[PATCH 3.13.y-ckt 17/80] x86: mm: move mmap_sem unlock from mm_fault_error() to caller

[Kamal Mostafa]

3.13.11-ckt17 -stable review patch.  If anyone has any objections, please let 
me know.

------------------

From: Linus Torvalds <torva...@linux-foundation.org>

commit 7fb08eca45270d0ae86e1ad9d39c40b7a55d0190 upstream.

This replaces four copies in various stages of mm_fault_error() handling
with just a single one.  It will also allow for more natural placement
of the unlocking after some further cleanup.

Signed-off-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
 arch/x86/mm/fault.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 6dea040..1ca1605 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -833,11 +833,8 @@ do_sigbus(struct pt_regs *regs, unsigned long error_code, 
unsigned long address,
          unsigned int fault)
 {
        struct task_struct *tsk = current;
-       struct mm_struct *mm = tsk->mm;
        int code = BUS_ADRERR;
 
-       up_read(&mm->mmap_sem);
-
        /* Kernel mode? Handle exceptions or die: */
        if (!(error_code & PF_USER)) {
                no_context(regs, error_code, address, SIGBUS, BUS_ADRERR);
@@ -868,7 +865,6 @@ mm_fault_error(struct pt_regs *regs, unsigned long 
error_code,
               unsigned long address, unsigned int fault)
 {
        if (fatal_signal_pending(current) && !(error_code & PF_USER)) {
-               up_read(&current->mm->mmap_sem);
                no_context(regs, error_code, address, 0, 0);
                return;
        }
@@ -876,14 +872,11 @@ mm_fault_error(struct pt_regs *regs, unsigned long 
error_code,
        if (fault & VM_FAULT_OOM) {
                /* Kernel mode? Handle exceptions or die: */
                if (!(error_code & PF_USER)) {
-                       up_read(&current->mm->mmap_sem);
                        no_context(regs, error_code, address,
                                   SIGSEGV, SEGV_MAPERR);
                        return;
                }
 
-               up_read(&current->mm->mmap_sem);
-
                /*
                 * We ran out of memory, call the OOM killer, and return the
                 * userspace (which will retry the fault, or kill us if we got
@@ -1215,6 +1208,7 @@ good_area:
                return;
 
        if (unlikely(fault & VM_FAULT_ERROR)) {
+               up_read(&mm->mmap_sem);
                mm_fault_error(regs, error_code, address, fault);
                return;
        }
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/