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From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>,
	Christoph Hellwig <hch@lst.de>,
	James Bottomley <james.bottomley@hansenpartnership.com>,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH] sd: fixup capacity calculation for 4k drives
Date: Mon, 21 Mar 2016 15:31:30 +0100	[thread overview]
Message-ID: <20160321143130.GA12542@lst.de> (raw)
In-Reply-To: <1458563249-91200-1-git-send-email-hare@suse.de>

On Mon, Mar 21, 2016 at 01:27:29PM +0100, Hannes Reinecke wrote:
> in sd_read_capacity() the sdkp->capacity field changes its meaning:
> after the call to read_capacity_XX() it carries the _unscaled_ values,
> making the comparison between the original value and the new value
> always false for drives with a sector size != 512.
> So introduce a 'new_capacity' carrying the new, scaled, capacity.

While this fixes a bug and adds a comment to clarify things I think
the whole function is still a mess.  And the way how your first
calculate new_capacity but then keep the duplicated scaling on
sdkp->capacity a littler later isn't really helpful either.

Is there any chance to rewrite it so that the unscaled capacity has its
own local variable, and sdkp->capacity is always either the correct
old or new capacity?

  reply	other threads:[~2016-03-21 14:31 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-21 12:27 [PATCH] sd: fixup capacity calculation for 4k drives Hannes Reinecke
2016-03-21 14:31 ` Christoph Hellwig [this message]
2016-03-22  1:16 ` Martin K. Petersen
2016-03-22  6:55   ` Christoph Hellwig
2016-03-22  7:14   ` Hannes Reinecke
2016-03-22 14:16     ` Ewan D. Milne
2016-03-29  1:14       ` Martin K. Petersen
2016-03-29  1:18       ` [PATCH v2] sd: Fix excessive capacity printing on devices with blocks bigger than 512 bytes Martin K. Petersen
2016-03-30  8:06         ` Hannes Reinecke
2016-03-30 16:34         ` Ewan D. Milne
  -- strict thread matches above, loose matches on Subject: below --
2016-03-29  8:06 [PATCH] sd: fixup capacity calculation for 4k drives Hannes Reinecke
2016-04-10  2:02 ` Lee Duncan

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