Hi Bart,
here's my first stab at using scatterlists in ide-floppy. I've adapted your
ide-scsi version to fit in here. The change here is that i use pc->b_count as
a sort-of completion counter to know when i'm at the end of the sg element and
be able to switch to the next/finish transfer. I've tested the patch with the
Iomega ZIP drive i have here - it works. We should do some more testing first
though, before sending it upstream.
---
From: Borislav Petkov <petkovbb@xxxxxxxxx>
Date: Tue, 5 Aug 2008 06:57:44 +0200
Subject: [PATCH] ide-floppy: use scatterlists for pio transfers
Use hwif->sg_table for pio transfers instead of fumbling
with block layer internals in the driver. Also, make debug
statements more informative in .._do_request() while at it.
Signed-off-by: Borislav Petkov <petkovbb@xxxxxxxxx>
---
drivers/ide/ide-floppy.c | 58 +++++++++++++++++++++++++++------------------
1 files changed, 35 insertions(+), 23 deletions(-)
diff --git a/drivers/ide/ide-floppy.c b/drivers/ide/ide-floppy.c
index de8d42b..5820d3a 100644
--- a/drivers/ide/ide-floppy.c
+++ b/drivers/ide/ide-floppy.c
@@ -224,29 +224,37 @@ static void ide_floppy_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount, int direction)
{
ide_hwif_t *hwif = drive->hwif;
- struct request *rq = pc->rq;
- struct req_iterator iter;
- struct bio_vec *bvec;
- unsigned long flags;
+ const struct ide_tp_ops *tp_ops = hwif->tp_ops;
+ xfer_func_t *xf = direction ? tp_ops->output_data : tp_ops->input_data;
+ struct scatterlist *sg = hwif->sg_table;
+ char *buf;
int count, done = 0;
- char *data;
- rq_for_each_segment(bvec, rq, iter) {
- if (!bcount)
- break;
+ while (bcount) {
- count = min(bvec->bv_len, bcount);
-
- data = bvec_kmap_irq(bvec, &flags);
- if (direction)
- hwif->tp_ops->output_data(drive, NULL, data, count);
- else
- hwif->tp_ops->input_data(drive, NULL, data, count);
- bvec_kunmap_irq(data, &flags);
+ count = min(sg->length - pc->b_count, bcount);
+ if (PageHighMem(sg_page(sg))) {
+ unsigned long flags;
+ local_irq_save(flags);
+ buf = kmap_atomic(sg_page(sg), KM_IRQ0) + sg->offset;
+ xf(drive, NULL, buf + pc->b_count, count);
+ kunmap_atomic(buf - sg->offset, KM_IRQ0);
+ local_irq_restore(flags);
+ } else {
+ buf = sg_virt(sg);
+ xf(drive, NULL, buf + pc->b_count, count);
+ }
bcount -= count;
pc->b_count += count;
done += count;
+
+ if (pc->b_count == sg->length) {
+ if (!--hwif->sg_nents)
+ break;
+ sg = sg_next(sg);
+ pc->b_count = 0;
+ }
}
idefloppy_end_request(drive, 1, done >> 9);
@@ -569,7 +577,7 @@ static void idefloppy_create_rw_cmd(idefloppy_floppy_t *floppy,
memcpy(rq->cmd, pc->c, 12);
pc->rq = rq;
- pc->b_count = cmd == READ ? 0 : rq->bio->bi_size;
+ pc->b_count = 0;
if (rq->cmd_flags & REQ_RW)
pc->flags |= PC_FLAG_WRITING;
pc->buf = NULL;
@@ -603,12 +611,13 @@ static ide_startstop_t idefloppy_do_request(ide_drive_t *drive,
struct ide_atapi_pc *pc;
unsigned long block = (unsigned long)block_s;
- debug_log("dev: %s, cmd_type: %x, errors: %d\n",
- rq->rq_disk ? rq->rq_disk->disk_name : "?",
- rq->cmd_type, rq->errors);
- debug_log("sector: %ld, nr_sectors: %ld, "
- "current_nr_sectors: %d\n", (long)rq->sector,
- rq->nr_sectors, rq->current_nr_sectors);
+ debug_log("%s: dev: %s, cmd: 0x%x, cmd_type: %x, errors: %d\n",
+ __func__, rq->rq_disk ? rq->rq_disk->disk_name : "?",
+ rq->cmd[0], rq->cmd_type, rq->errors);
+
+ debug_log("%s: sector: %ld, nr_sectors: %ld, current_nr_sectors: %d\n",
+ __func__, (long)rq->sector, rq->nr_sectors,
+ rq->current_nr_sectors);
if (rq->errors >= ERROR_MAX) {
if (floppy->failed_pc)
@@ -643,6 +652,9 @@ static ide_startstop_t idefloppy_do_request(ide_drive_t *drive,
pc->rq = rq;
+ ide_init_sg_cmd(drive, rq);
+ ide_map_sg(drive, rq);
+
return idefloppy_issue_pc(drive, pc);
}
--
1.5.5.4
--
Regards/Gruss,
Boris.
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