Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1551 insertions, 0 deletions

diff --git a/lib/bitmap.c b/lib/bitmap.c
new file mode 100644
index 000000000..ddb31015e
--- /dev/null
+++ b/lib/bitmap.c
@@ -0,0 +1,1551 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * lib/bitmap.c
+ * Helper functions for bitmap.h.
+ */
+
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/bug.h>
+#include <linux/ctype.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/thread_info.h>
+#include <linux/uaccess.h>
+
+#include <asm/page.h>
+
+#include "kstrtox.h"
+
+/**
+ * DOC: bitmap introduction
+ *
+ * bitmaps provide an array of bits, implemented using an
+ * array of unsigned longs.  The number of valid bits in a
+ * given bitmap does _not_ need to be an exact multiple of
+ * BITS_PER_LONG.
+ *
+ * The possible unused bits in the last, partially used word
+ * of a bitmap are 'don't care'.  The implementation makes
+ * no particular effort to keep them zero.  It ensures that
+ * their value will not affect the results of any operation.
+ * The bitmap operations that return Boolean (bitmap_empty,
+ * for example) or scalar (bitmap_weight, for example) results
+ * carefully filter out these unused bits from impacting their
+ * results.
+ *
+ * The byte ordering of bitmaps is more natural on little
+ * endian architectures.  See the big-endian headers
+ * include/asm-ppc64/bitops.h and include/asm-s390/bitops.h
+ * for the best explanations of this ordering.
+ */
+
+bool __bitmap_equal(const unsigned long *bitmap1,
+		    const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] != bitmap2[k])
+			return false;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return false;
+
+	return true;
+}
+EXPORT_SYMBOL(__bitmap_equal);
+
+bool __bitmap_or_equal(const unsigned long *bitmap1,
+		       const unsigned long *bitmap2,
+		       const unsigned long *bitmap3,
+		       unsigned int bits)
+{
+	unsigned int k, lim = bits / BITS_PER_LONG;
+	unsigned long tmp;
+
+	for (k = 0; k < lim; ++k) {
+		if ((bitmap1[k] | bitmap2[k]) != bitmap3[k])
+			return false;
+	}
+
+	if (!(bits % BITS_PER_LONG))
+		return true;
+
+	tmp = (bitmap1[k] | bitmap2[k]) ^ bitmap3[k];
+	return (tmp & BITMAP_LAST_WORD_MASK(bits)) == 0;
+}
+
+void __bitmap_complement(unsigned long *dst, const unsigned long *src, unsigned int bits)
+{
+	unsigned int k, lim = BITS_TO_LONGS(bits);
+	for (k = 0; k < lim; ++k)
+		dst[k] = ~src[k];
+}
+EXPORT_SYMBOL(__bitmap_complement);
+
+/**
+ * __bitmap_shift_right - logical right shift of the bits in a bitmap
+ *   @dst : destination bitmap
+ *   @src : source bitmap
+ *   @shift : shift by this many bits
+ *   @nbits : bitmap size, in bits
+ *
+ * Shifting right (dividing) means moving bits in the MS -> LS bit
+ * direction.  Zeros are fed into the vacated MS positions and the
+ * LS bits shifted off the bottom are lost.
+ */
+void __bitmap_shift_right(unsigned long *dst, const unsigned long *src,
+			unsigned shift, unsigned nbits)
+{
+	unsigned k, lim = BITS_TO_LONGS(nbits);
+	unsigned off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+	unsigned long mask = BITMAP_LAST_WORD_MASK(nbits);
+	for (k = 0; off + k < lim; ++k) {
+		unsigned long upper, lower;
+
+		/*
+		 * If shift is not word aligned, take lower rem bits of
+		 * word above and make them the top rem bits of result.
+		 */
+		if (!rem || off + k + 1 >= lim)
+			upper = 0;
+		else {
+			upper = src[off + k + 1];
+			if (off + k + 1 == lim - 1)
+				upper &= mask;
+			upper <<= (BITS_PER_LONG - rem);
+		}
+		lower = src[off + k];
+		if (off + k == lim - 1)
+			lower &= mask;
+		lower >>= rem;
+		dst[k] = lower | upper;
+	}
+	if (off)
+		memset(&dst[lim - off], 0, off*sizeof(unsigned long));
+}
+EXPORT_SYMBOL(__bitmap_shift_right);
+
+
+/**
+ * __bitmap_shift_left - logical left shift of the bits in a bitmap
+ *   @dst : destination bitmap
+ *   @src : source bitmap
+ *   @shift : shift by this many bits
+ *   @nbits : bitmap size, in bits
+ *
+ * Shifting left (multiplying) means moving bits in the LS -> MS
+ * direction.  Zeros are fed into the vacated LS bit positions
+ * and those MS bits shifted off the top are lost.
+ */
+
+void __bitmap_shift_left(unsigned long *dst, const unsigned long *src,
+			unsigned int shift, unsigned int nbits)
+{
+	int k;
+	unsigned int lim = BITS_TO_LONGS(nbits);
+	unsigned int off = shift/BITS_PER_LONG, rem = shift % BITS_PER_LONG;
+	for (k = lim - off - 1; k >= 0; --k) {
+		unsigned long upper, lower;
+
+		/*
+		 * If shift is not word aligned, take upper rem bits of
+		 * word below and make them the bottom rem bits of result.
