Re: [PATCH v3 38/77] ncr5380: Remove UNSAFE macro

2015-12-21 Thread Hannes Reinecke 

On 12/22/2015 02:18 AM, Finn Thain wrote:

Configuring core drivers using macros like this one prevents re-unifying
the core driver forks, and prevents implementing the core driver as a
library or a platform driver.

The UNSAFE macro in particular is a poor workaround for the problem of
interrupt latency. Releasing the locks complicates things because then we
would have to handle the possibility of EH handler invocation during a
PDMA transfer.

The comments say that instead of using this macro, "you're going to be
better off twiddling with transfersize". I agree. Remove this stuff.

Signed-off-by: Finn Thain 


Reviewed-by: Hannes Reinecke 

Cheers,

Hannes
--
Dr. Hannes Reinecke   zSeries & Storage
h...@suse.de  +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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[PATCH v3 38/77] ncr5380: Remove UNSAFE macro

2015-12-21 Thread Finn Thain 
Configuring core drivers using macros like this one prevents re-unifying
the core driver forks, and prevents implementing the core driver as a
library or a platform driver.

The UNSAFE macro in particular is a poor workaround for the problem of
interrupt latency. Releasing the locks complicates things because then we
would have to handle the possibility of EH handler invocation during a
PDMA transfer.

The comments say that instead of using this macro, "you're going to be
better off twiddling with transfersize". I agree. Remove this stuff.

Signed-off-by: Finn Thain 

---
 drivers/scsi/NCR5380.c |   15 ---
 drivers/scsi/dtc.c |2 --
 drivers/scsi/pas16.c   |1 -
 3 files changed, 18 deletions(-)

Index: linux/drivers/scsi/NCR5380.c
===
--- linux.orig/drivers/scsi/NCR5380.c   2015-12-22 12:16:24.0 +1100
+++ linux/drivers/scsi/NCR5380.c2015-12-22 12:16:27.0 +1100
@@ -195,12 +195,6 @@
  *  rely on phase mismatch and EOP interrupts to determine end 
  *  of phase.
  *
- * UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
- *  only really want to use this if you're having a problem with
- *  dropped characters during high speed communications, and even
- *  then, you're going to be better off twiddling with transfersize
- *  in the high level code.
- *
  * Defaults for these will be provided although the user may want to adjust 
  * these to allocate CPU resources to the SCSI driver or "real" code.
  * 
@@ -554,9 +548,6 @@ static void prepare_info(struct Scsi_Hos
 #ifdef PSEUDO_DMA
 "PSEUDO_DMA "
 #endif
-#ifdef UNSAFE
-"UNSAFE "
-#endif
 "");
 }
 
@@ -1582,9 +1573,6 @@ static int NCR5380_transfer_dma(struct S
 * before the setting of DMA mode to after transfer of the last byte.
 */
 
-#if defined(PSEUDO_DMA) && defined(UNSAFE)
-   spin_unlock_irq(instance->host_lock);
-#endif
/* KLL May need eop and parity in 53c400 */
if (hostdata->flags & FLAG_NCR53C400)
NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE |
@@ -1793,9 +1781,6 @@ static int NCR5380_transfer_dma(struct S
*data = d + c;
*count = 0;
*phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
-#if defined(PSEUDO_DMA) && defined(UNSAFE)
-   spin_lock_irq(instance->host_lock);
-#endif /* defined(REAL_DMA_POLL) */
return foo;
 #endif /* def REAL_DMA */
 }
Index: linux/drivers/scsi/dtc.c
===
--- linux.orig/drivers/scsi/dtc.c   2015-12-22 12:16:07.0 +1100
+++ linux/drivers/scsi/dtc.c2015-12-22 12:16:27.0 +1100
@@ -1,7 +1,5 @@
-
 #define PSEUDO_DMA
 #define DONT_USE_INTR
-#define UNSAFE /* Leave interrupts enabled during pseudo-dma 
I/O */
 #define DMA_WORKS_RIGHT
 
 
Index: linux/drivers/scsi/pas16.c
===
--- linux.orig/drivers/scsi/pas16.c 2015-12-22 12:15:56.0 +1100
+++ linux/drivers/scsi/pas16.c  2015-12-22 12:16:27.0 +1100
@@ -1,5 +1,4 @@
 #define PSEUDO_DMA
-#define UNSAFE  /* Not unsafe for PAS16 -- use it */
 
 /*
  * This driver adapted from Drew Eckhardt's Trantor T128 driver


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[PATCH v3 38/77] ncr5380: Remove UNSAFE macro

2015-12-21 Thread Finn Thain 
Configuring core drivers using macros like this one prevents re-unifying
the core driver forks, and prevents implementing the core driver as a
library or a platform driver.

