From: Julia Lawall <julia.lawall@lip6.fr>
To: Kalle Valo <kvalo@codeaurora.org>
Cc: YueHaibing <yuehaibing@huawei.com>,
Maya Erez <merez@codeaurora.org>,
linux-wireless@vger.kernel.org, wil6210@qti.qualcomm.com,
kernel-janitors@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH] wil6210: fix debugfs_simple_attr.cocci warnings
Date: Fri, 5 Oct 2018 16:29:54 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.20.1810051629140.3364@hadrien> (raw)
In-Reply-To: <877eiw1wol.fsf@codeaurora.org>
On Fri, 5 Oct 2018, Kalle Valo wrote:
> YueHaibing <yuehaibing@huawei.com> writes:
>
> > Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE
> > for debugfs files.
> >
> > Semantic patch information:
> > Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()
> > imposes some significant overhead as compared to
> > DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().
> >
> > Generated by: scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci
>
> Just out of curiosity, what kind of overhead are we talking about here?
The log message on the commit introducing the semantic patch says the
following:
In order to protect against file removal races, debugfs files created via
debugfs_create_file() now get wrapped by a struct file_operations at their
opening.
If the original struct file_operations are known to be safe against removal
races by themselves already, the proxy creation may be bypassed by creating
the files through debugfs_create_file_unsafe().
In order to help debugfs users who use the common
DEFINE_SIMPLE_ATTRIBUTE() + debugfs_create_file()
idiom to transition to removal safe struct file_operations, the helper
macro DEFINE_DEBUGFS_ATTRIBUTE() has been introduced.
Thus, the preferred strategy is to use
DEFINE_DEBUGFS_ATTRIBUTE() + debugfs_create_file_unsafe()
now.
julia
>
> --
> Kalle Valo
>
next prev parent reply other threads:[~2018-10-05 14:30 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-05 11:07 [PATCH] wil6210: fix debugfs_simple_attr.cocci warnings YueHaibing
2018-10-05 11:04 ` Kalle Valo
2018-10-05 11:51 ` YueHaibing
2018-10-05 14:29 ` Julia Lawall [this message]
2018-10-06 12:11 ` Kalle Valo
2018-10-06 12:22 ` Julia Lawall
2018-10-06 12:54 ` Kalle Valo
2018-10-13 17:29 ` Kalle Valo
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