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[xen master] xen/bitmap: Consistently use unsigned bits values



commit 558e84b7ffec77cc8b1b4cf3256b5febc84f17f9
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Wed Jan 31 17:05:47 2024 +0000
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Thu Feb 1 19:52:44 2024 +0000

    xen/bitmap: Consistently use unsigned bits values
    
    Right now, most of the static inline helpers take an unsigned nbits 
quantity,
    and most of the library functions take a signed quanity.  Because
    BITMAP_LAST_WORD_MASK() is expressed as a divide, the compiler is forced to
    emit two different paths to get the correct semantics for signed division.
    
    Swap all signed bit-counts to being unsigned bit-counts for the simple 
cases.
    This includes the return value of bitmap_weight().
    
    Bloat-o-meter for a random x86 build reports:
      add/remove: 0/0 grow/shrink: 8/19 up/down: 167/-413 (-246)
    
    which all comes from compiler not emitting "dead" logic paths for negative 
bit
    counts.
    
    No functional change.
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/common/bitmap.c      | 24 ++++++++++++------------
 xen/include/xen/bitmap.h | 43 ++++++++++++++++++++++---------------------
 2 files changed, 34 insertions(+), 33 deletions(-)

diff --git a/xen/common/bitmap.c b/xen/common/bitmap.c
index 7d4551f782..c57b35f004 100644
--- a/xen/common/bitmap.c
+++ b/xen/common/bitmap.c
@@ -55,7 +55,7 @@ static void clamp_last_byte(uint8_t *bp, unsigned int nbits)
                bp[nbits/8] &= (1U << remainder) - 1;
 }
 
-int __bitmap_empty(const unsigned long *bitmap, int bits)
+int __bitmap_empty(const unsigned long *bitmap, unsigned int bits)
 {
        int k, lim = bits/BITS_PER_LONG;
        for (k = 0; k < lim; ++k)
@@ -70,7 +70,7 @@ int __bitmap_empty(const unsigned long *bitmap, int bits)
 }
 EXPORT_SYMBOL(__bitmap_empty);
 
-int __bitmap_full(const unsigned long *bitmap, int bits)
+int __bitmap_full(const unsigned long *bitmap, unsigned int bits)
 {
        int k, lim = bits/BITS_PER_LONG;
        for (k = 0; k < lim; ++k)
@@ -86,7 +86,7 @@ int __bitmap_full(const unsigned long *bitmap, int bits)
 EXPORT_SYMBOL(__bitmap_full);
 
 int __bitmap_equal(const unsigned long *bitmap1,
-               const unsigned long *bitmap2, int bits)
+                   const unsigned long *bitmap2, unsigned int bits)
 {
        int k, lim = bits/BITS_PER_LONG;
        for (k = 0; k < lim; ++k)
@@ -101,7 +101,7 @@ int __bitmap_equal(const unsigned long *bitmap1,
 }
 EXPORT_SYMBOL(__bitmap_equal);
 
-void __bitmap_complement(unsigned long *dst, const unsigned long *src, int 
bits)
+void __bitmap_complement(unsigned long *dst, const unsigned long *src, 
unsigned int bits)
 {
        int k, lim = bits/BITS_PER_LONG;
        for (k = 0; k < lim; ++k)
@@ -113,7 +113,7 @@ void __bitmap_complement(unsigned long *dst, const unsigned 
long *src, int bits)
 EXPORT_SYMBOL(__bitmap_complement);
 
 void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
-                               const unsigned long *bitmap2, int bits)
+                  const unsigned long *bitmap2, unsigned int bits)
 {
        int k;
        int nr = BITS_TO_LONGS(bits);
@@ -124,7 +124,7 @@ void __bitmap_and(unsigned long *dst, const unsigned long 
*bitmap1,
 EXPORT_SYMBOL(__bitmap_and);
 
 void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
-                               const unsigned long *bitmap2, int bits)
+                 const unsigned long *bitmap2, unsigned int bits)
 {
        int k;
        int nr = BITS_TO_LONGS(bits);
@@ -135,7 +135,7 @@ void __bitmap_or(unsigned long *dst, const unsigned long 
*bitmap1,
 EXPORT_SYMBOL(__bitmap_or);
 
 void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
-                               const unsigned long *bitmap2, int bits)
+                  const unsigned long *bitmap2, unsigned int bits)
 {
        int k;
        int nr = BITS_TO_LONGS(bits);
@@ -146,7 +146,7 @@ void __bitmap_xor(unsigned long *dst, const unsigned long 
*bitmap1,
 EXPORT_SYMBOL(__bitmap_xor);
 
