dma-mapping: use vmap insted of reimplementing it

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>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Gao Xiang <xiang@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "K. Y. Srinivasan" <kys@microsoft.com>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Kelley <mikelley@microsoft.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Nitin Gupta <ngupta@vflare.org>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Sakari Ailus <sakari.ailus@linux.intel.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Wei Liu <wei.liu@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/20200414131348.444715-6-hch@lst.de
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/dma/remap.c b/kernel/dma/remap.c
index d14cbc8..914ff5a 100644 (file)
--- 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;
 }
 
 /*