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/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 */