diff mbox series

[4/8] dma-direct: warn when coherent allocations aren't supported

Message ID 20231020054024.78295-5-hch@lst.de (mailing list archive)
State Not Applicable
Headers show
Series [1/8] dma-direct: add depdenencies to CONFIG_DMA_GLOBAL_POOL | expand

Checks

Context Check Description
netdev/series_format warning Series does not have a cover letter
netdev/tree_selection success Guessed tree name to be net-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1365 this patch: 1365
netdev/cc_maintainers success CCed 4 of 4 maintainers
netdev/build_clang success Errors and warnings before: 1389 this patch: 1389
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1390 this patch: 1390
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 11 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Christoph Hellwig Oct. 20, 2023, 5:40 a.m. UTC 
Log a warning once when dma_alloc_coherent fails because the platform
does not support coherent allocations at all.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Greg Ungerer <gerg@linux-m68k.org>
Tested-by: Greg Ungerer <gerg@linux-m68k.org>
---
 kernel/dma/direct.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
index 9657ef7c055eaa..ed3056eb20b8bd 100644
--- a/kernel/dma/direct.c
+++ b/kernel/dma/direct.c
@@ -240,8 +240,10 @@  void *dma_direct_alloc(struct device *dev, size_t size,
 		 */
 		set_uncached = IS_ENABLED(CONFIG_ARCH_HAS_DMA_SET_UNCACHED);
 		remap = IS_ENABLED(CONFIG_DMA_DIRECT_REMAP);
-		if (!set_uncached && !remap)
+		if (!set_uncached && !remap) {
+			pr_warn_once("coherent DMA allocations not supported on this platform.\n");
 			return NULL;
+		}
 	}
 
 	/*