From 7fb08eca45270d0ae86e1ad9d39c40b7a55d0190 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Mon, 15 Dec 2014 14:46:06 -0800
Subject: [PATCH] x86: mm: move mmap_sem unlock from mm_fault_error() to caller
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 <torvalds@linux-foundation.org>
---
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 d973e61e450dc..d7de5b8657d51 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -844,11 +844,8 @@ 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);
@@ -879,7 +876,6 @@ 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(¤t->mm->mmap_sem);
no_context(regs, error_code, address, 0, 0);
return;
}
@@ -887,14 +883,11 @@ 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(¤t->mm->mmap_sem);
no_context(regs, error_code, address,
SIGSEGV, SEGV_MAPERR);
return;
}
- up_read(¤t->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
@@ -1247,6 +1240,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
return;
if (unlikely(fault & VM_FAULT_ERROR)) {
+ up_read(&mm->mmap_sem);
mm_fault_error(regs, error_code, address, fault);
return;
}
--
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