mm: create the new vm_fault_t type

Page fault handlers are supposed to return VM_FAULT codes, but some
drivers/file systems mistakenly return error numbers.  Now that all
drivers/file systems have been converted to use the vm_fault_t return
type, change the type definition to no longer be compatible with 'int'.
By making it an unsigned int, the function prototype becomes
incompatible with a function which returns int.  Sparse will detect any
attempts to return a value which is not a VM_FAULT code.

VM_FAULT_SET_HINDEX and VM_FAULT_GET_HINDEX values are changed to avoid
conflict with other VM_FAULT codes.

[jrdr.linux@gmail.com: fix warnings]
  Link: http://lkml.kernel.org/r/20190109183742.GA24326@jordon-HP-15-Notebook-PC
Link: http://lkml.kernel.org/r/20190108183041.GA12137@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 0 insertions, 46 deletions

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 20ec56f8e2bb..5801ee849f36 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1323,52 +1323,6 @@ static inline void clear_page_pfmemalloc(struct page *page)
 }
 
 /*
- * Different kinds of faults, as returned by handle_mm_fault().
- * Used to decide whether a process gets delivered SIGBUS or
- * just gets major/minor fault counters bumped up.
- */
-
-#define VM_FAULT_OOM	0x0001
-#define VM_FAULT_SIGBUS	0x0002
-#define VM_FAULT_MAJOR	0x0004
-#define VM_FAULT_WRITE	0x0008	/* Special case for get_user_pages */
-#define VM_FAULT_HWPOISON 0x0010	/* Hit poisoned small page */
-#define VM_FAULT_HWPOISON_LARGE 0x0020  /* Hit poisoned large page. Index encoded in upper bits */
-#define VM_FAULT_SIGSEGV 0x0040
-
-#define VM_FAULT_NOPAGE	0x0100	/* ->fault installed the pte, not return page */
-#define VM_FAULT_LOCKED	0x0200	/* ->fault locked the returned page */
-#define VM_FAULT_RETRY	0x0400	/* ->fault blocked, must retry */
-#define VM_FAULT_FALLBACK 0x0800	/* huge page fault failed, fall back to small */
-#define VM_FAULT_DONE_COW   0x1000	/* ->fault has fully handled COW */
-#define VM_FAULT_NEEDDSYNC  0x2000	/* ->fault did not modify page tables
-					 * and needs fsync() to complete (for
-					 * synchronous page faults in DAX) */
-
-#define VM_FAULT_ERROR	(VM_FAULT_OOM | VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | \
-			 VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE | \
-			 VM_FAULT_FALLBACK)
-
-#define VM_FAULT_RESULT_TRACE \
-	{ VM_FAULT_OOM,			"OOM" }, \
-	{ VM_FAULT_SIGBUS,		"SIGBUS" }, \
-	{ VM_FAULT_MAJOR,		"MAJOR" }, \
-	{ VM_FAULT_WRITE,		"WRITE" }, \
-	{ VM_FAULT_HWPOISON,		"HWPOISON" }, \
-	{ VM_FAULT_HWPOISON_LARGE,	"HWPOISON_LARGE" }, \
-	{ VM_FAULT_SIGSEGV,		"SIGSEGV" }, \
-	{ VM_FAULT_NOPAGE,		"NOPAGE" }, \
-	{ VM_FAULT_LOCKED,		"LOCKED" }, \
-	{ VM_FAULT_RETRY,		"RETRY" }, \
-	{ VM_FAULT_FALLBACK,		"FALLBACK" }, \
-	{ VM_FAULT_DONE_COW,		"DONE_COW" }, \
-	{ VM_FAULT_NEEDDSYNC,		"NEEDDSYNC" }
-
-/* Encode hstate index for a hwpoisoned large page */
-#define VM_FAULT_SET_HINDEX(x) ((x) << 12)
-#define VM_FAULT_GET_HINDEX(x) (((x) >> 12) & 0xf)
-
-/*
  * Can be called by the pagefault handler when it gets a VM_FAULT_OOM.
  */
 extern void pagefault_out_of_memory(void);