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 <[email protected]>
---
aio.h | 11 +++++++++--
1 files changed, 9 insertions(+), 2 deletions(-)
Index: 2.6.14-mm1-aio-cleanups/include/linux/aio.h
===================================================================
--- 2.6.14-mm1-aio-cleanups.orig/include/linux/aio.h 2005-11-09 14:25:00.848063628 -0800
+++ 2.6.14-mm1-aio-cleanups/include/linux/aio.h 2005-11-09 14:29:44.469674748 -0800
@@ -210,8 +210,15 @@
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 */
-
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