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Commit f818b82b authored by Matthew Wilcox's avatar Matthew Wilcox
Browse files

XArray: Mark xa_insert and xa_reserve as must_check 



If the user doesn't care about the return value from xa_insert(), then
they should be using xa_store() instead.  The point of xa_reserve() is
to get the return value early before taking another lock, so this should
also be __must_check.

Signed-off-by: default avatarMatthew Wilcox <willy@infradead.org>
parent 2fa044e5

include/linux/xarray.h

+12 −11
Original line number Diff line number Diff line
@@ -497,12 +497,13 @@ 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 __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);

int __xa_reserve(struct xarray *, unsigned long index, 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);
@@ -704,8 +705,8 @@ static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, 
 * 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;
@@ -733,8 +734,8 @@ static inline int xa_insert(struct xarray *xa, unsigned long index, 
 * 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;
@@ -762,8 +763,8 @@ static inline int xa_insert_bh(struct xarray *xa, unsigned long index, 
 * 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;
@@ -978,7 +979,7 @@ static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, 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;
@@ -1002,7 +1003,7 @@ 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;
@@ -1026,7 +1027,7 @@ 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;

lib/test_xarray.c

+5 −5
Original line number Diff line number Diff line
@@ -364,21 +364,21 @@ static noinline void check_reserve(struct xarray *xa) 


	/* 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_reserve(xa, 12345678, GFP_KERNEL) != 0);

	XA_BUG_ON(xa, xa_cmpxchg(xa, 12345678, NULL, xa_mk_value(12345678),

				GFP_NOWAIT) != NULL);

	xa_release(xa, 12345678);
@@ -386,7 +386,7 @@ static noinline void check_reserve(struct xarray *xa) 
	XA_BUG_ON(xa, !xa_empty(xa));



	/* But xa_insert does not */

	xa_reserve(xa, 12345678, GFP_KERNEL);

	XA_BUG_ON(xa, xa_reserve(xa, 12345678, GFP_KERNEL) != 0);

	XA_BUG_ON(xa, xa_insert(xa, 12345678, xa_mk_value(12345678), 0) !=

			-EBUSY);

	XA_BUG_ON(xa, xa_empty(xa));
@@ -395,7 +395,7 @@ static noinline void check_reserve(struct xarray *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);



	xa_for_each(xa, index, entry) {