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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, John David Anglin <dave.anglin@bell.net>,
        Helge Deller <deller@gmx.de>
Subject: [PATCH 5.16 017/227] parisc: Fix sglist access in ccio-dma.c
Date:   Mon, 21 Feb 2022 09:47:16 +0100
Message-Id: <20220221084935.416055646@linuxfoundation.org>
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From: John David Anglin <dave.anglin@bell.net>

commit d7da660cab47183cded65e11b64497d0f56c6edf upstream.

This patch implements the same bug fix to ccio-dma.c as to sba_iommu.c.
It ensures that only the allocated entries of the sglist are accessed.

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/parisc/ccio-dma.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/parisc/ccio-dma.c
+++ b/drivers/parisc/ccio-dma.c
@@ -1003,7 +1003,7 @@ ccio_unmap_sg(struct device *dev, struct
 	ioc->usg_calls++;
 #endif
 
-	while(sg_dma_len(sglist) && nents--) {
+	while (nents && sg_dma_len(sglist)) {
 
 #ifdef CCIO_COLLECT_STATS
 		ioc->usg_pages += sg_dma_len(sglist) >> PAGE_SHIFT;
@@ -1011,6 +1011,7 @@ ccio_unmap_sg(struct device *dev, struct
 		ccio_unmap_page(dev, sg_dma_address(sglist),
 				  sg_dma_len(sglist), direction, 0);
 		++sglist;
+		nents--;
 	}
 
 	DBG_RUN_SG("%s() DONE (nents %d)\n", __func__, nents);