[RFC][PATCH v2 19/23] (x86) __vmalloc: add gfp flags variant of pte, pmd, and pud allocation

__vmalloc: propagating GFP allocation flag.

- adds functions to allow caller to pass the GFP flag for memory allocation
- helps in fixing the Bug 30702 (__vmalloc(GFP_NOFS) can callback
		  file system evict_inode).

Signed-off-by: Anand Mitra <redacted>
Signed-off-by: Prasad Joshi <redacted>
---
Chnagelog:
arch/x86/include/asm/pgalloc.h |   17 +++++++++++++++--
arch/x86/mm/pgtable.c          |    8 +++++++-
2 files changed, 22 insertions(+), 3 deletions(-)
---

diff --git a/arch/x86/include/asm/pgalloc.h b/arch/x86/include/asm/pgalloc.h
index b4389a4..db83bd4 100644
--- a/arch/x86/include/asm/pgalloc.h
+++ b/arch/x86/include/asm/pgalloc.h

@@ -34,6 +34,7 @@ extern pgd_t *pgd_alloc(struct mm_struct *);
 extern void pgd_free(struct mm_struct *mm, pgd_t *pgd);

 extern pte_t *pte_alloc_one_kernel(struct mm_struct *, unsigned long);
+extern pte_t *__pte_alloc_one_kernel(struct mm_struct *, unsigned long, gfp_t);
 extern pgtable_t pte_alloc_one(struct mm_struct *, unsigned long);

 /* Should really implement gc for free page table pages. This could be

@@ -78,9 +79,15 @@ static inline void pmd_populate(struct mm_struct

*mm, pmd_t *pmd,
 #define pmd_pgtable(pmd) pmd_page(pmd)

 #if PAGETABLE_LEVELS > 2
+static inline pmd_t *
+__pmd_alloc_one(struct mm_struct *mm, unsigned long addr, gfp_t gfp_mask)
+{
+	return (pmd_t *)get_zeroed_page(gfp_mask);
+}
+
 static inline pmd_t *pmd_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return (pmd_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+	return __pmd_alloc_one(mm, addr, GFP_KERNEL | __GFP_REPEAT);
 }

 static inline void pmd_free(struct mm_struct *mm, pmd_t *pmd)

@@ -114,9 +121,15 @@ static inline void pgd_populate(struct mm_struct

*mm, pgd_t *pgd, pud_t *pud)
 	set_pgd(pgd, __pgd(_PAGE_TABLE | __pa(pud)));
 }

+static inline pud_t *
+__pud_alloc_one(struct mm_struct *mm, unsigned long addr, gfp_t gfp_mask)
+{
+	return (pud_t *)get_zeroed_page(gfp_mask);
+}
+
 static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	return (pud_t *)get_zeroed_page(GFP_KERNEL|__GFP_REPEAT);
+	return __pud_alloc_one(mm, addr, GFP_KERNEL | __GFP_REPEAT);
 }

 static inline void pud_free(struct mm_struct *mm, pud_t *pud)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 500242d..c42a27c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c

@@ -15,9 +15,15 @@

 gfp_t __userpte_alloc_gfp = PGALLOC_GFP | PGALLOC_USER_GFP;

+pte_t *
+__pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address,

gfp_t gfp_mask)
+{
+	return (pte_t *)__get_free_page(gfp_mask | __GFP_NOTRACK | __GFP_ZERO);
+}
+
 pte_t *pte_alloc_one_kernel(struct mm_struct *mm, unsigned long address)
 {
-	return (pte_t *)__get_free_page(PGALLOC_GFP);
+	return __pte_alloc_one_kernel(mm, address, GFP_KERNEL | __GFP_REPEAT);
 }

 pgtable_t pte_alloc_one(struct mm_struct *mm, unsigned long address)