mm: introduce fault_env
The idea borrowed from Peter's patch from patchset on speculative page
faults[1]:
Instead of passing around the endless list of function arguments,
replace the lot with a single structure so we can change context without
endless function signature changes.
The changes are mostly mechanical with exception of faultaround code:
filemap_map_pages() got reworked a bit.
This patch is preparation for the next one.
[1] http://lkml.kernel.org/r/20141020222841.302891540@infradead.org
Link: http://lkml.kernel.org/r/1466021202-61880-9-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index f0a7a03..9bed924 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -1,20 +1,12 @@
#ifndef _LINUX_HUGE_MM_H
#define _LINUX_HUGE_MM_H
-extern int do_huge_pmd_anonymous_page(struct mm_struct *mm,
- struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd,
- unsigned int flags);
+extern int do_huge_pmd_anonymous_page(struct fault_env *fe);
extern int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
pmd_t *dst_pmd, pmd_t *src_pmd, unsigned long addr,
struct vm_area_struct *vma);
-extern void huge_pmd_set_accessed(struct mm_struct *mm,
- struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd,
- pmd_t orig_pmd, int dirty);
-extern int do_huge_pmd_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long address, pmd_t *pmd,
- pmd_t orig_pmd);
+extern void huge_pmd_set_accessed(struct fault_env *fe, pmd_t orig_pmd);
+extern int do_huge_pmd_wp_page(struct fault_env *fe, pmd_t orig_pmd);
extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
unsigned long addr,
pmd_t *pmd,
@@ -134,8 +126,7 @@
return 1;
}
-extern int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, pmd_t pmd, pmd_t *pmdp);
+extern int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t orig_pmd);
extern struct page *huge_zero_page;
@@ -196,8 +187,7 @@
return NULL;
}
-static inline int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr, pmd_t pmd, pmd_t *pmdp)
+static inline int do_huge_pmd_numa_page(struct fault_env *fe, pmd_t orig_pmd)
{
return 0;
}
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 646bc36..8bd7455 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -309,10 +309,27 @@
* VM_FAULT_DAX_LOCKED and fill in
* entry here.
*/
- /* for ->map_pages() only */
- pgoff_t max_pgoff; /* map pages for offset from pgoff till
- * max_pgoff inclusive */
- pte_t *pte; /* pte entry associated with ->pgoff */
+};
+
+/*
+ * Page fault context: passes though page fault handler instead of endless list
+ * of function arguments.
+ */
+struct fault_env {
+ struct vm_area_struct *vma; /* Target VMA */
+ unsigned long address; /* Faulting virtual address */
+ unsigned int flags; /* FAULT_FLAG_xxx flags */
+ pmd_t *pmd; /* Pointer to pmd entry matching
+ * the 'address'
+ */
+ pte_t *pte; /* Pointer to pte entry matching
+ * the 'address'. NULL if the page
+ * table hasn't been allocated.
+ */
+ spinlock_t *ptl; /* Page table lock.
+ * Protects pte page table if 'pte'
+ * is not NULL, otherwise pmd.
+ */
};
/*
@@ -327,7 +344,8 @@
int (*fault)(struct vm_area_struct *vma, struct vm_fault *vmf);
int (*pmd_fault)(struct vm_area_struct *, unsigned long address,
pmd_t *, unsigned int flags);
- void (*map_pages)(struct vm_area_struct *vma, struct vm_fault *vmf);
+ void (*map_pages)(struct fault_env *fe,
+ pgoff_t start_pgoff, pgoff_t end_pgoff);
/* notification that a previously read-only page is about to become
* writable, if an error is returned it will cause a SIGBUS */
@@ -600,8 +618,7 @@
return pte;
}
-void do_set_pte(struct vm_area_struct *vma, unsigned long address,
- struct page *page, pte_t *pte, bool write, bool anon);
+void do_set_pte(struct fault_env *fe, struct page *page);
#endif
/*
@@ -2062,7 +2079,8 @@
/* generic vm_area_ops exported for stackable file systems */
extern int filemap_fault(struct vm_area_struct *, struct vm_fault *);
-extern void filemap_map_pages(struct vm_area_struct *vma, struct vm_fault *vmf);
+extern void filemap_map_pages(struct fault_env *fe,
+ pgoff_t start_pgoff, pgoff_t end_pgoff);
extern int filemap_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf);
/* mm/page-writeback.c */
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 587480a..dd66a95 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -27,8 +27,7 @@
#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
-extern int handle_userfault(struct vm_area_struct *vma, unsigned long address,
- unsigned int flags, unsigned long reason);
+extern int handle_userfault(struct fault_env *fe, unsigned long reason);
extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
unsigned long src_start, unsigned long len);
@@ -56,10 +55,7 @@
#else /* CONFIG_USERFAULTFD */
/* mm helpers */
-static inline int handle_userfault(struct vm_area_struct *vma,
- unsigned long address,
- unsigned int flags,
- unsigned long reason)
+static inline int handle_userfault(struct fault_env *fe, unsigned long reason)
{
return VM_FAULT_SIGBUS;
}