diff options
Diffstat (limited to 'lib/bitmap.c')
| -rw-r--r-- | lib/bitmap.c | 117 |
1 files changed, 89 insertions, 28 deletions
diff --git a/lib/bitmap.c b/lib/bitmap.c index 0d5c2ece0bcb..b18e31ea6e66 100644 --- a/lib/bitmap.c +++ b/lib/bitmap.c @@ -45,19 +45,19 @@ * for the best explanations of this ordering. */ -int __bitmap_equal(const unsigned long *bitmap1, - const unsigned long *bitmap2, unsigned int bits) +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 0; + return false; if (bits % BITS_PER_LONG) if ((bitmap1[k] ^ bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) - return 0; + return false; - return 1; + return true; } EXPORT_SYMBOL(__bitmap_equal); @@ -303,33 +303,33 @@ void __bitmap_replace(unsigned long *dst, } EXPORT_SYMBOL(__bitmap_replace); -int __bitmap_intersects(const unsigned long *bitmap1, - const unsigned long *bitmap2, unsigned int bits) +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 1; + return true; if (bits % BITS_PER_LONG) if ((bitmap1[k] & bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) - return 1; - return 0; + return true; + return false; } EXPORT_SYMBOL(__bitmap_intersects); -int __bitmap_subset(const unsigned long *bitmap1, - const unsigned long *bitmap2, unsigned int bits) +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 0; + return false; if (bits % BITS_PER_LONG) if ((bitmap1[k] & ~bitmap2[k]) & BITMAP_LAST_WORD_MASK(bits)) - return 0; - return 1; + return false; + return true; } EXPORT_SYMBOL(__bitmap_subset); @@ -527,33 +527,39 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, * 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, + * 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, + * 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, + * 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. @@ -577,6 +583,7 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp, * 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. @@ -1505,5 +1512,59 @@ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap, unsigned int nbits) buf[halfwords - 1] &= (u32) (UINT_MAX >> ((-nbits) & 31)); } EXPORT_SYMBOL(bitmap_to_arr32); +#endif + +#if (BITS_PER_LONG == 32) && defined(__BIG_ENDIAN) +/** + * 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 % 64, 0); +} +EXPORT_SYMBOL(bitmap_to_arr64); #endif |