On 03/14/2016 05:27 AM, Finn Thain wrote:
> Only the atari_scsi and sun3_scsi drivers define DMA_MIN_SIZE.
> Both drivers also define NCR5380_dma_xfer_len, which means
> DMA_MIN_SIZE is redundant.
> 
> This removes another discrepancy between the two core drivers.
> 
> Signed-off-by: Finn Thain <fth...@telegraphics.com.au>
> 
> ---
>  drivers/scsi/atari_NCR5380.c |   16 ++++++++--------
>  drivers/scsi/atari_scsi.c    |    4 +++-
>  drivers/scsi/sun3_scsi.c     |   16 ++++++----------
>  3 files changed, 17 insertions(+), 19 deletions(-)
> 
> Index: linux/drivers/scsi/atari_NCR5380.c
> ===================================================================
> --- linux.orig/drivers/scsi/atari_NCR5380.c   2016-03-14 15:26:23.000000000 
> +1100
> +++ linux/drivers/scsi/atari_NCR5380.c        2016-03-14 15:26:26.000000000 
> +1100
> @@ -1857,12 +1857,11 @@ static void NCR5380_information_transfer
>                                       d = cmd->SCp.ptr;
>                               }
>                               /* this command setup for dma yet? */
> -                             if ((count >= DMA_MIN_SIZE) && 
> (sun3_dma_setup_done != cmd)) {
> -                                     if (cmd->request->cmd_type == 
> REQ_TYPE_FS) {
> -                                             sun3scsi_dma_setup(instance, d, 
> count,
> -                                                                
> rq_data_dir(cmd->request));
> -                                             sun3_dma_setup_done = cmd;
> -                                     }
> +                             if (sun3_dma_setup_done != cmd &&
> +                                 sun3scsi_dma_xfer_len(count, cmd) > 0) {
> +                                     sun3scsi_dma_setup(instance, d, count,
> +                                                        
> rq_data_dir(cmd->request));
> +                                     sun3_dma_setup_done = cmd;
>                               }
>  #ifdef SUN3_SCSI_VME
>                               dregs->csr |= CSR_INTR;
> @@ -1927,7 +1926,7 @@ static void NCR5380_information_transfer
>  #endif
>                                       transfersize = 
> NCR5380_dma_xfer_len(instance, cmd, phase);
>  
> -                             if (transfersize >= DMA_MIN_SIZE) {
> +                             if (transfersize > 0) {
>                                       len = transfersize;
>                                       cmd->SCp.phase = phase;
>                                       if (NCR5380_transfer_dma(instance, 
> &phase,
> @@ -2366,7 +2365,8 @@ static void NCR5380_reselect(struct Scsi
>                       d = tmp->SCp.ptr;
>               }
>               /* setup this command for dma if not already */
> -             if ((count >= DMA_MIN_SIZE) && (sun3_dma_setup_done != tmp)) {
> +             if (sun3_dma_setup_done != tmp &&
> +                 sun3scsi_dma_xfer_len(count, tmp) > 0) {
>                       sun3scsi_dma_setup(instance, d, count,
>                                          rq_data_dir(tmp->request));
>                       sun3_dma_setup_done = tmp;
> Index: linux/drivers/scsi/atari_scsi.c
> ===================================================================
> --- linux.orig/drivers/scsi/atari_scsi.c      2016-03-14 15:26:23.000000000 
> +1100
> +++ linux/drivers/scsi/atari_scsi.c   2016-03-14 15:26:26.000000000 +1100
> @@ -87,7 +87,6 @@
>  
>  #define SUPPORT_TAGS
>  #define MAX_TAGS                        32
> -#define DMA_MIN_SIZE                    32
>  
>  #define NCR5380_implementation_fields   /* none */
>  
> @@ -605,6 +604,9 @@ static unsigned long atari_dma_xfer_len(
>  {
>       unsigned long   possible_len, limit;
>  
> +     if (wanted_len < 32)
> +             return 0;
> +
>       if (IS_A_TT())
>               /* TT SCSI DMA can transfer arbitrary #bytes */
>               return wanted_len;
> Index: linux/drivers/scsi/sun3_scsi.c
> ===================================================================
> --- linux.orig/drivers/scsi/sun3_scsi.c       2016-03-14 15:26:23.000000000 
> +1100
> +++ linux/drivers/scsi/sun3_scsi.c    2016-03-14 15:26:26.000000000 +1100
> @@ -39,9 +39,6 @@
>  /* Definitions for the core NCR5380 driver. */
>  
>  /* #define SUPPORT_TAGS */
> -/* minimum number of bytes to do dma on */
> -#define DMA_MIN_SIZE                    129
> -
>  /* #define MAX_TAGS                     32 */
>  
>  #define NCR5380_implementation_fields   /* none */
> @@ -61,7 +58,7 @@
>  #define NCR5380_dma_residual(instance) \
>          sun3scsi_dma_residual(instance)
>  #define NCR5380_dma_xfer_len(instance, cmd, phase) \
> -        sun3scsi_dma_xfer_len(cmd->SCp.this_residual, cmd, !((phase) & 
> SR_IO))
> +        sun3scsi_dma_xfer_len(cmd->SCp.this_residual, cmd)
>  
>  #define NCR5380_acquire_dma_irq(instance)    (1)
>  #define NCR5380_release_dma_irq(instance)
> @@ -262,14 +259,13 @@ static inline unsigned long sun3scsi_dma
>       return last_residual;
>  }
>  
> -static inline unsigned long sun3scsi_dma_xfer_len(unsigned long wanted,
> -                                               struct scsi_cmnd *cmd,
> -                                               int write_flag)
> +static inline unsigned long sun3scsi_dma_xfer_len(unsigned long wanted_len,
> +                                                  struct scsi_cmnd *cmd)
>  {
> -     if (cmd->request->cmd_type == REQ_TYPE_FS)
> -             return wanted;
> -     else
> +     if (wanted_len < 129 || cmd->request->cmd_type != REQ_TYPE_FS)
>               return 0;
> +
> +     return wanted_len;
>  }
>  
>  static inline int sun3scsi_dma_start(unsigned long count, unsigned char 
> *data)
> 
> 
I still would keep the 'DMA_MIN_LEN' definition around for
sun3_scsi.c; makes it a bit more obvious what the magic number '129'
is supposed to mean.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Teamlead Storage & Networking
h...@suse.de                                   +49 911 74053 688
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: F. Imendörffer, J. Smithard, J. Guild, D. Upmanyu, G. Norton
HRB 21284 (AG Nürnberg)
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