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author | Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> | 2008-01-26 22:13:09 +0300 |
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committer | Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> | 2008-01-26 22:13:09 +0300 |
commit | 9e47be0c97f7357b80e91dc0632e9cce2eb025e0 (patch) | |
tree | 7047b2b3c9ac094b801d376e4bbb95292b1962ac /drivers/ide/ide-taskfile.c | |
parent | 3a5015cc9d7051ce8e706ef48276d8484aac0c4b (diff) | |
download | linux-9e47be0c97f7357b80e91dc0632e9cce2eb025e0.tar.xz |
ide: remove broken disk byte-swapping support
Remove broken disk byte-swapping support:
- it can cause a data corruption on SMP (or if using PREEMPT on UP)
- all data coming from disk are byte-swapped by taskfile_*_data() which
results in incorrect identify data being reported by /proc/ide/ and IOCTLs
- "hdx=bswap/byteswap" kernel parameter has been broken on m68k host drivers
(including Atari/Q40 ones) since 2.5.x days (because of 'hwif' zero-ing)
- byte-swapping is limited to PIO transfers (for working with TiVo disks on
x86 machines using user-space solutions or dm-byteswap should result in
much better performance because DMA can be used)
For previous discussions please see:
http://www.ussg.iu.edu/hypermail/linux/kernel/0201.0/0768.html
http://lkml.org/lkml/2004/2/28/111
[ I have dm-byteswap device mapper target if somebody is interested
(patch is for 2.6.4 though but I'll dust it off if needed). ]
Acked-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Diffstat (limited to 'drivers/ide/ide-taskfile.c')
-rw-r--r-- | drivers/ide/ide-taskfile.c | 32 |
1 files changed, 2 insertions, 30 deletions
diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c index c58edc86ed3e..3ecafab8f54e 100644 --- a/drivers/ide/ide-taskfile.c +++ b/drivers/ide/ide-taskfile.c @@ -35,34 +35,6 @@ #include <asm/uaccess.h> #include <asm/io.h> -static void ata_bswap_data (void *buffer, int wcount) -{ - u16 *p = buffer; - - while (wcount--) { - *p = *p << 8 | *p >> 8; p++; - *p = *p << 8 | *p >> 8; p++; - } -} - -static void taskfile_input_data(ide_drive_t *drive, void *buffer, u32 wcount) -{ - HWIF(drive)->ata_input_data(drive, buffer, wcount); - if (drive->bswap) - ata_bswap_data(buffer, wcount); -} - -static void taskfile_output_data(ide_drive_t *drive, void *buffer, u32 wcount) -{ - if (drive->bswap) { - ata_bswap_data(buffer, wcount); - HWIF(drive)->ata_output_data(drive, buffer, wcount); - ata_bswap_data(buffer, wcount); - } else { - HWIF(drive)->ata_output_data(drive, buffer, wcount); - } -} - void ide_tf_load(ide_drive_t *drive, ide_task_t *task) { ide_hwif_t *hwif = drive->hwif; @@ -352,9 +324,9 @@ static void ide_pio_sector(ide_drive_t *drive, unsigned int write) /* do the actual data transfer */ if (write) - taskfile_output_data(drive, buf, SECTOR_WORDS); + hwif->ata_output_data(drive, buf, SECTOR_WORDS); else - taskfile_input_data(drive, buf, SECTOR_WORDS); + hwif->ata_input_data(drive, buf, SECTOR_WORDS); kunmap_atomic(buf, KM_BIO_SRC_IRQ); #ifdef CONFIG_HIGHMEM |