[v6,2/3] bitmap: import bitmap_{set/clear} from Linux 5.5

Commit Message

Roger Pau Monné Feb. 19, 2020, 10:22 a.m. UTC

Import the functions and it's dependencies. Based on Linux 5.5, commit
id d5226fa6dbae0569ee43ecfc08bdcd6770fc4755.

Signed-off-by: Roger Pau Monné <[e-mail]>
Acked-by: Jan Beulich <[e-mail]>
---
Changes since v4:
 - Introduce BIT_WORD in generic header bitops.h (instead of the x86
   one).
 - Include byteorder.h for __LITTLE_ENDIAN
 - Remove EXPORT_SYMBOL.
---
 xen/common/bitmap.c      | 39 +++++++++++++++++++++++++++++++++++++++
 xen/include/xen/bitmap.h | 40 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

Patch

diff --git a/xen/common/bitmap.c b/xen/common/bitmap.c
index fd070bee97..88768bf8bc 100644
--- a/xen/common/bitmap.c
+++ b/xen/common/bitmap.c
@@ -212,6 +212,45 @@  int __bitmap_weight(const unsigned long *bitmap, int bits)
 #endif
 EXPORT_SYMBOL(__bitmap_weight);
 
+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;
+	}
+}
+
+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;
+	}
+}
 
 /**
  *	bitmap_find_free_region - find a contiguous aligned mem region
diff --git a/xen/include/xen/bitmap.h b/xen/include/xen/bitmap.h
index 4e1e690af1..c44e009f8c 100644
--- a/xen/include/xen/bitmap.h
+++ b/xen/include/xen/bitmap.h
@@ -85,6 +85,8 @@  extern int __bitmap_intersects(const unsigned long *bitmap1,
 extern int __bitmap_subset(const unsigned long *bitmap1,
 			const unsigned long *bitmap2, int bits);
 extern int __bitmap_weight(const unsigned long *bitmap, int bits);
+extern void __bitmap_set(unsigned long *map, unsigned int start, int len);
+extern void __bitmap_clear(unsigned long *map, unsigned int start, int len);
 
 extern int bitmap_find_free_region(unsigned long *bitmap, int bits, int order);
 extern void bitmap_release_region(unsigned long *bitmap, int pos, int order);
@@ -227,6 +229,44 @@  static inline int bitmap_weight(const unsigned long *src, int nbits)
 	return __bitmap_weight(src, nbits);
 }
 
+#include <asm/byteorder.h>
+
+#ifdef __LITTLE_ENDIAN
+#define BITMAP_MEM_ALIGNMENT 8
+#else
+#define BITMAP_MEM_ALIGNMENT (8 * sizeof(unsigned long))
+#endif
+#define BITMAP_MEM_MASK (BITMAP_MEM_ALIGNMENT - 1)
+#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
+
+static inline void bitmap_set(unsigned long *map, unsigned int start,
+		unsigned int nbits)
+{
+	if (__builtin_constant_p(nbits) && nbits == 1)
+		__set_bit(start, map);
+	else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
+		 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
+		 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
+		 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
+		memset((char *)map + start / 8, 0xff, nbits / 8);
+	else
+		__bitmap_set(map, start, nbits);
+}
+
+static inline void bitmap_clear(unsigned long *map, unsigned int start,
+		unsigned int nbits)
+{
+	if (__builtin_constant_p(nbits) && nbits == 1)
+		__clear_bit(start, map);
+	else if (__builtin_constant_p(start & BITMAP_MEM_MASK) &&
+		 IS_ALIGNED(start, BITMAP_MEM_ALIGNMENT) &&
+		 __builtin_constant_p(nbits & BITMAP_MEM_MASK) &&
+		 IS_ALIGNED(nbits, BITMAP_MEM_ALIGNMENT))
+		memset((char *)map + start / 8, 0, nbits / 8);
+	else
+		__bitmap_clear(map, start, nbits);
+}
+
 #undef bitmap_switch
 #undef bitmap_bytes