Re: [PATCH -v3 2/3] xen-blkback: repleace check kthread_should_stop() to remove_requested in xen_blkif_schedule() loop.

Konrad Rzeszutek Wilk
2011-08-04T19:49:00Z

On Thu, Aug 04, 2011 at 03:24:44PM +0800, Joe Jin wrote:
>
> When backend state change to XenbusStateClosed, remove_requested will be set,
> so repleace check kthread_should_stop() to remove_requested in
> xen_blkif_schedule() loop.
>
> Signed-off-by: Joe Jin <joe.jin@oracle.com>
> Cc: Daniel Stodden <daniel.stodden@citrix.com>
> Cc: Jens Axboe <jaxboe@fusionio.com>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> Cc: Annie Li <annie.li@oracle.com>
> Cc: Ian Campbell <Ian.Campbell@eu.citrix.com>
> --
> drivers/block/xen-blkback/blkback.c | 10 +++++-----
> 1 file changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/block/xen-blkback/blkback.c b/drivers/block/xen-blkback/blkback.c
> index 2330a9a..3d64b52 100644
> --- a/drivers/block/xen-blkback/blkback.c
> +++ b/drivers/block/xen-blkback/blkback.c
> @@ -274,7 +274,7 @@ int xen_blkif_schedule(void *arg)
>
> xen_blkif_get(blkif);
>
> - while (!kthread_should_stop()) {
> + while (!blkif->remove_requested) {
> if (try_to_freeze())
> continue;
> if (unlikely(vbd->size != vbd_sz(vbd)))
> @@ -282,11 +282,11 @@ int xen_blkif_schedule(void *arg)
>
> wait_event_interruptible(
> blkif->wq,
> - blkif->waiting_reqs || kthread_should_stop());
> + blkif->waiting_reqs || blkif->remove_requested);
> wait_event_interruptible(
> blkbk->pending_free_wq,
> !list_empty(&blkbk->pending_free) ||
> - kthread_should_stop());
> + blkif->remove_requested);
>
> blkif->waiting_reqs = 0;
> smp_mb(); /* clear flag *before* checking for work */
> @@ -301,8 +301,8 @@ int xen_blkif_schedule(void *arg)
> if (log_stats)
> print_stats(blkif);
>
> - blkif->xenblkd = NULL;
> xen_blkif_put(blkif);
> + xen_blkback_close(blkif);

<sigh> I can't believe I didn't catch this earlier, but this a
big NO NO. Each patch _MUST_ be compile on its own. If I commit
patch 1 and this patch, the compile (actually linker) process
stops b/c xen_blkback_close is not defined:

drivers/built-in.o: In function `xen_blkif_schedule':
/home/konrad/ssd/linux/drivers/block/xen-blkback/blkback.c:305: undefined reference to `xen_blkback_close'
make[2]: *** [.tmp_vmlinux1] Error 1

You can move the xen_blkback_close() to the third patch
instead of having it here.

I will be nice and do it for you.

>
> return 0;
> }
> @@ -476,7 +476,7 @@ __do_block_io_op(struct xen_blkif *blkif)
> if (RING_REQUEST_CONS_OVERFLOW(&blk_rings->common, rc))
> break;
>
> - if (kthread_should_stop()) {
> + if (blkif->remove_requested) {
> more_to_do = 1;
> break;
> }