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-rw-r--r--lib/bitmap.c259
1 files changed, 158 insertions, 101 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c
index 4250519d7d1c..89260aa342d6 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -168,6 +168,72 @@ void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
}
EXPORT_SYMBOL(__bitmap_shift_left);
+/**
+ * bitmap_cut() - remove bit region from bitmap and right shift remaining bits
+ * @dst: destination bitmap, might overlap with src
+ * @src: source bitmap
+ * @first: start bit of region to be removed
+ * @cut: number of bits to remove
+ * @nbits: bitmap size, in bits
+ *
+ * Set the n-th bit of @dst iff the n-th bit of @src is set and
+ * n is less than @first, or the m-th bit of @src is set for any
+ * m such that @first <= n < nbits, and m = n + @cut.
+ *
+ * In pictures, example for a big-endian 32-bit architecture:
+ *
+ * @src:
+ * 31 63
+ * | |
+ * 10000000 11000001 11110010 00010101 10000000 11000001 01110010 00010101
+ * | | | |
+ * 16 14 0 32
+ *
+ * if @cut is 3, and @first is 14, bits 14-16 in @src are cut and @dst is:
+ *
+ * 31 63
+ * | |
+ * 10110000 00011000 00110010 00010101 00010000 00011000 00101110 01000010
+ * | | |
+ * 14 (bit 17 0 32
+ * from @src)
+ *
+ * Note that @dst and @src might overlap partially or entirely.
+ *
+ * This is implemented in the obvious way, with a shift and carry
+ * step for each moved bit. Optimisation is left as an exercise
+ * for the compiler.
+ */
+void bitmap_cut(unsigned long *dst, const unsigned long *src,
+ unsigned int first, unsigned int cut, unsigned int nbits)
+{
+ unsigned int len = BITS_TO_LONGS(nbits);
+ unsigned long keep = 0, carry;
+ int i;
+
+ memmove(dst, src, len * sizeof(*dst));
+
+ if (first % BITS_PER_LONG) {
+ keep = src[first / BITS_PER_LONG] &
+ (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));
+ }
+
+ while (cut--) {
+ for (i = first / BITS_PER_LONG; i < len; i++) {
+ if (i < len - 1)
+ carry = dst[i + 1] & 1UL;
+ else
+ carry = 0;
+
+ dst[i] = (dst[i] >> 1) | (carry << (BITS_PER_LONG - 1));
+ }
+ }
+
+ dst[first / BITS_PER_LONG] &= ~0UL << (first % BITS_PER_LONG);
+ dst[first / BITS_PER_LONG] |= keep;
+}
+EXPORT_SYMBOL(bitmap_cut);
+
int __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int bits)
{
@@ -365,97 +431,6 @@ EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
* second version by Paul Jackson, third by Joe Korty.
*/
-#define CHUNKSZ 32
-#define nbits_to_hold_value(val) fls(val)
-#define BASEDEC 10 /* fancier cpuset lists input in decimal */
-
-/**
- * __bitmap_parse - convert an ASCII hex string into a bitmap.
- * @buf: pointer to buffer containing string.
- * @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: pointer to bitmap array that will contain result.
- * @nmaskbits: size of bitmap, in bits.
- *
- * Commas group hex digits into chunks. Each chunk defines exactly 32
- * bits of the resultant bitmask. No chunk may specify a value larger
- * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
- * then leading 0-bits are prepended. %-EINVAL is returned for illegal
- * characters and for grouping errors such as "1,,5", ",44", "," and "".
- * Leading and trailing whitespace accepted, but not embedded whitespace.
- */
-int __bitmap_parse(const char *buf, unsigned int buflen,
- int is_user, unsigned long *maskp,
- int nmaskbits)
-{
- int c, old_c, totaldigits, ndigits, nchunks, nbits;
- u32 chunk;
- const char __user __force *ubuf = (const char __user __force *)buf;
-
- bitmap_zero(maskp, nmaskbits);
-
- nchunks = nbits = totaldigits = c = 0;
- do {
- chunk = 0;
- ndigits = totaldigits;
-
- /* Get the next chunk of the bitmap */
- 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 the chunk */
- if (c == '\0' || c == ',')
- break;
-
- if (!isxdigit(c))
- return -EINVAL;
-
- /*
- * Make sure there are at least 4 free bits in 'chunk'.
- * If not, this hexdigit will overflow 'chunk', so
- * throw an error.
