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>

1 files changed, 0 insertions, 1 deletions

diff --git a/drivers/ide/ide-disk.c b/drivers/ide/ide-disk.c
index c1fb75c387ea..041be43a62cb 100644
--- a/drivers/ide/ide-disk.c
+++ b/drivers/ide/ide-disk.c
@@ -761,7 +761,6 @@ static void idedisk_add_settings(ide_drive_t *drive)
         ide_add_setting(drive,  "bios_head",    SETTING_RW,     TYPE_BYTE,      0,      255,                    1,      1,      &drive->bios_head,      NULL);
         ide_add_setting(drive,  "bios_sect",    SETTING_RW,     TYPE_BYTE,      0,      63,                     1,      1,      &drive->bios_sect,      NULL);
         ide_add_setting(drive,  "address",      SETTING_RW,     TYPE_BYTE,      0,      2,                      1,      1,      &drive->addressing,     set_lba_addressing);
-        ide_add_setting(drive,  "bswap",        SETTING_READ,   TYPE_BYTE,      0,      1,                      1,      1,      &drive->bswap,          NULL);
         ide_add_setting(drive,  "multcount",    SETTING_RW,     TYPE_BYTE,      0,      id->max_multsect,       1,      1,      &drive->mult_count,     set_multcount);
         ide_add_setting(drive,  "nowerr",       SETTING_RW,     TYPE_BYTE,      0,      1,                      1,      1,      &drive->nowerr,         set_nowerr);
         ide_add_setting(drive,  "lun",          SETTING_RW,     TYPE_INT,       0,      7,                      1,      1,      &drive->lun,            NULL);