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Commit 819cdcdb authored by Laurent Dufour's avatar Laurent Dufour Committed by Michael Ellerman
Browse files

powerpc/mm: Move mmap_sem unlocking in do_page_fault() 



Since the fault retry is now handled earlier, we can release the
mmap_sem lock earlier too and remove later unlocking previously done in
mm_fault_error().

Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: default avatarLaurent Dufour <ldufour@linux.vnet.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 14c02e41

arch/powerpc/mm/fault.c

+4 −15
Original line number Diff line number Diff line
@@ -152,13 +152,6 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault) 
	 * continue the pagefault.

	 */

	if (fatal_signal_pending(current)) {

		/*

		 * If we have retry set, the mmap semaphore will have

		 * alrady been released in __lock_page_or_retry(). Else

		 * we release it now.

		 */

		if (!(fault & VM_FAULT_RETRY))

			up_read(&current->mm->mmap_sem);

		/* Coming from kernel, we need to deal with uaccess fixups */

		if (user_mode(regs))

			return MM_FAULT_RETURN;
@@ -171,8 +164,6 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault) 


	/* Out of memory */

	if (fault & VM_FAULT_OOM) {

		up_read(&current->mm->mmap_sem);



		/*

		 * We ran out of memory, or some other thing happened to us that

		 * made us unable to handle the page fault gracefully.
@@ -183,10 +174,8 @@ 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)) {

		up_read(&current->mm->mmap_sem);

	if (fault & (VM_FAULT_SIGBUS|VM_FAULT_HWPOISON|VM_FAULT_HWPOISON_LARGE))

		return do_sigbus(regs, addr, fault);

	}



	/* We don't understand the fault code, this is fatal */

	BUG();
@@ -476,11 +465,12 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, 
				goto retry;

		}

		/* We will enter mm_fault_error() below */

	}

	} else

		up_read(&current->mm->mmap_sem);



	if (unlikely(fault & (VM_FAULT_RETRY|VM_FAULT_ERROR))) {

		if (fault & VM_FAULT_SIGSEGV)

			goto bad_area;

			goto bad_area_nosemaphore;

		rc = mm_fault_error(regs, address, fault);

		if (rc >= MM_FAULT_RETURN)

			goto bail;
@@ -512,7 +502,6 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, 
			      regs, address);

	}



	up_read(&mm->mmap_sem);

	goto bail;



bad_area: