Nack this.
Dean, you changed the list_for_each to list_for_each_safe where it was
not needed. I think you only needed to change that in the remove path.
IIRC, list_for_each_safe is intended for walking a list where you unlink
the entry as part of your operation. Keep it for the gen_pool_destroy
function since you are using kfree on those objects and somebody else
could reuse them (sort of a list delete), but do not change them for
the other case. The list_for_each does an explicit prefetch which will
improve performance in many cases.
Thanks,
Robin
On Thu, Sep 28, 2006 at 08:16:14AM -0500, Dean Nelson wrote:
> Modules using the genpool allocator need to be able to kfree() the memory
> used for the genpool data structures when unloading.
>
> Signed-off-by: Steve Wise <[email protected]>
> Signed-off-by: Dean Nelson <[email protected]>
>
> ---
>
> Hi Linus,
>
> Would you please accept this patch against the genpool allocator?
>
> There is still an issue with the block comments not being up to
> kernel-doc standards that plagues the entire file, which I will
> remedy in a followup patch.
>
> Thanks,
> Dean
>
> include/linux/genalloc.h | 1 +
> lib/genalloc.c | 37 +++++++++++++++++++++++++++++++++----
> 2 files changed, 34 insertions(+), 4 deletions(-)
>
>
> Index: linux-2.6/lib/genalloc.c
> ===================================================================
> --- linux-2.6.orig/lib/genalloc.c 2006-09-27 13:42:35.000000000 -0500
> +++ linux-2.6/lib/genalloc.c 2006-09-28 07:49:05.948568928 -0500
> @@ -71,6 +71,35 @@
>
>
> /*
> + * Destroy a memory pool. Verifies that there are no outstanding allocations.
> + *
> + * @pool: pool to destroy
> + */
> +void gen_pool_destroy(struct gen_pool *pool)
> +{
> + struct list_head *_chunk, *_next_chunk;
> + struct gen_pool_chunk *chunk;
> + int order = pool->min_alloc_order;
> + int bit, end_bit;
> +
> +
> + write_lock(&pool->lock);
> + list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
> + chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
> +
> + end_bit = (chunk->end_addr - chunk->start_addr) >> order;
> + bit = find_next_bit(chunk->bits, end_bit, 0);
> + BUG_ON(bit < end_bit);
> +
> + kfree(chunk);
> + }
> + kfree(pool);
> + return;
> +}
> +EXPORT_SYMBOL(gen_pool_destroy);
> +
> +
> +/*
> * Allocate the requested number of bytes from the specified pool.
> * Uses a first-fit algorithm.
> *
> @@ -79,7 +108,7 @@
> */
> unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
> {
> - struct list_head *_chunk;
> + struct list_head *_chunk, *_next_chunk;
> struct gen_pool_chunk *chunk;
> unsigned long addr, flags;
> int order = pool->min_alloc_order;
> @@ -91,7 +120,7 @@
> nbits = (size + (1UL << order) - 1) >> order;
>
> read_lock(&pool->lock);
> - list_for_each(_chunk, &pool->chunks) {
> + list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
> chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
>
> end_bit = (chunk->end_addr - chunk->start_addr) >> order;
> @@ -137,7 +166,7 @@
> */
> void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
> {
> - struct list_head *_chunk;
> + struct list_head *_chunk, *_next_chunk;
> struct gen_pool_chunk *chunk;
> unsigned long flags;
> int order = pool->min_alloc_order;
> @@ -146,7 +175,7 @@
> nbits = (size + (1UL << order) - 1) >> order;
>
> read_lock(&pool->lock);
> - list_for_each(_chunk, &pool->chunks) {
> + list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
> chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
>
> if (addr >= chunk->start_addr && addr < chunk->end_addr) {
> Index: linux-2.6/include/linux/genalloc.h
> ===================================================================
> --- linux-2.6.orig/include/linux/genalloc.h 2006-09-27 13:42:34.000000000 -0500
> +++ linux-2.6/include/linux/genalloc.h 2006-09-27 14:18:31.807816652 -0500
> @@ -31,5 +31,6 @@
>
> extern struct gen_pool *gen_pool_create(int, int);
> extern int gen_pool_add(struct gen_pool *, unsigned long, size_t, int);
> +extern void gen_pool_destroy(struct gen_pool *);
> extern unsigned long gen_pool_alloc(struct gen_pool *, size_t);
> extern void gen_pool_free(struct gen_pool *, unsigned long, size_t);
> -
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