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Subject[patch][4/6] ide: sg PIO for fs requests
Date

[patch] ide: sg PIO for fs requests

Convert CONFIG_IDE_TASKFILE_IO=n code to use
scatterlist for PIO transfers.

Fixes longstanding 'data integrity on error' issue.

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@elka.pw.edu.pl>
---

linux-2.6.9-rc1-bk16-bzolnier/Documentation/block/biodoc.txt | 3
linux-2.6.9-rc1-bk16-bzolnier/drivers/ide/ide-disk.c | 224 ++---------
linux-2.6.9-rc1-bk16-bzolnier/drivers/ide/ide-taskfile.c | 18
linux-2.6.9-rc1-bk16-bzolnier/include/linux/ide.h | 26 -
4 files changed, 76 insertions(+), 195 deletions(-)

diff -puN Documentation/block/biodoc.txt~ide_sg_pio Documentation/block/biodoc.txt
--- linux-2.6.9-rc1-bk16/Documentation/block/biodoc.txt~ide_sg_pio 2004-09-10 23:47:03.229550112 +0200
+++ linux-2.6.9-rc1-bk16-bzolnier/Documentation/block/biodoc.txt 2004-09-10 23:47:03.255546160 +0200
@@ -1172,8 +1172,7 @@ PIO drivers (or drivers that need to rev
while (IDE for example)), where the CPU is doing the actual data
transfer a virtual mapping is needed. If the driver supports highmem I/O,
(Sec 1.1, (ii) ) it needs to use __bio_kmap_atomic and bio_kmap_irq to
-temporarily map a bio into the virtual address space. See how IDE handles
-this with ide_map_buffer.
+temporarily map a bio into the virtual address space.


8. Prior/Related/Impacted patches
diff -puN drivers/ide/ide-disk.c~ide_sg_pio drivers/ide/ide-disk.c
--- linux-2.6.9-rc1-bk16/drivers/ide/ide-disk.c~ide_sg_pio 2004-09-10 23:47:03.231549808 +0200
+++ linux-2.6.9-rc1-bk16-bzolnier/drivers/ide/ide-disk.c 2004-09-10 23:47:03.260545400 +0200
@@ -128,55 +128,30 @@ static int lba_capacity_is_ok (struct hd
static ide_startstop_t read_intr (ide_drive_t *drive)
{
ide_hwif_t *hwif = HWIF(drive);
- u32 i = 0, nsect = 0, msect = drive->mult_count;
- struct request *rq;
- unsigned long flags;
+ struct request *rq = hwif->hwgroup->rq;
u8 stat;
- char *to;

/* new way for dealing with premature shared PCI interrupts */
if (!OK_STAT(stat=hwif->INB(IDE_STATUS_REG),DATA_READY,BAD_R_STAT)) {
if (stat & (ERR_STAT|DRQ_STAT)) {
- return DRIVER(drive)->error(drive, "read_intr", stat);
+ return task_error(drive, rq, __FUNCTION__, stat);
}
/* no data yet, so wait for another interrupt */
ide_set_handler(drive, &read_intr, WAIT_CMD, NULL);
return ide_started;
}
-
-read_next:
- rq = HWGROUP(drive)->rq;
- if (msect) {
- if ((nsect = rq->current_nr_sectors) > msect)
- nsect = msect;
- msect -= nsect;
- } else
- nsect = 1;
- to = ide_map_buffer(rq, &flags);
- taskfile_input_data(drive, to, nsect * SECTOR_WORDS);
-#ifdef DEBUG
- printk("%s: read: sectors(%ld-%ld), buffer=0x%08lx, remaining=%ld\n",
- drive->name, rq->sector, rq->sector+nsect-1,
- (unsigned long) rq->buffer+(nsect<<9), rq->nr_sectors-nsect);
-#endif
- ide_unmap_buffer(rq, to, &flags);
- rq->sector += nsect;
+
+ if (drive->mult_count)
+ ide_pio_multi(drive, 0);
+ else
+ ide_pio_sector(drive, 0);
rq->errors = 0;
- i = (rq->nr_sectors -= nsect);
- if (((long)(rq->current_nr_sectors -= nsect)) <= 0)
- ide_end_request(drive, 1, rq->hard_cur_sectors);
- /*
- * Another BH Page walker and DATA INTEGRITY Questioned on ERROR.
- * If passed back up on multimode read, BAD DATA could be ACKED
- * to FILE SYSTEMS above ...
- */
- if (i > 0) {
- if (msect)
- goto read_next;
- ide_set_handler(drive, &read_intr, WAIT_CMD, NULL);
- return ide_started;
+ if (!hwif->nleft) {
+ ide_end_request(drive, 1, hwif->nsect);
+ return ide_stopped;
}
- return ide_stopped;
+ ide_set_handler(drive, &read_intr, WAIT_CMD, NULL);
+ return ide_started;
}

