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Commit 962033d5 authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

XArray: Use xa_cmpxchg to implement xa_reserve 



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

Suggested-by: default avatarJason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent b38f6c50

Documentation/core-api/xarray.rst

+0 −1
Original line number Diff line number Diff line
@@ -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`

include/linux/xarray.h

+3 −22
Original line number Diff line number Diff line
@@ -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));

}



/**

lib/xarray.c

+0 −36
Original line number Diff line number Diff line
@@ -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)