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commit ea295481b6e313b4ea3ca2720ffcafd6005b5643
parent f3124ccf025caf25b764d900d1f9c49731673e49
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon, 11 Mar 2019 20:06:18 -0700

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:
MDocumentation/core-api/xarray.rst | 15++++++++++-----
Mdrivers/infiniband/core/device.c | 32++++++++++++--------------------
Mdrivers/infiniband/core/restrack.c | 25++-----------------------
Mfs/nilfs2/btnode.c | 2+-
Minclude/linux/xarray.h | 296++++++++++++++++++++++++++++++++++++++++++++++++++++++++-----------------------
Mlib/test_xarray.c | 288+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++----------------
Mlib/xarray.c | 163+++++++++++++++++++++++++++++++++++++++++++++----------------------------------
7 files changed, 561 insertions(+), 260 deletions(-)

diff --git a/Documentation/core-api/xarray.rst b/Documentation/core-api/xarray.rst @@ -85,7 +85,7 @@ which was at that index; if it returns the same entry which was passed as If you want to only store a new entry to an index if the current entry at that index is ``NULL``, you can use :c:func:`xa_insert` which -returns ``-EEXIST`` if the entry is not empty. +returns ``-EBUSY`` if the entry is not empty. You can enquire whether a mark is set on an entry by using :c:func:`xa_get_mark`. If the entry is not ``NULL``, you can set a mark @@ -131,17 +131,23 @@ If you use :c:func:`DEFINE_XARRAY_ALLOC` to define the XArray, or initialise it by passing ``XA_FLAGS_ALLOC`` to :c:func:`xa_init_flags`, the XArray changes to track whether entries are in use or not. -You can call :c:func:`xa_alloc` to store the entry at any unused index +You can call :c:func:`xa_alloc` to store the entry at an unused index in the XArray. If you need to modify the array from interrupt context, you can use :c:func:`xa_alloc_bh` or :c:func:`xa_alloc_irq` to disable interrupts while allocating the ID. -Using :c:func:`xa_store`, :c:func:`xa_cmpxchg` or :c:func:`xa_insert` -will mark the entry as being allocated. Unlike a normal XArray, storing +Using :c:func:`xa_store`, :c:func:`xa_cmpxchg` or :c:func:`xa_insert` will +also mark the entry as being allocated. Unlike a normal XArray, storing ``NULL`` will mark the entry as being in use, like :c:func:`xa_reserve`. To free an entry, use :c:func:`xa_erase` (or :c:func:`xa_release` if you only want to free the entry if it's ``NULL``). +By default, the lowest free entry is allocated starting from 0. If you +want to allocate entries starting at 1, it is more efficient to use +:c:func:`DEFINE_XARRAY_ALLOC1` or ``XA_FLAGS_ALLOC1``. If you want to +allocate IDs up to a maximum, then wrap back around to the lowest free +ID, you can use :c:func:`xa_alloc_cyclic`. + You cannot use ``XA_MARK_0`` with an allocating XArray as this mark is used to track whether an entry is free or not. The other marks are available for your use. @@ -209,7 +215,6 @@ Assumes xa_lock held on entry: * :c:func:`__xa_erase` * :c:func:`__xa_cmpxchg` * :c:func:`__xa_alloc` - * :c:func:`__xa_reserve` * :c:func:`__xa_set_mark` * :c:func:`__xa_clear_mark` diff --git a/drivers/infiniband/core/device.c b/drivers/infiniband/core/device.c @@ -668,19 +668,10 @@ static int assign_name(struct ib_device *device, const char *name) } strlcpy(device->name, dev_name(&device->dev), IB_DEVICE_NAME_MAX); - /* Cyclically allocate a user visible ID for the device */ - device->index = last_id; - ret = xa_alloc(&devices, &device->index, INT_MAX, device, GFP_KERNEL); - if (ret == -ENOSPC) { - device->index = 0; - ret = xa_alloc(&devices, &device->index, INT_MAX, device, - GFP_KERNEL); - } - if (ret) - goto out; - last_id = device->index + 1; - - ret = 0; + ret = xa_alloc_cyclic(&devices, &device->index, device, xa_limit_31b, + &last_id, GFP_KERNEL); + if (ret > 0) + ret = 0; out: up_write(&devices_rwsem); @@ -1059,14 +1050,15 @@ static int assign_client_id(struct ib_client *client) * to get the LIFO order. The extra linked list can go away if xarray * learns to reverse iterate. */ - if (list_empty(&client_list)) + if (list_empty(&client_list)) { client->client_id = 0; - else - client->client_id = - list_last_entry(&client_list, struct ib_client, list) - ->client_id; - ret = xa_alloc(&clients, &client->client_id, INT_MAX, client, - GFP_KERNEL); + } else { + struct ib_client *last; + + last = list_last_entry(&client_list, struct ib_client, list); + client->client_id = last->client_id + 1; + } + ret = xa_insert(&clients, client->client_id, client, GFP_KERNEL); if (ret) goto out; diff --git a/drivers/infiniband/core/restrack.c b/drivers/infiniband/core/restrack.c @@ -13,28 +13,6 @@ #include "cma_priv.h" #include "restrack.h" -static int rt_xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, - u32 *next) -{ - int err; - - *id = *next; - if (*next == U32_MAX) - *id = 0; - - xa_lock(xa); - err = __xa_alloc(xa, id, U32_MAX, entry, GFP_KERNEL); - if (err && *next != U32_MAX) { - *id = 0; - err = __xa_alloc(xa, id, *next, entry, GFP_KERNEL); - } - - if (!err) - *next = *id + 1; - xa_unlock(xa); - return err; -} - /** * rdma_restrack_init() - initialize and allocate resource tracking * @dev: IB device @@ -226,7 +204,8 @@ static void rdma_restrack_add(struct rdma_restrack_entry *res) kref_init(&res->kref); init_completion(&res->comp); if (res->type != RDMA_RESTRACK_QP) - ret = rt_xa_alloc_cyclic(&rt->xa, &res->id, res, &rt->next_id); + ret = xa_alloc_cyclic(&rt->xa, &res->id, res, xa_limit_32b, + &rt->next_id, GFP_KERNEL); else { /* Special case to ensure that LQPN points to right QP */ struct ib_qp *qp = container_of(res, struct ib_qp, res); diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c @@ -189,7 +189,7 @@ retry: */ if (!err) return 0; - else if (err != -EEXIST) + else if (err != -EBUSY) goto failed_unlock; err = invalidate_inode_pages2_range(btnc, newkey, newkey); diff --git a/include/linux/xarray.h b/include/linux/xarray.h @@ -131,6 +131,12 @@ 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 +169,22 @@ 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 @@ -200,6 +222,27 @@ 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. + * Two common ranges are predefined for you: + * * xa_limit_32b - [0 - UINT_MAX] + * * xa_limit_31b - [0 - INT_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) + typedef unsigned __bitwise xa_mark_t; #define XA_MARK_0 ((__force xa_mark_t)0U) #define XA_MARK_1 ((__force xa_mark_t)1U) @@ -220,10 +263,14 @@ 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_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. @@ -279,7 +326,7 @@ 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. @@ -287,6 +334,15 @@ struct xarray { */ #define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC) +/** + * 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); @@ -463,9 +519,12 @@ 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_insert(struct xarray *, unsigned long index, 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); @@ -526,9 +585,9 @@ 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. @@ -550,9 +609,9 @@ 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. @@ -664,11 +723,11 @@ static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, * * Context: Any 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. + * 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; @@ -693,11 +752,11 @@ static inline int xa_insert(struct xarray *xa, unsigned long index, * * 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. -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. */ -static inline int xa_insert_bh(struct xarray *xa, unsigned long index, - void *entry, gfp_t gfp) +static inline int __must_check xa_insert_bh(struct xarray *xa, + unsigned long index, void *entry, gfp_t gfp) { int err; @@ -722,11 +781,11 @@ static inline int xa_insert_bh(struct xarray *xa, unsigned long index, * * 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. -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. */ -static inline int xa_insert_irq(struct xarray *xa, unsigned long index, - void *entry, gfp_t gfp) +static inline int __must_check xa_insert_irq(struct xarray *xa, + unsigned long index, void *entry, gfp_t gfp) { int err; @@ -741,26 +800,26 @@ static inline int xa_insert_irq(struct xarray *xa, unsigned long index, * 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. * - * 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; xa_lock(xa); - err = __xa_alloc(xa, id, max, entry, gfp); + err = __xa_alloc(xa, id, entry, limit, gfp); xa_unlock(xa); return err; @@ -770,26 +829,26 @@ 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. * * 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; 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; @@ -799,26 +858,125 @@ 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. * * 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; 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. + * + * Context: Any context. Takes and releases the xa_lock. May sleep if + * the @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. + */ +static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, + struct xa_limit limit, u32 *next, gfp_t gfp) +{ + int err; + + xa_lock(xa); + err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); + xa_unlock(xa); + + return err; +} + +/** + * 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. + * + * 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 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. + */ +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; + + xa_lock_bh(xa); + err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); + xa_unlock_bh(xa); + + return err; +} + +/** + * 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. + * + * 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 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. + */ +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; + + xa_lock_irq(xa); + err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); xa_unlock_irq(xa); return err; @@ -842,16 +1000,10 @@ 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)); } /** @@ -866,16 +1018,10 @@ 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)); } /** @@ -890,16 +1036,10 @@ 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)); } /** @@ -913,7 +1053,7 @@ 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. */ @@ -1073,18 +1213,6 @@ static inline bool xa_is_sibling(const void *entry) } #define XA_RETRY_ENTRY xa_mk_internal(256) -#define XA_ZERO_ENTRY xa_mk_internal(257) - -/** - * xa_is_zero() - Is the entry a zero entry? - * @entry: Entry retrieved from the XArray - * - * 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_retry() - Is the entry a retry entry? diff --git 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 @@ -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));