[patch 03/18] drm: nopage

[npiggin@suse.de]

Convert drm from nopage to fault.
Remove redundant vma range checks.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: airlied@linux.ie
Cc: linux-kernel@vger.kernel.org
---
 drivers/char/drm/drm_vm.c |  131 +++++++++++++++++++++-------------------------
 1 file changed, 61 insertions(+), 70 deletions(-)

Index: linux-2.6/drivers/char/drm/drm_vm.c
===================================================================
--- linux-2.6.orig/drivers/char/drm/drm_vm.c
+++ linux-2.6/drivers/char/drm/drm_vm.c
@@ -66,7 +66,7 @@ static pgprot_t drm_io_prot(uint32_t map
 }
 
 /**
- * \c nopage method for AGP virtual memory.
+ * \c fault method for AGP virtual memory.
  *
  * \param vma virtual memory area.
  * \param address access address.
@@ -76,8 +76,8 @@ static pgprot_t drm_io_prot(uint32_t map
  * map, get the page, increment the use count and return it.
  */
 #if __OS_HAS_AGP
-static __inline__ struct page *drm_do_vm_nopage(struct vm_area_struct *vma,
-						unsigned long address)
+static __inline__ int drm_do_vm_fault(struct vm_area_struct *vma,
+						struct vm_fault *vmf)
 {
 	struct drm_file *priv = vma->vm_file->private_data;
 	struct drm_device *dev = priv->head->dev;
@@ -89,19 +89,24 @@ static __inline__ struct page *drm_do_vm
 	 * Find the right map
 	 */
 	if (!drm_core_has_AGP(dev))
-		goto vm_nopage_error;
+		goto vm_fault_error;
 
 	if (!dev->agp || !dev->agp->cant_use_aperture)
-		goto vm_nopage_error;
+		goto vm_fault_error;
 
 	if (drm_ht_find_item(&dev->map_hash, vma->vm_pgoff, &hash))
-		goto vm_nopage_error;
+		goto vm_fault_error;
 
 	r_list = drm_hash_entry(hash, struct drm_map_list, hash);
 	map = r_list->map;
 
 	if (map && map->type == _DRM_AGP) {
-		unsigned long offset = address - vma->vm_start;
+		/*
+		 * Using vm_pgoff as a selector forces us to use this unusual
+		 * addressing scheme.
+		 */
+		unsigned long offset = (unsigned long)vmf->virtual_address -
+								vma->vm_start;
 		unsigned long baddr = map->offset + offset;
 		struct drm_agp_mem *agpmem;
 		struct page *page;
@@ -123,7 +128,7 @@ static __inline__ struct page *drm_do_vm
 		}
 
 		if (!agpmem)
-			goto vm_nopage_error;
+			goto vm_fault_error;
 
 		/*
 		 * Get the page, inc the use count, and return it
@@ -131,27 +136,28 @@ static __inline__ struct page *drm_do_vm
 		offset = (baddr - agpmem->bound) >> PAGE_SHIFT;
 		page = virt_to_page(__va(agpmem->memory->memory[offset]));
 		get_page(page);
+		vmf->page = page;
 
 		DRM_DEBUG
 		    ("baddr = 0x%lx page = 0x%p, offset = 0x%lx, count=%d\n",
 		     baddr, __va(agpmem->memory->memory[offset]), offset,
 		     page_count(page));
 
-		return page;
+		return 0;
 	}
-      vm_nopage_error:
-	return NOPAGE_SIGBUS;	/* Disallow mremap */
+      vm_fault_error:
+	return VM_FAULT_SIGBUS;	/* Disallow mremap */
 }
 #else				/* __OS_HAS_AGP */
-static __inline__ struct page *drm_do_vm_nopage(struct vm_area_struct *vma,
-						unsigned long address)
+static __inline__ int drm_do_vm_fault(struct vm_area_struct *vma,
+						struct vm_fault *vmf)
 {
-	return NOPAGE_SIGBUS;
+	return VM_FAULT_SIGBUS;
 }
 #endif				/* __OS_HAS_AGP */
 
