If an architecture opted in to DMA bouncing of unaligned kmalloc()
buffers (ARCH_WANT_KMALLOC_DMA_BOUNCE), reduce the minimum kmalloc()
cache alignment below cache-line size to ARCH_KMALLOC_MINALIGN.
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Robin Murphy <robin.murphy@xxxxxxx>
---
mm/slab_common.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 7c6475847fdf..84e5a5e435d6 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -18,6 +18,7 @@
#include <linux/uaccess.h>
#include <linux/seq_file.h>
#include <linux/dma-mapping.h>
+#include <linux/swiotlb.h>
#include <linux/proc_fs.h>
#include <linux/debugfs.h>
#include <linux/kasan.h>
@@ -865,7 +866,13 @@ void __init setup_kmalloc_cache_index_table(void)
static unsigned int __kmalloc_minalign(void)
{
- return dma_get_cache_alignment();
+ int cache_align = dma_get_cache_alignment();
+
+ if (!IS_ENABLED(CONFIG_DMA_BOUNCE_UNALIGNED_KMALLOC) ||
+ io_tlb_default_mem.nslabs == 0)
+ return cache_align;
+
+ return ARCH_KMALLOC_MINALIGN;
}
void __init