+		 */
+		if (rem && k > 0)
+			lower = src[k - 1] >> (BITS_PER_LONG - rem);
+		else
+			lower = 0;
+		upper = src[k] << rem;
+		dst[k + off] = lower | upper;
+	}
+	if (off)
+		memset(dst, 0, off*sizeof(unsigned long));
+}
+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:
+ *
+ * The @src bitmap is::
+ *
+ *   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;
+
+	if (first % BITS_PER_LONG) {
+		keep = src[first / BITS_PER_LONG] &
+		       (~0UL >> (BITS_PER_LONG - first % BITS_PER_LONG));
+	}
+
+	memmove(dst, src, len * sizeof(*dst));
+
+	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);
+
+bool __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int lim = bits/BITS_PER_LONG;
+	unsigned long result = 0;
+
+	for (k = 0; k < lim; k++)
+		result |= (dst[k] = bitmap1[k] & bitmap2[k]);
+	if (bits % BITS_PER_LONG)
+		result |= (dst[k] = bitmap1[k] & bitmap2[k] &
+			   BITMAP_LAST_WORD_MASK(bits));
+	return result != 0;
+}
+EXPORT_SYMBOL(__bitmap_and);
+
+void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] | bitmap2[k];
+}
+EXPORT_SYMBOL(__bitmap_or);
+
+void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int nr = BITS_TO_LONGS(bits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = bitmap1[k] ^ bitmap2[k];
+}
+EXPORT_SYMBOL(__bitmap_xor);
+
+bool __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k;
+	unsigned int lim = bits/BITS_PER_LONG;
+	unsigned long result = 0;
+
+	for (k = 0; k < lim; k++)
+		result |= (dst[k] = bitmap1[k] & ~bitmap2[k]);
+	if (bits % BITS_PER_LONG)
+		result |= (dst[k] = bitmap1[k] & ~bitmap2[k] &
+			   BITMAP_LAST_WORD_MASK(bits));
+	return result != 0;
+}
+EXPORT_SYMBOL(__bitmap_andnot);
+
+void __bitmap_replace(unsigned long *dst,
+		      const unsigned long *old, const unsigned long *new,
+		      const unsigned long *mask, unsigned int nbits)
+{
+	unsigned int k;
+	unsigned int nr = BITS_TO_LONGS(nbits);
+
+	for (k = 0; k < nr; k++)
+		dst[k] = (old[k] & ~mask[k]) | (new[k] & mask[k]);
+}
+EXPORT_SYMBOL(__bitmap_replace);
+
+bool __bitmap_intersects(const unsigned long *bitmap1,
+			 const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] & bitmap2[k])
+			return true;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return true;
+	return false;
+}
+EXPORT_SYMBOL(__bitmap_intersects);
+
+bool __bitmap_subset(const unsigned long *bitmap1,
+		     const unsigned long *bitmap2, unsigned int bits)
+{
+	unsigned int k, lim = bits/BITS_PER_LONG;
+	for (k = 0; k < lim; ++k)
+		if (bitmap1[k] & ~bitmap2[k])
+			return false;
+
+	if (bits % BITS_PER_LONG)
+		if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits))
+			return false;
+	return true;
+}
+EXPORT_SYMBOL(__bitmap_subset);
+
+#define BITMAP_WEIGHT(FETCH, bits)	\
+({										\
+	unsigned int __bits = (bits), idx, w = 0;				\
+										\
+	for (idx = 0; idx < __bits / BITS_PER_LONG; idx++)			\
+		w += hweight_long(FETCH);					\
+										\
+	if (__bits % BITS_PER_LONG)						\
+		w += hweight_long((FETCH) & BITMAP_LAST_WORD_MASK(__bits));	\
+										\
+	w;									\
+})
+
+unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
+{
+	return BITMAP_WEIGHT(bitmap[idx], bits);
+}
+EXPORT_SYMBOL(__bitmap_weight);
+
+unsigned int __bitmap_weight_and(const unsigned long *bitmap1,
+				const unsigned long *bitmap2, unsigned int bits)
+{
+	return BITMAP_WEIGHT(bitmap1[idx] & bitmap2[idx], bits);
+}
+EXPORT_SYMBOL(__bitmap_weight_and);
+
+void __bitmap_set(unsigned long *map, unsigned int start, int len)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const unsigned int size = start + len;
+	int bits_to_set = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_set = BITMAP_FIRST_WORD_MASK(start);
+
+	while (len - bits_to_set >= 0) {
+		*p |= mask_to_set;
+		len -= bits_to_set;
+		bits_to_set = BITS_PER_LONG;
+		mask_to_set = ~0UL;
+		p++;
+	}
+	if (len) {
+		mask_to_set &= BITMAP_LAST_WORD_MASK(size);
+		*p |= mask_to_set;
+	}
+}
+EXPORT_SYMBOL(__bitmap_set);
+
+void __bitmap_clear(unsigned long *map, unsigned int start, int len)
+{
+	unsigned long *p = map + BIT_WORD(start);
+	const unsigned int size = start + len;
+	int bits_to_clear = BITS_PER_LONG - (start % BITS_PER_LONG);
+	unsigned long mask_to_clear = BITMAP_FIRST_WORD_MASK(start);
+
+	while (len - bits_to_clear >= 0) {
+		*p &= ~mask_to_clear;
+		len -= bits_to_clear;
+		bits_to_clear = BITS_PER_LONG;
+		mask_to_clear = ~0UL;
+		p++;
+	}
+	if (len) {
+		mask_to_clear &= BITMAP_LAST_WORD_MASK(size);
+		*p &= ~mask_to_clear;
+	}
+}
+EXPORT_SYMBOL(__bitmap_clear);
+
+/**
+ * bitmap_find_next_zero_area_off - find a contiguous aligned zero area
+ * @map: The address to base the search on
+ * @size: The bitmap size in bits
+ * @start: The bitnumber to start searching at
+ * @nr: The number of zeroed bits we're looking for
+ * @align_mask: Alignment mask for zero area
+ * @align_offset: Alignment offset for zero area.
+ *
+ * The @align_mask should be one less than a power of 2; the effect is that
+ * the bit offset of all zero areas this function finds plus @align_offset
+ * is multiple of that power of 2.
+ */
+unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
+					     unsigned long size,
+					     unsigned long start,
+					     unsigned int nr,
+					     unsigned long align_mask,
+					     unsigned long align_offset)
+{
+	unsigned long index, end, i;
+again:
+	index = find_next_zero_bit(map, size, start);
+
+	/* Align allocation */
+	index = __ALIGN_MASK(index + align_offset, align_mask) - align_offset;
+
+	end = index + nr;
+	if (end > size)
+		return end;
+	i = find_next_bit(map, end, index);
+	if (i < end) {
+		start = i + 1;
+		goto again;
+	}
+	return index;
+}
+EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
+
+/*
+ * Bitmap printing & parsing functions: first version by Nadia Yvette Chambers,
+ * second version by Paul Jackson, third by Joe Korty.
+ */
+
+/**
+ * bitmap_parse_user - convert an ASCII hex string in a user buffer into a bitmap
+ *
+ * @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.
