mm: stack based kmap_atomic()

Keep the current interface but ignore the KM_type and use a stack based
approach.

The advantage is that we get rid of crappy code like:

	#define __KM_PTE			\
		(in_nmi() ? KM_NMI_PTE : 	\
		 in_irq() ? KM_IRQ_PTE :	\
		 KM_PTE0)

and in general can stop worrying about what context we're in and what kmap
slots might be appropriate for that.

The downside is that FRV kmap_atomic() gets more expensive.

For now we use a CPP trick suggested by Andrew:

  #define kmap_atomic(page, args...) __kmap_atomic(page)

to avoid having to touch all kmap_atomic() users in a single patch.

[ not compiled on:
  - mn10300: the arch doesn't actually build with highmem to begin with ]

[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c]
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Chris Metcalf <cmetcalf@tilera.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Miller <davem@davemloft.net>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Airlie <airlied@linux.ie>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 90b1d6753b9d..eb6c473c6d1b 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -155,11 +155,11 @@ fast_shmem_read(struct page **pages,
         char __iomem *vaddr;
         int unwritten;
 
-        vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);
+        vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT]);
         if (vaddr == NULL)
                 return -ENOMEM;
         unwritten = __copy_to_user_inatomic(data, vaddr + page_offset, length);
-        kunmap_atomic(vaddr, KM_USER0);
+        kunmap_atomic(vaddr);
 
         if (unwritten)
                 return -EFAULT;
@@ -509,10 +509,10 @@ fast_user_write(struct io_mapping *mapping,
         char *vaddr_atomic;
         unsigned long unwritten;
 
-        vaddr_atomic = io_mapping_map_atomic_wc(mapping, page_base, KM_USER0);
+        vaddr_atomic = io_mapping_map_atomic_wc(mapping, page_base);
         unwritten = __copy_from_user_inatomic_nocache(vaddr_atomic + page_offset,
                                                       user_data, length);
-        io_mapping_unmap_atomic(vaddr_atomic, KM_USER0);
+        io_mapping_unmap_atomic(vaddr_atomic);
         if (unwritten)
                 return -EFAULT;
         return 0;
@@ -551,11 +551,11 @@ fast_shmem_write(struct page **pages,
         char __iomem *vaddr;
         unsigned long unwritten;
 
-        vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT], KM_USER0);
+        vaddr = kmap_atomic(pages[page_base >> PAGE_SHIFT]);
         if (vaddr == NULL)
                 return -ENOMEM;
         unwritten = __copy_from_user_inatomic(vaddr + page_offset, data, length);
-        kunmap_atomic(vaddr, KM_USER0);
+        kunmap_atomic(vaddr);
 
         if (unwritten)
                 return -EFAULT;
@@ -3346,8 +3346,7 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                 reloc_offset = obj_priv->gtt_offset + reloc->offset;
                 reloc_page = io_mapping_map_atomic_wc(dev_priv->mm.gtt_mapping,
                                                       (reloc_offset &
-                                                       ~(PAGE_SIZE - 1)),
-                                                      KM_USER0);
+                                                       ~(PAGE_SIZE - 1)));
                 reloc_entry = (uint32_t __iomem *)(reloc_page +
                                                    (reloc_offset & (PAGE_SIZE - 1)));
                 reloc_val = target_obj_priv->gtt_offset + reloc->delta;
@@ -3358,7 +3357,7 @@ i915_gem_object_pin_and_relocate(struct drm_gem_object *obj,
                           readl(reloc_entry), reloc_val);
 #endif
                 writel(reloc_val, reloc_entry);
-                io_mapping_unmap_atomic(reloc_page, KM_USER0);
+                io_mapping_unmap_atomic(reloc_page);
 
                 /* The updated presumed offset for this entry will be
                  * copied back out to the user.
@@ -4772,11 +4771,11 @@ void i915_gem_detach_phys_object(struct drm_device *dev,
         page_count = obj->size / PAGE_SIZE;
 
         for (i = 0; i < page_count; i++) {
-                char *dst = kmap_atomic(obj_priv->pages[i], KM_USER0);
+                char *dst = kmap_atomic(obj_priv->pages[i]);
                 char *src = obj_priv->phys_obj->handle->vaddr + (i * PAGE_SIZE);
 
                 memcpy(dst, src, PAGE_SIZE);
-                kunmap_atomic(dst, KM_USER0);
+                kunmap_atomic(dst);
         }
         drm_clflush_pages(obj_priv->pages, page_count);
         drm_agp_chipset_flush(dev);
@@ -4833,11 +4832,11 @@ i915_gem_attach_phys_object(struct drm_device *dev,
         page_count = obj->size / PAGE_SIZE;
 
         for (i = 0; i < page_count; i++) {
-                char *src = kmap_atomic(obj_priv->pages[i], KM_USER0);
+                char *src = kmap_atomic(obj_priv->pages[i]);
                 char *dst = obj_priv->phys_obj->handle->vaddr + (i * PAGE_SIZE);
 
                 memcpy(dst, src, PAGE_SIZE);
-                kunmap_atomic(src, KM_USER0);
+                kunmap_atomic(src);
         }
 
         i915_gem_object_put_pages(obj);