[PATCH v3] lib/bitmap: Make count and length parameters unsigned
From: Paul Menzel
Date: Thu Jul 14 2022 - 12:45:16 EST
Counts and the length are non-negative, so make them unsigned, and adapt the
while condition in `__bitmap_set()` and `__bitmap_clear()` accordingly.
For `__bitmap_set()` six less intstructions are used as a result:
```
__bitmap_set: __bitmap_set:
movl %esi, %eax movl %esi, %eax
movq %rdi, %r8 <
movl %esi, %ecx movl %esi, %ecx
movl %edx, %edi | movl %esi, %r8d
> movl $64, %esi
> andl $63, %ecx
shrl $6, %eax shrl $6, %eax
andl $63, %esi | movl %edx, %r9d
movq $-1, %rdx | leaq (%rdi,%rax,8), %rax
leaq (%r8,%rax,8), %rax | subl %ecx, %esi
leal -64(%rsi,%rdi), %r8d | movq $-1, %rdi
salq %cl, %rdx | salq %cl, %rdi
testl %r8d, %r8d | cmpl %edx, %esi
js .L88 | ja .L85
movl %r8d, %r9d <
shrl $6, %r9d <
leal 1(%r9), %esi <
leaq (%rax,%rsi,8), %rsi <
.L86: .L86:
orq %rdx, (%rax) | subl %esi, %edx
> orq %rdi, (%rax)
> movl $64, %esi
addq $8, %rax addq $8, %rax
movq $-1, %rdx | movq $-1, %rdi
cmpq %rsi, %rax | cmpl $63, %edx
jne .L86 | ja .L86
sall $6, %r9d <
subl %r9d, %r8d <
.L85: .L85:
testl %r8d, %r8d | testl %edx, %edx
je .L84 je .L84
addl %edi, %ecx | leal (%r8,%r9), %ecx
movq $-1, %rax | movq $-1, %rdx
negl %ecx negl %ecx
shrq %cl, %rax | shrq %cl, %rdx
andq %rax, %rdx | andq %rdx, %rdi
orq %rdx, (%rsi) | orq %rdi, (%rax)
.L84: .L84:
ret ret
.L88: <
movq %rax, %rsi <
movl %edi, %r8d <
jmp .L85 <
.size __bitmap_set, .-__bitmap_set .size __bitmap_set, .-__bitmap_set
.p2align 4 .p2align 4
.globl __bitmap_clear .globl __bitmap_clear
.type __bitmap_clear, @function .type __bitmap_clear, @function
```
$ diff lib/bitmap.1.S lib/bitmap.2.S | diffstat
unknown | 55 ++++++++++++++++++++++++-------------------------------
1 file changed, 24 insertions(+), 31 deletions(-)
Signed-off-by: Paul Menzel <pmenzel@xxxxxxxxxxxxx>
---
v2: Update signature in header file
v3: Adapt more functions to use unsigned int
include/linux/bitmap.h | 20 ++++++++++----------
lib/bitmap.c | 26 +++++++++++++-------------
2 files changed, 23 insertions(+), 23 deletions(-)
diff --git a/include/linux/bitmap.h b/include/linux/bitmap.h
index 2e6cd5681040..9f1a097cd5d4 100644
--- a/include/linux/bitmap.h
+++ b/include/linux/bitmap.h
@@ -164,8 +164,8 @@ bool __bitmap_intersects(const unsigned long *bitmap1,
bool __bitmap_subset(const unsigned long *bitmap1,
const unsigned long *bitmap2, unsigned int nbits);
int __bitmap_weight(const unsigned long *bitmap, unsigned int nbits);
-void __bitmap_set(unsigned long *map, unsigned int start, int len);
-void __bitmap_clear(unsigned long *map, unsigned int start, int len);
+void __bitmap_set(unsigned long *map, unsigned int start, unsigned int len);
+void __bitmap_clear(unsigned long *map, unsigned int start, unsigned int len);
unsigned long bitmap_find_next_zero_area_off(unsigned long *map,
unsigned long size,
@@ -198,17 +198,17 @@ bitmap_find_next_zero_area(unsigned long *map,
}
int bitmap_parse(const char *buf, unsigned int buflen,
- unsigned long *dst, int nbits);
+ unsigned long *dst, unsigned int nbits);
int bitmap_parse_user(const char __user *ubuf, unsigned int ulen,
- unsigned long *dst, int nbits);
+ unsigned long *dst, unsigned int nbits);
int bitmap_parselist(const char *buf, unsigned long *maskp,
- int nmaskbits);
+ unsigned int nmaskbits);
int bitmap_parselist_user(const char __user *ubuf, unsigned int ulen,
- unsigned long *dst, int nbits);
+ unsigned long *dst, unsigned int nbits);
void bitmap_remap(unsigned long *dst, const unsigned long *src,
const unsigned long *old, const unsigned long *new, unsigned int nbits);
int bitmap_bitremap(int oldbit,
- const unsigned long *old, const unsigned long *new, int bits);
+ const unsigned long *old, const unsigned long *new, unsigned int bits);
void bitmap_onto(unsigned long *dst, const unsigned long *orig,
const unsigned long *relmap, unsigned int bits);
void bitmap_fold(unsigned long *dst, const unsigned long *orig,
@@ -224,13 +224,13 @@ void bitmap_copy_le(unsigned long *dst, const unsigned long *src, unsigned int n
#endif
unsigned int bitmap_ord_to_pos(const unsigned long *bitmap, unsigned int ord, unsigned int nbits);
