linux-kernel - Re: [REGRESSION, BISECTED] pci: nvme device with HMB fails on arm64

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Message-ID: <20190104173446.GA24554@lst.de>
Date:   Fri, 4 Jan 2019 18:34:47 +0100
From:   Christoph Hellwig <hch@....de>
To:     Liviu Dudau <liviu@...au.co.uk>
Cc:     Christoph Hellwig <hch@....de>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Robin Murphy <robin.murphy@....com>, linux-pci@...r.kernel.org,
        LAKML <linux-arm-kernel@...ts.infradead.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [REGRESSION, BISECTED] pci: nvme device with HMB fails on arm64

Hi Liviu,

please try the patch below.  Note that this is in top of mainline,
as the commit you found already needed another fixup, which has
made it to Linus already.

--
>From a959cc1a8ee00dcb274922f9d74f6ed632709047 Mon Sep 17 00:00:00 2001
From: Christoph Hellwig <hch@....de>
Date: Fri, 4 Jan 2019 18:31:48 +0100
Subject: dma-direct: fix DMA_ATTR_NO_KERNEL_MAPPING for remapped allocations

We need to return a dma_addr_t even if we don't have a kernel mapping.
Do so by consolidating the phys_to_dma call in a single place and jump
to it from all the branches that return successfully.

Fixes: bfd56cd60521 ("dma-mapping: support highmem in the generic remap allocator")
Reported-by: Liviu Dudau <liviu@...au.co.uk
Signed-off-by: Christoph Hellwig <hch@....de>
---
 kernel/dma/remap.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index 18cc09fc27b9..7a723194ecbe 100644
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -204,8 +204,7 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		ret = dma_alloc_from_pool(size, &page, flags);
 		if (!ret)
 			return NULL;
-		*dma_handle = phys_to_dma(dev, page_to_phys(page));
-		return ret;
+		goto done;
 	}
 
 	page = __dma_direct_alloc_pages(dev, size, dma_handle, flags, attrs);
@@ -215,8 +214,10 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	/* remove any dirty cache lines on the kernel alias */
 	arch_dma_prep_coherent(page, size);
 
-	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
-		return page; /* opaque cookie */
+	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING) {
+		ret = page; /* opaque cookie */
+		goto done;
+	}
 
 	/* create a coherent mapping */
 	ret = dma_common_contiguous_remap(page, size, VM_USERMAP,
@@ -227,9 +228,9 @@ void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle,
 		return ret;
 	}
 
-	*dma_handle = phys_to_dma(dev, page_to_phys(page));
 	memset(ret, 0, size);
-
+done:
+	*dma_handle = phys_to_dma(dev, page_to_phys(page));
 	return ret;
 }
 
-- 
2.20.1