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Subject[PATCH] lib/genalloc: Set chunk size to real size which gen_pool managed.
Date
The demand size (chunk->avail > size > round_down(chunk->avail)) will
lead to meaningless algo calls in gen_pool_alloc_algo_owner without the
patch, alse move the follow code:
size = nbits << order
out of read-side critical section.

Signed-off-by: wuchi <wuchi.zero@gmail.com>
---
lib/genalloc.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/lib/genalloc.c b/lib/genalloc.c
index 00fc50d0a640..1b1843613fb8 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -193,6 +193,7 @@ int gen_pool_add_owner(struct gen_pool *pool, unsigned long virt, phys_addr_t ph
if (unlikely(chunk == NULL))
return -ENOMEM;

+ size = nbits << pool->min_alloc_order;
chunk->phys_addr = phys;
chunk->start_addr = virt;
chunk->end_addr = virt + size - 1;
@@ -293,6 +294,7 @@ unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
return 0;

nbits = (size + (1UL << order) - 1) >> order;
+ size = nbits << order;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
if (size > atomic_long_read(&chunk->avail))
@@ -314,7 +316,6 @@ unsigned long gen_pool_alloc_algo_owner(struct gen_pool *pool, size_t size,
}

addr = chunk->start_addr + ((unsigned long)start_bit << order);
- size = nbits << order;
atomic_long_sub(size, &chunk->avail);
if (owner)
*owner = chunk->owner;
@@ -499,6 +500,7 @@ void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
*owner = NULL;

nbits = (size + (1UL << order) - 1) >> order;
+ size = nbits << order;
rcu_read_lock();
list_for_each_entry_rcu(chunk, &pool->chunks, next_chunk) {
if (addr >= chunk->start_addr && addr <= chunk->end_addr) {
@@ -506,7 +508,6 @@ void gen_pool_free_owner(struct gen_pool *pool, unsigned long addr, size_t size,
start_bit = (addr - chunk->start_addr) >> order;
remain = bitmap_clear_ll(chunk->bits, start_bit, nbits);
BUG_ON(remain);
- size = nbits << order;
atomic_long_add(size, &chunk->avail);
if (owner)
*owner = chunk->owner;
--
2.20.1
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