Viewing file:  pr18241-1.c (1.98 KB) -rw-r--r--
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/* { dg-do run } */
/* { dg-options "-std=gnu99 -Wall -Wextra -O1" } */
extern void *memset (void*, int, __SIZE_TYPE__);
extern void abort (void);
struct radix_tree_root {
unsigned int height;
struct radix_tree_node *rnode;
};
struct radix_tree_node {
unsigned int count;
void *slots[64];
unsigned long tags[2][2];
};
struct radix_tree_path {
struct radix_tree_node *node, **slot;
int offset;
};
static unsigned long height_to_maxindex[7] =
{0, 63, 4095, 262143, 16777215, 1073741823, 4294967295};
static inline void tag_clear(struct radix_tree_node *node, int tag, int offset)
{
int nr;
volatile unsigned long *addr;
#if(__SIZEOF_INT__ >= 4)
int mask;
#else
long mask;
#endif
nr = offset;
addr = &node->tags[tag][0];
addr += nr >> 5;
mask = 1 << (nr & 0x1f);
*addr &= ~mask;
}
void *radix_tree_tag_clear(struct radix_tree_root *root, unsigned long index, int tag)
{
struct radix_tree_path path[7], *pathp = path;
unsigned int height, shift;
void *ret = 0;
height = root->height;
if (index > height_to_maxindex[height])
goto out;
shift = (height - 1) * 6;
pathp->node = 0;
pathp->slot = &root->rnode;
while (height > 0) {
int offset;
if (*pathp->slot == 0)
goto out;
offset = (index >> shift) & (64-1);
pathp[1].offset = offset;
pathp[1].node = *pathp[0].slot;
pathp[1].slot = (struct radix_tree_node **)
(pathp[1].node->slots + offset);
pathp++;
shift -= 6;
height--;
}
ret = *pathp[0].slot;
if (ret == 0)
goto out;
do {
int idx;
tag_clear(pathp[0].node, tag, pathp[0].offset);
for (idx = 0; idx < 2; idx++) {
if (pathp[0].node->tags[tag][idx])
goto out;
}
pathp--;
} while (pathp[0].node);
out:
return ret;
}
int main ()
{
struct radix_tree_root r;
struct radix_tree_node node;
void *p = (void *) 0xdeadbeef;
r.height = 1;
r.rnode = &node;
memset (&node, 0, sizeof (node));
node.count = 1;
node.slots [13] = p;
radix_tree_tag_clear (&r, 13, 1);
if (r.rnode->slots[13] != p)
abort ();
return 0;
}
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