int bitmap_print_to_pagebuf(bool list, char *buf,
- const unsigned long *maskp, int nmaskbits);
+ const unsigned long *maskp, unsigned int nmaskbits);
extern int bitmap_print_bitmask_to_buf(char *buf, const unsigned long *maskp,
- int nmaskbits, loff_t off, size_t count);
+ unsigned int nmaskbits, loff_t off, size_t count);
extern int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
- int nmaskbits, loff_t off, size_t count);
+ unsigned int nmaskbits, loff_t off, size_t count);
#define BITMAP_FIRST_WORD_MASK(start) (~0UL << ((start) & (BITS_PER_LONG - 1)))
#define BITMAP_LAST_WORD_MASK(nbits) (~0UL >> (-(nbits) & (BITS_PER_LONG - 1)))
diff --git a/lib/bitmap.c b/lib/bitmap.c
index b18e31ea6e66..d529f7dffc48 100644
--- a/lib/bitmap.c
+++ b/lib/bitmap.c
@@ -348,14 +348,14 @@ int __bitmap_weight(const unsigned long *bitmap, unsigned int bits)
}
EXPORT_SYMBOL(__bitmap_weight);
-void __bitmap_set(unsigned long *map, unsigned int start, int len)
+void __bitmap_set(unsigned long *map, unsigned int start, unsigned 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) {
+ while (len >= bits_to_set) {
*p |= mask_to_set;
len -= bits_to_set;
bits_to_set = BITS_PER_LONG;
@@ -369,7 +369,7 @@ void __bitmap_set(unsigned long *map, unsigned int start, int len)
}
EXPORT_SYMBOL(__bitmap_set);
-void __bitmap_clear(unsigned long *map, unsigned int start, int len)
+void __bitmap_clear(unsigned long *map, unsigned int start, unsigned int len)
{
unsigned long *p = map + BIT_WORD(start);
const unsigned int size = start + len;
@@ -445,7 +445,7 @@ EXPORT_SYMBOL(bitmap_find_next_zero_area_off);
*/
int bitmap_parse_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
- int nmaskbits)
+ unsigned int nmaskbits)
{
char *buf;
int ret;
@@ -478,7 +478,7 @@ EXPORT_SYMBOL(bitmap_parse_user);
* actually printed to @buf, excluding terminating '\0'.
*/
int bitmap_print_to_pagebuf(bool list, char *buf, const unsigned long *maskp,
- int nmaskbits)
+ unsigned int nmaskbits)
{
ptrdiff_t len = PAGE_SIZE - offset_in_page(buf);
@@ -499,7 +499,7 @@ EXPORT_SYMBOL(bitmap_print_to_pagebuf);
* @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)
+ unsigned int nmaskbits, loff_t off, size_t count)
{
const char *fmt = list ? "%*pbl\n" : "%*pb\n";
ssize_t size;
@@ -542,7 +542,7 @@ static int bitmap_print_to_buf(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)
+ * unsigned int nmaskbits)
* {
* }
*
@@ -600,7 +600,7 @@ static int bitmap_print_to_buf(bool list, char *buf, const unsigned long *maskp,
* 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)
+ unsigned int nmaskbits, loff_t off, size_t count)
{
return bitmap_print_to_buf(false, buf, maskp, nmaskbits, off, count);
}
@@ -618,7 +618,7 @@ EXPORT_SYMBOL(bitmap_print_bitmask_to_buf);
* the print format.
*/
int bitmap_print_list_to_buf(char *buf, const unsigned long *maskp,
- int nmaskbits, loff_t off, size_t count)
+ unsigned int nmaskbits, loff_t off, size_t count)
{
return bitmap_print_to_buf(true, buf, maskp, nmaskbits, off, count);
}
@@ -793,7 +793,7 @@ static const char *bitmap_parse_region(const char *str, struct region *r)
* - ``-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)
+int bitmap_parselist(const char *buf, unsigned long *maskp, unsigned int nmaskbits)
{
struct region r;
long ret;
@@ -836,7 +836,7 @@ EXPORT_SYMBOL(bitmap_parselist);
*/
int bitmap_parselist_user(const char __user *ubuf,
unsigned int ulen, unsigned long *maskp,
- int nmaskbits)
+ unsigned int nmaskbits)
{
char *buf;
int ret;
@@ -893,7 +893,7 @@ static const char *bitmap_get_x32_reverse(const char *start,
* Leading, embedded and trailing whitespace accepted.
*/
int bitmap_parse(const char *start, unsigned int buflen,
- unsigned long *maskp, int nmaskbits)
+ unsigned long *maskp, unsigned int nmaskbits)
{
const char *end = strnchrnul(start, buflen, '\n') - 1;
int chunks = BITS_TO_U32(nmaskbits);
@@ -1068,7 +1068,7 @@ EXPORT_SYMBOL(bitmap_remap);
* returns 13.
*/
int bitmap_bitremap(int oldbit, const unsigned long *old,
- const unsigned long *new, int bits)
+ const unsigned long *new, unsigned int bits)
{
int w = bitmap_weight(new, bits);
int n = bitmap_pos_to_ord(old, oldbit, bits);
--
2.36.1