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| author |   Zach Brown <zach.brown@oracle.com> | 2005-11-13 16:07:35 -0800 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2005-11-13 18:14:16 -0800 |
| commit | 5ef1c49f8f9f0d6b5b8d57bb4b66c605a3d65876 (patch) | |
| tree | 8431e60b0f5ebb4f22b0f4bffbc6f0ebb0faf601 /include/linux/aio.h | |
| parent | [PATCH] aio: replace locking comments with assert_spin_locked() (diff) | |
| download | linux-dev-5ef1c49f8f9f0d6b5b8d57bb4b66c605a3d65876.tar.xz linux-dev-5ef1c49f8f9f0d6b5b8d57bb4b66c605a3d65876.zip | |
[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/aio.h')
| -rw-r--r-- | include/linux/aio.h | 11 |
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 */ |