+ */
+int bitmap_parse_user(const char __user *ubuf,
+			unsigned int ulen, unsigned long *maskp,
+			int 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);
+
+/**
+ * bitmap_print_to_pagebuf - convert bitmap to list or hex format ASCII string
+ * @list: indicates whether the bitmap must be list
+ * @buf: page aligned buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ *
+ * Output format is a comma-separated list of decimal numbers and
+ * ranges if list is specified or hex digits grouped into comma-separated
+ * sets of 8 digits/set. Returns the number of characters written to buf.
+ *
+ * It is assumed that @buf is a pointer into a PAGE_SIZE, page-aligned
+ * area and that sufficient storage remains at @buf to accommodate the
+ * bitmap_print_to_pagebuf() output. Returns the number of characters
+ * actually printed to @buf, excluding terminating '\0'.
+ */
+int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
+			    int nmaskbits)
+{
+	ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
+
+	return list ? scnprintf(buf, len, "%*pbl\n", nmaskbits, maskp) :
+		      scnprintf(buf, len, "%*pb\n", nmaskbits, maskp);
+}
+EXPORT_SYMBOL(bitmap_print_to_pagebuf);
+
+/**
+ * bitmap_print_to_buf  - convert bitmap to list or hex format ASCII string
+ * @list: indicates whether the bitmap must be list
+ *      true:  print in decimal list format
+ *      false: print in hexadecimal bitmask format
+ * @buf: buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ * @off: in the string from which we are copying, We copy to @buf
+ * @count: the maximum number of bytes to print
+ */
+static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
+		int nmaskbits, loff_t off, size_t count)
+{
+	const char *fmt = list ? "%*pbl\n" : "%*pb\n";
+	ssize_t size;
+	void *data;
+
+	data = kasprintf(GFP_KERNEL, fmt, nmaskbits, maskp);
+	if (!data)
+		return -ENOMEM;
+
+	size = memory_read_from_buffer(buf, count, &off, data, strlen(data) + 1);
+	kfree(data);
+
+	return size;
+}
+
+/**
+ * bitmap_print_bitmask_to_buf  - convert bitmap to hex bitmask format ASCII string
+ * @buf: buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ * @off: in the string from which we are copying, We copy to @buf
+ * @count: the maximum number of bytes to print
+ *
+ * The bitmap_print_to_pagebuf() is used indirectly via its cpumap wrapper
+ * cpumap_print_to_pagebuf() or directly by drivers to export hexadecimal
+ * bitmask and decimal list to userspace by sysfs ABI.
+ * Drivers might be using a normal attribute for this kind of ABIs. A
+ * normal attribute typically has show entry as below::
+ *
+ *   static ssize_t example_attribute_show(struct device *dev,
+ * 		struct device_attribute *attr, char *buf)
+ *   {
+ * 	...
+ * 	return bitmap_print_to_pagebuf(true, buf, &mask, nr_trig_max);
+ *   }
+ *
+ * show entry of attribute has no offset and count parameters and this
+ * means the file is limited to one page only.
+ * bitmap_print_to_pagebuf() API works terribly well for this kind of
+ * normal attribute with buf parameter and without offset, count::
+ *
+ *   bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
+ * 			   int nmaskbits)
+ *   {
+ *   }
+ *
+ * The problem is once we have a large bitmap, we have a chance to get a
+ * bitmask or list more than one page. Especially for list, it could be
+ * as complex as 0,3,5,7,9,... We have no simple way to know it exact size.
+ * It turns out bin_attribute is a way to break this limit. bin_attribute
+ * has show entry as below::
+ *
+ *   static ssize_t
+ *   example_bin_attribute_show(struct file *filp, struct kobject *kobj,
+ * 		struct bin_attribute *attr, char *buf,
+ * 		loff_t offset, size_t count)
+ *   {
+ * 	...
+ *   }
+ *
+ * With the new offset and count parameters, this makes sysfs ABI be able
+ * to support file size more than one page. For example, offset could be
+ * >= 4096.
+ * bitmap_print_bitmask_to_buf(), bitmap_print_list_to_buf() wit their
+ * cpumap wrapper cpumap_print_bitmask_to_buf(), cpumap_print_list_to_buf()
+ * make those drivers be able to support large bitmask and list after they
+ * move to use bin_attribute. In result, we have to pass the corresponding
+ * parameters such as off, count from bin_attribute show entry to this API.
+ *
+ * The role of cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf()
+ * is similar with cpumap_print_to_pagebuf(),  the difference is that
+ * bitmap_print_to_pagebuf() mainly serves sysfs attribute with the assumption
+ * the destination buffer is exactly one page and won't be more than one page.
+ * cpumap_print_bitmask_to_buf() and cpumap_print_list_to_buf(), on the other
+ * hand, mainly serves bin_attribute which doesn't work with exact one page,
+ * and it can break the size limit of converted decimal list and hexadecimal
+ * bitmask.
+ *
+ * WARNING!
+ *
+ * This function is not a replacement for sprintf() or bitmap_print_to_pagebuf().
+ * It is intended to workaround sysfs limitations discussed above and should be
+ * used carefully in general case for the following reasons:
+ *
+ *  - Time complexity is O(nbits^2/count), comparing to O(nbits) for snprintf().
+ *  - Memory complexity is O(nbits), comparing to O(1) for snprintf().
+ *  - @off and @count are NOT offset and number of bits to print.
+ *  - If printing part of bitmap as list, the resulting string is not a correct
+ *    list representation of bitmap. Particularly, some bits within or out of
+ *    related interval may be erroneously set or unset. The format of the string
+ *    may be broken, so bitmap_parselist-like parser may fail parsing it.
+ *  - If printing the whole bitmap as list by parts, user must ensure the order
+ *    of calls of the function such that the offset is incremented linearly.
+ *  - If printing the whole bitmap as list by parts, user must keep bitmap
+ *    unchanged between the very first and very last call. Otherwise concatenated
+ *    result may be incorrect, and format may be broken.
+ *
+ * Returns the number of characters actually printed to @buf
+ */
+int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
+				int nmaskbits, loff_t off, size_t count)
+{
+	return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
+}
+EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
+
+/**
+ * bitmap_print_list_to_buf  - convert bitmap to decimal list format ASCII string
+ * @buf: buffer into which string is placed
+ * @maskp: pointer to bitmap to convert
+ * @nmaskbits: size of bitmap, in bits
+ * @off: in the string from which we are copying, We copy to @buf
+ * @count: the maximum number of bytes to print
+ *
+ * Everything is same with the above bitmap_print_bitmask_to_buf() except
+ * the print format.
+ */
+int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
+			     int nmaskbits, loff_t off, size_t count)
+{
+	return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
+}
+EXPORT_SYMBOL(bitmap_print_list_to_buf);
+
+/*
+ * Region 9-38:4/10 describes the following bitmap structure:
+ * 0	   9  12    18			38	     N
+ * .........****......****......****..................
+ *	    ^  ^     ^			 ^	     ^
+ *      start  off   group_len	       end	 nbits
+ */
+struct region {
+	unsigned int start;
+	unsigned int off;
+	unsigned int group_len;
+	unsigned int end;
+	unsigned int nbits;
+};
+
+static void bitmap_set_region(const struct region *r, unsigned long *bitmap)
+{
+	unsigned int start;
+
+	for (start = r->start; start <= r->end; start += r->group_len)
+		bitmap_set(bitmap, start, min(r->end - start + 1, r->off));
+}
+
+static int bitmap_check_region(const struct region *r)
+{
+	if (r->start > r->end || r->group_len == 0 || r->off > r->group_len)
+		return -EINVAL;
+
+	if (r->end >= r->nbits)
+		return -ERANGE;
+
+	return 0;
+}
+
+static const char *bitmap_getnum(const char *str, unsigned int *num,
+				 unsigned int lastbit)
+{
+	unsigned long long n;
+	unsigned int len;
+
+	if (str[0] == 'N') {
+		*num = lastbit;
+		return str + 1;
+	}
+
+	len = _parse_integer(str, 10, &n);
+	if (!len)
+		return ERR_PTR(-EINVAL);
+	if (len & KSTRTOX_OVERFLOW || n != (unsigned int)n)
+		return ERR_PTR(-EOVERFLOW);
+
+	*num = n;
+	return str + len;
+}
+
+static inline bool end_of_str(char c)
+{
+	return c == '\0' || c == '\n';
+}
+
+static inline bool __end_of_region(char c)
+{
+	return isspace(c) || c == ',';
+}
+
+static inline bool end_of_region(char c)
+{
+	return __end_of_region(c) || end_of_str(c);
+}
+
+/*
+ * The format allows commas and whitespaces at the beginning
+ * of the region.
+ */
+static const char *bitmap_find_region(const char *str)
+{
+	while (__end_of_region(*str))
+		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)
+{
+	unsigned int lastbit = r->nbits - 1;
+
+	if (!strncasecmp(str, "all", 3)) {
+		r->start = 0;
+		r->end = lastbit;
+		str += 3;
+
+		goto check_pattern;
+	}
+
+	str = bitmap_getnum(str, &r->start, lastbit);
+	if (IS_ERR(str))
+		return str;
+
+	if (end_of_region(*str))
+		goto no_end;
+
+	if (*str != '-')
+		return ERR_PTR(-EINVAL);
+
+	str = bitmap_getnum(str + 1, &r->end, lastbit);
+	if (IS_ERR(str))
+		return str;
+
+check_pattern:
+	if (end_of_region(*str))
+		goto no_pattern;
+
+	if (*str != ':')
+		return ERR_PTR(-EINVAL);
+
+	str = bitmap_getnum(str + 1, &r->off, lastbit);
+	if (IS_ERR(str))
+		return str;
+
+	if (*str != '/')
+		return ERR_PTR(-EINVAL);
+
+	return bitmap_getnum(str + 1, &r->group_len, lastbit);
+
+no_end:
+	r->end = r->start;
+no_pattern:
+	r->off = r->end + 1;
+	r->group_len = r->end + 1;
+
+	return end_of_str(*str) ? NULL : str;
+}
+
+/**
+ * bitmap_parselist - convert list format ASCII string to bitmap
+ * @buf: read user string from this buffer; must be terminated
+ *    with a \0 or \n.
+ * @maskp: write resulting mask here
+ * @nmaskbits: number of bits in mask to be written
+ *
+ * Input format is a comma-separated list of decimal numbers and
+ * ranges.  Consecutively set bits are shown as two hyphen-separated
+ * decimal numbers, the smallest and largest bit numbers set in
+ * the range.
+ * Optionally each range can be postfixed to denote that only parts of it
+ * should be set. The range will divided to groups of specific size.
+ * From each group will be used only defined amount of bits.
+ * Syntax: range:used_size/group_size
+ * Example: 0-1023:2/256 ==> 0,1,256,257,512,513,768,769
+ * The value 'N' can be used as a dynamically substituted token for the
+ * maximum allowed value; i.e (nmaskbits - 1).  Keep in mind that it is
+ * dynamic, so if system changes cause the bitmap width to change, such
+ * as more cores in a CPU list, then any ranges using N will also change.
+ *
+ * Returns: 0 on success, -errno on invalid input strings. Error values:
+ *
+ *   - ``-EINVAL``: wrong region format
+ *   - ``-EINVAL``: invalid character in string
+ *   - ``-ERANGE``: bit number specified too large for mask
+ *   - ``-EOVERFLOW``: integer overflow in the input parameters
+ */
+int bitmap_parselist(const char *buf, unsigned long *maskp, int nmaskbits)
+{
+	struct region r;
+	long ret;
+
+	r.nbits = nmaskbits;
+	bitmap_zero(maskp, r.nbits);
+
+	while (buf) {
+		buf = bitmap_find_region(buf);
+		if (buf == NULL)
+			return 0;
+
+		buf = bitmap_parse_region(buf, &r);
+		if (IS_ERR(buf))
+			return PTR_ERR(buf);
+
+		ret = bitmap_check_region(&r);
+		if (ret)
+			return ret;
+
+		bitmap_set_region(&r, maskp);
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(bitmap_parselist);
+
+
+/**
+ * bitmap_parselist_user() - convert user buffer's list format ASCII
+ * string to bitmap
+ *
+ * @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.