/*
@@ -187,106 +162,27 @@ static ide_startstop_t write_intr (ide_d
ide_hwgroup_t *hwgroup = HWGROUP(drive);
ide_hwif_t *hwif = HWIF(drive);
struct request *rq = hwgroup->rq;
- u32 i = 0;
u8 stat;

if (!OK_STAT(stat = hwif->INB(IDE_STATUS_REG),
DRIVE_READY, drive->bad_wstat)) {
- printk("%s: write_intr error1: nr_sectors=%ld, stat=0x%02x\n",
- drive->name, rq->nr_sectors, stat);
+ printk("%s: write_intr error1: nr_sectors=%u, stat=0x%02x\n",
+ drive->name, hwif->nleft, stat);
} else {
-#ifdef DEBUG
- printk("%s: write: sector %ld, buffer=0x%08lx, remaining=%ld\n",
- drive->name, rq->sector, (unsigned long) rq->buffer,
- rq->nr_sectors-1);
-#endif
- if ((rq->nr_sectors == 1) ^ ((stat & DRQ_STAT) != 0)) {
- rq->sector++;
+ if ((hwif->nleft == 0) ^ ((stat & DRQ_STAT) != 0)) {
rq->errors = 0;
- i = --rq->nr_sectors;
- --rq->current_nr_sectors;
- if (((long)rq->current_nr_sectors) <= 0)
- ide_end_request(drive, 1, rq->hard_cur_sectors);
- if (i > 0) {
- unsigned long flags;
- char *to = ide_map_buffer(rq, &flags);
- taskfile_output_data(drive, to, SECTOR_WORDS);
- ide_unmap_buffer(rq, to, &flags);
- ide_set_handler(drive, &write_intr, WAIT_CMD, NULL);
- return ide_started;
+ if (!hwif->nleft) {
+ ide_end_request(drive, 1, hwif->nsect);
+ return ide_stopped;
}
- return ide_stopped;
+ ide_pio_sector(drive, 1);
+ ide_set_handler(drive, &write_intr, WAIT_CMD, NULL);
+ return ide_started;
}
/* the original code did this here (?) */
return ide_stopped;
}
- return DRIVER(drive)->error(drive, "write_intr", stat);
-}
-
-/*
- * ide_multwrite() transfers a block of up to mcount sectors of data
- * to a drive as part of a disk multiple-sector write operation.
- *
- * Note that we may be called from two contexts - __ide_do_rw_disk() context
- * and IRQ context. The IRQ can happen any time after we've output the
- * full "mcount" number of sectors, so we must make sure we update the
- * state _before_ we output the final part of the data!
- *
- * The update and return to BH is a BLOCK Layer Fakey to get more data
- * to satisfy the hardware atomic segment. If the hardware atomic segment
- * is shorter or smaller than the BH segment then we should be OKAY.
- * This is only valid if we can rewind the rq->current_nr_sectors counter.
- */
-static void ide_multwrite(ide_drive_t *drive, unsigned int mcount)
-{
- ide_hwgroup_t *hwgroup = HWGROUP(drive);
- struct request *rq = &hwgroup->wrq;
-
- do {
- char *buffer;
- int nsect = rq->current_nr_sectors;
- unsigned long flags;
-
- if (nsect > mcount)
- nsect = mcount;
- mcount -= nsect;
- buffer = ide_map_buffer(rq, &flags);
-
- rq->sector += nsect;
- rq->nr_sectors -= nsect;
- rq->current_nr_sectors -= nsect;
-
- /* Do we move to the next bh after this? */
- if (!rq->current_nr_sectors) {
- struct bio *bio = rq->bio;
-
- /*
- * only move to next bio, when we have processed
- * all bvecs in this one.
- */
- if (++bio->bi_idx >= bio->bi_vcnt) {
- bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
- bio = bio->bi_next;
- }
-
- /* end early early we ran out of requests */
- if (!bio) {
- mcount = 0;
- } else {
- rq->bio = bio;
- rq->nr_cbio_segments = bio_segments(bio);
- rq->current_nr_sectors = bio_cur_sectors(bio);
- rq->hard_cur_sectors = rq->current_nr_sectors;
- }
- }
-
- /*
- * Ok, we're all setup for the interrupt
- * re-entering us on the last transfer.
- */
- taskfile_output_data(drive, buffer, nsect<<7);
- ide_unmap_buffer(rq, buffer, &flags);
- } while (mcount);
+ return task_error(drive, rq, __FUNCTION__, stat);
}

