From: Douglas Gilbert <dgilbert@interlog.com>
To: Akinobu Mita <akinobu.mita@gmail.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
"James E.J. Bottomley" <JBottomley@parallels.com>,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH v3 4/4] scsi_debug: fix do_device_access() with wrap around range
Date: Tue, 25 Jun 2013 01:34:46 +0200 [thread overview]
Message-ID: <51C8D796.8000005@interlog.com> (raw)
In-Reply-To: <1371991061-19437-5-git-send-email-akinobu.mita@gmail.com>
On 13-06-23 02:37 PM, Akinobu Mita wrote:
> do_device_access() is a function that abstracts copying SG list from/to
> ramdisk storage (fake_storep).
>
> It must deal with the ranges exceeding actual fake_storep size, because
> such ranges are valid if virtual_gb is set greater than zero, and they
> should be treated as fake_storep is repeatedly mirrored up to virtual size.
>
> Unfortunately, it can't deal with the range which wraps around the end of
> fake_storep. A wrap around range is copied by two sg_copy_{from,to}_buffer()
> calls, but sg_copy_{from,to}_buffer() can't copy from/to in the middle of
> SG list, therefore the second call can't copy correctly.
>
> This fixes it by using sg_pcopy_{from,to}_buffer() that can copy from/to
> the middle of SG list.
>
> This also simplifies the assignment of sdb->resid in fill_from_dev_buffer().
> Because fill_from_dev_buffer() is now only called once per command
> execution cycle. So it is not necessary to take care to decrease
> sdb->resid if fill_from_dev_buffer() is called more than once.
>
> Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
> Cc: "James E.J. Bottomley" <JBottomley@parallels.com>
> Cc: Douglas Gilbert <dgilbert@interlog.com>
> Cc: linux-scsi@vger.kernel.org
> ---
>
> * No change from v2
Acked-by: Douglas Gilbert <dgilbert@interlog.com>
prev parent reply other threads:[~2013-06-24 23:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-23 12:37 [PATCH v3 0/4] introduce sg_pcopy_from_buffer() and sg_pcopy_to_buffer() Akinobu Mita
2013-06-23 12:37 ` [PATCH v3 1/4] lib/scatterlist: factor out sg_miter_get_next_page() from sg_miter_next() Akinobu Mita
2013-06-23 12:37 ` [PATCH v3 2/4] lib/scatterlist: introduce sg_pcopy_from_buffer() and sg_pcopy_to_buffer() Akinobu Mita
2013-06-24 23:27 ` Tejun Heo
2013-06-23 12:37 ` [PATCH v3 3/4] crypto: talitos: use sg_pcopy_to_buffer() Akinobu Mita
2013-06-23 12:37 ` [PATCH v3 4/4] scsi_debug: fix do_device_access() with wrap around range Akinobu Mita
2013-06-24 23:34 ` Douglas Gilbert [this message]
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