From 3ee06a6d532f75f20528ff4d2c473cda36c484fe Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Mon, 8 Jun 2020 15:22:17 +0200 Subject: [PATCH] dma-pool: fix too large DMA pools on medium memory size systems On systems with at least 32 MiB, but less than 32 GiB of RAM, the DMA memory pools are much larger than intended (e.g. 2 MiB instead of 128 KiB on a 256 MiB system). Fix this by correcting the calculation of the number of GiBs of RAM in the system. Invert the order of the min/max operations, to keep on calculating in pages until the last step, which aids readability. Fixes: 1d659236fb43c4d2 ("dma-pool: scale the default DMA coherent pool size with memory capacity") Signed-off-by: Geert Uytterhoeven Acked-by: David Rientjes Signed-off-by: Christoph Hellwig --- kernel/dma/pool.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/kernel/dma/pool.c b/kernel/dma/pool.c index 35bb51c..8cfa012 100644 --- a/kernel/dma/pool.c +++ b/kernel/dma/pool.c @@ -175,10 +175,9 @@ static int __init dma_atomic_pool_init(void) * sizes to 128KB per 1GB of memory, min 128KB, max MAX_ORDER-1. */ if (!atomic_pool_size) { - atomic_pool_size = max(totalram_pages() >> PAGE_SHIFT, 1UL) * - SZ_128K; - atomic_pool_size = min_t(size_t, atomic_pool_size, - 1 << (PAGE_SHIFT + MAX_ORDER-1)); + 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); } INIT_WORK(&atomic_pool_work, atomic_pool_work_fn); -- 2.7.4