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XArray updates for 5.1-rc1

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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
This commit is contained in:
Linus Torvalds 2019-03-11 20:06:18 -07:00
commit ea295481b6
7 changed files with 560 additions and 259 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
Documentation/core-api/xarray.rst
View File

@ -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`

32
drivers/infiniband/core/device.c
View File

@ -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;

25
drivers/infiniband/core/restrack.c
View File

@ -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);

2
fs/nilfs2/btnode.c
View File

@ -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);

296
include/linux/xarray.h
View File

@ -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?

286
lib/test_xarray.c
View File

@ -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 0 again */
xa_alloc_index(&xa0, 0, GFP_KERNEL);
/* 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);
/* 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);
/* 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 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);
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);
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, 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);

163
lib/xarray.c
View File

@ -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;
@ -1634,21 +1604,70 @@ 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.
@ -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));