[PATCH v1 16/16] dma-mapping: Disallow .map_sg operations from returning zero on error
From: Logan Gunthorpe <logang@deltatee.com>
Date: 2021-07-15 16:46:22
Also in:
linux-alpha, linux-iommu, linux-mips, linux-s390, linuxppc-dev, 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 and update the comment for the map_sg operation. Signed-off-by: Logan Gunthorpe <logang@deltatee.com> --- include/linux/dma-map-ops.h | 8 +++----- kernel/dma/mapping.c | 6 +++--- 2 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index eaa969be8284..f299bc1e317b 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h@@ -42,11 +42,9 @@ struct dma_map_ops { unsigned long attrs); /* * map_sg should return a negative error code on error. - * dma_map_sgtable() will return the error code returned and convert - * a zero return (for legacy implementations) into -EINVAL. - * - * dma_map_sg() will always return zero on any negative or zero - * return to satisfy its own calling convention. + * dma_map_sgtable() will return the error code returned by the + * operation and dma_map_sg() will always convert any error to zero + * to satisfy its own calling convention. */ int (*map_sg)(struct device *dev, struct scatterlist *sg, int nents, enum dma_data_direction dir, unsigned long attrs);
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index 30f89d244566..978a6a16aaf7 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c@@ -194,6 +194,8 @@ static int __dma_map_sg_attrs(struct device *dev, struct scatterlist *sg, else ents = ops->map_sg(dev, sg, nents, dir, attrs); + WARN_ON_ONCE(ents == 0); + if (ents > 0) debug_dma_map_sg(dev, sg, nents, ents, dir);
@@ -251,9 +253,7 @@ 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 -EINVAL; - else if (nents < 0) + if (nents < 0) return nents; sgt->nents = nents;
--
2.20.1
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel