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, 1 insertions, 5 deletions

diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 5f3e53ec5838..52115ef1f01a 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -1303,7 +1303,7 @@ static int __init ide_setup(char *s)
         if (s[0] == 'h' && s[1] == 'd' && s[2] >= 'a' && s[2] <= max_drive) {
                 const char *hd_words[] = {
                         "none", "noprobe", "nowerr", "cdrom", "nodma",
-                        "autotune", "noautotune", "minus8", "swapdata", "bswap",
+                        "autotune", "noautotune", "-8", "-9", "-10",
                         "noflush", "remap", "remap63", "scsi", NULL };
                 unit = s[2] - 'a';
                 hw   = unit / MAX_DRIVES;
@@ -1339,10 +1339,6 @@ static int __init ide_setup(char *s)
                         case -7: /* "noautotune" */
                                 drive->autotune = IDE_TUNE_NOAUTO;
                                 goto obsolete_option;
-                        case -9: /* "swapdata" */
-                        case -10: /* "bswap" */
-                                drive->bswap = 1;
-                                goto done;
                         case -11: /* noflush */
                                 drive->noflush = 1;
                                 goto done;