Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley
        Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United
        Kingdom.
        Registered in England and Wales under Company Registration No. 3798903
From:   David Howells <dhowells@redhat.com>
To:     Jens Axboe <axboe@kernel.dk>
cc:     dhowells@redhat.com, Ayush Jain <ayush.jain3@amd.com>,
        Christoph Hellwig <hch@lst.de>,
        Al Viro <viro@zeniv.linux.org.uk>,
        David Hildenbrand <david@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Steve French <stfrench@microsoft.com>, linux-mm@kvack.org,
        linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH] splice: Fix filemap of a blockdev
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <1770754.1681894451.1@warthog.procyon.org.uk>
Content-Transfer-Encoding: quoted-printable
Date:   Wed, 19 Apr 2023 09:54:11 +0100
Message-ID: <1770755.1681894451@warthog.procyon.org.uk>
Precedence: bulk

Fix the new filemap_splice_read() function to get i_size from
in->f_mapping->host, not in->f_inode so that it works with block devices
too (in->f_inode points to the device file, which is typically zero size).

Fixes: 07073eb01c5f ("splice: Add a func to do a splice from a buffered fi=
le without ITER_PIPE")
Link: https://lore.kernel.org/r/0c6b661c-f7ff-cf12-b7f0-00b6b2f1317b@amd.c=
om/
Reported-by: Ayush Jain <ayush.jain3@amd.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: David Hildenbrand <david@redhat.com>
cc: John Hubbard <jhubbard@nvidia.com>
cc: Steve French <stfrench@microsoft.com>
cc: linux-mm@kvack.org
cc: linux-block@vger.kernel.org
cc: linux-fsdevel@vger.kernel.org
---
 mm/filemap.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index 470be06b6096..f86cc8acf33a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2902,7 +2902,7 @@ ssize_t filemap_splice_read(struct file *in, loff_t =
*ppos,
 	do {
 		cond_resched();
 =

-		if (*ppos >=3D i_size_read(file_inode(in)))
+		if (*ppos >=3D i_size_read(in->f_mapping->host))
 			break;
 =

 		iocb.ki_pos =3D *ppos;
@@ -2918,7 +2918,7 @@ ssize_t filemap_splice_read(struct file *in, loff_t =
*ppos,
 		 * part of the page is not copied back to userspace (unless
 		 * another truncate extends the file - this is desired though).
 		 */
-		isize =3D i_size_read(file_inode(in));
+		isize =3D i_size_read(in->f_mapping->host);
 		if (unlikely(*ppos >=3D isize))
 			break;
 		end_offset =3D min_t(loff_t, isize, *ppos + len);