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Date:   Tue, 29 May 2018 07:50:55 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Souptick Joarder <jrdr.linux@gmail.com>
Cc:     viro@zeniv.linux.org.uk, hughd@google.com,
        akpm@linux-foundation.org, mhocko@suse.com,
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        gregkh@linuxfoundation.org, mark.rutland@arm.com, riel@redhat.com,
        pasha.tatashin@oracle.com, jschoenh@amazon.de,
        kstewart@linuxfoundation.org, rientjes@google.com,
        tglx@linutronix.de, peterz@infradead.org, mgorman@suse.de,
        yang.s@alibaba-inc.com, minchan@kernel.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org
Subject: Re: [PATCH] mm: Change return type to vm_fault_t
Message-ID: <20180529145055.GA15148@bombadil.infradead.org>
References: <20180529143126.GA19698@jordon-HP-15-Notebook-PC>
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On Tue, May 29, 2018 at 08:01:26PM +0530, Souptick Joarder wrote:
> Use new return type vm_fault_t for fault handler. For
> now, this is just documenting that the function returns
> a VM_FAULT value rather than an errno. Once all instances
> are converted, vm_fault_t will become a distinct type.

I don't believe you've checked this with sparse.

> @@ -802,7 +802,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
>  		     bool *unlocked)
>  {
>  	struct vm_area_struct *vma;
> -	int ret, major = 0;
> +	int major = 0;
> +	vm_fault_t ret;
>  
>  	if (unlocked)
>  		fault_flags |= FAULT_FLAG_ALLOW_RETRY;

...
        major |= ret & VM_FAULT_MAJOR;

That should be throwing a warning.