[PATCH] ceph: fix an oops in error handling in ceph_netfs_issue_op

[Jeff Layton]

Dan reported a potential oops in the cleanup if ceph_osdc_new_request
returns an error. Eliminate the unneeded initialization of "req" and
then just set it to NULL in the case where it holds an ERR_PTR.

Also, drop the unneeded NULL check before calling
ceph_osdc_put_request.

Fixes: 1cf7fdf52d5a ("ceph: convert readpage to fscache read helper")
Reported-by: Dan Carpenter <dan.carpen...@oracle.com>
Suggested-by: Ilya Dryomov <idryo...@gmail.com>
Signed-off-by: Jeff Layton <jlay...@kernel.org>
---
 fs/ceph/addr.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 5eec6f66fe52..0dd64d31eff6 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -234,7 +234,7 @@ static void ceph_netfs_issue_op(struct 
netfs_read_subrequest *subreq)
        struct inode *inode = rreq->mapping->host;
        struct ceph_inode_info *ci = ceph_inode(inode);
        struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
-       struct ceph_osd_request *req = NULL;
+       struct ceph_osd_request *req;
        struct ceph_vino vino = ceph_vino(inode);
        struct iov_iter iter;
        struct page **pages;
@@ -248,6 +248,7 @@ static void ceph_netfs_issue_op(struct 
netfs_read_subrequest *subreq)
                        NULL, ci->i_truncate_seq, ci->i_truncate_size, false);
        if (IS_ERR(req)) {
                err = PTR_ERR(req);
+               req = NULL;
                goto out;
        }
 
@@ -273,8 +274,7 @@ static void ceph_netfs_issue_op(struct 
netfs_read_subrequest *subreq)
        if (err)
                iput(inode);
 out:
-       if (req)
-               ceph_osdc_put_request(req);
+       ceph_osdc_put_request(req);
        if (err)
                netfs_subreq_terminated(subreq, err);
        dout("%s: result %d\n", __func__, err);
-- 
2.29.2