From: Christoph Hellwig <hch@lst.de>
To: Roman Skakun <rm.skakun@gmail.com>
Cc: Christoph Hellwig <hch@lst.de>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Juergen Gross <jgross@suse.com>,
Stefano Stabellini <sstabellini@kernel.org>,
xen-devel@lists.xenproject.org, iommu@lists.linux-foundation.org,
linux-kernel@vger.kernel.org,
Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com>,
Oleksandr Andrushchenko <oleksandr_andrushchenko@epam.com>,
Volodymyr Babchuk <volodymyr_babchuk@epam.com>,
Andrii Anisov <andrii_anisov@epam.com>,
Roman Skakun <Roman_Skakun@epam.com>
Subject: Re: [PATCH v2] dma-mapping: use vmalloc_to_page for vmalloc addresses
Date: Fri, 16 Jul 2021 11:35:51 +0200 [thread overview]
Message-ID: <20210716093551.GA17981@lst.de> (raw)
In-Reply-To: <20210716083934.154992-1-rm.skakun@gmail.com>
Technically this looks good. But given that exposing a helper
that does either vmalloc_to_page or virt_to_page is one of the
never ending MM discussions I don't want to get into that discussion
and just keep it local in the DMA code.
Are you fine with me applying this version?
---
From 40ac971eab89330d6153e7721e88acd2d98833f9 Mon Sep 17 00:00:00 2001
From: Roman Skakun <Roman_Skakun@epam.com>
Date: Fri, 16 Jul 2021 11:39:34 +0300
Subject: dma-mapping: handle vmalloc addresses in
dma_common_{mmap,get_sgtable}
xen-swiotlb can use vmalloc backed addresses for dma coherent allocations
and uses the common helpers. Properly handle them to unbreak Xen on
ARM platforms.
Fixes: 1b65c4e5a9af ("swiotlb-xen: use xen_alloc/free_coherent_pages")
Signed-off-by: Roman Skakun <roman_skakun@epam.com>
Reviewed-by: Andrii Anisov <andrii_anisov@epam.com>
[hch: split the patch, renamed the helpers]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
kernel/dma/ops_helpers.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/kernel/dma/ops_helpers.c b/kernel/dma/ops_helpers.c
index 910ae69cae77..af4a6ef48ce0 100644
--- a/kernel/dma/ops_helpers.c
+++ b/kernel/dma/ops_helpers.c
@@ -5,6 +5,13 @@
*/
#include <linux/dma-map-ops.h>
+static struct page *dma_common_vaddr_to_page(void *cpu_addr)
+{
+ if (is_vmalloc_addr(cpu_addr))
+ return vmalloc_to_page(cpu_addr);
+ return virt_to_page(cpu_addr);
+}
+
/*
* Create scatter-list for the already allocated DMA buffer.
*/
@@ -12,7 +19,7 @@ int dma_common_get_sgtable(struct device *dev, struct sg_table *sgt,
void *cpu_addr, dma_addr_t dma_addr, size_t size,
unsigned long attrs)
{
- struct page *page = virt_to_page(cpu_addr);
+ struct page *page = dma_common_vaddr_to_page(cpu_addr);
int ret;
ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
@@ -32,6 +39,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
unsigned long user_count = vma_pages(vma);
unsigned long count = PAGE_ALIGN(size) >> PAGE_SHIFT;
unsigned long off = vma->vm_pgoff;
+ struct page *page = dma_common_vaddr_to_page(cpu_addr);
int ret = -ENXIO;
vma->vm_page_prot = dma_pgprot(dev, vma->vm_page_prot, attrs);
@@ -43,7 +51,7 @@ int dma_common_mmap(struct device *dev, struct vm_area_struct *vma,
return -ENXIO;
return remap_pfn_range(vma, vma->vm_start,
- page_to_pfn(virt_to_page(cpu_addr)) + vma->vm_pgoff,
+ page_to_pfn(page) + vma->vm_pgoff,
user_count << PAGE_SHIFT, vma->vm_page_prot);
#else
return -ENXIO;
--
2.30.2
next prev parent reply other threads:[~2021-07-16 9:35 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-11 9:55 [PATCH] swiotlb-xen: override common mmap and get_sgtable dma ops Roman Skakun
2021-06-11 15:19 ` Boris Ostrovsky
2021-06-14 12:47 ` Roman Skakun
2021-06-14 15:45 ` Boris Ostrovsky
2021-06-16 11:45 ` Roman Skakun
2021-06-16 11:42 ` [PATCH 1/2] Revert "swiotlb-xen: remove xen_swiotlb_dma_mmap and xen_swiotlb_dma_get_sgtable" Roman Skakun
2021-06-16 11:42 ` [PATCH 2/2] swiotlb-xen: override common mmap and get_sgtable dma ops Roman Skakun
2021-06-16 14:12 ` Boris Ostrovsky
2021-06-16 14:21 ` Christoph Hellwig
2021-06-16 15:33 ` Boris Ostrovsky
2021-06-16 15:35 ` Christoph Hellwig
2021-06-16 15:39 ` Boris Ostrovsky
2021-06-16 15:44 ` Christoph Hellwig
2021-06-22 13:34 ` [PATCH v2] dma-mapping: use vmalloc_to_page for vmalloc addresses Roman Skakun
2021-07-14 0:15 ` Konrad Rzeszutek Wilk
2021-07-15 7:39 ` Roman Skakun
2021-07-15 16:58 ` Boris Ostrovsky
2021-07-15 17:00 ` Christoph Hellwig
2021-07-16 8:39 ` Roman Skakun
2021-07-16 9:35 ` Christoph Hellwig [this message]
2021-07-16 12:53 ` Roman Skakun
2021-07-16 15:29 ` Stefano Stabellini
2021-07-17 8:39 ` Roman Skakun
2021-07-19 9:22 ` Christoph Hellwig
2021-07-21 18:39 ` Roman Skakun
2021-07-14 1:23 ` Stefano Stabellini
2021-07-15 7:31 ` Roman Skakun
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