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From:   David Howells <dhowells@redhat.com>
In-Reply-To: <87a61ckowk.fsf@oc8242746057.ibm.com>
References: <87a61ckowk.fsf@oc8242746057.ibm.com>
To:     Alexander Egorenkov <egorenar@linux.ibm.com>
Cc:     dhowells@redhat.com, axboe@kernel.dk, david@redhat.com,
        hch@infradead.org, hch@lst.de, hdanton@sina.com, jack@suse.cz,
        jgg@nvidia.com, jhubbard@nvidia.com, jlayton@kernel.org,
        linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        logang@deltatee.com, viro@zeniv.linux.org.uk, willy@infradead.org,
        Marc Hartmayer <mhartmay@linux.ibm.com>
Subject: Re: [PATCH v14 08/17] splice: Do splice read from a file without using ITER_PIPE
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Date:   Fri, 17 Feb 2023 21:47:43 +0000
Message-ID: <732891.1676670463@warthog.procyon.org.uk>
Precedence: bulk

Does the attached fix the problem for you?  The data being written into th=
e
pipe needs to be limited to the size of the file.

David

diff --git a/mm/filemap.c b/mm/filemap.c
index c01bbcb9fa92..6362ac697a70 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2948,7 +2948,8 @@ ssize_t filemap_splice_read(struct file *in, loff_t =
*ppos,
 			if (writably_mapped)
 				flush_dcache_folio(folio);
 =

-			n =3D splice_folio_into_pipe(pipe, folio, *ppos, len);
+			n =3D min_t(loff_t, len, isize - *ppos);
+			n =3D splice_folio_into_pipe(pipe, folio, *ppos, n);
 			if (!n)
 				goto out;
 			len -=3D n;