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authorMauro Carvalho Chehab <mchehab@redhat.com>2012-10-17 09:32:49 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2012-10-17 09:32:49 -0300
commit214e2ca2b82d335935a861c253fe94c61ad77aad (patch)
treeeee42ff74d10470789d919b8499737ad0e919360 /include/linux/atomic.h
parent1fdead8ad31d3aa833bc37739273fcde89ace93c (diff)
parentddffeb8c4d0331609ef2581d84de4d763607bd37 (diff)
Merge tag 'v3.7-rc1' into staging/for_v3.8
Linux 3.7-rc1 * tag 'v3.7-rc1': (9579 commits) Linux 3.7-rc1 x86, boot: Explicitly include autoconf.h for hostprogs perf: Fix UAPI fallout ARM: config: make sure that platforms are ordered by option string ARM: config: sort select statements alphanumerically UAPI: (Scripted) Disintegrate include/linux/byteorder UAPI: (Scripted) Disintegrate include/linux UAPI: Unexport linux/blk_types.h UAPI: Unexport part of linux/ppp-comp.h perf: Handle new rbtree implementation procfs: don't need a PATH_MAX allocation to hold a string representation of an int vfs: embed struct filename inside of names_cache allocation if possible audit: make audit_inode take struct filename vfs: make path_openat take a struct filename pointer vfs: turn do_path_lookup into wrapper around struct filename variant audit: allow audit code to satisfy getname requests from its names_list vfs: define struct filename and have getname() return it btrfs: Fix compilation with user namespace support enabled userns: Fix posix_acl_file_xattr_userns gid conversion userns: Properly print bluetooth socket uids ...
Diffstat (limited to 'include/linux/atomic.h')
-rw-r--r--include/linux/atomic.h25
1 files changed, 25 insertions, 0 deletions
diff --git a/include/linux/atomic.h b/include/linux/atomic.h
index 70cfcb2d63c..5b08a8540ec 100644
--- a/include/linux/atomic.h
+++ b/include/linux/atomic.h
@@ -86,6 +86,31 @@ static inline int atomic_dec_unless_positive(atomic_t *p)
}
#endif
+/*
+ * atomic_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+#ifndef atomic_dec_if_positive
+static inline int atomic_dec_if_positive(atomic_t *v)
+{
+ int c, old, dec;
+ c = atomic_read(v);
+ for (;;) {
+ dec = c - 1;
+ if (unlikely(dec < 0))
+ break;
+ old = atomic_cmpxchg((v), c, dec);
+ if (likely(old == c))
+ break;
+ c = old;
+ }
+ return dec;
+}
+#endif
+
#ifndef CONFIG_ARCH_HAS_ATOMIC_OR
static inline void atomic_or(int i, atomic_t *v)
{