linux-kernel - [PATCH v2 18/21] x86/amd_gart: return error code from gart_map

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Date:   Fri, 23 Jul 2021 11:50:05 -0600
From:   Logan Gunthorpe <logang@...tatee.com>
To:     linux-kernel@...r.kernel.org, linux-alpha@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-ia64@...r.kernel.org,
        linux-mips@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-s390@...r.kernel.org, sparclinux@...r.kernel.org,
        iommu@...ts.linux-foundation.org, linux-parisc@...r.kernel.org,
        xen-devel@...ts.xenproject.org
Cc:     Christoph Hellwig <hch@....de>,
        Marek Szyprowski <m.szyprowski@...sung.com>,
        Robin Murphy <robin.murphy@....com>,
        Stephen Bates <sbates@...thlin.com>,
        Martin Oliveira <martin.oliveira@...eticom.com>,
        Logan Gunthorpe <logang@...tatee.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        "H. Peter Anvin" <hpa@...or.com>,
        Niklas Schnelle <schnelle@...ux.ibm.com>,
        Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH v2 18/21] x86/amd_gart: return error code from gart_map_sg()

From: Martin Oliveira <martin.oliveira@...eticom.com>

The .map_sg() op now expects an error code instead of zero on failure.

So make __dma_map_cont() return a valid errno (which is then propagated
to gart_map_sg() via dma_map_cont()) and return it in case of failure.

Also, return -EINVAL in case of invalid nents.

Signed-off-by: Martin Oliveira <martin.oliveira@...eticom.com>
Signed-off-by: Logan Gunthorpe <logang@...tatee.com>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Ingo Molnar <mingo@...hat.com>
Cc: Borislav Petkov <bp@...en8.de>
Cc: "H. Peter Anvin" <hpa@...or.com>
Cc: Niklas Schnelle <schnelle@...ux.ibm.com>
Cc: Thomas Bogendoerfer <tsbogend@...ha.franken.de>
Cc: Michael Ellerman <mpe@...erman.id.au>
---
 arch/x86/kernel/amd_gart_64.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/amd_gart_64.c b/arch/x86/kernel/amd_gart_64.c
index 9ac696487b13..46aea9a4f26b 100644
--- a/arch/x86/kernel/amd_gart_64.c
+++ b/arch/x86/kernel/amd_gart_64.c
@@ -331,7 +331,7 @@ static int __dma_map_cont(struct device *dev, struct scatterlist *start,
 	int i;
 
 	if (iommu_start == -1)
-		return -1;
+		return -ENOMEM;
 
 	for_each_sg(start, s, nelems, i) {
 		unsigned long pages, addr;
@@ -380,13 +380,13 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 		       enum dma_data_direction dir, unsigned long attrs)
 {
 	struct scatterlist *s, *ps, *start_sg, *sgmap;
-	int need = 0, nextneed, i, out, start;
+	int need = 0, nextneed, i, out, start, ret;
 	unsigned long pages = 0;
 	unsigned int seg_size;
 	unsigned int max_seg_size;
 
 	if (nents == 0)
-		return 0;
+		return -EINVAL;
 
 	out		= 0;
 	start		= 0;
@@ -414,8 +414,9 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 			if (!iommu_merge || !nextneed || !need || s->offset ||
 			    (s->length + seg_size > max_seg_size) ||
 			    (ps->offset + ps->length) % PAGE_SIZE) {
-				if (dma_map_cont(dev, start_sg, i - start,
-						 sgmap, pages, need) < 0)
+				ret = dma_map_cont(dev, start_sg, i - start,
+						   sgmap, pages, need);
+				if (ret < 0)
 					goto error;
 				out++;
 
@@ -432,7 +433,8 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 		pages += iommu_num_pages(s->offset, s->length, PAGE_SIZE);
 		ps = s;
 	}
-	if (dma_map_cont(dev, start_sg, i - start, sgmap, pages, need) < 0)
+	ret = dma_map_cont(dev, start_sg, i - start, sgmap, pages, need);
+	if (ret < 0)
 		goto error;
 	out++;
 	flush_gart();
@@ -458,7 +460,7 @@ static int gart_map_sg(struct device *dev, struct scatterlist *sg, int nents,
 	iommu_full(dev, pages << PAGE_SHIFT, dir);
 	for_each_sg(sg, s, nents, i)
 		s->dma_address = DMA_MAPPING_ERROR;
-	return 0;
+	return ret;
 }
 
 /* allocate and map a coherent mapping */
-- 
2.20.1