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From: Tejun Heo <tj@kernel.org>
To: Ian Kent <raven@themaw.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Minchan Kim <minchan@kernel.org>,
	Eric Sandeen <sandeen@sandeen.net>,
	Al Viro <viro@zeniv.linux.org.uk>,
	Rick Lindsley <ricklind@linux.vnet.ibm.com>,
	David Howells <dhowells@redhat.com>,
	Miklos Szeredi <miklos@szeredi.hu>,
	Carlos Maiolino <cmaiolino@redhat.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] kernfs: dont take i_lock on inode attr read
Date: Mon, 31 Oct 2022 12:30:58 -1000	[thread overview]
Message-ID: <Y2BMonmS0SdOn5yh@slm.duckdns.org> (raw)
In-Reply-To: <166606036215.13363.1288735296954908554.stgit@donald.themaw.net>

On Tue, Oct 18, 2022 at 10:32:42AM +0800, Ian Kent wrote:
> The kernfs write lock is held when the kernfs node inode attributes
> are updated. Therefore, when either kernfs_iop_getattr() or
> kernfs_iop_permission() are called the kernfs node inode attributes
> won't change.
> 
> Consequently concurrent kernfs_refresh_inode() calls always copy the
> same values from the kernfs node.
> 
> So there's no need to take the inode i_lock to get consistent values
> for generic_fillattr() and generic_permission(), the kernfs read lock
> is sufficient.
> 
> Signed-off-by: Ian Kent <raven@themaw.net>

Acked-by: Tejun Heo <tj@kernel.org>

Thanks.

-- 
tejun

  parent reply	other threads:[~2022-10-31 22:31 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-10-18  2:32 [PATCH 0/2] kernfs: remove i_lock usage that isn't needed Ian Kent
2022-10-18  2:32 ` [PATCH 1/2] kernfs: dont take i_lock on inode attr read Ian Kent
2022-10-24  8:50   ` Miklos Szeredi
2022-10-31 22:30   ` Tejun Heo [this message]
2022-12-21 13:34     ` Anders Roxell
2022-12-22 23:11       ` Ian Kent
2022-12-29  9:20         ` Arnd Bergmann
2022-12-29 13:07           ` Ian Kent
2023-01-23  3:11             ` Ian Kent
2023-07-18 19:00               ` Anders Roxell
2023-07-19  4:23                 ` Ian Kent
2023-07-20  2:03                   ` Ian Kent
2023-07-26 13:49                     ` Miklos Szeredi
2023-07-27  0:38                     ` Ian Kent
2023-07-27  4:30                       ` Imran Khan
2023-07-27  5:35                         ` Imran Khan
2023-07-28  0:00                         ` Ian Kent
2023-07-28  0:16                           ` Ian Kent
2023-07-28  1:06                             ` Imran Khan
2023-07-28  1:29                               ` Ian Kent
2022-10-18  2:32 ` [PATCH 2/2] kernfs: dont take i_lock on revalidate Ian Kent
2022-10-24  8:38   ` Miklos Szeredi
2022-10-31 22:31   ` Tejun Heo
2022-11-01  7:46   ` Amir Goldstein
2022-11-01  8:09     ` Ian Kent

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