bitmap, irq: add smp_affinity_list interface to /proc/irq

Manually adjusting the smp_affinity for IRQ's becomes unwieldy when the
cpu count is large.

Setting smp affinity to cpus 256 to 263 would be:

	echo 000000ff,00000000,00000000,00000000,00000000,00000000,00000000,00000000 > smp_affinity

instead of:

	echo 256-263 > smp_affinity_list

Think about what it looks like for cpus around say, 4088 to 4095.

We already have many alternate "list" interfaces:

/sys/devices/system/cpu/cpuX/indexY/shared_cpu_list
/sys/devices/system/cpu/cpuX/topology/thread_siblings_list
/sys/devices/system/cpu/cpuX/topology/core_siblings_list
/sys/devices/system/node/nodeX/cpulist
/sys/devices/pci***/***/local_cpulist

Add a companion interface, smp_affinity_list to use cpu lists instead of
cpu maps.  This conforms to other companion interfaces where both a map
and a list interface exists.

This required adding a bitmap_parselist_user() function in a manner
similar to the bitmap_parse_user() function.

[akpm@linux-foundation.org: make __bitmap_parselist() static]
Signed-off-by: Mike Travis <travis@sgi.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 97 insertions, 12 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
index 91e0ccfdb42..41baf02924e 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -571,8 +571,11 @@ int bitmap_scnlistprintf(char *buf, unsigned int buflen,
 EXPORT_SYMBOL(bitmap_scnlistprintf);
 
 /**
- * bitmap_parselist - convert list format ASCII string to bitmap
+ * __bitmap_parselist - convert list format ASCII string to bitmap
  * @bp: read nul-terminated user string from this buffer
+ * @buflen: buffer size in bytes.  If string is smaller than this
+ *    then it must be terminated with a \0.
+ * @is_user: location of buffer, 0 indicates kernel space
  * @maskp: write resulting mask here
  * @nmaskbits: number of bits in mask to be written
  *
@@ -587,20 +590,63 @@ EXPORT_SYMBOL(bitmap_scnlistprintf);
  *    %-EINVAL: invalid character in string
  *    %-ERANGE: bit number specified too large for mask
  */
-int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
+static int __bitmap_parselist(const char *buf, unsigned int buflen,
+		int is_user, unsigned long *maskp,
+		int nmaskbits)
 {
 	unsigned a, b;
+	int c, old_c, totaldigits;
+	const char __user *ubuf = buf;
+	int exp_digit, in_range;
 
+	totaldigits = c = 0;
 	bitmap_zero(maskp, nmaskbits);
 	do {
-		if (!isdigit(*bp))
-			return -EINVAL;
-		b = a = simple_strtoul(bp, (char **)&bp, BASEDEC);
-		if (*bp == '-') {
-			bp++;
-			if (!isdigit(*bp))
+		exp_digit = 1;
+		in_range = 0;
+		a = b = 0;
+
+		/* Get the next cpu# or a range of cpu#'s */
+		while (buflen) {
+			old_c = c;
+			if (is_user) {
+				if (__get_user(c, ubuf++))
+					return -EFAULT;
+			} else
+				c = *buf++;
+			buflen--;
+			if (isspace(c))
+				continue;
+
+			/*
+			 * If the last character was a space and the current
+			 * character isn't '\0', we've got embedded whitespace.
+			 * This is a no-no, so throw an error.
+			 */
+			if (totaldigits && c && isspace(old_c))
+				return -EINVAL;
+
+			/* A '\0' or a ',' signal the end of a cpu# or range */
+			if (c == '\0' || c == ',')
+				break;
+
+			if (c == '-') {
+				if (exp_digit || in_range)
+					return -EINVAL;
+				b = 0;
+				in_range = 1;
+				exp_digit = 1;
+				continue;
+			}
+
+			if (!isdigit(c))
 				return -EINVAL;
-			b = simple_strtoul(bp, (char **)&bp, BASEDEC);
+
+			b = b * 10 + (c - '0');
+			if (!in_range)
+				a = b;
+			exp_digit = 0;
+			totaldigits++;
 		}
 		if (!(a <= b))
 			return -EINVAL;
@@ -610,13 +656,52 @@ int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
 			set_bit(a, maskp);
 			a++;
 		}
-		if (*bp == ',')
-			bp++;
-	} while (*bp != '\0' && *bp != '\n');
+	} while (buflen && c == ',');
 	return 0;
 }
+
+int bitmap_parselist(const char *bp, unsigned long *maskp, int nmaskbits)
+{
+	char *nl  = strchr(bp, '\n');
+	int len;
+
+	if (nl)
+		len = nl - bp;
+	else
+		len = strlen(bp);
+
+	return __bitmap_parselist(bp, len, 0, maskp, nmaskbits);
+}
 EXPORT_SYMBOL(bitmap_parselist);
 
+
+/**
+ * bitmap_parselist_user()
+ *
+ * @ubuf: pointer to user buffer containing string.
+ * @ulen: buffer size in bytes.  If string is smaller than this
+ *    then it must be terminated with a \0.
+ * @maskp: pointer to bitmap array that will contain result.
+ * @nmaskbits: size of bitmap, in bits.
+ *
+ * Wrapper for bitmap_parselist(), providing it with user buffer.
+ *
+ * We cannot have this as an inline function in bitmap.h because it needs
+ * linux/uaccess.h to get the access_ok() declaration and this causes
+ * cyclic dependencies.
+ */
+int bitmap_parselist_user(const char __user *ubuf,
+			unsigned int ulen, unsigned long *maskp,
+			int nmaskbits)
+{
+	if (!access_ok(VERIFY_READ, ubuf, ulen))
+		return -EFAULT;
+	return __bitmap_parselist((const char *)ubuf,
+					ulen, 1, maskp, nmaskbits);
+}
+EXPORT_SYMBOL(bitmap_parselist_user);
+
+
 /**
  * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
  *	@buf: pointer to a bitmap