+ */
+int bitmap_parselist_user(const char __user *ubuf,
+			unsigned int ulen, unsigned long *maskp,
+			int nmaskbits)
+{
+	char *buf;
+	int ret;
+
+	buf = memdup_user_nul(ubuf, ulen);
+	if (IS_ERR(buf))
+		return PTR_ERR(buf);
+
+	ret = bitmap_parselist(buf, maskp, nmaskbits);
+
+	kfree(buf);
+	return ret;
+}
+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;
+	int chunk;
+
+	for (chunk = 0; ; chunk++) {
+		end = bitmap_find_region_reverse(start, end);
+		if (start > end)
+			break;
+
+		if (!chunks--)
+			return -EOVERFLOW;
+
+#if defined(CONFIG_64BIT) && defined(__BIG_ENDIAN)
+		end = bitmap_get_x32_reverse(start, end, &bitmap[chunk ^ 1]);
+#else
+		end = bitmap_get_x32_reverse(start, end, &bitmap[chunk]);
+#endif
+		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);
+
+/**
+ * bitmap_pos_to_ord - find ordinal of set bit at given position in bitmap
+ *	@buf: pointer to a bitmap
+ *	@pos: a bit position in @buf (0 <= @pos < @nbits)
+ *	@nbits: number of valid bit positions in @buf
+ *
+ * Map the bit at position @pos in @buf (of length @nbits) to the
+ * ordinal of which set bit it is.  If it is not set or if @pos
+ * is not a valid bit position, map to -1.
+ *
+ * If for example, just bits 4 through 7 are set in @buf, then @pos
+ * values 4 through 7 will get mapped to 0 through 3, respectively,
+ * and other @pos values will get mapped to -1.  When @pos value 7
+ * gets mapped to (returns) @ord value 3 in this example, that means
+ * that bit 7 is the 3rd (starting with 0th) set bit in @buf.
+ *
+ * The bit positions 0 through @bits are valid positions in @buf.
+ */
+static int bitmap_pos_to_ord(const unsigned long *buf, unsigned int pos, unsigned int nbits)
+{
+	if (pos >= nbits || !test_bit(pos, buf))
+		return -1;
+
+	return bitmap_weight(buf, pos);
+}
+
+/**
+ * bitmap_remap - Apply map defined by a pair of bitmaps to another bitmap
+ *	@dst: remapped result
+ *	@src: subset to be remapped
+ *	@old: defines domain of map
+ *	@new: defines range of map
+ *	@nbits: number of bits in each of these bitmaps
+ *
+ * Let @old and @new define a mapping of bit positions, such that
+ * whatever position is held by the n-th set bit in @old is mapped
+ * to the n-th set bit in @new.  In the more general case, allowing
+ * for the possibility that the weight 'w' of @new is less than the
+ * weight of @old, map the position of the n-th set bit in @old to
+ * the position of the m-th set bit in @new, where m == n % w.
+ *
+ * If either of the @old and @new bitmaps are empty, or if @src and
+ * @dst point to the same location, then this routine copies @src
+ * to @dst.
+ *
+ * The positions of unset bits in @old are mapped to themselves
+ * (the identify map).
+ *
+ * Apply the above specified mapping to @src, placing the result in
+ * @dst, clearing any bits previously set in @dst.
+ *
+ * For example, lets say that @old has bits 4 through 7 set, and
+ * @new has bits 12 through 15 set.  This defines the mapping of bit
+ * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
+ * bit positions unchanged.  So if say @src comes into this routine
+ * with bits 1, 5 and 7 set, then @dst should leave with bits 1,
+ * 13 and 15 set.
+ */
+void bitmap_remap(unsigned long *dst, const unsigned long *src,
+		const unsigned long *old, const unsigned long *new,
+		unsigned int nbits)
+{
+	unsigned int oldbit, w;
+
+	if (dst == src)		/* following doesn't handle inplace remaps */
+		return;
+	bitmap_zero(dst, nbits);
+
+	w = bitmap_weight(new, nbits);
+	for_each_set_bit(oldbit, src, nbits) {
+		int n = bitmap_pos_to_ord(old, oldbit, nbits);
+
+		if (n < 0 || w == 0)
+			set_bit(oldbit, dst);	/* identity map */
+		else
+			set_bit(find_nth_bit(new, nbits, n % w), dst);
+	}
+}
+EXPORT_SYMBOL(bitmap_remap);
+
+/**
+ * bitmap_bitremap - Apply map defined by a pair of bitmaps to a single bit
+ *	@oldbit: bit position to be mapped
+ *	@old: defines domain of map
+ *	@new: defines range of map
+ *	@bits: number of bits in each of these bitmaps
+ *
+ * Let @old and @new define a mapping of bit positions, such that
+ * whatever position is held by the n-th set bit in @old is mapped
+ * to the n-th set bit in @new.  In the more general case, allowing
+ * for the possibility that the weight 'w' of @new is less than the
+ * weight of @old, map the position of the n-th set bit in @old to
+ * the position of the m-th set bit in @new, where m == n % w.
+ *
+ * The positions of unset bits in @old are mapped to themselves
+ * (the identify map).
+ *
+ * Apply the above specified mapping to bit position @oldbit, returning
+ * the new bit position.
+ *
+ * For example, lets say that @old has bits 4 through 7 set, and
+ * @new has bits 12 through 15 set.  This defines the mapping of bit
+ * position 4 to 12, 5 to 13, 6 to 14 and 7 to 15, and of all other
+ * bit positions unchanged.  So if say @oldbit is 5, then this routine
+ * returns 13.
+ */
+int bitmap_bitremap(int oldbit, const unsigned long *old,
+				const unsigned long *new, int bits)
+{
+	int w = bitmap_weight(new, bits);
+	int n = bitmap_pos_to_ord(old, oldbit, bits);
+	if (n < 0 || w == 0)
+		return oldbit;
+	else
+		return find_nth_bit(new, bits, n % w);
+}
+EXPORT_SYMBOL(bitmap_bitremap);
+
+#ifdef CONFIG_NUMA
+/**
+ * bitmap_onto - translate one bitmap relative to another
+ *	@dst: resulting translated bitmap
+ * 	@orig: original untranslated bitmap
+ * 	@relmap: bitmap relative to which translated
+ *	@bits: number of bits in each of these bitmaps
+ *
+ * Set the n-th bit of @dst iff there exists some m such that the
+ * n-th bit of @relmap is set, the m-th bit of @orig is set, and
+ * the n-th bit of @relmap is also the m-th _set_ bit of @relmap.
+ * (If you understood the previous sentence the first time your
+ * read it, you're overqualified for your current job.)
