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From: Christoph Hellwig <hch@lst.de>
To: "Arkadiusz Kozdra (Arusekk)" <arek_koz@o2.pl>
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	Alexey Dobriyan <adobriyan@gmail.com>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Christoph Hellwig <hch@lst.de>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH] proc: Use seq_read_iter where possible
Date: Wed, 28 Apr 2021 08:12:59 +0200	[thread overview]
Message-ID: <20210428061259.GA5084@lst.de> (raw)
In-Reply-To: <20210427183414.12499-1-arek_koz@o2.pl>

On Tue, Apr 27, 2021 at 08:34:15PM +0200, Arkadiusz Kozdra (Arusekk) wrote:
> Since seq_read_iter looks mature enough to be used for all procfs files,
> re-allow applications to perform zero-copy data forwarding from them.
> According to the sendfile(2) man-page, it is still enough for the file
> being read to support mmap-like operations, and the proc files support
> memory mapping, so returning -EINVAL was an inconsistency.

Linus did object to blindly switching over all instances.

> Some executable-inspecting tools rely on patching entry point
> instructions with minimal machine code that uses sendfile to read
> /proc/self/maps to stdout.  The sendfile call allows them to do it
> faster and without excessive allocations.

Patching what entry point?

  reply	other threads:[~2021-04-28  6:13 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-27 18:34 [PATCH] proc: Use seq_read_iter where possible Arkadiusz Kozdra (Arusekk)
2021-04-28  6:12 ` Christoph Hellwig [this message]
2021-04-28 13:02   ` Arusekk
2021-04-28 13:03     ` Christoph Hellwig
2021-04-28 17:46       ` Linus Torvalds
2021-04-29 10:05         ` [PATCH v2] proc: Use seq_read_iter for /proc/*/maps Arkadiusz Kozdra (Arusekk)
2021-04-29 10:07           ` Greg Kroah-Hartman
2021-05-04 11:53             ` [PATCH v3] " Arkadiusz Kozdra (Arusekk)
2021-05-04 16:01               ` Linus Torvalds
2021-05-04 20:23                 ` Arusekk
2021-05-04 20:24                   ` Linus Torvalds
2021-04-29 16:36           ` [PATCH v2] " Linus Torvalds

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