linux-kernel - [PATCH 1/3] powerpc/mm: move mmap_sem unlock up from do

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Date:   Tue, 14 Feb 2017 17:45:10 +0100
From:   Laurent Dufour <ldufour@...ux.vnet.ibm.com>
To:     mpe@...erman.id.au, benh@...nel.crashing.org, paulus@...ba.org,
        aneesh.kumar@...ux.vnet.ibm.com, bsingharora@...il.com,
        npiggin@...il.com
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH 1/3] powerpc/mm: move mmap_sem unlock up from do_sigbus

Move mmap_sem releasing in the do_sigbus()'s unique caller : mm_fault_error()

No functional changes.

Signed-off-by: Laurent Dufour <ldufour@...ux.vnet.ibm.com>
---
 arch/powerpc/mm/fault.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 62a50d6d1053..ee09604bbe12 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -119,8 +119,6 @@ static int do_sigbus(struct pt_regs *regs, unsigned long address,
 	siginfo_t info;
 	unsigned int lsb = 0;
 
-	up_read(&current->mm->mmap_sem);
-
 	if (!user_mode(regs))
 		return MM_FAULT_ERR(SIGBUS);
 
@@ -184,8 +182,10 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault)
 		return MM_FAULT_RETURN;
 	}
 
-	if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE))
+	if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE)) {
+		up_read(&current->mm->mmap_sem);
 		return do_sigbus(regs, addr, fault);
+	}
 
 	/* We don't understand the fault code, this is fatal */
 	BUG();
-- 
2.7.4