(I missed Cc'ing linux-numa@xxxxxxxxxxxxxxx on the first send)
Arnd Bergmann and Mijo Safradin called my attention to problems with
libnuma's read_mask() on a big-endian 64-bit machine.
In testing that function I found it to be buggy on little-endian and 32-bit
systems as well.
I propose a function that looks like the below. The patch is farther below.
(Arnd, I did not switch to longs, as that proved problematic. The ascii hex
strings being scanned are 32-bit values.)
I tested on a 64-bit MIPS system. Could you test on your platform?
/*
* Read a mask consisting of a sequence of hexadecimal longs separated by
* commas. Order them correctly and return the number of the last bit
* set.
*/
static int
read_mask(char *s, struct bitmask *bmp)
{
char *end = s;
unsigned int *start = (unsigned int *)bmp->maskp;
unsigned int *p = start;
unsigned int *q;
unsigned int i;
unsigned int n = 0;
i = strtoul(s, &end, 16);
/* Skip leading zeros */
while (!i && *end++ == ',') {
i = strtoul(end, &end, 16);
}
end++; /* past the , */
if (!i)
/* End of string. No mask */
return -1;
start[n++] = i;
/* Read sequence of ints */
do {
i = strtoul(end, &end, 16);
if (i)
start[n++] = i;
} while (*end++ == ',');
n--;
/*
* Invert sequence of ints if necessary since the first int
* is the highest and we put it first because we read it first.
*/
for (q = start + n, p = start; p < q; q--, p++) {
unsigned int x = *q;
*q = *p;
*p = x;
}
/* Poor mans fls() */
for(i = 31; i >= 0; i--)
if (test_bit(i, start + n))
break;
/*
* Return the last bit set
*/
return ((sizeof(unsigned int)*8) * n) + i;
}
Signed-off-by: Cliff Wickman <cpw@xxxxxxx>
---
libnuma.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
Index: numactl-dev/libnuma.c
===================================================================
--- numactl-dev.orig/libnuma.c
+++ numactl-dev/libnuma.c
@@ -371,7 +371,6 @@ static int
read_mask(char *s, struct bitmask *bmp)
{
char *end = s;
- char *prevend;
unsigned int *start = (unsigned int *)bmp->maskp;
unsigned int *p = start;
unsigned int *q;
@@ -380,22 +379,22 @@ read_mask(char *s, struct bitmask *bmp)
i = strtoul(s, &end, 16);
- prevend = end;
/* Skip leading zeros */
while (!i && *end++ == ',') {
- prevend = end;
i = strtoul(end, &end, 16);
}
- end = prevend;
+ end++; /* past the , */
if (!i)
/* End of string. No mask */
return -1;
+ start[n++] = i;
/* Read sequence of ints */
do {
- start[n++] = i;
i = strtoul(end, &end, 16);
+ if (i)
+ start[n++] = i;
} while (*end++ == ',');
n--;
--
To unsubscribe from this list: send the line "unsubscribe linux-numa" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
