mm: fault feedback #2

This patch completes Linus's wish that the fault return codes be made into
bit flags, which I agree makes everything nicer.  This requires requires
all handle_mm_fault callers to be modified (possibly the modifications
should go further and do things like fault accounting in handle_mm_fault --
however that would be for another patch).

[akpm@linux-foundation.org: fix alpha build]
[akpm@linux-foundation.org: fix s390 build]
[akpm@linux-foundation.org: fix sparc build]
[akpm@linux-foundation.org: fix sparc64 build]
[akpm@linux-foundation.org: fix ia64 build]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Ian Molton <spyro@f2s.com>
Cc: Bryan Wu <bryan.wu@analog.com>
Cc: Mikael Starvik <starvik@axis.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Hirokazu Takata <takata@linux-m32r.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Roman Zippel <zippel@linux-m68k.org>
Cc: Greg Ungerer <gerg@uclinux.org>
Cc: Matthew Wilcox <willy@debian.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Kazumoto Kojima <kkojima@rr.iij4u.or.jp>
Cc: Richard Curnow <rc@rc0.org.uk>
Cc: William Lee Irwin III <wli@holomorphy.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Miles Bader <uclinux-v850@lsi.nec.co.jp>
Cc: Chris Zankel <chris@zankel.net>
Acked-by: Kyle McMartin <kyle@mcmartin.ca>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
[ Still apparently needs some ARM and PPC loving - Linus ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 26 insertions, 27 deletions

diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index 63181671e3e3..60604b2819b2 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -20,6 +20,7 @@ static int __handle_fault(struct mm_struct *mm, unsigned long address,
 {
         struct vm_area_struct *vma;
         int ret = -EFAULT;
+        int fault;
 
         if (in_atomic())
                 return ret;
@@ -44,20 +45,18 @@ static int __handle_fault(struct mm_struct *mm, unsigned long address,
         }
 
 survive:
-        switch (handle_mm_fault(mm, vma, address, write_access)) {
-        case VM_FAULT_MINOR:
-                current->min_flt++;
-                break;
-        case VM_FAULT_MAJOR:
-                current->maj_flt++;
-                break;
-        case VM_FAULT_SIGBUS:
-                goto out_sigbus;
-        case VM_FAULT_OOM:
-                goto out_of_memory;
-        default:
+        fault = handle_mm_fault(mm, vma, address, write_access);
+        if (unlikely(fault & VM_FAULT_ERROR)) {
+                if (fault & VM_FAULT_OOM)
+                        goto out_of_memory;
+                else if (fault & VM_FAULT_SIGBUS)
+                        goto out_sigbus;
                 BUG();
         }
+        if (fault & VM_FAULT_MAJOR)
+                current->maj_flt++;
+        else
+                current->min_flt++;
         ret = 0;
 out:
         up_read(&mm->mmap_sem);
diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index d855cdbf8fb8..54055194e9af 100644
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -307,6 +307,7 @@ do_exception(struct pt_regs *regs, unsigned long error_code, int write)
         unsigned long address;
         int space;
         int si_code;
+        int fault;
 
         if (notify_page_fault(regs, error_code))
                 return;
@@ -377,23 +378,22 @@ survive:
          * make sure we exit gracefully rather than endlessly redo
          * the fault.
          */
-        switch (handle_mm_fault(mm, vma, address, write)) {
-        case VM_FAULT_MINOR:
-                tsk->min_flt++;
-                break;
-        case VM_FAULT_MAJOR:
-                tsk->maj_flt++;
-                break;
-        case VM_FAULT_SIGBUS:
-                do_sigbus(regs, error_code, address);
-                return;
-        case VM_FAULT_OOM:
-                if (do_out_of_memory(regs, error_code, address))
-                        goto survive;
-                return;
-        default:
+        fault = handle_mm_fault(mm, vma, address, write);
+        if (unlikely(fault & VM_FAULT_ERROR)) {
+                if (fault & VM_FAULT_OOM) {
+                        if (do_out_of_memory(regs, error_code, address))
+                                goto survive;
+                        return;
+                } else if (fault & VM_FAULT_SIGBUS) {
+                        do_sigbus(regs, error_code, address);
+                        return;
+                }
                 BUG();
         }
+        if (fault & VM_FAULT_MAJOR)
+                tsk->maj_flt++;
+        else
+                tsk->min_flt++;
 
         up_read(&mm->mmap_sem);
         /*