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Date: Mon, 14 Mar 2016 08:25:53 +0100
From: Hannes Reinecke <hare@...e.de>
To: Finn Thain <fthain@...egraphics.com.au>,
"James E.J. Bottomley" <James.Bottomley@...senPartnership.com>,
"Martin K. Petersen" <martin.petersen@...cle.com>,
Michael Schmitz <schmitzmic@...il.com>,
linux-m68k@...r.kernel.org, linux-scsi@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: Ondrej Zary <linux@...nbow-software.org>,
Sam Creasey <sammy@...my.net>
Subject: Re: [PATCH 04/22] atari_NCR5380: Remove DMA_MIN_SIZE macro
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 <fthain@...egraphics.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
hare@...e.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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