ide: ide.c 'clear' fix, update "ide=nodma" documentation

Documentation/kernel-parameters.txt
- ide=nodma is no longer valid.

drivers/ide/Kconfig
- The module is ide-core.ko not ide.

drivers/ide/ide.c
- It took me a while to figure out what the arguments %d.%d:%d to nodma
  module parameter ment, so I added a comment to each.
- Added a comment to each of the sscanf lines.
- There is a bug, if j is 0 it would previously clear all the other bits
  except the current device, changed in three different places.
  mask &= (1 << i) should be mask &= ~(1 << i).

Signed-off-by: David Fries <david@fries.net>
[bart: s/disk/device/ in ide.c, beautify patch description]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/drivers/ide/ide.c b/drivers/ide/ide.c
index 258805da15c3..0920e3b0c962 100644
--- a/drivers/ide/ide.c
+++ b/drivers/ide/ide.c
@@ -337,6 +337,7 @@ static int ide_set_dev_param_mask(const char *s, struct kernel_param *kp)
 	int a, b, i, j = 1;
 	unsigned int *dev_param_mask = (unsigned int *)kp->arg;
 
+	/* controller . device (0 or 1) [ : 1 (set) | 0 (clear) ] */
 	if (sscanf(s, "%d.%d:%d", &a, &b, &j) != 3 &&
 	    sscanf(s, "%d.%d", &a, &b) != 2)
 		return -EINVAL;
@@ -349,7 +350,7 @@ static int ide_set_dev_param_mask(const char *s, struct kernel_param *kp)
 	if (j)
 		*dev_param_mask |= (1 << i);
 	else
-		*dev_param_mask &= (1 << i);
+		*dev_param_mask &= ~(1 << i);
 
 	return 0;
 }
@@ -392,6 +393,8 @@ static int ide_set_disk_chs(const char *str, struct kernel_param *kp)
 {
 	int a, b, c = 0, h = 0, s = 0, i, j = 1;
 
+	/* controller . device (0 or 1) : Cylinders , Heads , Sectors */
+	/* controller . device (0 or 1) : 1 (use CHS) | 0 (ignore CHS) */
 	if (sscanf(str, "%d.%d:%d,%d,%d", &a, &b, &c, &h, &s) != 5 &&
 	    sscanf(str, "%d.%d:%d", &a, &b, &j) != 3)
 		return -EINVAL;
@@ -407,7 +410,7 @@ static int ide_set_disk_chs(const char *str, struct kernel_param *kp)
 	if (j)
 		ide_disks |= (1 << i);
 	else
-		ide_disks &= (1 << i);
+		ide_disks &= ~(1 << i);
 
 	ide_disks_chs[i].cyl  = c;
 	ide_disks_chs[i].head = h;
@@ -469,6 +472,8 @@ static int ide_set_ignore_cable(const char *s, struct kernel_param *kp)
 {
 	int i, j = 1;
 
+	/* controller (ignore) */
+	/* controller : 1 (ignore) | 0 (use) */
 	if (sscanf(s, "%d:%d", &i, &j) != 2 && sscanf(s, "%d", &i) != 1)
 		return -EINVAL;
 
@@ -478,7 +483,7 @@ static int ide_set_ignore_cable(const char *s, struct kernel_param *kp)
 	if (j)
 		ide_ignore_cable |= (1 << i);
 	else
-		ide_ignore_cable &= (1 << i);
+		ide_ignore_cable &= ~(1 << i);
 
 	return 0;
 }