 void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
-                               const unsigned long *bitmap2, int bits)
+                     const unsigned long *bitmap2, unsigned int bits)
 {
        int k;
        int nr = BITS_TO_LONGS(bits);
@@ -157,7 +157,7 @@ void __bitmap_andnot(unsigned long *dst, const unsigned 
long *bitmap1,
 EXPORT_SYMBOL(__bitmap_andnot);
 
 int __bitmap_intersects(const unsigned long *bitmap1,
-                               const unsigned long *bitmap2, int bits)
+                        const unsigned long *bitmap2, unsigned int bits)
 {
        int k, lim = bits/BITS_PER_LONG;
        for (k = 0; k < lim; ++k)
@@ -172,7 +172,7 @@ int __bitmap_intersects(const unsigned long *bitmap1,
 EXPORT_SYMBOL(__bitmap_intersects);
 
 int __bitmap_subset(const unsigned long *bitmap1,
-                               const unsigned long *bitmap2, int bits)
+                    const unsigned long *bitmap2, unsigned int bits)
 {
        int k, lim = bits/BITS_PER_LONG;
        for (k = 0; k < lim; ++k)
@@ -187,7 +187,7 @@ int __bitmap_subset(const unsigned long *bitmap1,
 EXPORT_SYMBOL(__bitmap_subset);
 
 #if BITS_PER_LONG == 32
-int __bitmap_weight(const unsigned long *bitmap, int bits)
+unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
 {
        int k, w = 0, lim = bits/BITS_PER_LONG;
 
@@ -200,7 +200,7 @@ int __bitmap_weight(const unsigned long *bitmap, int bits)
        return w;
 }
 #else
-int __bitmap_weight(const unsigned long *bitmap, int bits)
+unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
 {
        int k, w = 0, lim = bits/BITS_PER_LONG;
 
diff --git a/xen/include/xen/bitmap.h b/xen/include/xen/bitmap.h
index 657390e32e..b9f980e919 100644
--- a/xen/include/xen/bitmap.h
+++ b/xen/include/xen/bitmap.h
@@ -66,25 +66,25 @@
  * lib/bitmap.c provides these functions:
  */
 
-extern int __bitmap_empty(const unsigned long *bitmap, int bits);
-extern int __bitmap_full(const unsigned long *bitmap, int bits);
-extern int __bitmap_equal(const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern void __bitmap_complement(unsigned long *dst, const unsigned long *src,
-                       int bits);
-extern void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern int __bitmap_intersects(const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern int __bitmap_subset(const unsigned long *bitmap1,
-                       const unsigned long *bitmap2, int bits);
-extern int __bitmap_weight(const unsigned long *bitmap, int bits);
+int __bitmap_empty(const unsigned long *bitmap, unsigned int bits);
+int __bitmap_full(const unsigned long *bitmap, unsigned int bits);
+int __bitmap_equal(const unsigned long *bitmap1,
+                   const unsigned long *bitmap2, unsigned int bits);
+void __bitmap_complement(unsigned long *dst, const unsigned long *src,
+                         unsigned int bits);
+void __bitmap_and(unsigned long *dst, const unsigned long *bitmap1,
+                  const unsigned long *bitmap2, unsigned int bits);
+void __bitmap_or(unsigned long *dst, const unsigned long *bitmap1,
+                 const unsigned long *bitmap2, unsigned int bits);
+void __bitmap_xor(unsigned long *dst, const unsigned long *bitmap1,
+                  const unsigned long *bitmap2, unsigned int bits);
+void __bitmap_andnot(unsigned long *dst, const unsigned long *bitmap1,
+                     const unsigned long *bitmap2, unsigned int bits);
+int __bitmap_intersects(const unsigned long *bitmap1,
+                        const unsigned long *bitmap2, unsigned int bits);
+int __bitmap_subset(const unsigned long *bitmap1,
+                    const unsigned long *bitmap2, unsigned int bits);
+unsigned int __bitmap_weight(const unsigned long *bitmap, unsigned 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);
 
@@ -117,7 +117,7 @@ static inline void bitmap_zero(unsigned long *dst, unsigned 
int nbits)
                memset(dst, 0, bitmap_bytes(nbits)));
 }
 
-static inline void bitmap_fill(unsigned long *dst, int nbits)
+static inline void bitmap_fill(unsigned long *dst, unsigned int nbits)
 {
        size_t nlongs = BITS_TO_LONGS(nbits);
 
@@ -224,7 +224,8 @@ static inline int bitmap_full(const unsigned long *src, 
unsigned int nbits)
                return __bitmap_full(src, nbits));
 }
 
-static inline int bitmap_weight(const unsigned long *src, int nbits)
+static inline unsigned int bitmap_weight(const unsigned long *src,
+                                         unsigned int nbits)
 {
        return __bitmap_weight(src, nbits);
 }
--
generated by git-patchbot for /home/xen/git/xen.git#master



 


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