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

Finn Thain
2015-12-22T01:18:16Z

[-- Attachment #1: ncr5380-remove-UNSAFE-macro --]
[-- Type: text/plain, Size: 3270 bytes --]

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 <fthain@telegraphics.com.au>

---
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 12:16:24.000000000 +1100
+++ linux/drivers/scsi/NCR5380.c 2015-12-22 12:16:27.000000000 +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 12:16:07.000000000 +1100
+++ linux/drivers/scsi/dtc.c 2015-12-22 12:16:27.000000000 +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 12:15:56.000000000 +1100
+++ linux/drivers/scsi/pas16.c 2015-12-22 12:16:27.000000000 +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