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From: "Martin K. Petersen" <martin.petersen@oracle.com>
To: "James E.J. Bottomley" <James.Bottomley@suse.de>
Cc: Matthew Wilcox <matthew@wil.cx>,
	Dan Carpenter <error27@gmail.com>,
	linux-scsi@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: bug report: sd:  off by one in sd_read_block_limits()
Date: Tue, 02 Mar 2010 08:36:35 -0500	[thread overview]
Message-ID: <yq1fx4i26cc.fsf@sermon.lab.mkp.net> (raw)
In-Reply-To: <yq1k4tu2716.fsf@sermon.lab.mkp.net> (Martin K. Petersen's message of "Tue, 02 Mar 2010 08:21:41 -0500")


James,

While I agree the original VPD code's double kmalloc() was a bit of a
wart at least it did the right thing because it allocated a suitably
sized buffer for page 0.

My concern with the interface you introduced in e3deec09 is that for
devices that support a large number of VPD pages we won't be able to fit
the page list in the allocated buffer.  And callers are likely to pick a
buffer size that makes sense for the VPD page they are interested in.
It's not a big deal in the block limits/block device characteristics
case because they are big enough.

But at the very minimum that interface should come with a big fat
warning in the comment section that describes that the page list must
also be able to fit.

-- 
Martin K. Petersen	Oracle Linux Engineering

  parent reply	other threads:[~2010-03-02 13:38 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-03-02  8:21 bug report: sd: off by one in sd_read_block_limits() Dan Carpenter
2010-03-02 13:12 ` Martin K. Petersen
2010-03-02 13:21   ` Martin K. Petersen
2010-03-02 13:31     ` Matthew Wilcox
2010-03-02 13:36     ` Martin K. Petersen [this message]
2010-03-02 14:56       ` Matthew Wilcox
2010-03-03  7:08       ` James Bottomley
2010-03-02 13:44     ` Martin K. Petersen

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