The UNSAFE macro in particular is a poor workaround for the problem of
interrupt latency. Releasing the locks complicates things because then we
would have to handle the possibility of EH handler invocation during a
PDMA transfer.

The comments say that instead of using this macro, "you're going to be
better off twiddling with transfersize". I agree. Remove this stuff.

Signed-off-by: Finn Thain 

---
 drivers/scsi/NCR5380.c |   15 ---
 drivers/scsi/dtc.c |2 --
 drivers/scsi/pas16.c   |1 -
 3 files changed, 18 deletions(-)

Index: linux/drivers/scsi/NCR5380.c
===
--- linux.orig/drivers/scsi/NCR5380.c   2015-12-22 12:16:24.0 +1100
+++ linux/drivers/scsi/NCR5380.c2015-12-22 12:16:27.0 +1100
@@ -195,12 +195,6 @@
  *  rely on phase mismatch and EOP interrupts to determine end 
  *  of phase.
  *
- * UNSAFE - leave interrupts enabled during pseudo-DMA transfers.  You
- *  only really want to use this if you're having a problem with
- *  dropped characters during high speed communications, and even
- *  then, you're going to be better off twiddling with transfersize
- *  in the high level code.
- *
  * Defaults for these will be provided although the user may want to adjust 
  * these to allocate CPU resources to the SCSI driver or "real" code.
  * 
@@ -554,9 +548,6 @@ static void prepare_info(struct Scsi_Hos
 #ifdef PSEUDO_DMA
 "PSEUDO_DMA "
 #endif
-#ifdef UNSAFE
-"UNSAFE "
-#endif
 "");
 }
 
@@ -1582,9 +1573,6 @@ static int NCR5380_transfer_dma(struct S
 * before the setting of DMA mode to after transfer of the last byte.
 */
 
-#if defined(PSEUDO_DMA) && defined(UNSAFE)
-   spin_unlock_irq(instance->host_lock);
-#endif
/* KLL May need eop and parity in 53c400 */
if (hostdata->flags & FLAG_NCR53C400)
NCR5380_write(MODE_REG, MR_BASE | MR_DMA_MODE |
@@ -1793,9 +1781,6 @@ static int NCR5380_transfer_dma(struct S
*data = d + c;
*count = 0;
*phase = NCR5380_read(STATUS_REG) & PHASE_MASK;
-#if defined(PSEUDO_DMA) && defined(UNSAFE)
-   spin_lock_irq(instance->host_lock);
-#endif /* defined(REAL_DMA_POLL) */
return foo;
 #endif /* def REAL_DMA */
 }
Index: linux/drivers/scsi/dtc.c
===
--- linux.orig/drivers/scsi/dtc.c   2015-12-22 12:16:07.0 +1100
+++ linux/drivers/scsi/dtc.c2015-12-22 12:16:27.0 +1100
@@ -1,7 +1,5 @@
-
 #define PSEUDO_DMA
 #define DONT_USE_INTR
-#define UNSAFE /* Leave interrupts enabled during pseudo-dma 
I/O */
 #define DMA_WORKS_RIGHT
 
 
Index: linux/drivers/scsi/pas16.c
===
--- linux.orig/drivers/scsi/pas16.c 2015-12-22 12:15:56.0 +1100
+++ linux/drivers/scsi/pas16.c  2015-12-22 12:16:27.0 +1100
@@ -1,5 +1,4 @@
 #define PSEUDO_DMA
-#define UNSAFE  /* Not unsafe for PAS16 -- use it */
 
 /*
  * This driver adapted from Drew Eckhardt's Trantor T128 driver


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Re: [PATCH v3 38/77] ncr5380: Remove UNSAFE macro

2015-12-21 Thread Hannes Reinecke 

On 12/22/2015 02:18 AM, Finn Thain wrote:

Configuring core drivers using macros like this one prevents re-unifying
the core driver forks, and prevents implementing the core driver as a
library or a platform driver.

The UNSAFE macro in particular is a poor workaround for the problem of
interrupt latency. Releasing the locks complicates things because then we
would have to handle the possibility of EH handler invocation during a
PDMA transfer.

The comments say that instead of using this macro, "you're going to be
better off twiddling with transfersize". I agree. Remove this stuff.

Signed-off-by: Finn Thain 


Reviewed-by: Hannes Reinecke 

Cheers,

Hannes
--
Dr. Hannes Reinecke   zSeries & Storage
h...@suse.de  +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/