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Subject[PATCH] NCR5380: Support chained sg lists
Date
My understanding is that support for chained scatterlists is to
become mandatory for LLDs.

Cc: Michael Schmitz <schmitzmic@gmail.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
drivers/scsi/NCR5380.c | 41 ++++++++++++++++++-----------------------
1 file changed, 18 insertions(+), 23 deletions(-)

diff --git a/drivers/scsi/NCR5380.c b/drivers/scsi/NCR5380.c
index d9fa9cf2fd8b..536426f25e86 100644
--- a/drivers/scsi/NCR5380.c
+++ b/drivers/scsi/NCR5380.c
@@ -149,12 +149,10 @@ static inline void initialize_SCp(struct scsi_cmnd *cmd)

if (scsi_bufflen(cmd)) {
cmd->SCp.buffer = scsi_sglist(cmd);
- cmd->SCp.buffers_residual = scsi_sg_count(cmd) - 1;
cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
cmd->SCp.this_residual = cmd->SCp.buffer->length;
} else {
cmd->SCp.buffer = NULL;
- cmd->SCp.buffers_residual = 0;
cmd->SCp.ptr = NULL;
cmd->SCp.this_residual = 0;
}
@@ -163,6 +161,17 @@ static inline void initialize_SCp(struct scsi_cmnd *cmd)
cmd->SCp.Message = 0;
}

+static inline void advance_sg_buffer(struct scsi_cmnd *cmd)
+{
+ struct scatterlist *s = cmd->SCp.buffer;
+
+ if (!cmd->SCp.this_residual && s && !sg_is_last(s)) {
+ cmd->SCp.buffer = sg_next(s);
+ cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
+ cmd->SCp.this_residual = cmd->SCp.buffer->length;
+ }
+}
+
/**
* NCR5380_poll_politely2 - wait for two chip register values
* @hostdata: host private data
@@ -1670,12 +1679,7 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
sun3_dma_setup_done != cmd) {
int count;

- if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
- ++cmd->SCp.buffer;
- --cmd->SCp.buffers_residual;
- cmd->SCp.this_residual = cmd->SCp.buffer->length;
- cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
- }
+ advance_sg_buffer(cmd);

count = sun3scsi_dma_xfer_len(hostdata, cmd);

@@ -1725,15 +1729,11 @@ static void NCR5380_information_transfer(struct Scsi_Host *instance)
* scatter-gather list, move onto the next one.
*/

- if (!cmd->SCp.this_residual && cmd->SCp.buffers_residual) {
- ++cmd->SCp.buffer;
- --cmd->SCp.buffers_residual;
- cmd->SCp.this_residual = cmd->SCp.buffer->length;
- cmd->SCp.ptr = sg_virt(cmd->SCp.buffer);
- dsprintk(NDEBUG_INFORMATION, instance, "%d bytes and %d buffers left\n",
- cmd->SCp.this_residual,
- cmd->SCp.buffers_residual);
- }
+ advance_sg_buffer(cmd);
+ dsprintk(NDEBUG_INFORMATION, instance,
+ "this residual %d, sg ents %d\n",
+ cmd->SCp.this_residual,
+ sg_nents(cmd->SCp.buffer));

/*
* The preferred transfer method is going to be
@@ -2126,12 +2126,7 @@ static void NCR5380_reselect(struct Scsi_Host *instance)
if (sun3_dma_setup_done != tmp) {
int count;

- if (!tmp->SCp.this_residual && tmp->SCp.buffers_residual) {
- ++tmp->SCp.buffer;
- --tmp->SCp.buffers_residual;
- tmp->SCp.this_residual = tmp->SCp.buffer->length;
- tmp->SCp.ptr = sg_virt(tmp->SCp.buffer);
- }
+ advance_sg_buffer(tmp);

count = sun3scsi_dma_xfer_len(hostdata, tmp);

--
2.21.0
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