From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julia Lawall Date: Fri, 05 Oct 2018 14:29:54 +0000 Subject: Re: [PATCH] wil6210: fix debugfs_simple_attr.cocci warnings Message-Id: List-Id: References: <1538737646-118337-1-git-send-email-yuehaibing@huawei.com> <877eiw1wol.fsf@codeaurora.org> In-Reply-To: <877eiw1wol.fsf@codeaurora.org> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Kalle Valo Cc: YueHaibing , Maya Erez , linux-wireless@vger.kernel.org, wil6210@qti.qualcomm.com, kernel-janitors@vger.kernel.org, netdev@vger.kernel.org On Fri, 5 Oct 2018, Kalle Valo wrote: > YueHaibing 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 >