linux-kernel - Re: [PATCH 2/9] dma: Convert from tasklet to BH workqueue

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Tue, 2 Apr 2024 14:25:15 +0200
From: Linus Walleij <linus.walleij@...aro.org>
To: Allen Pais <apais@...ux.microsoft.com>
Cc: linux-kernel@...r.kernel.org, tj@...nel.org, keescook@...omium.org, 
	vkoul@...nel.org, marcan@...can.st, sven@...npeter.dev, 
	florian.fainelli@...adcom.com, rjui@...adcom.com, sbranden@...adcom.com, 
	paul@...pouillou.net, Eugeniy.Paltsev@...opsys.com, 
	manivannan.sadhasivam@...aro.org, vireshk@...nel.org, Frank.Li@....com, 
	leoyang.li@....com, zw@...kernel.org, wangzhou1@...ilicon.com, 
	haijie1@...wei.com, shawnguo@...nel.org, s.hauer@...gutronix.de, 
	sean.wang@...iatek.com, matthias.bgg@...il.com, 
	angelogioacchino.delregno@...labora.com, afaerber@...e.de, 
	logang@...tatee.com, daniel@...que.org, haojian.zhuang@...il.com, 
	robert.jarzmik@...e.fr, andersson@...nel.org, konrad.dybcio@...aro.org, 
	orsonzhai@...il.com, baolin.wang@...ux.alibaba.com, zhang.lyra@...il.com, 
	patrice.chotard@...s.st.com, wens@...e.org, jernej.skrabec@...il.com, 
	peter.ujfalusi@...il.com, kys@...rosoft.com, haiyangz@...rosoft.com, 
	wei.liu@...nel.org, decui@...rosoft.com, jassisinghbrar@...il.com, 
	mchehab@...nel.org, maintainers@...echerrydvr.com, 
	aubin.constans@...rochip.com, ulf.hansson@...aro.org, manuel.lauss@...il.com, 
	mirq-linux@...e.qmqm.pl, jh80.chung@...sung.com, oakad@...oo.com, 
	hayashi.kunihiko@...ionext.com, mhiramat@...nel.org, brucechang@....com.tw, 
	HaraldWelte@...tech.com, pierre@...man.eu, duncan.sands@...e.fr, 
	stern@...land.harvard.edu, oneukum@...e.com, 
	openipmi-developer@...ts.sourceforge.net, dmaengine@...r.kernel.org, 
	asahi@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
	linux-rpi-kernel@...ts.infradead.org, linux-mips@...r.kernel.org, 
	imx@...ts.linux.dev, linuxppc-dev@...ts.ozlabs.org, 
	linux-mediatek@...ts.infradead.org, linux-actions@...ts.infradead.org, 
	linux-arm-msm@...r.kernel.org, linux-riscv@...ts.infradead.org, 
	linux-sunxi@...ts.linux.dev, linux-tegra@...r.kernel.org, 
	linux-hyperv@...r.kernel.org, linux-rdma@...r.kernel.org, 
	linux-media@...r.kernel.org, linux-mmc@...r.kernel.org, 
	linux-omap@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
	linux-s390@...r.kernel.org, netdev@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH 2/9] dma: Convert from tasklet to BH workqueue

Hi Allen,

thanks for your patch!

On Wed, Mar 27, 2024 at 5:03 PM Allen Pais <apais@...ux.microsoft.com> wrote:

> The only generic interface to execute asynchronously in the BH context is
> tasklet; however, it's marked deprecated and has some design flaws. To
> replace tasklets, BH workqueue support was recently added. A BH workqueue
> behaves similarly to regular workqueues except that the queued work items
> are executed in the BH context.
>
> This patch converts drivers/dma/* from tasklet to BH workqueue.
>
> Based on the work done by Tejun Heo <tj@...nel.org>
> Branch: git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-6.10
>
> Signed-off-by: Allen Pais <allen.lkml@...il.com>
(...)
> diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
(...)
>         if (d40c->pending_tx)
> -               tasklet_schedule(&d40c->tasklet);
> +               queue_work(system_bh_wq, &d40c->work);

Why is "my" driver not allowed to use system_bh_highpri_wq?

I can't see the reasoning between some drivers using system_bh_wq
and others being highpri?

Given the DMA usecase I would expect them all to be high prio.

Yours,
Linus Walleij