# \[PATCH v3 21/21\] dma-mapping: Disallow .map\_sg operations from returning zero on error - From: Logan Gunthorpe \ - Date: 2021-07-29 20:16:08 - List: linuxppc-dev - Page: https://ratatoskr.run/linuxppc-dev/2021/07/1462533 - Thread: https://ratatoskr.run/linux-alpha/2021/07/1462534/t.md ```text 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 --- 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 ```