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[PATCH] Simplify pte_offset_{map,map_nested}() on 32 bits [try #2]

To: Ralf Baechle <ralf@linux-mips.org>
Subject: [PATCH] Simplify pte_offset_{map,map_nested}() on 32 bits [try #2]
From: Franck Bui-Huu <vagabon.xyz@gmail.com>
Date: Fri, 04 May 2007 12:57:03 +0200
Cc: linux-mips <linux-mips@linux-mips.org>
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From: Franck Bui-Huu <fbuihuu@gmail.com>

Since both kernel and process page tables are never allocated in
highmem these 2 macros were doing unnecessary extra works for getting
a pte from a pmd.

This patch also clean up pte allocation functions by passing
__GFP_ZERO to alloc_pages() and by removing a useless local variable.

With this patch the size of the kernel is slighly reduced.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
---

 Hi Ralf,

 Maybe I'm missing something but it seems that page tables are
 never allocated from highmem. Please correct me if I'm wrong.
 This patch boot fine on a 32-bits platform without highmem
 though.

 This patch does not include any modifications for 64-bits
 platforms since I can't test them but this assertion
 should be more true since there's no highmem on these
 platforms. I can make another patch for such platforms if
 you think it makes sense.

 Please consider,

                Franck

 include/asm-mips/pgalloc.h    |   22 ++++++----------------
 include/asm-mips/pgtable-32.h |   13 +++++--------
 2 files changed, 11 insertions(+), 24 deletions(-)

diff --git a/include/asm-mips/pgalloc.h b/include/asm-mips/pgalloc.h
index 5685d4f..a3b9953 100644
--- a/include/asm-mips/pgalloc.h
+++ b/include/asm-mips/pgalloc.h
@@ -62,26 +62,16 @@ static inline void pgd_free(pgd_t *pgd)
        free_pages((unsigned long)pgd, PGD_ORDER);
 }
 
-static inline pte_t *pte_alloc_one_kernel(struct mm_struct *mm,
-       unsigned long address)
+static inline pte_t *
+pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 {
-       pte_t *pte;
-
-       pte = (pte_t *) __get_free_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 
PTE_ORDER);
-
-       return pte;
+       return (pte_t *)__get_free_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, 
PTE_ORDER);
 }
 
-static inline struct page *pte_alloc_one(struct mm_struct *mm,
-       unsigned long address)
+static inline struct page *
+pte_alloc_one(struct mm_struct *mm, unsigned long address)
 {
-       struct page *pte;
-
-       pte = alloc_pages(GFP_KERNEL | __GFP_REPEAT, PTE_ORDER);
-       if (pte)
-               clear_highpage(pte);
-
-       return pte;
+       return alloc_pages(GFP_KERNEL|__GFP_REPEAT|__GFP_ZERO, PTE_ORDER);
 }
 
 static inline void pte_free_kernel(pte_t *pte)
diff --git a/include/asm-mips/pgtable-32.h b/include/asm-mips/pgtable-32.h
index 2fbd47e..9e0a8c7 100644
--- a/include/asm-mips/pgtable-32.h
+++ b/include/asm-mips/pgtable-32.h
@@ -143,6 +143,7 @@ pfn_pte(unsigned long pfn, pgprot_t prot)
 #define __pgd_offset(address)  pgd_index(address)
 #define __pud_offset(address)  (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
 #define __pmd_offset(address)  (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
+#define __pte_offset(address)  (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE-1))
 
 /* to find an entry in a kernel page-table-directory */
 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
@@ -153,19 +154,15 @@ pfn_pte(unsigned long pfn, pgprot_t prot)
 #define pgd_offset(mm,addr)    ((mm)->pgd + pgd_index(addr))
 
 /* Find an entry in the third-level page table.. */
-#define __pte_offset(address)                                          \
-       (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 #define pte_offset(dir, address)                                       \
        ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 #define pte_offset_kernel(dir, address)                                        
\
        ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 
-#define pte_offset_map(dir, address)                                    \
-       ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
-#define pte_offset_map_nested(dir, address)                             \
-       ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
-#define pte_unmap(pte) ((void)(pte))
-#define pte_unmap_nested(pte) ((void)(pte))
+#define pte_offset_map(dir, address)           pte_offset_kernel(dir,address)
+#define pte_offset_map_nested(dir, address)    pte_offset_kernel(dir,address)
+#define pte_unmap(pte)                         ((void)(pte))
+#define pte_unmap_nested(pte)                  ((void)(pte))
 
 #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX)
 
-- 
1.5.1.3


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