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XArray: Use xa_cmpxchg to implement xa_reserve

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Jason feels this is clearer, and it saves a function and an exported
symbol.

Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2019-02-20 11:51:22 -05:00
parent b38f6c5027
commit 962033d55d
3 changed files with 3 additions and 59 deletions
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1
Documentation/core-api/xarray.rst
View File

@ -215,7 +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`

25
include/linux/xarray.h
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@ -525,7 +525,6 @@ 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);
int __must_check __xa_reserve(struct xarray *, unsigned long index, 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);
@ -1004,13 +1003,7 @@ static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, void *entry,
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));
}
/**
@ -1028,13 +1021,7 @@ int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
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));
}
/**
@ -1052,13 +1039,7 @@ int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp)
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));
}
/**

36
lib/xarray.c
View File

@ -1484,42 +1484,6 @@ 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)