- */
- if (chunk & ~((1UL << (CHUNKSZ - 4)) - 1))
- return -EOVERFLOW;
-
- chunk = (chunk << 4) | hex_to_bin(c);
- totaldigits++;
- }
- if (ndigits == totaldigits)
- return -EINVAL;
- if (nchunks == 0 && chunk == 0)
- continue;
-
- __bitmap_shift_left(maskp, maskp, CHUNKSZ, nmaskbits);
- *maskp |= chunk;
- nchunks++;
- nbits += (nchunks == 1) ? nbits_to_hold_value(chunk) : CHUNKSZ;
- if (nbits > nmaskbits)
- return -EOVERFLOW;
- } while (buflen && c == ',');
-
- return 0;
-}
-EXPORT_SYMBOL(__bitmap_parse);
-
/**
* bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
*
@@ -464,22 +439,22 @@ EXPORT_SYMBOL(__bitmap_parse);
* 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_parse(), 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_parse_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
int nmaskbits)
{
- if (!access_ok(ubuf, ulen))
- return -EFAULT;
- return __bitmap_parse((const char __force *)ubuf,
- ulen, 1, maskp, nmaskbits);
+ char *buf;
+ int ret;
+ buf = memdup_user_nul(ubuf, ulen);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ ret = bitmap_parse(buf, UINT_MAX, maskp, nmaskbits);
+
+ kfree(buf);
+ return ret;
}
EXPORT_SYMBOL(bitmap_parse_user);
@@ -587,6 +562,14 @@ static const char *bitmap_find_region(const char *str)
return end_of_str(*str) ? NULL : str;
}
+static const char *bitmap_find_region_reverse(const char *start, const char *end)
+{
+ while (start <= end && __end_of_region(*end))
+ end--;
+
+ return end;
+}
+
static const char *bitmap_parse_region(const char *str, struct region *r)
{
str = bitmap_getnum(str, &r->start);
@@ -710,6 +693,80 @@ int bitmap_parselist_user(const char __user *ubuf,
}
EXPORT_SYMBOL(bitmap_parselist_user);
+static const char *bitmap_get_x32_reverse(const char *start,
+ const char *end, u32 *num)
+{
+ u32 ret = 0;
+ int c, i;
+
+ for (i = 0; i < 32; i += 4) {
+ c = hex_to_bin(*end--);
+ if (c < 0)
+ return ERR_PTR(-EINVAL);
+
+ ret |= c << i;
+
+ if (start > end || __end_of_region(*end))
+ goto out;
+ }
+
+ if (hex_to_bin(*end--) >= 0)
+ return ERR_PTR(-EOVERFLOW);
+out:
+ *num = ret;
+ return end;
+}
+
+/**
+ * bitmap_parse - convert an ASCII hex string into a bitmap.
+ * @start: pointer to buffer containing string.
+ * @buflen: buffer size in bytes. If string is smaller than this
+ * then it must be terminated with a \0 or \n. In that case,
+ * UINT_MAX may be provided instead of string length.
+ * @maskp: pointer to bitmap array that will contain result.
+ * @nmaskbits: size of bitmap, in bits.
+ *
+ * Commas group hex digits into chunks. Each chunk defines exactly 32
+ * bits of the resultant bitmask. No chunk may specify a value larger
+ * than 32 bits (%-EOVERFLOW), and if a chunk specifies a smaller value
+ * then leading 0-bits are prepended. %-EINVAL is returned for illegal
+ * characters. Grouping such as "1,,5", ",44", "," or "" is allowed.
+ * Leading, embedded and trailing whitespace accepted.
+ */
+int bitmap_parse(const char *start, unsigned int buflen,
+ unsigned long *maskp, int nmaskbits)
+{
+ const char *end = strnchrnul(start, buflen, '\n') - 1;
+ int chunks = BITS_TO_U32(nmaskbits);
+ u32 *bitmap = (u32 *)maskp;
+ int unset_bit;
+
+ while (1) {
+ end = bitmap_find_region_reverse(start, end);
+ if (start > end)
+ break;
+
+ if (!chunks--)
+ return -EOVERFLOW;
+
+ end = bitmap_get_x32_reverse(start, end, bitmap++);
+ if (IS_ERR(end))
+ return PTR_ERR(end);
+ }
+
+ unset_bit = (BITS_TO_U32(nmaskbits) - chunks) * 32;
+ if (unset_bit < nmaskbits) {
+ bitmap_clear(maskp, unset_bit, nmaskbits - unset_bit);
+ return 0;
+ }
+
+ if (find_next_bit(maskp, unset_bit, nmaskbits) != unset_bit)
+ return -EOVERFLOW;
+
+ return 0;
+}
+EXPORT_SYMBOL(bitmap_parse);
+
#ifdef CONFIG_NUMA
/**
generated by cgit v1.2.3 (git 2.39.1) at 2025-01-24 14:58:20 +0100