Re: [PATCH 21/22] fix: flush workqueue on put_ioctx

[Suparna Bhattacharya <suparna@in.ibm.com>]

On Fri, Jul 02, 2004 at 06:30:30PM +0530, Suparna Bhattacharya wrote:
> The patchset contains modifications and fixes to the AIO core
> to support the full retry model, an implementation of AIO
> support for buffered filesystem AIO reads and O_SYNC writes
> (the latter courtesy O_SYNC speedup changes from Andrew Morton),
> an implementation of AIO reads and writes to pipes (from
> Chris Mason) and AIO poll (again from Chris Mason).
> 
> Full retry infrastructure and fixes
> [1] aio-retry.patch
> [2] 4g4g-aio-hang-fix.patch
> [3] aio-retry-elevated-refcount.patch
> [4] aio-splice-runlist.patch
> 
> FS AIO read
> [5] aio-wait-page.patch
> [6] aio-fs_read.patch
> [7] aio-upfront-readahead.patch
> 
> AIO for pipes
> [8] aio-cancel-fix.patch
> [9] aio-read-immediate.patch
> [10] aio-pipe.patch
> [11] aio-context-switch.patch
> 
> Concurrent O_SYNC write speedups using radix-tree walks
> [12] writepages-range.patch
> [13] fix-writeback-range.patch
> [14] fix-writepages-range.patch
> [15] fdatawrite-range.patch
> [16] O_SYNC-speedup.patch
> 
> AIO O_SYNC write
> [17] aio-wait_on_page_writeback_range.patch
> [18] aio-O_SYNC.patch
> [19] O_SYNC-write-fix.patch
> 
> AIO poll
> [20] aio-poll.patch
> 
> Infrastructure fixes
> [21] aio-putioctx-flushworkqueue.patch

-- 
Suparna Bhattacharya (suparna@in.ibm.com)
Linux Technology Center
IBM Software Lab, India
------------------------------------------------------

From: Chris Mason

While testing fsaio here, I hit an oops in kick_iocb because iocb->mm
was null.  This was right as the program was exiting.

With the patch below, I wasn't able to reproduce, it makes sure we flush
the workqueue every time __put_ioctx gets called.


 aio.c |    6 +-----
 1 files changed, 1 insertion(+), 5 deletions(-)

--- aio/fs/aio.c	2004-06-21 11:09:50.143627384 -0700
+++ aio-putioctx-flushworkqueue/fs/aio.c  2004-06-21 11:12:55.359470296 -0700
@@ -367,6 +367,7 @@ void fastcall __put_ioctx(struct kioctx 
 	if (unlikely(ctx->reqs_active))
 		BUG();
 
+	flush_workqueue(aio_wq);
 	aio_free_ring(ctx);
 	mmdrop(ctx->mm);
 	ctx->mm = NULL;
@@ -1205,11 +1206,6 @@ static void io_destroy(struct kioctx *io
 
 	aio_cancel_all(ioctx);
 	wait_for_all_aios(ioctx);
-	/*
-	 * this is an overkill, but ensures we don't leave
-	 * the ctx on the aio_wq
-	 */
-	flush_workqueue(aio_wq);
 	put_ioctx(ioctx);	/* once for the lookup */
 }