/*
@@ -294,42 +190,29 @@ static void ide_multwrite(ide_drive_t *d
*/
static ide_startstop_t multwrite_intr (ide_drive_t *drive)
{
- ide_hwgroup_t *hwgroup = HWGROUP(drive);
ide_hwif_t *hwif = HWIF(drive);
- struct request *rq = &hwgroup->wrq;
- struct bio *bio = rq->bio;
+ struct request *rq = hwif->hwgroup->rq;
u8 stat;

stat = hwif->INB(IDE_STATUS_REG);
if (OK_STAT(stat, DRIVE_READY, drive->bad_wstat)) {
if (stat & DRQ_STAT) {
- /*
- * The drive wants data. Remember rq is the copy
- * of the request
- */
- if (rq->nr_sectors) {
- ide_multwrite(drive, drive->mult_count);
+ /* The drive wants data. */
+ if (hwif->nleft) {
+ ide_pio_multi(drive, 1);
ide_set_handler(drive, &multwrite_intr, WAIT_CMD, NULL);
return ide_started;
}
} else {
- /*
- * If the copy has all the blocks completed then
- * we can end the original request.
- */
- if (!rq->nr_sectors) { /* all done? */
- bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
- rq = hwgroup->rq;
- ide_end_request(drive, 1, rq->nr_sectors);
+ if (!hwif->nleft) { /* all done? */
+ ide_end_request(drive, 1, hwif->nsect);
return ide_stopped;
}
}
- bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
/* the original code did this here (?) */
return ide_stopped;
}
- bio->bi_idx = bio->bi_vcnt - rq->nr_cbio_segments;
- return DRIVER(drive)->error(drive, "multwrite_intr", stat);
+ return task_error(drive, rq, __FUNCTION__, stat);
}

/*
@@ -352,6 +235,9 @@ ide_startstop_t __ide_do_rw_disk (ide_dr
dma = 0;
}

+ if (!dma)
+ ide_init_sg_cmd(drive, rq);
+
if (IDE_CONTROL_REG)
hwif->OUTB(drive->ctl, IDE_CONTROL_REG);

@@ -419,24 +305,40 @@ ide_startstop_t __ide_do_rw_disk (ide_dr
hwif->OUTB(head|drive->select.all,IDE_SELECT_REG);
}

+ if (dma) {
+ if (rq_data_dir(rq)) {
+ if (!hwif->ide_dma_write(drive))
+ return ide_started;
+ } else {
+ if (!hwif->ide_dma_read(drive))
+ return ide_started;
+ }
+ ide_init_sg_cmd(drive, rq);
+ }
+
if (rq_data_dir(rq) == READ) {
- if (dma && !hwif->ide_dma_read(drive))
- return ide_started;

- command = ((drive->mult_count) ?
- ((lba48) ? WIN_MULTREAD_EXT : WIN_MULTREAD) :
- ((lba48) ? WIN_READ_EXT : WIN_READ));
+ if (drive->mult_count) {
+ hwif->data_phase = TASKFILE_MULTI_IN;
+ command = lba48 ? WIN_MULTREAD_EXT : WIN_MULTREAD;
+ } else {
+ hwif->data_phase = TASKFILE_IN;
+ command = lba48 ? WIN_READ_EXT : WIN_READ;
+ }
+
ide_execute_command(drive, command, &read_intr, WAIT_CMD, NULL);
return ide_started;
} else {
ide_startstop_t startstop;

- if (dma && !hwif->ide_dma_write(drive))
- return ide_started;
+ if (drive->mult_count) {
+ hwif->data_phase = TASKFILE_MULTI_OUT;
+ command = lba48 ? WIN_MULTWRITE_EXT : WIN_MULTWRITE;
+ } else {
+ hwif->data_phase = TASKFILE_OUT;
+ command = lba48 ? WIN_WRITE_EXT : WIN_WRITE;
+ }

- command = ((drive->mult_count) ?
- ((lba48) ? WIN_MULTWRITE_EXT : WIN_MULTWRITE) :
- ((lba48) ? WIN_WRITE_EXT : WIN_WRITE));
hwif->OUTB(command, IDE_COMMAND_REG);

if (ide_wait_stat(&startstop, drive, DATA_READY,
@@ -449,17 +351,11 @@ ide_startstop_t __ide_do_rw_disk (ide_dr
if (!drive->unmask)
local_irq_disable();
if (drive->mult_count) {
- ide_hwgroup_t *hwgroup = HWGROUP(drive);
-
- hwgroup->wrq = *rq; /* scratchpad */
ide_set_handler(drive, &multwrite_intr, WAIT_CMD, NULL);
- ide_multwrite(drive, drive->mult_count);
+ ide_pio_multi(drive, 1);
} else {
- unsigned long flags;
- char *to = ide_map_buffer(rq, &flags);
ide_set_handler(drive, &write_intr, WAIT_CMD, NULL);
- taskfile_output_data(drive, to, SECTOR_WORDS);
- ide_unmap_buffer(rq, to, &flags);
+ ide_pio_sector(drive, 1);
}
return ide_started;
}
diff -puN drivers/ide/ide-taskfile.c~ide_sg_pio drivers/ide/ide-taskfile.c
--- linux-2.6.9-rc1-bk16/drivers/ide/ide-taskfile.c~ide_sg_pio 2004-09-10 23:47:03.235549200 +0200
+++ linux-2.6.9-rc1-bk16-bzolnier/drivers/ide/ide-taskfile.c 2004-09-10 23:47:55.460609784 +0200
@@ -301,7 +301,7 @@ static u8 wait_drive_not_busy(ide_drive_
return stat;
}

