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authorZach Brown <zach.brown@oracle.com>2005-11-13 16:07:35 -0800
committerLinus Torvalds <torvalds@g5.osdl.org>2005-11-13 18:14:16 -0800
commit5ef1c49f8f9f0d6b5b8d57bb4b66c605a3d65876 (patch)
tree8431e60b0f5ebb4f22b0f4bffbc6f0ebb0faf601 /include/linux
parentd00689af6b3b6ba9e1fdefec3bd62edc860c385d (diff)
[PATCH] aio: don't ref kioctx after decref in put_ioctx
put_ioctx's refcount debugging was doing an atomic_read after dropping its reference when it wasn't the last ref, leaving a tiny race for another freeing thread to sneak into. This shifts the debugging before the ops, uses BUG_ON, and reformats the defines a little. Sadly, moving to inlines increased the code size but this change decreases the code size by a whole 9 bytes :) Signed-off-by: Zach Brown <zach.brown@oracle.com> Cc: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/aio.h11
1 files changed, 9 insertions, 2 deletions
diff --git a/include/linux/aio.h b/include/linux/aio.h
index 9e0ae8711276..49fd37629ee4 100644
--- a/include/linux/aio.h
+++ b/include/linux/aio.h
@@ -210,8 +210,15 @@ struct kioctx *lookup_ioctx(unsigned long ctx_id);
int FASTCALL(io_submit_one(struct kioctx *ctx, struct iocb __user *user_iocb,
struct iocb *iocb));
-#define get_ioctx(kioctx) do { if (unlikely(atomic_read(&(kioctx)->users) <= 0)) BUG(); atomic_inc(&(kioctx)->users); } while (0)
-#define put_ioctx(kioctx) do { if (unlikely(atomic_dec_and_test(&(kioctx)->users))) __put_ioctx(kioctx); else if (unlikely(atomic_read(&(kioctx)->users) < 0)) BUG(); } while (0)
+#define get_ioctx(kioctx) do { \
+ BUG_ON(unlikely(atomic_read(&(kioctx)->users) <= 0)); \
+ atomic_inc(&(kioctx)->users); \
+} while (0)
+#define put_ioctx(kioctx) do { \
+ BUG_ON(unlikely(atomic_read(&(kioctx)->users) <= 0)); \
+ if (unlikely(atomic_dec_and_test(&(kioctx)->users))) \
+ __put_ioctx(kioctx); \
+} while (0)
#define in_aio() !is_sync_wait(current->io_wait)
/* may be used for debugging */