[PATCH 1/3] dma-pool: factor out a calculate_pool_size helper

From: Christoph Hellwig
Date: Wed Aug 17 2022 - 02:07:13 EST


Add a helper to calculate the pool size from dma_atomic_pool_init,
and fix up the last max_t to use the proper type.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
kernel/dma/pool.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c
index 4d40dcce7604b..56f96678934bf 100644
--- a/kernel/dma/pool.c
+++ b/kernel/dma/pool.c
@@ -184,6 +184,15 @@ static __init struct gen_pool *__dma_atomic_pool_init(size_t pool_size,
return pool;
}

+static unsigned long calculate_pool_size(unsigned long zone_pages)
+{
+ unsigned long nr_pages = min_t(unsigned long,
+ zone_pages / (SZ_1G / SZ_128K),
+ MAX_ORDER_NR_PAGES);
+
+ return max_t(unsigned long, nr_pages << PAGE_SHIFT, SZ_128K);
+}
+
static int __init dma_atomic_pool_init(void)
{
int ret = 0;
@@ -192,11 +201,9 @@ static int __init dma_atomic_pool_init(void)
* If coherent_pool was not used on the command line, default the pool
* sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1.
*/
- if (!atomic_pool_size) {
- unsigned long pages = totalram_pages() / (SZ_1G / SZ_128K);
- pages = min_t(unsigned long, pages, MAX_ORDER_NR_PAGES);
- atomic_pool_size = max_t(size_t, pages << PAGE_SHIFT, SZ_128K);
- }
+ if (!atomic_pool_size)
+ atomic_pool_size = calculate_pool_size(totalram_pages());
+
INIT_WORK(&atomic_pool_work, atomic_pool_work_fn);

atomic_pool_kernel = __dma_atomic_pool_init(atomic_pool_size,
--
2.30.2