[PATCH 05/29] dma-mapping: use vmap insted of reimplementing it

[Christoph Hellwig]

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 <h...@lst.de>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
---
 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..914ff5a58dd5 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, size >> PAGE_SHIFT, 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