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Date:   Mon, 15 Jul 2019 12:29:17 +0530
From:   Bharath Vedartham <linux.bhar@gmail.com>
To:     Jens Axboe <axboe@kernel.dk>
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Subject: Re: [PATCH] mm/gup: Use put_user_page*() instead of put_page*()
Message-ID: <20190715065917.GB3716@bharath12345-Inspiron-5559>
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 <018ee3d1-e2f0-ca12-9f63-945056c09985@kernel.dk>
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On Sun, Jul 14, 2019 at 08:33:57PM -0600, Jens Axboe wrote:
> On 7/14/19 1:08 PM, Bharath Vedartham wrote:
> > diff --git a/fs/io_uring.c b/fs/io_uring.c
> > index 4ef62a4..b4a4549 100644
> > --- a/fs/io_uring.c
> > +++ b/fs/io_uring.c
> > @@ -2694,10 +2694,9 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
> >   			 * if we did partial map, or found file backed vmas,
> >   			 * release any pages we did get
> >   			 */
> > -			if (pret > 0) {
> > -				for (j = 0; j < pret; j++)
> > -					put_page(pages[j]);
> > -			}
> > +			if (pret > 0)
> > +				put_user_pages(pages, pret);
> > +
> >   			if (ctx->account_mem)
> >   				io_unaccount_mem(ctx->user, nr_pages);
> >   			kvfree(imu->bvec);
> 
> You handled just the failure case of the buffer registration, but not
> the actual free in io_sqe_buffer_unregister().
> 
> -- 
> Jens Axboe
Yup got it! Thanks! I won't be sending a patch again as fs/io_uring.c
may have larger local changes for put_user_pages.

Thanks