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From: Dave Jones <davej@redhat.com>
To: Rolf Eike Beer <eike-kernel@sf-tec.de>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Saripalli, Venkata Ramanamurthy (STSD)" <saripalli@hp.com>,
	linux-scsi@vger.kernel.org, axboe@suse.de
Subject: Re: [PATCH 1/2] cpqfc: fix for "Using too much stach" in 2.6 kernel
Date: Thu, 4 Aug 2005 11:40:23 -0400	[thread overview]
Message-ID: <20050804154023.GA22886@redhat.com> (raw)
In-Reply-To: <200508041138.38216@bilbo.math.uni-mannheim.de>

On Thu, Aug 04, 2005 at 11:38:30AM +0200, Rolf Eike Beer wrote:
 > 
 > >+	  ulFibreFrame = kmalloc((2048/4), GFP_KERNEL);
 > The size bug was already found by Dave Jones. This never should be written 
 > this way (not your fault). The array should have been [2048/sizeof(ULONG)].

wasteful. We only ever use 2048 bytes of this array, so doubling
its size on 64bit is pointless, unless you make changes later on
in the driver. (Which I think don't make sense, as we just copy
32 64byte chunks).

Ermm, actually this looks totally bogus..
CpqTsGetSFQEntry() ...

    if( total_bytes <= 2048 )
    {
      memcpy( ulDestPtr,
              &fcChip->SFQ->QEntry[consumerIndex],
              64 );  // each SFQ entry is 64 bytes
      ulDestPtr += 16;   // advance pointer to next 64 byte block
    }

we're trashing the last 48 bytes of every copy we make.
Does this driver even work ?

		Dave


  parent reply	other threads:[~2005-08-04 15:45 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-08-04  4:39 [PATCH 1/2] cpqfc: fix for "Using too much stach" in 2.6 kernel Saripalli, Venkata Ramanamurthy (STSD)
2005-08-04  4:49 ` Dave Jones
2005-08-04  9:38 ` Rolf Eike Beer
2005-08-04 12:13   ` Denis Vlasenko
2005-08-04 15:40   ` Dave Jones [this message]
2005-08-04 15:56     ` Rolf Eike Beer
2005-08-04 16:42       ` Dave Jones
2005-08-04 17:11         ` Rolf Eike Beer
2005-08-04 17:38           ` Dave Jones
2005-08-04 13:53 ` Jesper Juhl
2005-08-06  1:13   ` Jesper Juhl

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