From: Christoph Hellwig <hch@infradead.org>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
io-uring@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
Miklos Szeredi <mszeredi@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
ZiyangZhang <ZiyangZhang@linux.alibaba.com>
Subject: Re: [RFC PATCH 1/4] io_uring/splice: support do_splice_direct
Date: Mon, 7 Nov 2022 23:42:42 -0800 [thread overview]
Message-ID: <Y2oIcpXINyU2MDL3@infradead.org> (raw)
In-Reply-To: <20221103085004.1029763-2-ming.lei@redhat.com>
On Thu, Nov 03, 2022 at 04:50:01PM +0800, Ming Lei wrote:
> do_splice_direct() has at least two advantages:
>
> 1) the extra pipe isn't required from user viewpoint, so userspace
> code can be simplified, meantime easy to relax current pipe
> limit since curret->splice_pipe is used for direct splice
>
> 2) in some situation, it isn't good to expose file data via
> ->splice_read() to userspace, such as the coming ublk driver's
> zero copy support, request pages will be spliced to pipe for
> supporting zero copy, and if it is READ, userspace may read
> data of kernel pages, and direct splice can avoid this kind
> of info leaks
Please make this a separate opcode instead of overloading the splice
op with a flag that causes very different behavior and isn't supported
for the regular splice syscall.
next prev parent reply other threads:[~2022-11-08 7:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-03 8:50 [RFC PATCH 0/4] io_uring/splice: extend splice for supporting ublk zero copy Ming Lei
2022-11-03 8:50 ` [RFC PATCH 1/4] io_uring/splice: support do_splice_direct Ming Lei
2022-11-08 7:42 ` Christoph Hellwig [this message]
2022-11-03 8:50 ` [RFC PATCH 2/4] fs/splice: add helper of splice_dismiss_pipe() Ming Lei
2022-11-03 8:50 ` [RFC PATCH 3/4] io_uring/splice: support splice from ->splice_read to ->splice_read Ming Lei
2022-11-08 7:45 ` Christoph Hellwig
2022-11-08 8:29 ` Ming Lei
2022-11-03 8:50 ` [RFC PATCH 4/4] ublk_drv: support splice based read/write zero copy Ming Lei
2022-11-03 22:28 ` Bernd Schubert
2022-11-04 0:44 ` Ming Lei
2022-11-04 23:37 ` Bernd Schubert
2022-11-07 1:05 ` Ming Lei
2022-11-04 9:15 ` [RFC PATCH 0/4] io_uring/splice: extend splice for supporting ublk " Ziyang Zhang
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