might_alloc(gfp); + xa_lock_bh(xa); + err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); + xa_unlock_bh(xa); + + return err < 0 ? err : 0; +} + +/** + * xa_alloc_cyclic_irq() - 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. + * + * Must only be operated on an xarray initialized with flag XA_FLAGS_ALLOC set + * in xa_init_flags(). + * + * Note that callers interested in whether wrapping has occurred should + * use __xa_alloc_cyclic() instead. + * + * Context: Process context. Takes and releases the xa_lock while + * disabling interrupts. May sleep if the @gfp flags permit. + * Return: 0 if the allocation succeeded, -ENOMEM if memory could not be + * allocated or -EBUSY if there are no free entries in @limit. + */ +static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, u32 *next, gfp_t gfp) +{ + int err; + + might_alloc(gfp); + xa_lock_irq(xa); + err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); + xa_unlock_irq(xa); + + return err < 0 ? err : 0; +} + +/** * xa_reserve() - Reserve this index in the XArray. * @xa: XArray. * @index: Index into array. @@ -740,16 +1082,10 @@ static inline int xa_alloc_irq(struct xarray *xa, u32 *id, u32 max, void *entry, * May sleep if the @gfp flags permit. * Return: 0 if the reservation succeeded or -ENOMEM if it failed. */ -static inline +static inline __must_check int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) { - int ret; - - xa_lock(xa); - ret = __xa_reserve(xa, index, gfp); - xa_unlock(xa); - - return ret; + return xa_err(xa_cmpxchg(xa, index, NULL, XA_ZERO_ENTRY, gfp)); } /** @@ -764,16 +1100,10 @@ int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) * disabling softirqs. * Return: 0 if the reservation succeeded or -ENOMEM if it failed. */ -static inline +static inline __must_check int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp) { - int ret; - - xa_lock_bh(xa); - ret = __xa_reserve(xa, index, gfp); - xa_unlock_bh(xa); - - return ret; + return xa_err(xa_cmpxchg_bh(xa, index, NULL, XA_ZERO_ENTRY, gfp)); } /** @@ -788,16 +1118,10 @@ int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp) * disabling interrupts. * Return: 0 if the reservation succeeded or -ENOMEM if it failed. */ -static inline +static inline __must_check int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) { - int ret; - - xa_lock_irq(xa); - ret = __xa_reserve(xa, index, gfp); - xa_unlock_irq(xa); - - return ret; + return xa_err(xa_cmpxchg_irq(xa, index, NULL, XA_ZERO_ENTRY, gfp)); } /** @@ -811,7 +1135,7 @@ int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) */ static inline void xa_release(struct xarray *xa, unsigned long index) { - xa_cmpxchg(xa, index, NULL, NULL, 0); + xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, 0); } /* Everything below here is the Advanced API. Proceed with caution. */ @@ -827,12 +1151,12 @@ static inline void xa_release(struct xarray *xa, unsigned long index) * doubled the number of slots per node, we'd get only 3 nodes per 4kB page. */ #ifndef XA_CHUNK_SHIFT -#define XA_CHUNK_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) +#define XA_CHUNK_SHIFT (IS_ENABLED(CONFIG_BASE_SMALL) ? 4 : 6) #endif #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT) #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1) #define XA_MAX_MARKS 3 -#define XA_MARK_LONGS DIV_ROUND_UP(XA_CHUNK_SIZE, BITS_PER_LONG) +#define XA_MARK_LONGS BITS_TO_LONGS(XA_CHUNK_SIZE) /* * @count is the count of every non-NULL element in the ->slots array @@ -970,29 +1294,28 @@ static inline bool xa_is_sibling(const void *entry) (entry < xa_mk_sibling(XA_CHUNK_SIZE - 1)); } -#define XA_ZERO_ENTRY xa_mk_internal(256) -#define XA_RETRY_ENTRY xa_mk_internal(257) +#define XA_RETRY_ENTRY xa_mk_internal(256) /** - * xa_is_zero() - Is the entry a zero entry? + * xa_is_retry() - Is the entry a retry entry? * @entry: Entry retrieved from the XArray * - * Return: %true if the entry is a zero entry. + * Return: %true if the entry is a retry entry. */ -static inline bool xa_is_zero(const void *entry) +static inline bool xa_is_retry(const void *entry) { - return unlikely(entry == XA_ZERO_ENTRY); + return unlikely(entry == XA_RETRY_ENTRY); } /** - * xa_is_retry() - Is the entry a retry entry? - * @entry: Entry retrieved from the XArray + * xa_is_advanced() - Is the entry only permitted for the advanced API? + * @entry: Entry to be stored in the XArray. * - * Return: %true if the entry is a retry entry. + * Return: %true if the entry cannot be stored by the normal API. */ -static inline bool xa_is_retry(const void *entry) +static inline bool xa_is_advanced(const void *entry) { - return unlikely(entry == XA_RETRY_ENTRY); + return xa_is_internal(entry) && (entry <= XA_RETRY_ENTRY); } /** @@ -1009,6 +1332,8 @@ static inline bool xa_is_retry(const void *entry) */ typedef void (*xa_update_node_t)(struct xa_node *node); +void xa_delete_node(struct xa_node *, xa_update_node_t); + /* * The xa_state is opaque to its users. It contains various different pieces * of state involved in the current operation on the XArray. It should be @@ -1036,6 +1361,7 @@ struct xa_state { struct xa_node *xa_node; struct xa_node *xa_alloc; xa_update_node_t xa_update; + struct list_lru *xa_lru; }; /* @@ -1055,7 +1381,8 @@ struct xa_state { .xa_pad = 0, \ .xa_node = XAS_RESTART, \ .xa_alloc = NULL, \ - .xa_update = NULL \ + .xa_update = NULL, \ + .xa_lru = NULL, \ } /** @@ -1224,10 +1551,52 @@ void *xas_find_marked(struct xa_state *, unsigned long max, xa_mark_t); void xas_init_marks(const struct xa_state *); bool xas_nomem(struct xa_state *, gfp_t); +void xas_destroy(struct xa_state *); void xas_pause(struct xa_state *); void xas_create_range(struct xa_state *); +#ifdef CONFIG_XARRAY_MULTI +int xa_get_order(struct xarray *, unsigned long index); +int xas_get_order(struct xa_state *xas); +void xas_split(struct xa_state *, void *entry, unsigned int order); +void xas_split_alloc(struct xa_state *, void *entry, unsigned int order, gfp_t); +void xas_try_split(struct xa_state *xas, void *entry, unsigned int order); +unsigned int xas_try_split_min_order(unsigned int order); +#else +static inline int xa_get_order(struct xarray *xa, unsigned long index) +{ + return 0; +} + +static inline int xas_get_order(struct xa_state *xas) +{ + return 0; +} + +static inline void xas_split(struct xa_state *xas, void *entry, + unsigned int order) +{ + xas_store(xas, entry); +} + +static inline void xas_split_alloc(struct xa_state *xas, void *entry, + unsigned int order, gfp_t gfp) +{ +} + +static inline void xas_try_split(struct xa_state *xas, void *entry, + unsigned int order) +{ +} + +static inline unsigned int xas_try_split_min_order(unsigned int order) +{ + return 0; +} + +#endif + /** * xas_reload() - Refetch an entry from the xarray. * @xas: XArray operation state. @@ -1245,10 +1614,21 @@ void xas_create_range(struct xa_state *); static inline void *xas_reload(struct xa_state *xas) { struct xa_node *node = xas->xa_node; - - if (node) - return xa_entry(xas->xa, node, xas->xa_offset); - return xa_head(xas->xa); + void *entry; + char offset; + + if (!node) + return xa_head(xas->xa); + if (IS_ENABLED(CONFIG_XARRAY_MULTI)) { + offset = (xas->xa_index >> node->shift) & XA_CHUNK_MASK; + entry = xa_entry(xas->xa, node, offset); + if (!xa_is_sibling(entry)) + return entry; + offset = xa_to_sibling(entry); + } else { + offset = xas->xa_offset; + } + return xa_entry(xas->xa, node, offset); } /** @@ -1267,6 +1647,24 @@ static inline void xas_set(struct xa_state *xas, unsigned long index) } /** + * xas_advance() - Skip over sibling entries. + * @xas: XArray operation state. + * @index: Index of last sibling entry. + * + * Move the operation state to refer to the last sibling entry. + * This is useful for loops that normally want to see sibling + * entries but sometimes want to skip them. Use xas_set() if you + * want to move to an index which is not part of this entry. + */ +static inline void xas_advance(struct xa_state *xas, unsigned long index) +{ + unsigned char shift = xas_is_node(xas) ? xas->xa_node->shift : 0; + + xas->xa_index = index; + xas->xa_offset = (index >> shift) & XA_CHUNK_MASK; +} + +/** * xas_set_order() - Set up XArray operation state for a multislot entry. * @xas: XArray operation state. * @index: Target of the operation. @@ -1292,13 +1690,19 @@ static inline void xas_set_order(struct xa_state *xas, unsigned long index, * @update: Function to call when updating a node. * * The XArray can notify a caller after it has updated an xa_node. - * This is advanced functionality and is only needed by the page cache. + * This is advanced functionality and is only needed by the page + * cache and swap cache. */ static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update) { xas->xa_update = update; } +static inline void xas_set_lru(struct xa_state *xas, struct list_lru *lru) +{ + xas->xa_lru = lru; +} + /** * xas_next_entry() - Advance iterator to next present entry. * @xas: XArray operation state. @@ -1371,6 +1775,7 @@ static inline void *xas_next_marked(struct xa_state *xas, unsigned long max, xa_mark_t mark) { struct xa_node *node = xas->xa_node; + void *entry; unsigned int offset; if (unlikely(xas_not_node(node) || node->shift)) @@ -1382,7 +1787,10 @@ static inline void *xas_next_marked(struct xa_state *xas, unsigned long max, return NULL; if (offset == XA_CHUNK_SIZE) return xas_find_marked(xas, max, mark); - return xa_entry(xas->xa, node, offset); + entry = xa_entry(xas->xa, node, offset); + if (!entry) + return xas_find_marked(xas, max, mark); + return entry; } /* @@ -1433,13 +1841,12 @@ enum { * @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. + * The loop body will be executed for each entry in the XArray that + * lies within the range specified by @xas. If the loop terminates + * normally, @entry will be %NULL. The user may break out of the loop, + * which will leave @entry set to the conflicting entry. 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_find_conflict(xas))) |