From: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
To: Mark Brown <broonie@kernel.org>
Cc: linux-spi@vger.kernel.org,
"Linux-Kernel@Vger. Kernel. Org" <linux-kernel@vger.kernel.org>,
Tejun Heo <tj@kernel.org>
Subject: Re: [PATCH] spi: spi-sh: Remove deprecated create_singlethread_workqueue
Date: Sat, 16 Jul 2016 13:36:17 +0530 [thread overview]
Message-ID: <CAFNHFT_T+GRqD4dboVuEJHUL8E-wdq0J9rbi+Mbah-SEx1qqLw@mail.gmail.com> (raw)
In-Reply-To: <20160716080502.GA4700@Karyakshetra>
Please ignore this mail. I have already sent a patch for this driver
Thanks,
Bhaktipriya
On Sat, Jul 16, 2016 at 1:35 PM, Bhaktipriya Shridhar
<bhaktipriya96@gmail.com> wrote:
> The workqueue has a single workitem(&ss->ws) and hence doesn't require
> ordering. Also, it is not being used on a memory reclaim path. Hence, the
> singlethreaded workqueue has been replaced with the use of system_wq.
>
> System workqueues have been able to handle high level of concurrency
> for a long time now and hence it's not required to have a singlethreaded
> workqueue just to gain concurrency. Unlike a dedicated per-cpu workqueue
> created with create_singlethread_workqueue(), system_wq allows multiple
> work items to overlap executions even on the same CPU; however, a
> per-cpu workqueue doesn't have any CPU locality or global ordering
> guarantee unless the target CPU is explicitly specified and thus the
> increase of local concurrency shouldn't make any difference.
>
> Work item has been flushed in spi_sh_remove() to ensure that
> there are no pending tasks while disconnecting the driver.
>
> Signed-off-by: Bhaktipriya Shridhar <bhaktipriya96@gmail.com>
> ---
> drivers/spi/spi-sh.c | 16 +++-------------
> 1 file changed, 3 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/spi/spi-sh.c b/drivers/spi/spi-sh.c
> index 5025011..2bf53f0 100644
> --- a/drivers/spi/spi-sh.c
> +++ b/drivers/spi/spi-sh.c
> @@ -82,7 +82,6 @@ struct spi_sh_data {
> int irq;
> struct spi_master *master;
> struct list_head queue;
> - struct workqueue_struct *workqueue;
> struct work_struct ws;
> unsigned long cr1;
> wait_queue_head_t wait;
> @@ -380,7 +379,7 @@ static int spi_sh_transfer(struct spi_device *spi, struct spi_message *mesg)
> spi_sh_clear_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
>
> list_add_tail(&mesg->queue, &ss->queue);
> - queue_work(ss->workqueue, &ss->ws);
> + schedule_work(&ss->ws);
>
> spin_unlock_irqrestore(&ss->lock, flags);
>
> @@ -425,7 +424,7 @@ static int spi_sh_remove(struct platform_device *pdev)
> struct spi_sh_data *ss = platform_get_drvdata(pdev);
>
> spi_unregister_master(ss->master);
> - destroy_workqueue(ss->workqueue);
> + flush_work(&ss->ws);
> free_irq(ss->irq, ss);
>
> return 0;
> @@ -484,18 +483,11 @@ static int spi_sh_probe(struct platform_device *pdev)
> spin_lock_init(&ss->lock);
> INIT_WORK(&ss->ws, spi_sh_work);
> init_waitqueue_head(&ss->wait);
> - ss->workqueue = create_singlethread_workqueue(
> - dev_name(master->dev.parent));
> - if (ss->workqueue == NULL) {
> - dev_err(&pdev->dev, "create workqueue error\n");
> - ret = -EBUSY;
> - goto error1;
> - }
>
> ret = request_irq(irq, spi_sh_irq, 0, "spi_sh", ss);
> if (ret < 0) {
> dev_err(&pdev->dev, "request_irq error\n");
> - goto error2;
> + goto error1;
> }
>
> master->num_chipselect = 2;
> @@ -514,8 +506,6 @@ static int spi_sh_probe(struct platform_device *pdev)
>
> error3:
> free_irq(irq, ss);
> - error2:
> - destroy_workqueue(ss->workqueue);
> error1:
> spi_master_put(master);
>
> --
> 2.1.4
>
next prev parent reply other threads:[~2016-07-16 8:07 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-16 8:05 [PATCH] spi: spi-sh: Remove deprecated create_singlethread_workqueue Bhaktipriya Shridhar
2016-07-16 8:06 ` Bhaktipriya Shridhar [this message]
-- strict thread matches above, loose matches on Subject: below --
2016-07-02 8:45 Bhaktipriya Shridhar
2016-07-02 10:58 ` kbuild test robot
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