+ *
+ * In other words, @orig is mapped onto (surjectively) @dst,
+ * using the map { <n, m> | the n-th bit of @relmap is the
+ * m-th set bit of @relmap }.
+ *
+ * Any set bits in @orig above bit number W, where W is the
+ * weight of (number of set bits in) @relmap are mapped nowhere.
+ * In particular, if for all bits m set in @orig, m >= W, then
+ * @dst will end up empty.  In situations where the possibility
+ * of such an empty result is not desired, one way to avoid it is
+ * to use the bitmap_fold() operator, below, to first fold the
+ * @orig bitmap over itself so that all its set bits x are in the
+ * range 0 <= x < W.  The bitmap_fold() operator does this by
+ * setting the bit (m % W) in @dst, for each bit (m) set in @orig.
+ *
+ * Example [1] for bitmap_onto():
+ *  Let's say @relmap has bits 30-39 set, and @orig has bits
+ *  1, 3, 5, 7, 9 and 11 set.  Then on return from this routine,
+ *  @dst will have bits 31, 33, 35, 37 and 39 set.
+ *
+ *  When bit 0 is set in @orig, it means turn on the bit in
+ *  @dst corresponding to whatever is the first bit (if any)
+ *  that is turned on in @relmap.  Since bit 0 was off in the
+ *  above example, we leave off that bit (bit 30) in @dst.
+ *
+ *  When bit 1 is set in @orig (as in the above example), it
+ *  means turn on the bit in @dst corresponding to whatever
+ *  is the second bit that is turned on in @relmap.  The second
+ *  bit in @relmap that was turned on in the above example was
+ *  bit 31, so we turned on bit 31 in @dst.
+ *
+ *  Similarly, we turned on bits 33, 35, 37 and 39 in @dst,
+ *  because they were the 4th, 6th, 8th and 10th set bits
+ *  set in @relmap, and the 4th, 6th, 8th and 10th bits of
+ *  @orig (i.e. bits 3, 5, 7 and 9) were also set.
+ *
+ *  When bit 11 is set in @orig, it means turn on the bit in
+ *  @dst corresponding to whatever is the twelfth bit that is
+ *  turned on in @relmap.  In the above example, there were
+ *  only ten bits turned on in @relmap (30..39), so that bit
+ *  11 was set in @orig had no affect on @dst.
+ *
+ * Example [2] for bitmap_fold() + bitmap_onto():
+ *  Let's say @relmap has these ten bits set::
+ *
+ *		40 41 42 43 45 48 53 61 74 95
+ *
+ *  (for the curious, that's 40 plus the first ten terms of the
+ *  Fibonacci sequence.)
+ *
+ *  Further lets say we use the following code, invoking
+ *  bitmap_fold() then bitmap_onto, as suggested above to
+ *  avoid the possibility of an empty @dst result::
+ *
+ *	unsigned long *tmp;	// a temporary bitmap's bits
+ *
+ *	bitmap_fold(tmp, orig, bitmap_weight(relmap, bits), bits);
+ *	bitmap_onto(dst, tmp, relmap, bits);
+ *
+ *  Then this table shows what various values of @dst would be, for
+ *  various @orig's.  I list the zero-based positions of each set bit.
+ *  The tmp column shows the intermediate result, as computed by
+ *  using bitmap_fold() to fold the @orig bitmap modulo ten
+ *  (the weight of @relmap):
+ *
+ *      =============== ============== =================
+ *      @orig           tmp            @dst
+ *      0                0             40
+ *      1                1             41
+ *      9                9             95
+ *      10               0             40 [#f1]_
+ *      1 3 5 7          1 3 5 7       41 43 48 61
+ *      0 1 2 3 4        0 1 2 3 4     40 41 42 43 45
+ *      0 9 18 27        0 9 8 7       40 61 74 95
+ *      0 10 20 30       0             40
+ *      0 11 22 33       0 1 2 3       40 41 42 43
+ *      0 12 24 36       0 2 4 6       40 42 45 53
+ *      78 102 211       1 2 8         41 42 74 [#f1]_
+ *      =============== ============== =================
+ *
+ * .. [#f1]
+ *
+ *     For these marked lines, if we hadn't first done bitmap_fold()
+ *     into tmp, then the @dst result would have been empty.
+ *
+ * If either of @orig or @relmap is empty (no set bits), then @dst
+ * will be returned empty.
+ *
+ * If (as explained above) the only set bits in @orig are in positions
+ * m where m >= W, (where W is the weight of @relmap) then @dst will
+ * once again be returned empty.
+ *
+ * All bits in @dst not set by the above rule are cleared.
+ */
+void bitmap_onto(unsigned long *dst, const unsigned long *orig,
+			const unsigned long *relmap, unsigned int bits)
+{
+	unsigned int n, m;	/* same meaning as in above comment */
+
+	if (dst == orig)	/* following doesn't handle inplace mappings */
+		return;
+	bitmap_zero(dst, bits);
+
+	/*
+	 * The following code is a more efficient, but less
+	 * obvious, equivalent to the loop:
+	 *	for (m = 0; m < bitmap_weight(relmap, bits); m++) {
+	 *		n = find_nth_bit(orig, bits, m);
+	 *		if (test_bit(m, orig))
+	 *			set_bit(n, dst);
+	 *	}
+	 */
+
+	m = 0;
+	for_each_set_bit(n, relmap, bits) {
+		/* m == bitmap_pos_to_ord(relmap, n, bits) */
+		if (test_bit(m, orig))
+			set_bit(n, dst);
+		m++;
+	}
+}
+
+/**
+ * bitmap_fold - fold larger bitmap into smaller, modulo specified size
+ *	@dst: resulting smaller bitmap
+ *	@orig: original larger bitmap
+ *	@sz: specified size
+ *	@nbits: number of bits in each of these bitmaps
+ *
+ * For each bit oldbit in @orig, set bit oldbit mod @sz in @dst.
+ * Clear all other bits in @dst.  See further the comment and
+ * Example [2] for bitmap_onto() for why and how to use this.
+ */
+void bitmap_fold(unsigned long *dst, const unsigned long *orig,
+			unsigned int sz, unsigned int nbits)
+{
+	unsigned int oldbit;
+
+	if (dst == orig)	/* following doesn't handle inplace mappings */
+		return;
+	bitmap_zero(dst, nbits);
+
+	for_each_set_bit(oldbit, orig, nbits)
+		set_bit(oldbit % sz, dst);
+}
+#endif /* CONFIG_NUMA */
+
+/*
+ * Common code for bitmap_*_region() routines.
