Re: [PATCH 27/32] scsi_data_buffer

[Boaz Harrosh <bharrosh@panasas.com>]

On Thu, Oct 18 2007 at 1:40 +0200, FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp> wrote:
> On Wed, 17 Oct 2007 20:21:15 +0200
> Boaz Harrosh <bharrosh@panasas.com> wrote:
> 
>>   In preparation for bidi we abstract all IO members of scsi_cmnd,
>>   that will need to duplicate, into a substructure.
>>
>>   - Group all IO members of scsi_cmnd into a scsi_data_buffer
>>     structure.
>>   - Adjust accessors to new members.
>>   - scsi_{alloc,free}_sgtable receive a scsi_data_buffer instead of
>>     scsi_cmnd. And work on it.
>>   - Adjust scsi_init_io() and  scsi_release_buffers() for above
>>     change.
>>   - Fix other parts of scsi_lib/scsi.c to members migration. Use
>>     accessors where appropriate.
>>
>>   - Old I/O members are kept for backward compatibility, since
>>     not all of scsi-ml/ul is converted yet. Once done they will
>>     be removed in a closing patch. (Other wise the patchset will
>>     not be bisectable)
> 
> (snip)
> 
>> @@ -114,6 +112,22 @@ struct scsi_cmnd {
>>  	int result;		/* Status code from lower level driver */
>>  
>>  	unsigned char tag;	/* SCSI-II queued command tag */
>> +
>> +	union {
>> +		struct scsi_data_buffer sdb;
>> +		/*
>> +		 * FIXME: Here for compatibility with unconverted drivers.
>> +		 *        Must be kept in sync with exact type and order
>> +		 *        of struct scsi_data_buffer members.
>> +		 */
>> +		struct {
>> +			unsigned __deprecated request_bufflen;
>> +			int __deprecated resid;
>> +			unsigned short __deprecated use_sg;
>> +			unsigned short __deprecated place_holder_sg_alloc;
>> +			void __deprecated *request_buffer;
>> +		};
>> +	};
>>  };
> 
> If we add something like this, why couldn't we merge the
> scsi_data_buffer patchset when I submitted last month?
> 
> I thought that I wait you to fix all the old LLDs, then will send a
> clean scsi_data_buffer patchset.

We do have all the old LLDs fixed. After this patchset the entire tree
is clean. I have just forgot to send the last [33/33] patch that removes
this. I have just sent it now, sorry.
(The change log above explains exactly why this is done here)

Boaz