Re: [PATCH v4 1/2] aio: make kiocb->private NUll in init_sync_kiocb()
From: Andrew Morton <akpm@linux-foundation.org>
Date: 2012-06-28 22:39:59
Also in:
lkml, ocfs2-devel
On Wed, 27 Jun 2012 17:09:54 +0800 Junxiao Bi [off-list ref] wrote:
quoted hunk ↗ jump to hunk
Ocfs2 uses kiocb.*private as a flag of unsigned long size. In commit a11f7e6 ocfs2: serialize unaligned aio, the unaligned io flag is involved in it to serialize the unaligned aio. As *private is not initialized in init_sync_kiocb() of do_sync_write(), this unaligned io flag may be unexpectly set in an aligned dio. And this will cause OCFS2_I(inode)->ip_unaligned_aio decreased to -1 in ocfs2_dio_end_io(), thus the following unaligned dio will hang forever at ocfs2_aiodio_wait() in ocfs2_file_aio_write(). Signed-off-by: Junxiao Bi <redacted> Cc: stable@vger.kernel.org Acked-by: Jeff Moyer <redacted> Acked-by: Joel Becker <jlbec@evilplan.org> --- include/linux/aio.h | 1 + 1 file changed, 1 insertion(+)diff --git a/include/linux/aio.h b/include/linux/aio.h index 2314ad8..b1a520e 100644 --- a/include/linux/aio.h +++ b/include/linux/aio.h@@ -140,6 +140,7 @@ struct kiocb { (x)->ki_dtor = NULL; \ (x)->ki_obj.tsk = tsk; \ (x)->ki_user_data = 0; \ + (x)->private = NULL; \ } while (0) #define AIO_RING_MAGIC 0xa10a10a1
hm, that code is rather cruddy. Pointless macromania.
If we do this:
static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
{
struct task_struct *tsk = current;
kiocb->ki_flags = 0;
kiocb->ki_users = 1;
kiocb->ki_key = KIOCB_SYNC_KEY;
kiocb->ki_filp = filp;
kiocb->ki_ctx = NULL;
kiocb->ki_cancel = NULL;
kiocb->ki_retry = NULL;
kiocb->ki_dtor = NULL;
kiocb->ki_obj.tsk = tsk;
kiocb->ki_user_data = 0;
}
it is nicer and there is no impact on code size.
If we do this:
static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
{
*kiocb = (struct kiocb) {
.ki_users = 1,
.ki_key = KIOCB_SYNC_KEY,
.ki_filp = filp,
.ki_obj.tsk = current,
};
}
then fs/read_write.o's .text is shrunk from 9857 bytes to 9714, which
is rather a lot.
But that's all rather irrelevant to your bugfix.