Messages in this thread | | | Date | Thu, 28 Jun 2012 15:39:56 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH v4 1/2] aio: make kiocb->private NUll in init_sync_kiocb() |
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On Wed, 27 Jun 2012 17:09:54 +0800 Junxiao Bi <junxiao.bi@oracle.com> wrote:
> 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 <junxiao.bi@oracle.com> > Cc: stable@vger.kernel.org > Acked-by: Jeff Moyer <jmoyer@redhat.com> > 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.
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