linux-kernel - Re: [PATCH 1/2] scsi: smartpqi: Replace semaphore sync_request

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Message-ID: <3118730.6uvAdDZXCF@wuerfel>
Date:   Thu, 20 Oct 2016 11:10:39 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Binoy Jayan <binoy.jayan@...aro.org>
Cc:     "James E.J. Bottomley" <jejb@...ux.vnet.ibm.com>,
        "Martin K. Petersen" <martin.petersen@...cle.com>,
        kevin Barnett <kevin.barnett@...rosemi.com>,
        Don Brace <don.brace@...rosemi.com>,
        Scott Benesh <scott.benesh@...rosemi.com>,
        Johannes Thumshirn <jthumshirn@...e.de>,
        linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] scsi: smartpqi: Replace semaphore sync_request_sem with mutex

On Thursday, October 20, 2016 2:24:01 PM CEST Binoy Jayan wrote:
> -       sema_init(&ctrl_info->sync_request_sem,
> -               PQI_RESERVED_IO_SLOTS_SYNCHRONOUS_REQUESTS);
> +       mutex_init(&ctrl_info->sync_request_mutex);
> 

Looking at this again, I see that PQI_RESERVED_IO_SLOTS_SYNCHRONOUS_REQUESTS
is '3', so this is in fact a counting semaphore rather than a mutex,
and the conversion is changing the behavior.

The patch can't go in unless you either show that it should be
a normal mutex rather than a counting semaphore, or you find a way
to keep the behavior the same.

	Arnd