mm: Change return type int to vm_fault_t for fault handlers

Use new return type vm_fault_t for fault handler.  For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno.  Once all instances are converted, vm_fault_t will become a
distinct type.

Ref-> commit 1c8f422059ae ("mm: change return type to vm_fault_t")

The aim is to change the return type of finish_fault() and
handle_mm_fault() to vm_fault_t type.  As part of that clean up return
type of all other recursively called functions have been changed to
vm_fault_t type.

The places from where handle_mm_fault() is getting invoked will be
change to vm_fault_t type but in a separate patch.

vmf_error() is the newly introduce inline function in 4.17-rc6.

[akpm@linux-foundation.org: don't shadow outer local `ret' in __do_huge_pmd_anonymous_page()]
Link: http://lkml.kernel.org/r/20180604171727.GA20279@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 20 insertions, 17 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index a8a126259bc4..27e3e32135a8 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -6,7 +6,7 @@
 
 #include <linux/fs.h> /* only for vma_is_dax() */
 
-extern int do_huge_pmd_anonymous_page(struct vm_fault *vmf);
+extern vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf);
 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);
@@ -23,7 +23,7 @@ static inline void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
 }
 #endif
 
-extern int do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd);
+extern vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf, pmd_t orig_pmd);
 extern struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
 					  unsigned long addr,
 					  pmd_t *pmd,
@@ -216,7 +216,7 @@ struct page *follow_devmap_pmd(struct vm_area_struct *vma, unsigned long addr,
 struct page *follow_devmap_pud(struct vm_area_struct *vma, unsigned long addr,
 		pud_t *pud, int flags);
 
-extern int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);
+extern vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd);
 
 extern struct page *huge_zero_page;
 
@@ -321,7 +321,8 @@ static inline spinlock_t *pud_trans_huge_lock(pud_t *pud,
 	return NULL;
 }
 
-static inline int do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t orig_pmd)
+static inline vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf,
+		pmd_t orig_pmd)
 {
 	return 0;
 }
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index c39d9170a8a0..6b68e345f0ca 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h
@@ -105,7 +105,7 @@ void hugetlb_report_meminfo(struct seq_file *);
 int hugetlb_report_node_meminfo(int, char *);
 void hugetlb_show_meminfo(void);
 unsigned long hugetlb_total_pages(void);
-int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
+vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
 			unsigned long address, unsigned int flags);
 int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, pte_t *dst_pte,
 				struct vm_area_struct *dst_vma,
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a9e733b5fb76..8fcc36660de6 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -728,10 +728,10 @@ static inline pte_t maybe_mkwrite(pte_t pte, struct vm_area_struct *vma)
 	return pte;
 }
 
-int alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
+vm_fault_t alloc_set_pte(struct vm_fault *vmf, struct mem_cgroup *memcg,
 		struct page *page);
-int finish_fault(struct vm_fault *vmf);
-int finish_mkwrite_fault(struct vm_fault *vmf);
+vm_fault_t finish_fault(struct vm_fault *vmf);
+vm_fault_t finish_mkwrite_fault(struct vm_fault *vmf);
 #endif
 
 /*
@@ -1403,8 +1403,8 @@ int generic_error_remove_page(struct address_space *mapping, struct page *page);
 int invalidate_inode_page(struct page *page);
 
 #ifdef CONFIG_MMU
-extern int handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
-		unsigned int flags);
+extern vm_fault_t handle_mm_fault(struct vm_area_struct *vma,
+			unsigned long address, unsigned int flags);
 extern int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
 			    unsigned long address, unsigned int fault_flags,
 			    bool *unlocked);
@@ -1413,7 +1413,7 @@ void unmap_mapping_pages(struct address_space *mapping,
 void unmap_mapping_range(struct address_space *mapping,
 		loff_t const holebegin, loff_t const holelen, int even_cows);
 #else
-static inline int handle_mm_fault(struct vm_area_struct *vma,
+static inline vm_fault_t handle_mm_fault(struct vm_area_struct *vma,
 		unsigned long address, unsigned int flags)
 {
 	/* should never happen if there's no MMU */
@@ -2563,7 +2563,7 @@ static inline struct page *follow_page(struct vm_area_struct *vma,
 #define FOLL_COW	0x4000	/* internal GUP flag */
 #define FOLL_ANON	0x8000	/* don't do file mappings */
 
-static inline int vm_fault_to_errno(int vm_fault, int foll_flags)
+static inline int vm_fault_to_errno(vm_fault_t vm_fault, int foll_flags)
 {
 	if (vm_fault & VM_FAULT_OOM)
 		return -ENOMEM;
diff --git a/include/linux/oom.h b/include/linux/oom.h
index 92f70e4c6252..69864a547663 100644
--- a/include/linux/oom.h
+++ b/include/linux/oom.h
@@ -88,7 +88,7 @@ static inline bool mm_is_oom_victim(struct mm_struct *mm)
  *
  * Return 0 when the PF is safe VM_FAULT_SIGBUS otherwise.
  */
-static inline int check_stable_address_space(struct mm_struct *mm)
+static inline vm_fault_t check_stable_address_space(struct mm_struct *mm)
 {
 	if (unlikely(test_bit(MMF_UNSTABLE, &mm->flags)))
 		return VM_FAULT_SIGBUS;
diff --git a/include/linux/swapops.h b/include/linux/swapops.h
index 568a3553d918..22af9d8a84ae 100644
--- a/include/linux/swapops.h
+++ b/include/linux/swapops.h
@@ -4,6 +4,7 @@
 
 #include <linux/radix-tree.h>
 #include <linux/bug.h>
+#include <linux/mm_types.h>
 
 /*
  * swapcache pages are stored in the swapper_space radix tree.  We want to
@@ -134,7 +135,7 @@ static inline struct page *device_private_entry_to_page(swp_entry_t entry)
 	return pfn_to_page(swp_offset(entry));
 }
 
-int device_private_entry_fault(struct vm_area_struct *vma,
+vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
 		       unsigned long addr,
 		       swp_entry_t entry,
 		       unsigned int flags,
@@ -169,7 +170,7 @@ static inline struct page *device_private_entry_to_page(swp_entry_t entry)
 	return NULL;
 }
 
-static inline int device_private_entry_fault(struct vm_area_struct *vma,
+static inline vm_fault_t device_private_entry_fault(struct vm_area_struct *vma,
 				     unsigned long addr,
 				     swp_entry_t entry,
 				     unsigned int flags,
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index e091f0a11b11..37c9eba75c98 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -28,7 +28,7 @@
 #define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
 #define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
 
-extern int handle_userfault(struct vm_fault *vmf, unsigned long reason);
+extern vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason);
 
 extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
 			    unsigned long src_start, unsigned long len,
@@ -77,7 +77,8 @@ extern void userfaultfd_unmap_complete(struct mm_struct *mm,
 #else /* CONFIG_USERFAULTFD */
 
 /* mm helpers */
-static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
+static inline vm_fault_t handle_userfault(struct vm_fault *vmf,
+				unsigned long reason)
 {
 	return VM_FAULT_SIGBUS;
 }