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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Wed, 31 Jan 2024 15:19:01 -0800
Message-ID: <CAHk-=wjMz_1mb+WJsPhfp5VBNrM=o8f-x2=6UW2eK5n4DHff9g@mail.gmail.com>
Subject: Re: [PATCH 8/8] dm-verity: Convert from tasklet to BH workqueue
To: Tejun Heo <tj@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>, linux-kernel@vger.kernel.org, 
	dm-devel@lists.linux.dev, msnitzer@redhat.com, ignat@cloudflare.com, 
	damien.lemoal@wdc.com, bob.liu@oracle.com, houtao1@huawei.com, 
	peterz@infradead.org, mingo@kernel.org, netdev@vger.kernel.org, 
	allen.lkml@gmail.com, kernel-team@meta.com, Alasdair Kergon <agk@redhat.com>, 
	Mike Snitzer <snitzer@kernel.org>
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On Wed, 31 Jan 2024 at 13:32, Tejun Heo <tj@kernel.org> wrote:
>
> I don't know, so just did the dumb thing. If the caller always guarantees
> that the work items are never queued at the same time, reusing is fine.

So the reason I thought it would be a good cleanup to introduce that
"atomic" workqueue thing (now "bh") was that this case literally has a
switch between "use tasklets' or "use workqueues".

So it's not even about "reusing" the workqueue, it's literally a
matter of making it always just use workqueues, and the switch then
becomes just *which* workqueue to use - system or bh.

In fact, I suspect there is very little reason ever to *not* just use
the bh one, and even the switch could be removed.

Because I think the only reason the "workqueue of tasklet" choice
existed in the first place was that workqueues were the "proper" data
structure, and the tasklet case was added later as a latency hack, and
everybody knew that tasklets were deprecated.

             Linus