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Subject: Re: [PATCH v5 1/7] mm: pass task and mm to do_madvise
To:     Minchan Kim <minchan@kernel.org>
Cc:     Jann Horn <jannh@google.com>, io-uring <io-uring@vger.kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-mm <linux-mm@kvack.org>,
        Linux API <linux-api@vger.kernel.org>,
        Oleksandr Natalenko <oleksandr@redhat.com>,
        Suren Baghdasaryan <surenb@google.com>,
        Tim Murray <timmurray@google.com>,
        Daniel Colascione <dancol@google.com>,
        Sandeep Patil <sspatil@google.com>,
        Sonny Rao <sonnyrao@google.com>,
        Brian Geffon <bgeffon@google.com>,
        Michal Hocko <mhocko@suse.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Shakeel Butt <shakeelb@google.com>,
        John Dias <joaodias@google.com>,
        Joel Fernandes <joel@joelfernandes.org>, sj38.park@gmail.com,
        Alexander Duyck <alexander.h.duyck@linux.intel.com>
References: <20200214170520.160271-1-minchan@kernel.org>
 <20200214170520.160271-2-minchan@kernel.org>
 <CAG48ez3S5+EasZ1ZWcMQYZQQ5zJOBtY-_C7oz6DMfG4Gcyig1g@mail.gmail.com>
 <68044a15-6a31-e432-3105-f2f1af9f4b74@kernel.dk>
 <20200214184514.GA165785@google.com>
From:   Jens Axboe <axboe@kernel.dk>
Message-ID: <93aadcc6-3ef5-4ea0-be6b-23c06862002e@kernel.dk>
Date:   Fri, 14 Feb 2020 12:09:50 -0700
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On 2/14/20 11:45 AM, Minchan Kim wrote:
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 63beda9bafc5..1c7e9cd6c8ce 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2736,7 +2736,7 @@ static int io_madvise(struct io_kiocb *req, struct io_kiocb **nxt,
>  	if (force_nonblock)
>  		return -EAGAIN;
>  
> -	ret = do_madvise(ma->addr, ma->len, ma->advice);
> +	ret = do_madvise(NULL, current->mm, ma->addr, ma->len, ma->advice);
>  	if (ret < 0)
>  		req_set_fail_links(req);
>  	io_cqring_add_event(req, ret);

I think we want to use req->work.mm here - it'll be the same as
current->mm at this point, but it makes it clear that we're using a
grabbed mm.

-- 
Jens Axboe