linux-kernel - Re: [PATCH] staging: pi433: add rw semaphore fixing concurrency issues

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Message-ID: <20180602180808.GA2052@hle-laptop.local>
Date:   Sat, 2 Jun 2018 14:08:08 -0400
From:   Hugo Lefeuvre <hle@....eu.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     devel@...verdev.osuosl.org, linux-kernel@...r.kernel.org,
        kernelnewbies@...nelnewbies.org
Subject: Re: [PATCH] staging: pi433: add rw semaphore fixing concurrency
 issues

Hi,

> Unless you can measure the performance difference, do not use a rw
> semaphore, just use a normal mutex please.  Odds are it will be faster
> in the end and take up less space.
> 
> So please test, or if you can't test, just use a mutex.

I don't have the device yet, so I won't be able to test. I have opted for the
mutex instead.

I have just sent an updated version fixing another issue in my code: The
mutex can't be included in pi433_instance because we have to lock it
before dereferencing our pi433_instance pointer. The best solution I
could think of was to create a wrapper struct pi433_data which would contain
pointers to the pi433_instance and its mutex. I couldn't find any
similar situation in the kernel, so I'm not sure it's the right way to
go though.

Thanks !

Regards,
 Hugo

-- 
             Hugo Lefeuvre (hle)    |    www.owl.eu.com
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