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: Matthew Wilcox <willy@infradead.org>

diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index 5ed6b462e7545c7f5e48d08e8756b1f76eda2904..687c150071a543756b37c100fc8a1b330a3c6d5a 100644 (file)
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -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;

diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index eaf53f742c724987c1cc0b28e666ac50b4d33224..3eaa40ddc390878ef68fa0914d1c379e4a7757cf 100644 (file)
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -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) {