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From: Christoph Hellwig <hch@lst.de>
To: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@lst.de>,
	James Bottomley <James.Bottomley@HansenPartnership.com>,
	"Martin K. Petersen" <martin.petersen@oracle.com>,
	linux-scsi@vger.kernel.org
Subject: Re: [PATCH 05/10] sd: don't use scsi_setup_blk_pc_cmnd for write same requests
Date: Fri, 11 Jul 2014 17:15:15 +0200	[thread overview]
Message-ID: <20140711151515.GA23254@lst.de> (raw)
In-Reply-To: <53BFD7A1.7040205@suse.de>

>> -	rq->__data_len = sdp->sector_size;

>> +	rq->__data_len = sdp->sector_size;
>> +	ret = scsi_init_io(cmd, GFP_ATOMIC);
>> +	rq->__data_len = nr_bytes;
>>   	return ret;
>>   }
>>
> Hmm? __data_len is the amount of data written _on the target_.
> Do we actually care about it?
> And if so, why didn't it break with the original version?
> In either case a short description in the patch would be nice.

The drivers care about it, and scsi_init_io uses it as transfer size,
thus we have to set it to the tranfer length before the scsi_init_io
call, and to the full number of bytes to be written after it.

We already do this before the patch, I just moved the first assginment
next to the call to scsi_init_io so that it's more obvious.


  reply	other threads:[~2014-07-11 15:15 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-29 13:34 RFC: clean up command setup Christoph Hellwig
2014-06-29 13:34 ` [PATCH 01/10] scsi: move the nr_phys_segments assert into scsi_init_io Christoph Hellwig
2014-07-11 12:17   ` Hannes Reinecke
2014-07-13 14:03   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 02/10] scsi: restructure command initialization for TYPE_FS requests Christoph Hellwig
2014-07-11 12:18   ` Hannes Reinecke
2014-07-13 14:04   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 03/10] scsi: set sc_data_direction in common code Christoph Hellwig
2014-07-11 12:19   ` Hannes Reinecke
2014-07-13 14:06   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 04/10] sd: don't use scsi_setup_blk_pc_cmnd for flush requests Christoph Hellwig
2014-07-11 12:20   ` Hannes Reinecke
2014-07-13 14:07   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 05/10] sd: don't use scsi_setup_blk_pc_cmnd for write same requests Christoph Hellwig
2014-07-11 12:25   ` Hannes Reinecke
2014-07-11 15:15     ` Christoph Hellwig [this message]
2014-07-13 14:14   ` Martin K. Petersen
2014-07-17 15:29   ` Christoph Hellwig
2014-06-29 13:34 ` [PATCH 06/10] sd: don't use scsi_setup_blk_pc_cmnd for discard requests Christoph Hellwig
2014-07-07  0:01   ` Elliott, Robert (Server Storage)
2014-07-07  2:01     ` Elliott, Robert (Server Storage)
2014-07-07  9:24     ` Christoph Hellwig
2014-07-11 12:26   ` Hannes Reinecke
2014-07-11 15:15     ` Christoph Hellwig
2014-07-13 14:35   ` Martin K. Petersen
2014-07-13 14:52     ` Douglas Gilbert
2014-07-13 14:56       ` Christoph Hellwig
2014-07-13 15:03         ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 07/10] sd: retry write same commands Christoph Hellwig
2014-07-11 12:26   ` Hannes Reinecke
2014-07-13 14:36   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 08/10] sd: retry discard commands Christoph Hellwig
2014-07-11 12:27   ` Hannes Reinecke
2014-07-13 14:36   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 09/10] sd: split sd_init_command Christoph Hellwig
2014-07-11 12:33   ` Hannes Reinecke
2014-07-13 14:37   ` Martin K. Petersen
2014-06-29 13:34 ` [PATCH 10/10] scsi: mark scsi_setup_blk_pc_cmnd static Christoph Hellwig
2014-07-11 12:33   ` Hannes Reinecke
2014-07-13 14:38   ` Martin K. Petersen
2014-07-11  9:16 ` RFC: clean up command setup Christoph Hellwig

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