Re: [PATCH 09/19] staging: lustre: open code polling loop instead of using l_wait_event()

James Simmons
2018-01-17T15:32:04Z

> Two places that LWI_TIMEOUT_INTERVAL() is used, the outcome is a
> simple polling loop that polls every second for some event (with a
> limit).
>
> So write a simple loop to make this more apparent.

Reviewed-by: James Simmons <jsimmons@infradead.org>

> Signed-off-by: NeilBrown <neilb@suse.com>
> ---
> drivers/staging/lustre/lustre/llite/llite_lib.c | 11 +++++------
> drivers/staging/lustre/lustre/lov/lov_request.c | 12 +++++-------
> 2 files changed, 10 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
> index 33dc15e9aebb..f6642fa30428 100644
> --- a/drivers/staging/lustre/lustre/llite/llite_lib.c
> +++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
> @@ -1984,8 +1984,7 @@ void ll_umount_begin(struct super_block *sb)
> struct ll_sb_info *sbi = ll_s2sbi(sb);
> struct obd_device *obd;
> struct obd_ioctl_data *ioc_data;
> - wait_queue_head_t waitq;
> - struct l_wait_info lwi;
> + int cnt = 0;
>
> CDEBUG(D_VFSTRACE, "VFS Op: superblock %p count %d active %d\n", sb,
> sb->s_count, atomic_read(&sb->s_active));
> @@ -2021,10 +2020,10 @@ void ll_umount_begin(struct super_block *sb)
> * and then continue. For now, we just periodically checking for vfs
> * to decrement mnt_cnt and hope to finish it within 10sec.
> */
> - init_waitqueue_head(&waitq);
> - lwi = LWI_TIMEOUT_INTERVAL(10 * HZ,
> - HZ, NULL, NULL);
> - l_wait_event(waitq, may_umount(sbi->ll_mnt.mnt), &lwi);
> + while (cnt < 10 && !may_umount(sbi->ll_mnt.mnt)) {
> + schedule_timeout_uninterruptible(HZ);
> + cnt ++;
> + }
>
> schedule();
> }
> diff --git a/drivers/staging/lustre/lustre/lov/lov_request.c b/drivers/staging/lustre/lustre/lov/lov_request.c
> index fb3b7a7fa32a..c1e58fcc30b3 100644
> --- a/drivers/staging/lustre/lustre/lov/lov_request.c
> +++ b/drivers/staging/lustre/lustre/lov/lov_request.c
> @@ -99,8 +99,7 @@ static int lov_check_set(struct lov_obd *lov, int idx)
> */
> static int lov_check_and_wait_active(struct lov_obd *lov, int ost_idx)
> {
> - wait_queue_head_t waitq;
> - struct l_wait_info lwi;
> + int cnt = 0;
> struct lov_tgt_desc *tgt;
> int rc = 0;
>
> @@ -125,11 +124,10 @@ static int lov_check_and_wait_active(struct lov_obd *lov, int ost_idx)
>
> mutex_unlock(&lov->lov_lock);
>
> - init_waitqueue_head(&waitq);
> - lwi = LWI_TIMEOUT_INTERVAL(obd_timeout * HZ,
> - HZ, NULL, NULL);
> -
> - rc = l_wait_event(waitq, lov_check_set(lov, ost_idx), &lwi);
> + while (cnt < obd_timeout && !lov_check_set(lov, ost_idx)) {
> + schedule_timeout_uninterruptible(HZ);
> + cnt ++;
> + }
> if (tgt->ltd_active)
> return 1;
>
>
>
>