[PATCH 04/28] dma-mapping: use vmap insted of reimplementing it

From: Christoph Hellwig <hch@lst.de>
To: Andrew Morton <akpm@linux-foundation.org>,
	"K. Y. Srinivasan" <kys@microsoft.com>,
	Haiyang Zhang <haiyangz@microsoft.com>,
	Stephen Hemminger <sthemmin@microsoft.com>,
	Wei Liu <wei.liu@kernel.org>,
	x86@kernel.org, David Airlie <airlied@linux.ie>,
	Daniel Vetter <daniel@ffwll.ch>,
	Laura Abbott <labbott@redhat.com>,
	Sumit Semwal <sumit.semwal@linaro.org>,
	Sakari Ailus <sakari.ailus@linux.intel.com>,
	Minchan Kim <minchan@kernel.org>, Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>,
	Christophe Leroy <christophe.leroy@c-s.fr>,
	Peter Zijlstra <peterz@infradead.org>,
	linuxppc-dev@lists.ozlabs.org, linux-hyperv@vger.kernel.org,
	dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org,
	linux-arch@vger.kernel.org, linux-mm@kvack.org,
	iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org, linux-s390@vger.kernel.org,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH 04/28] dma-mapping: use vmap insted of reimplementing it
Date: Wed,  8 Apr 2020 13:59:02 +0200	[thread overview]
Message-ID: <20200408115926.1467567-5-hch@lst.de> (raw)
In-Reply-To: <20200408115926.1467567-1-hch@lst.de>

Replace the open coded instance of vmap with the actual function.  In
the non-contiguous (IOMMU) case this requires an extra find_vm_area,
but given that this isn't a fast path function that is a small price
to pay.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 kernel/dma/remap.c | 48 ++++++++++++----------------------------------
 1 file changed, 12 insertions(+), 36 deletions(-)

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index d14cbc83986a..7a8ba60951e8 100644
--- a/kernel/dma/remap.c
+++ b/kernel/dma/remap.c
@@ -20,23 +20,6 @@ struct page **dma_common_find_pages(void *cpu_addr)
 	return area->pages;
 }
 
-static struct vm_struct *__dma_common_pages_remap(struct page **pages,
-			size_t size, pgprot_t prot, const void *caller)
-{
-	struct vm_struct *area;
-
-	area = get_vm_area_caller(size, VM_DMA_COHERENT, caller);
-	if (!area)
-		return NULL;
-
-	if (map_vm_area(area, prot, pages)) {
-		vunmap(area->addr);
-		return NULL;
-	}
-
-	return area;
-}
-
 /*
  * Remaps an array of PAGE_SIZE pages into another vm_area.
  * Cannot be used in non-sleeping contexts
@@ -44,15 +27,12 @@ static struct vm_struct *__dma_common_pages_remap(struct page **pages,
 void *dma_common_pages_remap(struct page **pages, size_t size,
 			 pgprot_t prot, const void *caller)
 {
-	struct vm_struct *area;
+	void *vaddr;
 
-	area = __dma_common_pages_remap(pages, size, prot, caller);
-	if (!area)
-		return NULL;
-
-	area->pages = pages;
-
-	return area->addr;
+	vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
+	if (vaddr)
+		find_vm_area(vaddr)->pages = pages;
+	return vaddr;
 }
 
 /*
@@ -62,24 +42,20 @@ void *dma_common_pages_remap(struct page **pages, size_t size,
 void *dma_common_contiguous_remap(struct page *page, size_t size,
 			pgprot_t prot, const void *caller)
 {
-	int i;
+	int count = size >> PAGE_SHIFT;
 	struct page **pages;
-	struct vm_struct *area;
+	void *vaddr;
+	int i;
 
-	pages = kmalloc(sizeof(struct page *) << get_order(size), GFP_KERNEL);
+	pages = kmalloc_array(count, sizeof(struct page *), GFP_KERNEL);
 	if (!pages)
 		return NULL;
-
-	for (i = 0; i < (size >> PAGE_SHIFT); i++)
+	for (i = 0; i < count; i++)
 		pages[i] = nth_page(page, i);
-
-	area = __dma_common_pages_remap(pages, size, prot, caller);
-
+	vaddr = vmap(pages, count, VM_DMA_COHERENT, prot);
 	kfree(pages);
 
-	if (!area)
-		return NULL;
-	return area->addr;
+	return vaddr;
 }
 
 /*
-- 
2.25.1