+ *	bitmap: array of unsigned longs corresponding to the bitmap
+ *	pos: the beginning of the region
+ *	order: region size (log base 2 of number of bits)
+ *	reg_op: operation(s) to perform on that region of bitmap
+ *
+ * Can set, verify and/or release a region of bits in a bitmap,
+ * depending on which combination of REG_OP_* flag bits is set.
+ *
+ * A region of a bitmap is a sequence of bits in the bitmap, of
+ * some size '1 << order' (a power of two), aligned to that same
+ * '1 << order' power of two.
+ *
+ * Returns 1 if REG_OP_ISFREE succeeds (region is all zero bits).
+ * Returns 0 in all other cases and reg_ops.
+ */
+
+enum {
+	REG_OP_ISFREE,		/* true if region is all zero bits */
+	REG_OP_ALLOC,		/* set all bits in region */
+	REG_OP_RELEASE,		/* clear all bits in region */
+};
+
+static int __reg_op(unsigned long *bitmap, unsigned int pos, int order, int reg_op)
+{
+	int nbits_reg;		/* number of bits in region */
+	int index;		/* index first long of region in bitmap */
+	int offset;		/* bit offset region in bitmap[index] */
+	int nlongs_reg;		/* num longs spanned by region in bitmap */
+	int nbitsinlong;	/* num bits of region in each spanned long */
+	unsigned long mask;	/* bitmask for one long of region */
+	int i;			/* scans bitmap by longs */
+	int ret = 0;		/* return value */
+
+	/*
+	 * Either nlongs_reg == 1 (for small orders that fit in one long)
+	 * or (offset == 0 && mask == ~0UL) (for larger multiword orders.)
+	 */
+	nbits_reg = 1 << order;
+	index = pos / BITS_PER_LONG;
+	offset = pos - (index * BITS_PER_LONG);
+	nlongs_reg = BITS_TO_LONGS(nbits_reg);
+	nbitsinlong = min(nbits_reg,  BITS_PER_LONG);
+
+	/*
+	 * Can't do "mask = (1UL << nbitsinlong) - 1", as that
+	 * overflows if nbitsinlong == BITS_PER_LONG.
+	 */
+	mask = (1UL << (nbitsinlong - 1));
+	mask += mask - 1;
+	mask <<= offset;
+
+	switch (reg_op) {
+	case REG_OP_ISFREE:
+		for (i = 0; i < nlongs_reg; i++) {
+			if (bitmap[index + i] & mask)
+				goto done;
+		}
+		ret = 1;	/* all bits in region free (zero) */
+		break;
+
+	case REG_OP_ALLOC:
+		for (i = 0; i < nlongs_reg; i++)
+			bitmap[index + i] |= mask;
+		break;
+
+	case REG_OP_RELEASE:
+		for (i = 0; i < nlongs_reg; i++)
+			bitmap[index + i] &= ~mask;
+		break;
+	}
+done:
+	return ret;
+}
+
+/**
+ * bitmap_find_free_region - find a contiguous aligned mem region
+ *	@bitmap: array of unsigned longs corresponding to the bitmap
+ *	@bits: number of bits in the bitmap
+ *	@order: region size (log base 2 of number of bits) to find
+ *
+ * Find a region of free (zero) bits in a @bitmap of @bits bits and
+ * allocate them (set them to one).  Only consider regions of length
+ * a power (@order) of two, aligned to that power of two, which
+ * makes the search algorithm much faster.
+ *
+ * Return the bit offset in bitmap of the allocated region,
+ * or -errno on failure.
+ */
+int bitmap_find_free_region(unsigned long *bitmap, unsigned int bits, int order)
+{
+	unsigned int pos, end;		/* scans bitmap by regions of size order */
+
+	for (pos = 0 ; (end = pos + (1U << order)) <= bits; pos = end) {
+		if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
+			continue;
+		__reg_op(bitmap, pos, order, REG_OP_ALLOC);
+		return pos;
+	}
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(bitmap_find_free_region);
+
+/**
+ * bitmap_release_region - release allocated bitmap region
+ *	@bitmap: array of unsigned longs corresponding to the bitmap
+ *	@pos: beginning of bit region to release
+ *	@order: region size (log base 2 of number of bits) to release
+ *
+ * This is the complement to __bitmap_find_free_region() and releases
+ * the found region (by clearing it in the bitmap).
+ *
+ * No return value.
+ */
+void bitmap_release_region(unsigned long *bitmap, unsigned int pos, int order)
+{
+	__reg_op(bitmap, pos, order, REG_OP_RELEASE);
+}
+EXPORT_SYMBOL(bitmap_release_region);
+
+/**
+ * bitmap_allocate_region - allocate bitmap region
+ *	@bitmap: array of unsigned longs corresponding to the bitmap
+ *	@pos: beginning of bit region to allocate
+ *	@order: region size (log base 2 of number of bits) to allocate
+ *
+ * Allocate (set bits in) a specified region of a bitmap.
+ *
+ * Return 0 on success, or %-EBUSY if specified region wasn't
+ * free (not all bits were zero).
+ */
+int bitmap_allocate_region(unsigned long *bitmap, unsigned int pos, int order)
+{
+	if (!__reg_op(bitmap, pos, order, REG_OP_ISFREE))
+		return -EBUSY;
+	return __reg_op(bitmap, pos, order, REG_OP_ALLOC);
+}
+EXPORT_SYMBOL(bitmap_allocate_region);
+
+/**
+ * bitmap_copy_le - copy a bitmap, putting the bits into little-endian order.
+ * @dst:   destination buffer
+ * @src:   bitmap to copy
+ * @nbits: number of bits in the bitmap
+ *
+ * Require nbits % BITS_PER_LONG == 0.