-static void ide_pio_sector(ide_drive_t *drive, unsigned int write)
+void ide_pio_sector(ide_drive_t *drive, unsigned int write)
{
ide_hwif_t *hwif = drive->hwif;
struct scatterlist *sg = hwif->sg_table;
@@ -338,7 +338,9 @@ static void ide_pio_sector(ide_drive_t *
#endif
}

-static void ide_pio_multi(ide_drive_t *drive, unsigned int write)
+EXPORT_SYMBOL_GPL(ide_pio_sector);
+
+void ide_pio_multi(ide_drive_t *drive, unsigned int write)
{
unsigned int nsect;

@@ -347,6 +349,8 @@ static void ide_pio_multi(ide_drive_t *d
ide_pio_sector(drive, write);
}

+EXPORT_SYMBOL_GPL(ide_pio_multi);
+
static inline void ide_pio_datablock(ide_drive_t *drive, struct request *rq,
unsigned int write)
{
@@ -364,9 +368,8 @@ static inline void ide_pio_datablock(ide
}
}

-#ifdef CONFIG_IDE_TASKFILE_IO
-static ide_startstop_t task_error(ide_drive_t *drive, struct request *rq,
- const char *s, u8 stat)
+ide_startstop_t task_error(ide_drive_t *drive, struct request *rq,
+ const char *s, u8 stat)
{
if (rq->bio) {
ide_hwif_t *hwif = drive->hwif;
@@ -395,9 +398,8 @@ static ide_startstop_t task_error(ide_dr
}
return drive->driver->error(drive, s, stat);
}
-#else
-# define task_error(d, rq, s, stat) drive->driver->error(d, s, stat)
-#endif
+
+EXPORT_SYMBOL_GPL(task_error);

static void task_end_request(ide_drive_t *drive, struct request *rq, u8 stat)
{
diff -puN include/linux/ide.h~ide_sg_pio include/linux/ide.h
--- linux-2.6.9-rc1-bk16/include/linux/ide.h~ide_sg_pio 2004-09-10 23:47:03.237548896 +0200
+++ linux-2.6.9-rc1-bk16-bzolnier/include/linux/ide.h 2004-09-10 23:48:31.686102672 +0200
@@ -796,27 +796,6 @@ typedef struct ide_drive_s {
struct gendisk *disk;
} ide_drive_t;

-/*
- * mapping stuff, prepare for highmem...
- *
- * temporarily mapping a (possible) highmem bio for PIO transfer
- */
-#ifndef CONFIG_IDE_TASKFILE_IO
-
-#define ide_rq_offset(rq) \
- (((rq)->hard_cur_sectors - (rq)->current_nr_sectors) << 9)
-
-static inline void *ide_map_buffer(struct request *rq, unsigned long *flags)
-{
- return bio_kmap_irq(rq->bio, flags) + ide_rq_offset(rq);
-}
-
-static inline void ide_unmap_buffer(struct request *rq, char *buffer, unsigned long *flags)
-{
- bio_kunmap_irq(buffer, flags);
-}
-#endif /* !CONFIG_IDE_TASKFILE_IO */
-
#define IDE_CHIPSET_PCI_MASK \
((1<<ide_pci)|(1<<ide_cmd646)|(1<<ide_ali14xx))
#define IDE_CHIPSET_IS_PCI(c) ((IDE_CHIPSET_PCI_MASK >> (c)) & 1)
@@ -1382,6 +1361,11 @@ extern void atapi_output_bytes(ide_drive
extern void taskfile_input_data(ide_drive_t *, void *, u32);
extern void taskfile_output_data(ide_drive_t *, void *, u32);

+extern void ide_pio_sector(ide_drive_t *, unsigned int);
+extern void ide_pio_multi(ide_drive_t *, unsigned int);
+
+extern ide_startstop_t task_error(ide_drive_t *, struct request *, const char *, u8);
+
extern int drive_is_ready(ide_drive_t *);
extern int wait_for_ready(ide_drive_t *, int /* timeout */);

_
-
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