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Date: Fri, 10 Jun 2011 09:41:35 -0700
From: Nitin Gupta <ngupta@vflare.org>
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To: Jerome Marchand <jmarchan@redhat.com>
CC: Greg Kroah-Hartman <gregkh@suse.de>,
        Linux Kernel List <linux-kernel@vger.kernel.org>,
        Robert Jennings <rcj@linux.vnet.ibm.com>,
        Jeff Moyer <jmoyer@redhat.com>
Subject: Re: [PATCH 3/4] Staging: zram: allow partial page operations
References: <1307712529-9757-1-git-send-email-jmarchan@redhat.com> <1307712529-9757-2-git-send-email-jmarchan@redhat.com> <1307712529-9757-3-git-send-email-jmarchan@redhat.com>
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On 06/10/2011 06:28 AM, Jerome Marchand wrote:
> Commit 7b19b8d45b216ff3186f066b31937bdbde066f08 (zram: Prevent overflow
> in logical block size) introduced ZRAM_LOGICAL_BLOCK_SIZE constant to
> prevent overflow of logical block size on 64k page kernel.
> However, the current implementation of zram only allow operation on block
> of the same size as a page. That makes theorically legit 4k requests fail
> on 64k page kernel.
>
> This patch makes zram allow operation on partial pages. Basically, it
> means we still do operations on full pages internally, but only copy the
> relevent segments from/to the user memory.
>

Couldn't we just change struct queue_limits.logical_block_size type to 
unsigned int or something so it could hold value of 64K? Then we could
avoid making all these changes to handle partial page requests.

Thanks,
Nitin