+ */
+#ifdef __BIG_ENDIAN
+void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int nbits)
+{
+	unsigned int i;
+
+	for (i = 0; i < nbits/BITS_PER_LONG; i++) {
+		if (BITS_PER_LONG == 64)
+			dst[i] = cpu_to_le64(src[i]);
+		else
+			dst[i] = cpu_to_le32(src[i]);
+	}
+}
+EXPORT_SYMBOL(bitmap_copy_le);
+#endif
+
+unsigned long *bitmap_alloc(unsigned int nbits, gfp_t flags)
+{
+	return kmalloc_array(BITS_TO_LONGS(nbits), sizeof(unsigned long),
+			     flags);
+}
+EXPORT_SYMBOL(bitmap_alloc);
+
+unsigned long *bitmap_zalloc(unsigned int nbits, gfp_t flags)
+{
+	return bitmap_alloc(nbits, flags | __GFP_ZERO);
+}
+EXPORT_SYMBOL(bitmap_zalloc);
+
+unsigned long *bitmap_alloc_node(unsigned int nbits, gfp_t flags, int node)
+{
+	return kmalloc_array_node(BITS_TO_LONGS(nbits), sizeof(unsigned long),
+				  flags, node);
+}
+EXPORT_SYMBOL(bitmap_alloc_node);
+
+unsigned long *bitmap_zalloc_node(unsigned int nbits, gfp_t flags, int node)
+{
+	return bitmap_alloc_node(nbits, flags | __GFP_ZERO, node);
+}
+EXPORT_SYMBOL(bitmap_zalloc_node);
+
+void bitmap_free(const unsigned long *bitmap)
+{
+	kfree(bitmap);
+}
+EXPORT_SYMBOL(bitmap_free);
+
+static void devm_bitmap_free(void *data)
+{
+	unsigned long *bitmap = data;
+
+	bitmap_free(bitmap);
+}
+
+unsigned long *devm_bitmap_alloc(struct device *dev,
+				 unsigned int nbits, gfp_t flags)
+{
+	unsigned long *bitmap;
+	int ret;
+
+	bitmap = bitmap_alloc(nbits, flags);
+	if (!bitmap)
+		return NULL;
+
+	ret = devm_add_action_or_reset(dev, devm_bitmap_free, bitmap);
+	if (ret)
+		return NULL;
+
+	return bitmap;
+}
+EXPORT_SYMBOL_GPL(devm_bitmap_alloc);
+
+unsigned long *devm_bitmap_zalloc(struct device *dev,
+				  unsigned int nbits, gfp_t flags)
+{
+	return devm_bitmap_alloc(dev, nbits, flags | __GFP_ZERO);
+}
+EXPORT_SYMBOL_GPL(devm_bitmap_zalloc);
+
+#if BITS_PER_LONG == 64
+/**
+ * bitmap_from_arr32 - copy the contents of u32 array of bits to bitmap
+ *	@bitmap: array of unsigned longs, the destination bitmap
+ *	@buf: array of u32 (in host byte order), the source bitmap
+ *	@nbits: number of bits in @bitmap
+ */
+void bitmap_from_arr32(unsigned long *bitmap, const u32 *buf, unsigned int nbits)
+{
+	unsigned int i, halfwords;
+
+	halfwords = DIV_ROUND_UP(nbits, 32);
+	for (i = 0; i < halfwords; i++) {
+		bitmap[i/2] = (unsigned long) buf[i];
+		if (++i < halfwords)
+			bitmap[i/2] |= ((unsigned long) buf[i]) << 32;
+	}
+
+	/* Clear tail bits in last word beyond nbits. */
+	if (nbits % BITS_PER_LONG)
+		bitmap[(halfwords - 1) / 2] &= BITMAP_LAST_WORD_MASK(nbits);
+}
+EXPORT_SYMBOL(bitmap_from_arr32);
+
+/**
+ * bitmap_to_arr32 - copy the contents of bitmap to a u32 array of bits
+ *	@buf: array of u32 (in host byte order), the dest bitmap
+ *	@bitmap: array of unsigned longs, the source bitmap
+ *	@nbits: number of bits in @bitmap
+ */
+void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits)
+{
+	unsigned int i, halfwords;
+
+	halfwords = DIV_ROUND_UP(nbits, 32);
+	for (i = 0; i < halfwords; i++) {
+		buf[i] = (u32) (bitmap[i/2] & UINT_MAX);
+		if (++i < halfwords)
+			buf[i] = (u32) (bitmap[i/2] >> 32);
+	}
+
+	/* Clear tail bits in last element of array beyond nbits. */
+	if (nbits % BITS_PER_LONG)
+		buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31));
+}
+EXPORT_SYMBOL(bitmap_to_arr32);
+#endif
+
+#if BITS_PER_LONG == 32
+/**
+ * bitmap_from_arr64 - copy the contents of u64 array of bits to bitmap
+ *	@bitmap: array of unsigned longs, the destination bitmap
+ *	@buf: array of u64 (in host byte order), the source bitmap
+ *	@nbits: number of bits in @bitmap
+ */
+void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits)
+{
+	int n;
+
+	for (n = nbits; n > 0; n -= 64) {
+		u64 val = *buf++;
+
+		*bitmap++ = val;
+		if (n > 32)
+			*bitmap++ = val >> 32;
+	}
+
+	/*
+	 * Clear tail bits in the last word beyond nbits.
+	 *
+	 * Negative index is OK because here we point to the word next
+	 * to the last word of the bitmap, except for nbits == 0, which
+	 * is tested implicitly.
+	 */
+	if (nbits % BITS_PER_LONG)
+		bitmap[-1] &= BITMAP_LAST_WORD_MASK(nbits);
+}
+EXPORT_SYMBOL(bitmap_from_arr64);
+
+/**
+ * bitmap_to_arr64 - copy the contents of bitmap to a u64 array of bits
+ *	@buf: array of u64 (in host byte order), the dest bitmap
+ *	@bitmap: array of unsigned longs, the source bitmap
+ *	@nbits: number of bits in @bitmap
+ */
+void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits)
+{
+	const unsigned long *end = bitmap + BITS_TO_LONGS(nbits);
+
+	while (bitmap < end) {
+		*buf = *bitmap++;
+		if (bitmap < end)
+			*buf |= (u64)(*bitmap++) << 32;
+		buf++;
+	}
+
+	/* Clear tail bits in the last element of array beyond nbits. */
+	if (nbits % 64)
+		buf[-1] &= GENMASK_ULL((nbits - 1) % 64, 0);
+}
+EXPORT_SYMBOL(bitmap_to_arr64);
+#endif