From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Carpenter <error27@gmail.com>
Subject: Re: [PATCH 10/25] scsi/sg: remove casts from void*
Date: Thu, 1 Jul 2010 19:38:05 +0200
Message-ID: <20100701173805.GW19184@bicker>
References: <1277990204-22157-1-git-send-email-segooon@gmail.com>
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Sender: linux-kernel-owner@vger.kernel.org
To: Kulikov Vasiliy <segooon@gmail.com>
Cc: Kernel Janitors <kernel-janitors@vger.kernel.org>, Doug Gilbert <dgilbert@interlog.com>, "James E.J. Bottomley" <James.Bottomley@suse.de>, Andrew Morton <akpm@linux-foundation.org>, FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>, Jens Axboe <jens.axboe@oracle.com>, Alexey Dobriyan <adobriyan@gmail.com>, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org
List-Id: linux-scsi@vger.kernel.org

On Thu, Jul 01, 2010 at 05:16:43PM +0400, Kulikov Vasiliy wrote:
> -	Sg_fd *sfp;
> +	Sg_fd *sfp = filp->private_data;
                     ^^^^^^^^^^^^^^^^^^
	Dereferenced here.

>  	unsigned long req_sz, len, sa;
>  	Sg_scatter_hold *rsv_schp;
>  	int k, length;
>  
> -	if ((!filp) || (!vma) || (!(sfp = (Sg_fd *) filp->private_data)))
> +	if ((!filp) || (!vma) || !(sfp))
             ^^^^^

	Checked here.

I obviously just spotted that during the review but another way would be
to use smatch to catch these.  (http://smatch.sf.net)

$ /path/to/smatch_scripts/kchecker drivers/scsi/sg.c
  CHK     include/linux/version.h
  CHK     include/generated/utsrelease.h
  CALL    scripts/checksyscalls.sh
  CHECK   drivers/scsi/sg.c
drivers/scsi/sg.c +1236 sg_mmap(7) warn: variable dereferenced before check 'filp'
  CC [M]  drivers/scsi/sg.o
$

You could also get rid of the extra parenthesis.
+	if (!filp || !vma || !sfp)

>  		return -ENXIO;
>  	req_sz = vma->vm_end - vma->vm_start;
>  	SCSI_LOG_TIMEOUT(3, printk("sg_mmap starting, vm_start=%p, len=%d\n",

Btw.  These are _way_ better than when you sent them the first time.
Thanks for doing resending them.

regards,
dan carpenter