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authorJens Axboe <jens.axboe@oracle.com>2007-10-16 11:20:52 +0200
committerJens Axboe <jens.axboe@oracle.com>2007-10-16 11:20:52 +0200
commitd274a9878bcd028712ea4f3d96db72b63d3eba4d (patch)
tree156c237e5fa38e86e3caa57f8bdac07aef0da94d /drivers/scsi
parent2f08fe5221b79aa1e240aa3938e9de6ab0baf1d3 (diff)
ide-scsi: sg chaining support
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'drivers/scsi')
-rw-r--r--drivers/scsi/ide-scsi.c32
1 files changed, 18 insertions, 14 deletions
diff --git a/drivers/scsi/ide-scsi.c b/drivers/scsi/ide-scsi.c
index d81bb076a15a..d297f64cd432 100644
--- a/drivers/scsi/ide-scsi.c
+++ b/drivers/scsi/ide-scsi.c
@@ -70,6 +70,7 @@ typedef struct idescsi_pc_s {
u8 *buffer; /* Data buffer */
u8 *current_position; /* Pointer into the above buffer */
struct scatterlist *sg; /* Scatter gather table */
+ struct scatterlist *last_sg; /* Last sg element */
int b_count; /* Bytes transferred from current entry */
struct scsi_cmnd *scsi_cmd; /* SCSI command */
void (*done)(struct scsi_cmnd *); /* Scsi completion routine */
@@ -173,12 +174,6 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne
char *buf;
while (bcount) {
- if (pc->sg - scsi_sglist(pc->scsi_cmd) >
- scsi_sg_count(pc->scsi_cmd)) {
- printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
- idescsi_discard_data (drive, bcount);
- return;
- }
count = min(pc->sg->length - pc->b_count, bcount);
if (PageHighMem(pc->sg->page)) {
unsigned long flags;
@@ -197,10 +192,17 @@ static void idescsi_input_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigne
}
bcount -= count; pc->b_count += count;
if (pc->b_count == pc->sg->length) {
- pc->sg++;
+ if (pc->sg == pc->last_sg)
+ break;
+ pc->sg = sg_next(pc->sg);
pc->b_count = 0;
}
}
+
+ if (bcount) {
+ printk (KERN_ERR "ide-scsi: scatter gather table too small, discarding data\n");
+ idescsi_discard_data (drive, bcount);
+ }
}
static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsigned int bcount)
@@ -209,12 +211,6 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign
char *buf;
while (bcount) {
- if (pc->sg - scsi_sglist(pc->scsi_cmd) >
- scsi_sg_count(pc->scsi_cmd)) {
- printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
- idescsi_output_zeros (drive, bcount);
- return;
- }
count = min(pc->sg->length - pc->b_count, bcount);
if (PageHighMem(pc->sg->page)) {
unsigned long flags;
@@ -233,10 +229,17 @@ static void idescsi_output_buffers (ide_drive_t *drive, idescsi_pc_t *pc, unsign
}
bcount -= count; pc->b_count += count;
if (pc->b_count == pc->sg->length) {
- pc->sg++;
+ if (pc->sg == pc->last_sg)
+ break;
+ pc->sg = sg_next(pc->sg);
pc->b_count = 0;
}
}
+
+ if (bcount) {
+ printk (KERN_ERR "ide-scsi: scatter gather table too small, padding with zeros\n");
+ idescsi_output_zeros (drive, bcount);
+ }
}
static void hexdump(u8 *x, int len)
@@ -804,6 +807,7 @@ static int idescsi_queue (struct scsi_cmnd *cmd,
memcpy (pc->c, cmd->cmnd, cmd->cmd_len);
pc->buffer = NULL;
pc->sg = scsi_sglist(cmd);
+ pc->last_sg = sg_last(pc->sg, cmd->use_sg);
pc->b_count = 0;
pc->request_transfer = pc->buffer_size = scsi_bufflen(cmd);
pc->scsi_cmd = cmd;