On Tue, 18 Jul 2006, Dave Airlie wrote:
> AGP keeps its own copy of the protection_map, upcoming DRM changes
> will also require access to this map from modules.
I'm happy with the intent of your vm_get_page_prot() patch (and would
like to extend it to other places after, minimizing references to the
protection_map[]). But there's a few aspects which distress me - the
u8 type nowhere else in mm, the requirement that caller mask the arg,
agp_convert_mmap_flags still using its own conversion from PROT_ to VM_
while there's an inline in mm.h (though why someone thought to optimize
and so obscure that version puzzles me!). Would you be happy to insert
your Sign-off in the replacement below?
AGP keeps its own copy of the protection_map, upcoming DRM changes will
also require access to this map from modules.
Signed-off-by: Hugh Dickins <[email protected]>
---
drivers/char/agp/frontend.c | 27 ++-------------------------
include/linux/mm.h | 1 +
mm/mmap.c | 7 +++++++
3 files changed, 10 insertions(+), 25 deletions(-)
--- 2.6.18-rc2-git6/drivers/char/agp/frontend.c 2006-07-16 00:17:07.000000000 +0100
+++ linux/drivers/char/agp/frontend.c 2006-07-26 20:32:10.000000000 +0100
@@ -151,35 +151,12 @@ static void agp_add_seg_to_client(struct
client->segments = seg;
}
-/* Originally taken from linux/mm/mmap.c from the array
- * protection_map.
- * The original really should be exported to modules, or
- * some routine which does the conversion for you
- */
-
-static const pgprot_t my_protect_map[16] =
-{
- __P000, __P001, __P010, __P011, __P100, __P101, __P110, __P111,
- __S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
-};
-
static pgprot_t agp_convert_mmap_flags(int prot)
{
-#define _trans(x,bit1,bit2) \
-((bit1==bit2)?(x&bit1):(x&bit1)?bit2:0)
-
unsigned long prot_bits;
- pgprot_t temp;
-
- prot_bits = _trans(prot, PROT_READ, VM_READ) |
- _trans(prot, PROT_WRITE, VM_WRITE) |
- _trans(prot, PROT_EXEC, VM_EXEC);
-
- prot_bits |= VM_SHARED;
- temp = my_protect_map[prot_bits & 0x0000000f];
-
- return temp;
+ prot_bits = calc_vm_prot_bits(prot) | VM_SHARED;
+ return vm_get_page_prot(prot_bits);
}
static int agp_create_segment(struct agp_client *client, struct agp_region *region)
--- 2.6.18-rc2-git6/include/linux/mm.h 2006-07-16 00:17:31.000000000 +0100
+++ linux/include/linux/mm.h 2006-07-26 20:33:59.000000000 +0100
@@ -1012,6 +1012,7 @@ static inline unsigned long vma_pages(st
return (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
}
+pgprot_t vm_get_page_prot(unsigned long vm_flags);
struct vm_area_struct *find_extend_vma(struct mm_struct *, unsigned long addr);
struct page *vmalloc_to_page(void *addr);
unsigned long vmalloc_to_pfn(void *addr);
--- 2.6.18-rc2-git6/mm/mmap.c 2006-07-16 00:17:39.000000000 +0100
+++ linux/mm/mmap.c 2006-07-26 20:40:12.000000000 +0100
@@ -60,6 +60,13 @@ pgprot_t protection_map[16] = {
__S000, __S001, __S010, __S011, __S100, __S101, __S110, __S111
};
+pgprot_t vm_get_page_prot(unsigned long vm_flags)
+{
+ return protection_map[vm_flags &
+ (VM_READ|VM_WRITE|VM_EXEC|VM_SHARED)];
+}
+EXPORT_SYMBOL(vm_get_page_prot);
+
int sysctl_overcommit_memory = OVERCOMMIT_GUESS; /* heuristic overcommit */
int sysctl_overcommit_ratio = 50; /* default is 50% */
int sysctl_max_map_count __read_mostly = DEFAULT_MAX_MAP_COUNT;
-
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