[Precise][PATCH] mtip32xx: removed the irrelevant argument of mtip_hw_submit_io() and the unused member of struct driver_data

[James M Leddy]

On 03/30/2012 01:11 PM, Tim Gardner wrote:
> On 03/30/2012 10:14 AM, James M Leddy wrote:
>> From: Asai Thambi S P <asamymuthupa at micron.com>
>>
>> Removed the following:
>> 	* irrelevant argument 'barrier' of mtip_hw_submit_io()
>> 	* unused member 'eh_active' of struct driver_data
>>
>> Signed-off-by: Asai Thambi S P <asamymuthupa at micron.com>
>> Signed-off-by: Sam Bradshaw <sbradshaw at micron.com>
>> Signed-off-by: Jens Axboe <axboe at kernel.dk>
>> (cherry picked from commit 4e8670e26135d8fbfd5e084fddc1a8ed9f8eb4cb)
>>
>> From the merge:
>>
>>   - Killing the barrier part of mtip32xx.  It doesn't really support
>>     barriers, and it doesn't need them (writes are fully ordered).
>>
>> Follow on from mtip32xx support that was added in 3.2.0-13.22.
>> I have compile tested.
>>
>> Signed-off-by: James M Leddy <james.leddy at canonical.com>
>> ---
>>  drivers/block/mtip32xx/mtip32xx.c |   11 +++++------
>>  drivers/block/mtip32xx/mtip32xx.h |    5 -----
>>  2 files changed, 5 insertions(+), 11 deletions(-)
>>
>> diff --git a/drivers/block/mtip32xx/mtip32xx.c b/drivers/block/mtip32xx/mtip32xx.c
>> index b74eab7..8eb81c9 100644
>> --- a/drivers/block/mtip32xx/mtip32xx.c
>> +++ b/drivers/block/mtip32xx/mtip32xx.c
>> @@ -2068,8 +2068,6 @@ static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd,
>>   *	     when the read completes.
>>   * @data     Callback data passed to the callback function
>>   *	     when the read completes.
>> - * @barrier  If non-zero, this command must be completed before
>> - *	     issuing any other commands.
>>   * @dir      Direction (read or write)
>>   *
>>   * return value
>> @@ -2077,7 +2075,7 @@ static int mtip_hw_ioctl(struct driver_data *dd, unsigned int cmd,
>>   */
>>  static void mtip_hw_submit_io(struct driver_data *dd, sector_t start,
>>  			      int nsect, int nents, int tag, void *callback,
>> -			      void *data, int barrier, int dir)
>> +			      void *data, int dir)
>>  {
>>  	struct host_to_dev_fis	*fis;
>>  	struct mtip_port *port = dd->port;
>> @@ -2108,8 +2106,6 @@ static void mtip_hw_submit_io(struct driver_data *dd, sector_t start,
>>  	*((unsigned int *) &fis->lba_low) = (start & 0xFFFFFF);
>>  	*((unsigned int *) &fis->lba_low_ex) = ((start >> 24) & 0xFFFFFF);
>>  	fis->device	 = 1 << 6;
>> -	if (barrier)
>> -		fis->device |= FUA_BIT;
>>  	fis->features    = nsect & 0xFF;
>>  	fis->features_ex = (nsect >> 8) & 0xFF;
>>  	fis->sect_count  = ((tag << 3) | (tag >> 5));
>> @@ -3087,7 +3083,6 @@ static void mtip_make_request(struct request_queue *queue, struct bio *bio)
>>  				tag,
>>  				bio_endio,
>>  				bio,
>> -				bio->bi_rw & REQ_FUA,
>>  				bio_data_dir(bio));
>>  	} else
>>  		bio_io_error(bio);
>> @@ -3187,6 +3182,10 @@ skip_create_disk:
>>  	blk_queue_max_segments(dd->queue, MTIP_MAX_SG);
>>  	blk_queue_physical_block_size(dd->queue, 4096);
>>  	blk_queue_io_min(dd->queue, 4096);
>> +	/*
>> +	 * write back cache is not supported in the device. FUA depends on
>> +	 * write back cache support, hence setting flush support to zero.
>> +	 */
>>  	blk_queue_flush(dd->queue, 0);
>>  
>>  	/* Set the capacity of the device in 512 byte sectors. */
>> diff --git a/drivers/block/mtip32xx/mtip32xx.h b/drivers/block/mtip32xx/mtip32xx.h
>> index 723d7c4..e0554a8 100644
>> --- a/drivers/block/mtip32xx/mtip32xx.h
>> +++ b/drivers/block/mtip32xx/mtip32xx.h
>> @@ -104,9 +104,6 @@
>>  /* BAR number used to access the HBA registers. */
>>  #define MTIP_ABAR		5
>>  
>> -/* Forced Unit Access Bit */
>> -#define FUA_BIT			0x80
>> -
>>  #ifdef DEBUG
>>   #define dbg_printk(format, arg...)	\
>>  	printk(pr_fmt(format), ##arg);
>> @@ -415,8 +412,6 @@ struct driver_data {
>>  
>>  	atomic_t resumeflag; /* Atomic variable to track suspend/resume */
>>  
>> -	atomic_t eh_active; /* Flag for error handling tracking */
>> -
>>  	struct task_struct *mtip_svc_handler; /* task_struct of svc thd */
>>  };
>>  
> 
> Does this have an actual impact on driver performance or functionality ?

I'm not sure, I'll ask the reporter.