From: Christoph Hellwig <hch@lst.de>
To: Richard Weinberger <richard.weinberger@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
Richard Weinberger <richard@nod.at>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-um@lists.infradead.org,
"linux-mtd @ lists . infradead . org"
<linux-mtd@lists.infradead.org>
Subject: Re: [PATCH, RFC] ubd: remove use of blk_rq_map_sg
Date: Wed, 17 Oct 2018 08:14:18 +0200 [thread overview]
Message-ID: <20181017061418.GA21790@lst.de> (raw)
In-Reply-To: <CAFLxGvwx4TPTHRY91LMBdd7h4pgCjw2zY7Q67r3CRHTqfzSB1w@mail.gmail.com>
On Wed, Oct 17, 2018 at 12:43:14AM +0200, Richard Weinberger wrote:
> On Mon, Oct 15, 2018 at 8:56 AM Christoph Hellwig <hch@lst.de> wrote:
> >
> > There is no good reason to create a scatterlist in the ubd driver,
> > it can just iterate the request directly.
>
> BTW: Does it make sense to drop blk_rq_map_sq from()
> drivers/mtd/ubi/block.c too?
> If so we have to allocate a temporary structure for the worker thread
> for each segment, just like
> UBD does already. I'm not sure if that is cheaper than blk_rq_map_sq().
UBI should not need a new per-thread structure, mostly because there
are no threads involved. The scatterlist support in UBI only seems
to exists for ubiblock, but it goes down a few layers. In the end
all that could switch to a iov_iter-like setup and clean things up
a lot, but it would be a fair amount of work.
prev parent reply other threads:[~2018-10-17 6:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-15 6:56 [PATCH, RFC] ubd: remove use of blk_rq_map_sg Christoph Hellwig
2018-10-15 8:40 ` Richard Weinberger
2018-10-15 8:45 ` Christoph Hellwig
2018-10-15 19:17 ` Richard Weinberger
2018-10-15 20:42 ` Richard Weinberger
2018-10-15 20:55 ` Christoph Hellwig
2018-10-15 21:46 ` Richard Weinberger
2018-10-15 22:04 ` Jens Axboe
2018-10-15 22:44 ` Richard Weinberger
2018-10-16 2:19 ` Jens Axboe
2018-10-16 8:38 ` Richard Weinberger
2018-10-16 14:26 ` Jens Axboe
2018-10-17 6:21 ` Christoph Hellwig
2018-10-18 21:04 ` Richard Weinberger
2018-10-16 22:43 ` Richard Weinberger
2018-10-17 6:14 ` Christoph Hellwig [this message]
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