[PATCH 1/3] ide-{floppy,tape}: fix padding for PIO transfers

Borislav Petkov
2009-03-04T09:18:42Z

From: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

* Return number of bytes left to transfer from idetape_{in,out}put_buffers()
and number of bytes done from ide_tape_io_buffers().

* Fix padding for PIO transfers in ide_pc_intr() so read/write buffers are
always completely processed and then the transfer is padded if necessary.

* Remove invalid error messages.

* Remove now superfluous padding from ide{_io_buffers,tape_input_buffers}().

While at it:

* Set pc->bh to NULL in idetape_input_buffers() after all bh-s are done.

* Cache !!(pc->flags & PC_FLAG_WRITING) in local variable in ide_pc_intr().

Cc: Borislav Petkov <petkovbb@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
---
drivers/ide/ide-atapi.c | 57 +++++++++++++++-------------------------------
drivers/ide/ide-tape.c | 32 +++++++++++++-------------
2 files changed, 35 insertions(+), 54 deletions(-)

diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index ff6adea..314e6af 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -108,13 +108,6 @@ int ide_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
}
}

- if (bcount) {
- printk(KERN_ERR "%s: %d leftover bytes, %s\n", drive->name,
- bcount, write ? "padding with zeros"
- : "discarding data");
- ide_pad_transfer(drive, write, bcount);
- }
-
return done;
}
EXPORT_SYMBOL_GPL(ide_io_buffers);
@@ -316,9 +309,10 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
struct request *rq = hwif->rq;
const struct ide_tp_ops *tp_ops = hwif->tp_ops;
xfer_func_t *xferfunc;
- unsigned int timeout, temp;
+ unsigned int timeout, done;
u16 bcount;
u8 stat, ireason, dsc = 0;
+ u8 write = !!(pc->flags & PC_FLAG_WRITING);

debug_log("Enter %s - interrupt handler\n", __func__);

@@ -427,8 +421,7 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
return ide_do_reset(drive);
}

- if (((ireason & ATAPI_IO) == ATAPI_IO) ==
- !!(pc->flags & PC_FLAG_WRITING)) {
+ if (((ireason & ATAPI_IO) == ATAPI_IO) == write) {
/* Hopefully, we will never get here */
printk(KERN_ERR "%s: We wanted to %s, but the device wants us "
"to %s!\n", drive->name,
@@ -437,45 +430,33 @@ static ide_startstop_t ide_pc_intr(ide_drive_t *drive)
return ide_do_reset(drive);
}

- if (!(pc->flags & PC_FLAG_WRITING)) {
- /* Reading - Check that we have enough space */
- temp = pc->xferred + bcount;
- if (temp > pc->req_xfer) {
- if (temp > pc->buf_size) {
- printk(KERN_ERR "%s: The device wants to send "
- "us more data than expected - "
- "discarding data\n",
- drive->name);
-
- ide_pad_transfer(drive, 0, bcount);
- goto next_irq;
- }
- debug_log("The device wants to send us more data than "
- "expected - allowing transfer\n");
- }
- xferfunc = tp_ops->input_data;
- } else
- xferfunc = tp_ops->output_data;
+ xferfunc = write ? tp_ops->output_data : tp_ops->input_data;

if ((drive->media == ide_floppy && !pc->buf) ||
(drive->media == ide_tape && pc->bh)) {
- int done = drive->pc_io_buffers(drive, pc, bcount,
- !!(pc->flags & PC_FLAG_WRITING));
+ done = drive->pc_io_buffers(drive, pc, bcount, write);

/* FIXME: don't do partial completions */
if (drive->media == ide_floppy)
ide_complete_rq(drive, 0,
done ? done : ide_rq_bytes(rq));
- } else
- xferfunc(drive, NULL, pc->cur_pos, bcount);
+ } else {
+ done = min_t(unsigned int, bcount, pc->req_xfer - pc->xferred);
+ xferfunc(drive, NULL, pc->cur_pos, done);
+ }

/* Update the current position */
- pc->xferred += bcount;
- pc->cur_pos += bcount;
+ pc->xferred += done;
+ pc->cur_pos += done;
+
+ bcount -= done;
+
+ if (bcount)
+ ide_pad_transfer(drive, write, bcount);
+
+ debug_log("[cmd %x] transferred %d bytes, padded %d bytes\n",
+ rq->cmd[0], done, bcount);

- debug_log("[cmd %x] transferred %d bytes on that intr.\n",
- rq->cmd[0], bcount);
-next_irq:
/* And set the interrupt handler again */
ide_set_handler(drive, ide_pc_intr, timeout);
return ide_started;
diff --git a/drivers/ide/ide-tape.c b/drivers/ide/ide-tape.c
index 733cb51..12a6e5d 100644
--- a/drivers/ide/ide-tape.c
+++ b/drivers/ide/ide-tape.c
@@ -297,19 +297,15 @@ static struct ide_tape_obj *ide_tape_chrdev_get(unsigned int i)
return tape;
}

-static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
+static int idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount)
{
struct idetape_bh *bh = pc->bh;
int count;

while (bcount) {
- if (bh == NULL) {
- printk(KERN_ERR "ide-tape: bh == NULL in "
- "idetape_input_buffers\n");
- ide_pad_transfer(drive, 0, bcount);
- return;
- }
+ if (bh == NULL)
+ break;
count = min(
(unsigned int)(bh->b_size - atomic_read(&bh->b_count)),
bcount);
@@ -323,21 +319,21 @@ static void idetape_input_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
atomic_set(&bh->b_count, 0);
}
}
+
pc->bh = bh;
+
+ return bcount;
}

-static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
+static int idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount)
{
struct idetape_bh *bh = pc->bh;
int count;

while (bcount) {
- if (bh == NULL) {
- printk(KERN_ERR "ide-tape: bh == NULL in %s\n",
- __func__);
- return;
- }
+ if (bh == NULL)
+ break;
count = min((unsigned int)pc->b_count, (unsigned int)bcount);
drive->hwif->tp_ops->output_data(drive, NULL, pc->b_data, count);
bcount -= count;
@@ -352,6 +348,8 @@ static void idetape_output_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
}
}
}
+
+ return bcount;
}

static void idetape_update_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc)
@@ -563,12 +561,14 @@ static void ide_tape_handle_dsc(ide_drive_t *drive)
static int ide_tape_io_buffers(ide_drive_t *drive, struct ide_atapi_pc *pc,
unsigned int bcount, int write)
{
+ unsigned int bleft;
+
if (write)
- idetape_output_buffers(drive, pc, bcount);
+ bleft = idetape_output_buffers(drive, pc, bcount);
else
- idetape_input_buffers(drive, pc, bcount);
+ bleft = idetape_input_buffers(drive, pc, bcount);

- return bcount;
+ return bcount - bleft;
}

/*
--
1.6.1.3