linux-kernel - Re: [PATCH] statx: optimize copy of struct statx to userspace

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Message-ID: <20170311214410.GA672@zzz>
Date:   Sat, 11 Mar 2017 13:44:10 -0800
From:   Eric Biggers <ebiggers3@...il.com>
To:     linux-fsdevel@...r.kernel.org
Cc:     Al Viro <viro@...iv.linux.org.uk>,
        David Howells <dhowells@...hat.com>,
        linux-kernel@...r.kernel.org, Eric Biggers <ebiggers@...gle.com>
Subject: Re: [PATCH] statx: optimize copy of struct statx to userspace

On Sat, Mar 11, 2017 at 02:15:10AM -0800, Eric Biggers wrote:
> stat() instead initializes its struct on the stack and copies it to
> userspace with a single call to copy_to_user().  This turns out to be
> much faster, and changing statx to do this makes it almost as fast as
> stat:

Hmm, I missed that the access_ok() check in sys_statx() will no longer be
needed.  I'm sending a revised patch that removes that too.

Eric