 /**
- * \c nopage method for shared virtual memory.
+ * \c fault method for shared virtual memory.
  *
  * \param vma virtual memory area.
  * \param address access address.
@@ -160,28 +166,27 @@ static __inline__ struct page *drm_do_vm
  * Get the mapping, find the real physical page to map, get the page, and
  * return it.
  */
-static __inline__ struct page *drm_do_vm_shm_nopage(struct vm_area_struct *vma,
-						    unsigned long address)
+static __inline__ int drm_do_vm_shm_fault(struct vm_area_struct *vma,
+						    struct vm_fault *vmf)
 {
 	struct drm_map *map = (struct drm_map *) vma->vm_private_data;
 	unsigned long offset;
 	unsigned long i;
 	struct page *page;
 
-	if (address > vma->vm_end)
-		return NOPAGE_SIGBUS;	/* Disallow mremap */
 	if (!map)
-		return NOPAGE_SIGBUS;	/* Nothing allocated */
+		return VM_FAULT_SIGBUS;	/* Nothing allocated */
 
-	offset = address - vma->vm_start;
+	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
 	i = (unsigned long)map->handle + offset;
 	page = vmalloc_to_page((void *)i);
 	if (!page)
-		return NOPAGE_SIGBUS;
+		return VM_FAULT_SIGBUS;
 	get_page(page);
+	vmf->page = page;
 
-	DRM_DEBUG("shm_nopage 0x%lx\n", address);
-	return page;
+	DRM_DEBUG("shm_fault 0x%lx\n", offset);
+	return 0;
 }
 
 /**
@@ -263,7 +268,7 @@ static void drm_vm_shm_close(struct vm_a
 }
 
 /**
- * \c nopage method for DMA virtual memory.
+ * \c fault method for DMA virtual memory.
  *
  * \param vma virtual memory area.
  * \param address access address.
@@ -271,8 +276,8 @@ static void drm_vm_shm_close(struct vm_a
  *
  * Determine the page number from the page offset and get it from drm_device_dma::pagelist.
  */
-static __inline__ struct page *drm_do_vm_dma_nopage(struct vm_area_struct *vma,
-						    unsigned long address)
+static __inline__ int drm_do_vm_dma_fault(struct vm_area_struct *vma,
+						    struct vm_fault *vmf)
 {
 	struct drm_file *priv = vma->vm_file->private_data;
 	struct drm_device *dev = priv->head->dev;
@@ -282,24 +287,23 @@ static __inline__ struct page *drm_do_vm
 	struct page *page;
 
 	if (!dma)
-		return NOPAGE_SIGBUS;	/* Error */
-	if (address > vma->vm_end)
-		return NOPAGE_SIGBUS;	/* Disallow mremap */
+		return VM_FAULT_SIGBUS;	/* Error */
 	if (!dma->pagelist)
-		return NOPAGE_SIGBUS;	/* Nothing allocated */
+		return VM_FAULT_SIGBUS;	/* Nothing allocated */
 
-	offset = address - vma->vm_start;	/* vm_[pg]off[set] should be 0 */
-	page_nr = offset >> PAGE_SHIFT;
+	offset = (unsigned long)vmf->virtual_address - vma->vm_start;	/* vm_[pg]off[set] should be 0 */
+	page_nr = offset >> PAGE_SHIFT; /* page_nr could just be vmf->pgoff */
 	page = virt_to_page((dma->pagelist[page_nr] + (offset & (~PAGE_MASK))));
 
 	get_page(page);
+	vmf->page = page;
 
-	DRM_DEBUG("dma_nopage 0x%lx (page %lu)\n", address, page_nr);
-	return page;
+	DRM_DEBUG("dma_fault 0x%lx (page %lu)\n", offset, page_nr);
+	return 0;
 }
 
 /**
- * \c nopage method for scatter-gather virtual memory.
+ * \c fault method for scatter-gather virtual memory.
  *
  * \param vma virtual memory area.
  * \param address access address.
@@ -307,8 +311,8 @@ static __inline__ struct page *drm_do_vm
  *
  * Determine the map offset from the page offset and get it from drm_sg_mem::pagelist.
  */
-static __inline__ struct page *drm_do_vm_sg_nopage(struct vm_area_struct *vma,
-						   unsigned long address)
+static __inline__ int drm_do_vm_sg_fault(struct vm_area_struct *vma,
+						   struct vm_fault *vmf)
 {
 	struct drm_map *map = (struct drm_map *) vma->vm_private_data;
 	struct drm_file *priv = vma->vm_file->private_data;
@@ -320,77 +324,64 @@ static __inline__ struct page *drm_do_vm
 	struct page *page;
 
 	if (!entry)
-		return NOPAGE_SIGBUS;	/* Error */
-	if (address > vma->vm_end)
-		return NOPAGE_SIGBUS;	/* Disallow mremap */
+		return VM_FAULT_SIGBUS;	/* Error */
 	if (!entry->pagelist)
-		return NOPAGE_SIGBUS;	/* Nothing allocated */
+		return VM_FAULT_SIGBUS;	/* Nothing allocated */
 
