[PATCH v6 1/6] g_NCR5380: Fix PDMA transfer size

[Finn Thain]

From: Ondrej Zary <li...@rainbow-software.org>

generic_NCR5380_dma_xfer_len() incorrectly uses cmd->transfersize
which causes rescan-scsi-bus and CD-ROM access to hang the system.
Use cmd->SCp.this_residual instead, like other NCR5380 drivers.

Signed-off-by: Ondrej Zary <li...@rainbow-software.org>
Signed-off-by: Finn Thain <fth...@telegraphics.com.au>
---
 drivers/scsi/g_NCR5380.c | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/drivers/scsi/g_NCR5380.c b/drivers/scsi/g_NCR5380.c
index 67c8dac321ad..14ef4e8c4713 100644
--- a/drivers/scsi/g_NCR5380.c
+++ b/drivers/scsi/g_NCR5380.c
@@ -76,6 +76,7 @@
 #define IRQ_AUTO 254
 
 #define MAX_CARDS 8
+#define DMA_MAX_SIZE 32768
 
 /* old-style parameters for compatibility */
 static int ncr_irq = -1;
@@ -629,23 +630,16 @@ static inline int generic_NCR5380_pwrite(struct 
NCR5380_hostdata *hostdata,
 static int generic_NCR5380_dma_xfer_len(struct NCR5380_hostdata *hostdata,
                                         struct scsi_cmnd *cmd)
 {
-       int transfersize = cmd->transfersize;
+       int transfersize = cmd->SCp.this_residual;
 
        if (hostdata->flags & FLAG_NO_PSEUDO_DMA)
                return 0;
 
-       /* Limit transfers to 32K, for xx400 & xx406
-        * pseudoDMA that transfers in 128 bytes blocks.
-        */
-       if (transfersize > 32 * 1024 && cmd->SCp.this_residual &&
-           !(cmd->SCp.this_residual % transfersize))
-               transfersize = 32 * 1024;
-
        /* 53C400 datasheet: non-modulo-128-byte transfers should use PIO */
        if (transfersize % 128)
                transfersize = 0;
 
-       return transfersize;
+       return min(transfersize, DMA_MAX_SIZE);
 }
 
 /*
-- 
2.13.0