s390/mm,fault: move VM_FAULT_ERROR handling to do_exception()

Get rid of do_fault_error() and move its contents to do_exception(),
which makes do_exception(). With removing do_fault_error() it is also
possible to get rid of the handle_fault_error_nolock() wrapper.
Instead rename do_no_context() to handle_fault_error_nolock().

In result the whole fault handling looks much more like on other
architectures.

Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index bee22e91e14bfdd50bb86b70aa1fdab64e3cb4d1..249aefcf7c4e6e1fe5290f3712b0e6fac3ca8e10 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -225,7 +225,7 @@ static void do_sigsegv(struct pt_regs *regs, int si_code)
        force_sig_fault(SIGSEGV, si_code, (void __user *)get_fault_address(regs));
 }
 
-static void do_no_context(struct pt_regs *regs, int si_code)
+static void handle_fault_error_nolock(struct pt_regs *regs, int si_code)
 {
        enum fault_type fault_type;
        unsigned long address;
@@ -253,11 +253,6 @@ static void do_no_context(struct pt_regs *regs, int si_code)
        die(regs, "Oops");
 }
 
-static inline void handle_fault_error_nolock(struct pt_regs *regs, int si_code)
-{
-       do_no_context(regs, si_code);
-}
-
 static void handle_fault_error(struct pt_regs *regs, int si_code)
 {
        struct mm_struct *mm = current->mm;
@@ -271,31 +266,6 @@ static void do_sigbus(struct pt_regs *regs)
        force_sig_fault(SIGBUS, BUS_ADRERR, (void __user *)get_fault_address(regs));
 }
 
-static void do_fault_error(struct pt_regs *regs, vm_fault_t fault)
-{
-       /* fault & VM_FAULT_ERROR */
-       if (fault & VM_FAULT_OOM) {
-               if (!user_mode(regs))
-                       do_no_context(regs, 0);
-               else
-                       pagefault_out_of_memory();
-       } else if (fault & VM_FAULT_SIGSEGV) {
-               /* Kernel mode? Handle exceptions or die */
-               if (!user_mode(regs))
-                       do_no_context(regs, 0);
-               else
-                       do_sigsegv(regs, SEGV_MAPERR);
-       } else if (fault & VM_FAULT_SIGBUS) {
-               /* Kernel mode? Handle exceptions or die */
-               if (!user_mode(regs))
-                       do_no_context(regs, 0);
-               else
-                       do_sigbus(regs);
-       } else {
-               BUG();
-       }
-}
-
 /*
  * This routine handles page faults.  It determines the address,
  * and the problem, and then passes it off to one of the appropriate
@@ -362,9 +332,9 @@ static void do_exception(struct pt_regs *regs, int access)
                vma_end_read(vma);
        if (!(fault & VM_FAULT_RETRY)) {
                count_vm_vma_lock_event(VMA_LOCK_SUCCESS);
-               if (likely(!(fault & VM_FAULT_ERROR)))
-                       fault = 0;
-               goto out;
+               if (unlikely(fault & VM_FAULT_ERROR))
+                       goto error;
+               return;
        }
        count_vm_vma_lock_event(VMA_LOCK_RETRY);
        /* Quick path to respond to signals */
@@ -412,13 +382,14 @@ retry:
        if (fault & VM_FAULT_COMPLETED) {
                if (gmap) {
                        mmap_read_lock(mm);
-                       goto out_gmap;
+                       goto gmap;
                }
-               fault = 0;
-               goto out;
+               return;
+       }
+       if (unlikely(fault & VM_FAULT_ERROR)) {
+               mmap_read_unlock(mm);
+               goto error;
        }
-       if (unlikely(fault & VM_FAULT_ERROR))
-               goto out_up;
        if (fault & VM_FAULT_RETRY) {
                if (IS_ENABLED(CONFIG_PGSTE) && gmap && (flags & FAULT_FLAG_RETRY_NOWAIT)) {
                        /*
@@ -433,7 +404,7 @@ retry:
                mmap_read_lock(mm);
                goto retry;
        }
-out_gmap:
+gmap:
        if (IS_ENABLED(CONFIG_PGSTE) && gmap) {
                address =  __gmap_link(gmap, current->thread.gmap_addr,
                                       address);
@@ -441,15 +412,31 @@ out_gmap:
                        return handle_fault_error(regs, SEGV_MAPERR);
                if (address == -ENOMEM) {
                        fault = VM_FAULT_OOM;
-                       goto out_up;
+                       mmap_read_unlock(mm);
+                       goto error;
                }
        }
-       fault = 0;
-out_up:
        mmap_read_unlock(mm);
-out:
-       if (unlikely(fault))
-               do_fault_error(regs, fault);
+       return;
+error:
+       if (fault & VM_FAULT_OOM) {
+               if (!user_mode(regs))
+                       handle_fault_error_nolock(regs, 0);
+               else
+                       pagefault_out_of_memory();
+       } else if (fault & VM_FAULT_SIGSEGV) {
+               if (!user_mode(regs))
+                       handle_fault_error_nolock(regs, 0);
+               else
+                       do_sigsegv(regs, SEGV_MAPERR);
+       } else if (fault & VM_FAULT_SIGBUS) {
+               if (!user_mode(regs))
+                       handle_fault_error_nolock(regs, 0);
+               else
+                       do_sigbus(regs);
+       } else {
+               BUG();
+       }
 }
 
 void do_protection_exception(struct pt_regs *regs)
@@ -477,7 +464,7 @@ void do_protection_exception(struct pt_regs *regs)
                 * Low-address protection in kernel mode means
                 * NULL pointer write access in kernel mode.
                 */
-               return do_no_context(regs, 0);
+               return handle_fault_error_nolock(regs, 0);
        }
        if (unlikely(MACHINE_HAS_NX && teid.b56)) {
                regs->int_parm_long = (teid.addr * PAGE_SIZE) | (regs->psw.addr & PAGE_MASK);