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From: Matthew Wilcox <willy@infradead.org>
To: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Souptick Joarder <jrdr.linux@gmail.com>,
	linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/10] cramfs: Convert to use vmf_insert_mixed
Date: Tue, 28 Aug 2018 15:04:27 -0700	[thread overview]
Message-ID: <20180828220427.GA11400@bombadil.infradead.org> (raw)
In-Reply-To: <nycvar.YSQ.7.76.1808281235060.10215@knanqh.ubzr>

On Tue, Aug 28, 2018 at 01:49:25PM -0400, Nicolas Pitre wrote:
> On Tue, 28 Aug 2018, Matthew Wilcox wrote:
> > -			ret = vm_insert_mixed(vma, vma->vm_start + off, pfn);
> > +			vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn);
> > +			if (vmf & VM_FAULT_ERROR) {
> > +				pages = i;
> > +				break;
> > +			}
> 
> I'd suggest this to properly deal with errers instead:
> 
> -			ret = vm_insert_mixed(vma, vma->vm_start + off, pfn);
> +			vmf = vmf_insert_mixed(vma, vma->vm_start + off, pfn);
> +			if (vmf & VM_FAULT_ERROR)
> +				ret = vm_fault_to_errno(vmf, 0);

By my reading of this function, the intent is actually to return 0
here and allow demand paging to work.  Of course, I've spent all of
twenty minutes staring at this function, so I defer to the maintainer.
I think you'd need to be running a make-memory-allocations-fail fuzzer
to hit this, so it's likely never been tested.

  reply	other threads:[~2018-08-28 22:04 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-28 14:57 [PATCH 00/10] Push the vm_fault_t conversion further Matthew Wilcox
2018-08-28 14:57 ` [PATCH 01/10] cramfs: Convert to use vmf_insert_mixed Matthew Wilcox
2018-08-28 17:49   ` Nicolas Pitre
2018-08-28 22:04     ` Matthew Wilcox [this message]
2018-08-28 23:52       ` Nicolas Pitre
2018-08-28 14:57 ` [PATCH 02/10] mm: Remove vm_insert_mixed Matthew Wilcox
2018-08-28 14:57 ` [PATCH 03/10] mm: Introduce vmf_insert_pfn_prot Matthew Wilcox
2018-08-28 14:57 ` [PATCH 04/10] x86: Convert vdso to use vm_fault_t Matthew Wilcox
2018-08-28 14:57 ` [PATCH 05/10] mm: Make vm_insert_pfn_prot static Matthew Wilcox
2018-08-28 14:57 ` [PATCH 06/10] mm: Remove references to vm_insert_pfn Matthew Wilcox
2018-08-28 14:57 ` [PATCH 07/10] mm: Remove vm_insert_pfn Matthew Wilcox
2018-08-28 14:57 ` [PATCH 08/10] mm: Inline vm_insert_pfn_prot into caller Matthew Wilcox
2018-08-28 14:57 ` [PATCH 09/10] mm: Convert __vm_insert_mixed to vm_fault_t Matthew Wilcox
2018-08-28 14:57 ` [PATCH 10/10] mm: Convert insert_pfn " Matthew Wilcox

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