+++ /dev/null
-
-#include <linux/atomic.h>
-#include <linux/export.h>
-#include <linux/generic-radix-tree.h>
-#include <linux/gfp.h>
-
-#define GENRADIX_ARY (PAGE_SIZE / sizeof(struct genradix_node *))
-#define GENRADIX_ARY_SHIFT ilog2(GENRADIX_ARY)
-
-struct genradix_node {
- union {
- /* Interior node: */
- struct genradix_node *children[GENRADIX_ARY];
-
- /* Leaf: */
- u8 data[PAGE_SIZE];
- };
-};
-
-static inline int genradix_depth_shift(unsigned depth)
-{
- return PAGE_SHIFT + GENRADIX_ARY_SHIFT * depth;
-}
-
-/*
- * Returns size (of data, in bytes) that a tree of a given depth holds:
- */
-static inline size_t genradix_depth_size(unsigned depth)
-{
- return 1UL << genradix_depth_shift(depth);
-}
-
-/* depth that's needed for a genradix that can address up to ULONG_MAX: */
-#define GENRADIX_MAX_DEPTH \
- DIV_ROUND_UP(BITS_PER_LONG - PAGE_SHIFT, GENRADIX_ARY_SHIFT)
-
-#define GENRADIX_DEPTH_MASK \
- ((unsigned long) (roundup_pow_of_two(GENRADIX_MAX_DEPTH + 1) - 1))
-
-unsigned genradix_root_to_depth(struct genradix_root *r)
-{
- return (unsigned long) r & GENRADIX_DEPTH_MASK;
-}
-
-struct genradix_node *genradix_root_to_node(struct genradix_root *r)
-{
- return (void *) ((unsigned long) r & ~GENRADIX_DEPTH_MASK);
-}
-
-/*
- * Returns pointer to the specified byte @offset within @radix, or NULL if not
- * allocated
- */
-void *__genradix_ptr(struct __genradix *radix, size_t offset)
-{
- struct genradix_root *r = READ_ONCE(radix->root);
- struct genradix_node *n = genradix_root_to_node(r);
- unsigned level = genradix_root_to_depth(r);
-
- if (ilog2(offset) >= genradix_depth_shift(level))
- return NULL;
-
- while (1) {
- if (!n)
- return NULL;
- if (!level)
- break;
-
- level--;
-
- n = n->children[offset >> genradix_depth_shift(level)];
- offset &= genradix_depth_size(level) - 1;
- }
-
- return &n->data[offset];
-}
-EXPORT_SYMBOL(__genradix_ptr);
-
-/*
- * Returns pointer to the specified byte @offset within @radix, allocating it if
- * necessary - newly allocated slots are always zeroed out:
- */
-void *__genradix_ptr_alloc(struct __genradix *radix, size_t offset,
- gfp_t gfp_mask)
-{
- struct genradix_root *v = READ_ONCE(radix->root);
- struct genradix_node *n, *new_node = NULL;
- unsigned level;
-
- /* Increase tree depth if necessary: */
- while (1) {
- struct genradix_root *r = v, *new_root;
-
- n = genradix_root_to_node(r);
- level = genradix_root_to_depth(r);
-
- if (n && ilog2(offset) < genradix_depth_shift(level))
- break;
-
- if (!new_node) {
- new_node = (void *)
- __get_free_page(gfp_mask|__GFP_ZERO);
- if (!new_node)
- return NULL;
- }
-
- new_node->children[0] = n;
- new_root = ((struct genradix_root *)
- ((unsigned long) new_node | (n ? level + 1 : 0)));
-
- if ((v = cmpxchg_release(&radix->root, r, new_root)) == r) {
- v = new_root;
- new_node = NULL;
- }
- }
-
- while (level--) {
- struct genradix_node **p =
- &n->children[offset >> genradix_depth_shift(level)];
- offset &= genradix_depth_size(level) - 1;
-
- n = READ_ONCE(*p);
- if (!n) {
- if (!new_node) {
- new_node = (void *)
- __get_free_page(gfp_mask|__GFP_ZERO);
- if (!new_node)
- return NULL;
- }
-
- if (!(n = cmpxchg_release(p, NULL, new_node)))
- swap(n, new_node);
- }
- }
-
- if (new_node)
- free_page((unsigned long) new_node);
-
- return &n->data[offset];
-}
-EXPORT_SYMBOL(__genradix_ptr_alloc);
-
-void *__genradix_iter_peek(struct genradix_iter *iter,
- struct __genradix *radix,
- size_t objs_per_page)
-{
- struct genradix_root *r;
- struct genradix_node *n;
- unsigned level, i;
-
- if (iter->offset == SIZE_MAX)
- return NULL;
-
-restart:
- r = READ_ONCE(radix->root);
- if (!r)
- return NULL;
-
- n = genradix_root_to_node(r);
- level = genradix_root_to_depth(r);
-
- if (ilog2(iter->offset) >= genradix_depth_shift(level))
- return NULL;
-
- while (level) {
- level--;
-
- i = (iter->offset >> genradix_depth_shift(level)) &
- (GENRADIX_ARY - 1);
-
- while (!n->children[i]) {
- size_t objs_per_ptr = genradix_depth_size(level);
-
- if (iter->offset + objs_per_ptr < iter->offset) {
- iter->offset = SIZE_MAX;
- iter->pos = SIZE_MAX;
- return NULL;
- }
-
- i++;
- iter->offset = round_down(iter->offset + objs_per_ptr,
- objs_per_ptr);
- iter->pos = (iter->offset >> PAGE_SHIFT) *
- objs_per_page;
- if (i == GENRADIX_ARY)
- goto restart;
- }
-
- n = n->children[i];
- }
-
- return &n->data[iter->offset & (PAGE_SIZE - 1)];
-}
-EXPORT_SYMBOL(__genradix_iter_peek);
-
-static void genradix_free_recurse(struct genradix_node *n, unsigned level)
-{
- if (level) {
- unsigned i;
-
- for (i = 0; i < GENRADIX_ARY; i++)
- if (n->children[i])
- genradix_free_recurse(n->children[i], level - 1);
- }
-
- free_page((unsigned long) n);
-}
-
-int __genradix_prealloc(struct __genradix *radix, size_t size,
- gfp_t gfp_mask)
-{
- size_t offset;
-
- for (offset = 0; offset < size; offset += PAGE_SIZE)
- if (!__genradix_ptr_alloc(radix, offset, gfp_mask))
- return -ENOMEM;
-
- return 0;
-}
-EXPORT_SYMBOL(__genradix_prealloc);
-
-void __genradix_free(struct __genradix *radix)
-{
- struct genradix_root *r = xchg(&radix->root, NULL);
-
- genradix_free_recurse(genradix_root_to_node(r),
- genradix_root_to_depth(r));
-}
-EXPORT_SYMBOL(__genradix_free);
projects / bcachefs-tools-debian / blobdiff