From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756739AbdCUJMg (ORCPT ); Tue, 21 Mar 2017 05:12:36 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:57239 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756655AbdCUJMf (ORCPT ); Tue, 21 Mar 2017 05:12:35 -0400 From: "Aneesh Kumar K.V" To: Laurent Dufour , mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, bsingharora@gmail.com, npiggin@gmail.com Cc: linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/3] powerpc/mm: move mmap_sem unlocking in do_page_fault() In-Reply-To: <6515aebdbd7adad576f1c97753809547b273504a.1487090656.git.ldufour@linux.vnet.ibm.com> References: <6515aebdbd7adad576f1c97753809547b273504a.1487090656.git.ldufour@linux.vnet.ibm.com> Date: Tue, 21 Mar 2017 14:42:25 +0530 MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-MML: disable x-cbid: 17032109-0004-0000-0000-0000055521D1 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17032109-0005-0000-0000-000013523B7F Message-Id: <874lynoux2.fsf@skywalker.in.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-03-21_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=1 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1702020001 definitions=main-1703210082 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Laurent Dufour writes: > 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: Aneesh Kumar K.V > Signed-off-by: Laurent Dufour > --- > arch/powerpc/mm/fault.c | 19 ++++--------------- > 1 file changed, 4 insertions(+), 15 deletions(-) > > diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > index 2a6bc7e6e69a..21e06cce8984 100644 > --- a/arch/powerpc/mm/fault.c > +++ b/arch/powerpc/mm/fault.c > @@ -151,13 +151,6 @@ 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(¤t->mm->mmap_sem); > /* Coming from kernel, we need to deal with uaccess fixups */ > if (user_mode(regs)) > return MM_FAULT_RETURN; > @@ -170,8 +163,6 @@ static int mm_fault_error(struct pt_regs *regs, unsigned long addr, int fault) > > /* Out of memory */ > if (fault & VM_FAULT_OOM) { > - up_read(¤t->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. > @@ -182,10 +173,8 @@ 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(¤t->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(); > @@ -452,11 +441,12 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, > goto retry; > } > /* We will enter mm_fault_error() below */ > - } > + } else > + up_read(¤t->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; > @@ -488,7 +478,6 @@ int do_page_fault(struct pt_regs *regs, unsigned long address, > regs, address); > } > > - up_read(&mm->mmap_sem); > goto bail; > > bad_area: > -- > 2.7.4