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 91e0ccfdb424..41baf02924e6 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