cd1b413c5c
ulist_next gets the pointer to the previously returned element to find the next element from there. However, when we call ulist_add while iteration with ulist_next is in progress (ulist explicitly supports this), we can realloc the ulist internal memory, which makes the pointer to the previous element useless. Instead, we now use an iterator parameter that's independent from the internal pointers. Reported-by: Alexander Block <ablock84@googlemail.com> Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
75 lines
1.8 KiB
C
75 lines
1.8 KiB
C
/*
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* Copyright (C) 2011 STRATO AG
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* written by Arne Jansen <sensille@gmx.net>
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* Distributed under the GNU GPL license version 2.
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*
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*/
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#ifndef __ULIST__
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#define __ULIST__
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/*
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* ulist is a generic data structure to hold a collection of unique u64
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* values. The only operations it supports is adding to the list and
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* enumerating it.
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* It is possible to store an auxiliary value along with the key.
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*
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* The implementation is preliminary and can probably be sped up
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* significantly. A first step would be to store the values in an rbtree
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* as soon as ULIST_SIZE is exceeded.
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*/
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/*
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* number of elements statically allocated inside struct ulist
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*/
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#define ULIST_SIZE 16
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struct ulist_iterator {
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int i;
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};
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/*
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* element of the list
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*/
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struct ulist_node {
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u64 val; /* value to store */
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unsigned long aux; /* auxiliary value saved along with the val */
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};
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struct ulist {
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/*
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* number of elements stored in list
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*/
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unsigned long nnodes;
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/*
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* number of nodes we already have room for
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*/
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unsigned long nodes_alloced;
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/*
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* pointer to the array storing the elements. The first ULIST_SIZE
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* elements are stored inline. In this case the it points to int_nodes.
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* After exceeding ULIST_SIZE, dynamic memory is allocated.
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*/
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struct ulist_node *nodes;
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/*
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* inline storage space for the first ULIST_SIZE entries
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*/
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struct ulist_node int_nodes[ULIST_SIZE];
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};
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void ulist_init(struct ulist *ulist);
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void ulist_fini(struct ulist *ulist);
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void ulist_reinit(struct ulist *ulist);
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struct ulist *ulist_alloc(unsigned long gfp_mask);
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void ulist_free(struct ulist *ulist);
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int ulist_add(struct ulist *ulist, u64 val, unsigned long aux,
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unsigned long gfp_mask);
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struct ulist_node *ulist_next(struct ulist *ulist,
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struct ulist_iterator *uiter);
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#define ULIST_ITER_INIT(uiter) ((uiter)->i = 0)
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#endif
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