-	offset = address - vma->vm_start;
+	offset = (unsigned long)vmf->virtual_address - vma->vm_start;
 	map_offset = map->offset - (unsigned long)dev->sg->virtual;
 	page_offset = (offset >> PAGE_SHIFT) + (map_offset >> PAGE_SHIFT);
 	page = entry->pagelist[page_offset];
 	get_page(page);
+	vmf->page = page;
 
-	return page;
+	return 0;
 }
 
-static struct page *drm_vm_nopage(struct vm_area_struct *vma,
-				  unsigned long address, int *type)
+static int drm_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-	if (type)
-		*type = VM_FAULT_MINOR;
-	return drm_do_vm_nopage(vma, address);
+	return drm_do_vm_fault(vma, vmf);
 }
 
-static struct page *drm_vm_shm_nopage(struct vm_area_struct *vma,
-				      unsigned long address, int *type)
+static int drm_vm_shm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-	if (type)
-		*type = VM_FAULT_MINOR;
-	return drm_do_vm_shm_nopage(vma, address);
+	return drm_do_vm_shm_fault(vma, vmf);
 }
 
-static struct page *drm_vm_dma_nopage(struct vm_area_struct *vma,
-				      unsigned long address, int *type)
+static int drm_vm_dma_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-	if (type)
-		*type = VM_FAULT_MINOR;
-	return drm_do_vm_dma_nopage(vma, address);
+	return drm_do_vm_dma_fault(vma, vmf);
 }
 
-static struct page *drm_vm_sg_nopage(struct vm_area_struct *vma,
-				     unsigned long address, int *type)
+static int drm_vm_sg_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
 {
-	if (type)
-		*type = VM_FAULT_MINOR;
-	return drm_do_vm_sg_nopage(vma, address);
+	return drm_do_vm_sg_fault(vma, vmf);
 }
 
 /** AGP virtual memory operations */
 static struct vm_operations_struct drm_vm_ops = {
-	.nopage = drm_vm_nopage,
+	.fault = drm_vm_fault,
 	.open = drm_vm_open,
 	.close = drm_vm_close,
 };
 
 /** Shared virtual memory operations */
 static struct vm_operations_struct drm_vm_shm_ops = {
-	.nopage = drm_vm_shm_nopage,
+	.fault = drm_vm_shm_fault,
 	.open = drm_vm_open,
 	.close = drm_vm_shm_close,
 };
 
 /** DMA virtual memory operations */
 static struct vm_operations_struct drm_vm_dma_ops = {
-	.nopage = drm_vm_dma_nopage,
+	.fault = drm_vm_dma_fault,
 	.open = drm_vm_open,
 	.close = drm_vm_close,
 };
 
 /** Scatter-gather virtual memory operations */
 static struct vm_operations_struct drm_vm_sg_ops = {
-	.nopage = drm_vm_sg_nopage,
+	.fault = drm_vm_sg_fault,
 	.open = drm_vm_open,
 	.close = drm_vm_close,
 };
@@ -603,7 +594,7 @@ static int drm_mmap_locked(struct file *
 			/*
 			 * On some platforms we can't talk to bus dma address from the CPU, so for
 			 * memory of type DRM_AGP, we'll deal with sorting out the real physical
-			 * pages and mappings in nopage()
+			 * pages and mappings in fault()
 			 */
 #if defined(__powerpc__)
 			pgprot_val(vma->vm_page_prot) |= _PAGE_NO_CACHE;
@@ -633,7 +624,7 @@ static int drm_mmap_locked(struct file *
 		break;
 	case _DRM_CONSISTENT:
 		/* Consistent memory is really like shared memory. But
-		 * it's allocated in a different way, so avoid nopage */
+		 * it's allocated in a different way, so avoid fault */
 		if (remap_pfn_range(vma, vma->vm_start,
 		    page_to_pfn(virt_to_page(map->handle)),
 		    vma->vm_end - vma->vm_start, vma->vm_page_prot))

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