From: Catalin Marinas <catalin.marinas@arm.com> To: Anshuman Khandual <anshuman.khandual@arm.com> Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Will Deacon <will.deacon@arm.com>, Mark Rutland <mark.rutland@arm.com>, James Morse <james.morse@arm.com>, Andrey Konovalov <andreyknvl@google.com>, Christoph Hellwig <hch@infradead.org> Subject: Re: [PATCH V2 4/4] arm64/mm: Drop local variable vm_fault_t from __do_page_fault() Date: Tue, 4 Jun 2019 15:56:12 +0100 [thread overview] Message-ID: <20190604145612.GM6610@arrakis.emea.arm.com> (raw) In-Reply-To: <1559544085-7502-5-git-send-email-anshuman.khandual@arm.com> On Mon, Jun 03, 2019 at 12:11:25PM +0530, Anshuman Khandual wrote: > __do_page_fault() is over complicated with multiple goto statements. This > cleans up the code flow and while there drops local variable vm_fault_t. I'd change the subject as well here to something like refactor or simplify __do_page_fault(). > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 4bb65f3..41fa905 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -397,37 +397,29 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re > static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, > unsigned int mm_flags, unsigned long vm_flags) > { > - struct vm_area_struct *vma; > - vm_fault_t fault; > + struct vm_area_struct *vma = find_vma(mm, addr); > > - vma = find_vma(mm, addr); > - fault = VM_FAULT_BADMAP; > if (unlikely(!vma)) > - goto out; > - if (unlikely(vma->vm_start > addr)) > - goto check_stack; > + return VM_FAULT_BADMAP; > > /* > * Ok, we have a good vm_area for this memory access, so we can handle > * it. > */ > -good_area: > + if (unlikely(vma->vm_start > addr)) { > + if (!(vma->vm_flags & VM_GROWSDOWN)) > + return VM_FAULT_BADMAP; > + if (expand_stack(vma, addr)) > + return VM_FAULT_BADMAP; > + } You could have a single return here: if (unlikely(vma->vm_start > addr) && (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, addr))) return VM_FAULT_BADMAP; Not sure it's any clearer though. -- Catalin
WARNING: multiple messages have this Message-ID (diff)
From: Catalin Marinas <catalin.marinas@arm.com> To: Anshuman Khandual <anshuman.khandual@arm.com> Cc: Mark Rutland <mark.rutland@arm.com>, Andrey Konovalov <andreyknvl@google.com>, Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org, Christoph Hellwig <hch@infradead.org>, James Morse <james.morse@arm.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH V2 4/4] arm64/mm: Drop local variable vm_fault_t from __do_page_fault() Date: Tue, 4 Jun 2019 15:56:12 +0100 [thread overview] Message-ID: <20190604145612.GM6610@arrakis.emea.arm.com> (raw) In-Reply-To: <1559544085-7502-5-git-send-email-anshuman.khandual@arm.com> On Mon, Jun 03, 2019 at 12:11:25PM +0530, Anshuman Khandual wrote: > __do_page_fault() is over complicated with multiple goto statements. This > cleans up the code flow and while there drops local variable vm_fault_t. I'd change the subject as well here to something like refactor or simplify __do_page_fault(). > diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c > index 4bb65f3..41fa905 100644 > --- a/arch/arm64/mm/fault.c > +++ b/arch/arm64/mm/fault.c > @@ -397,37 +397,29 @@ static void do_bad_area(unsigned long addr, unsigned int esr, struct pt_regs *re > static vm_fault_t __do_page_fault(struct mm_struct *mm, unsigned long addr, > unsigned int mm_flags, unsigned long vm_flags) > { > - struct vm_area_struct *vma; > - vm_fault_t fault; > + struct vm_area_struct *vma = find_vma(mm, addr); > > - vma = find_vma(mm, addr); > - fault = VM_FAULT_BADMAP; > if (unlikely(!vma)) > - goto out; > - if (unlikely(vma->vm_start > addr)) > - goto check_stack; > + return VM_FAULT_BADMAP; > > /* > * Ok, we have a good vm_area for this memory access, so we can handle > * it. > */ > -good_area: > + if (unlikely(vma->vm_start > addr)) { > + if (!(vma->vm_flags & VM_GROWSDOWN)) > + return VM_FAULT_BADMAP; > + if (expand_stack(vma, addr)) > + return VM_FAULT_BADMAP; > + } You could have a single return here: if (unlikely(vma->vm_start > addr) && (!(vma->vm_flags & VM_GROWSDOWN) || expand_stack(vma, addr))) return VM_FAULT_BADMAP; Not sure it's any clearer though. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-06-04 14:56 UTC|newest] Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-06-03 6:41 [PATCH V2 0/4] arm64/mm: Clean ups for do_page_fault() Anshuman Khandual 2019-06-03 6:41 ` Anshuman Khandual 2019-06-03 6:41 ` [PATCH V2 1/4] arm64/mm: Drop mmap_sem before calling __do_kernel_fault() Anshuman Khandual 2019-06-03 6:41 ` Anshuman Khandual 2019-06-04 14:44 ` Catalin Marinas 2019-06-04 14:44 ` Catalin Marinas 2019-06-03 6:41 ` [PATCH V2 2/4] arm64/mm: Drop task_struct argument from __do_page_fault() Anshuman Khandual 2019-06-03 6:41 ` Anshuman Khandual 2019-06-04 14:45 ` Catalin Marinas 2019-06-04 14:45 ` Catalin Marinas 2019-06-03 6:41 ` [PATCH V2 3/4] arm64/mm: Consolidate page fault information capture Anshuman Khandual 2019-06-03 6:41 ` Anshuman Khandual 2019-06-04 14:42 ` Catalin Marinas 2019-06-04 14:42 ` Catalin Marinas 2019-06-06 9:38 ` Mark Rutland 2019-06-06 9:38 ` Mark Rutland 2019-06-06 11:23 ` Catalin Marinas 2019-06-06 11:23 ` Catalin Marinas 2019-06-03 6:41 ` [PATCH V2 4/4] arm64/mm: Drop local variable vm_fault_t from __do_page_fault() Anshuman Khandual 2019-06-03 6:41 ` Anshuman Khandual 2019-06-04 14:56 ` Catalin Marinas [this message] 2019-06-04 14:56 ` Catalin Marinas 2019-06-06 4:54 ` Anshuman Khandual 2019-06-06 4:54 ` Anshuman Khandual 2019-06-06 11:27 ` Catalin Marinas 2019-06-06 11:27 ` Catalin Marinas 2019-06-06 11:31 ` Mark Rutland 2019-06-06 11:31 ` Mark Rutland
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