Thread (23 messages) 23 messages, 2 authors, 2021-08-09
STALE1792d
Revisions (2)
  1. v2 [diff vs current]
  2. v3 current

[PATCH v3 21/21] dma-mapping: Disallow .map_sg operations from returning zero on error

From: Logan Gunthorpe <logang@deltatee.com>
Date: 2021-07-29 20:16:08
Also in: linux-alpha, linux-arm-kernel, linux-iommu, linux-mips, linux-s390, lkml, sparclinux, xen-devel
Subsystem: dma mapping helpers, the rest · Maintainers: Marek Szyprowski, Linus Torvalds

Now that all the .map_sg operations have been converted to returning
proper error codes, drop the code to handle a zero return value,
add a warning if a zero is returned.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
---
 kernel/dma/mapping.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 9f0bb56eb9aa..cbcbdc877458 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -196,8 +196,8 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg,
 
 	if (ents > 0)
 		debug_dma_map_sg(dev, sg, nents, ents, dir);
-	else if (WARN_ON_ONCE(ents != -EINVAL && ents != -ENOMEM &&
-			      ents != -EIO && ents != 0))
+	else if (WARN_ON_ONCE((ents != -EINVAL && ents != -ENOMEM &&
+			       ents != -EIO) || ents == 0))
 		return -EIO;
 
 	return ents;
@@ -262,9 +262,7 @@ int dma_map_sgtable(struct device *dev, struct sg_table *sgt,
 	int nents;
 
 	nents = __dma_map_sg_attrs(dev, sgt->sgl, sgt->orig_nents, dir, attrs);
-	if (nents == 0)
-		return -EIO;
-	else if (nents < 0)
+	if (nents < 0)
 		return nents;
 
 	sgt->nents = nents;
-- 
2.20.1
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