diff mbox series

[v4,1/2] dma: improve DMA zone selection

Message ID f8f4da7ea3ead153ca21e628ca90e24fd0e7206e.1722499975.git.baruch@tkos.co.il (mailing list archive)
State New, archived
Headers show
Series dma: support DMA zone starting above 4GB | expand

Commit Message

Baruch Siach Aug. 1, 2024, 8:25 a.m. UTC 
When device DMA limit does not fit in DMA32 zone it should use DMA zone,
even when DMA zone is stricter than needed.

Same goes for devices that can't allocate from the entire normal zone.
Limit to DMA32 in that case.

Reported-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
---
 kernel/dma/direct.c  | 6 +++---
 kernel/dma/swiotlb.c | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

Comments

Catalin Marinas Aug. 1, 2024, 8:56 a.m. UTC | #1 
On Thu, Aug 01, 2024 at 11:25:06AM +0300, Baruch Siach wrote:
> When device DMA limit does not fit in DMA32 zone it should use DMA zone,
> even when DMA zone is stricter than needed.
> 
> Same goes for devices that can't allocate from the entire normal zone.
> Limit to DMA32 in that case.
> 
> Reported-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Baruch Siach <baruch@tkos.co.il>

This looks fine to me now.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
diff mbox series

Patch

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 4480a3cd92e0..3b4be4ca3b08 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -4,7 +4,7 @@ 
  *
  * DMA operations that map physical memory directly without using an IOMMU.
  */
-#include <linux/memblock.h> /* for max_pfn */
+#include <linux/memblock.h>
 #include <linux/export.h>
 #include <linux/mm.h>
 #include <linux/dma-map-ops.h>
@@ -59,9 +59,9 @@  static gfp_t dma_direct_optimal_gfp_mask(struct device *dev, u64 *phys_limit)
 	 * zones.
 	 */
 	*phys_limit = dma_to_phys(dev, dma_limit);
-	if (*phys_limit <= DMA_BIT_MASK(zone_dma_bits))
+	if (*phys_limit < DMA_BIT_MASK(32))
 		return GFP_DMA;
-	if (*phys_limit <= DMA_BIT_MASK(32))
+	if (*phys_limit < memblock_end_of_DRAM())
 		return GFP_DMA32;
 	return 0;
 }
diff --git a/kernel/dma/swiotlb.c b/kernel/dma/swiotlb.c
index df68d29740a0..043b0ecd3e8d 100644
--- a/kernel/dma/swiotlb.c
+++ b/kernel/dma/swiotlb.c
@@ -629,9 +629,9 @@  static struct page *swiotlb_alloc_tlb(struct device *dev, size_t bytes,
 	}
 
 	gfp &= ~GFP_ZONEMASK;
-	if (phys_limit <= DMA_BIT_MASK(zone_dma_bits))
+	if (phys_limit < DMA_BIT_MASK(32))
 		gfp |= __GFP_DMA;
-	else if (phys_limit <= DMA_BIT_MASK(32))
+	else if (phys_limit < memblock_end_of_DRAM())
 		gfp |= __GFP_DMA32;
 
 	while (IS_ERR(page = alloc_dma_pages(gfp, bytes, phys_limit))) {