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From: Dominique Martinet <asmadeus@codewreck.org>
To: Eric Van Hensbergen <ericvh@gmail.com>,
	 Latchesar Ionkov <lucho@ionkov.net>,
	 Christian Schoenebeck <linux_oss@crudebyte.com>,
	 "David S. Miller" <davem@davemloft.net>,
	Eric Dumazet <edumazet@google.com>,
	 Jakub Kicinski <kuba@kernel.org>,
	Paolo Abeni <pabeni@redhat.com>
Cc: v9fs@lists.linux.dev, linux-kernel@vger.kernel.org,
	 netdev@vger.kernel.org,
	Dominique Martinet <asmadeus@codewreck.org>
Subject: [PATCH 5/5] 9p: remove dead stores (variable set again without being read)
Date: Thu, 27 Apr 2023 20:23:38 +0900	[thread overview]
Message-ID: <20230427-scan-build-v1-5-efa05d65e2da@codewreck.org> (raw)
In-Reply-To: <20230427-scan-build-v1-0-efa05d65e2da@codewreck.org>

The 9p code for some reason used to initialize variables outside of the
declaration, e.g. instead of just initializing the variable like this:

int retval = 0

We would be doing this:

int retval;
retval = 0;

This is perfectly fine and the compiler will just optimize dead stores
anyway, but scan-build seems to think this is a problem and there are
many of these warnings making the output of scan-build full of such
warnings:
fs/9p/vfs_inode.c:916:2: warning: Value stored to 'retval' is never read [deadcode.DeadStores]
        retval = 0;
        ^        ~

I have no strong opinion here, but if we want to regularily run
scan-build we should fix these just to silence the messages.

I've confirmed these all are indeed ok to remove.

Signed-off-by: Dominique Martinet <asmadeus@codewreck.org>
---
 fs/9p/vfs_inode.c      |  6 ------
 fs/9p/vfs_inode_dotl.c |  1 -
 net/9p/client.c        | 46 ++++++++++++----------------------------------
 3 files changed, 12 insertions(+), 41 deletions(-)

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 54dfe4f10f43..82589d1d9bbe 100644
--- a/fs/9p/vfs_inode.c
+++ b/fs/9p/vfs_inode.c
@@ -164,7 +164,6 @@ int v9fs_uflags2omode(int uflags, int extended)
 {
 	int ret;
 
-	ret = 0;
 	switch (uflags&3) {
 	default:
 	case O_RDONLY:
@@ -604,7 +603,6 @@ v9fs_create(struct v9fs_session_info *v9ses, struct inode *dir,
 
 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
 
-	err = 0;
 	name = dentry->d_name.name;
 	dfid = v9fs_parent_fid(dentry);
 	if (IS_ERR(dfid)) {
@@ -816,8 +814,6 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry *dentry,
 	if (!(flags & O_CREAT) || d_really_is_positive(dentry))
 		return finish_no_open(file, res);
 
-	err = 0;
-
 	v9ses = v9fs_inode2v9ses(dir);
 	perm = unixmode2p9mode(v9ses, mode);
 	p9_omode = v9fs_uflags2omode(flags, v9fs_proto_dotu(v9ses));
@@ -913,7 +909,6 @@ v9fs_vfs_rename(struct mnt_idmap *idmap, struct inode *old_dir,
 		return -EINVAL;
 
 	p9_debug(P9_DEBUG_VFS, "\n");
-	retval = 0;
 	old_inode = d_inode(old_dentry);
 	new_inode = d_inode(new_dentry);
 	v9ses = v9fs_inode2v9ses(old_inode);
@@ -1067,7 +1062,6 @@ static int v9fs_vfs_setattr(struct mnt_idmap *idmap,
 	if (retval)
 		return retval;
 
-	retval = -EPERM;
 	v9ses = v9fs_dentry2v9ses(dentry);
 	if (iattr->ia_valid & ATTR_FILE) {
 		fid = iattr->ia_file->private_data;
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index f9371b5b70ea..df7023af17cf 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/fs/9p/vfs_inode_dotl.c
@@ -367,7 +367,6 @@ static int v9fs_vfs_mkdir_dotl(struct mnt_idmap *idmap,
 	struct posix_acl *dacl = NULL, *pacl = NULL;
 
 	p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry);
-	err = 0;
 	v9ses = v9fs_inode2v9ses(dir);
 
 	omode |= S_IFDIR;
diff --git a/net/9p/client.c b/net/9p/client.c
index a3340268ec8d..86bbc7147fc1 100644
--- a/net/9p/client.c
+++ b/net/9p/client.c
@@ -904,7 +904,7 @@ EXPORT_SYMBOL(do_trace_9p_fid_put);
 
 static int p9_client_version(struct p9_client *c)
 {
-	int err = 0;
+	int err;
 	struct p9_req_t *req;
 	char *version = NULL;
 	int msize;
@@ -975,7 +975,6 @@ struct p9_client *p9_client_create(const char *dev_name, char *options)
 	struct p9_client *clnt;
 	char *client_id;
 
-	err = 0;
 	clnt = kmalloc(sizeof(*clnt), GFP_KERNEL);
 	if (!clnt)
 		return ERR_PTR(-ENOMEM);
@@ -1094,7 +1093,7 @@ struct p9_fid *p9_client_attach(struct p9_client *clnt, struct p9_fid *afid,
 				const char *uname, kuid_t n_uname,
 				const char *aname)
 {
-	int err = 0;
+	int err;
 	struct p9_req_t *req;
 	struct p9_fid *fid;
 	struct p9_qid qid;
@@ -1147,7 +1146,6 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid, uint16_t nwname,
 	struct p9_req_t *req;
 	u16 nwqids, count;
 
-	err = 0;
 	wqids = NULL;
 	clnt = oldfid->clnt;
 	if (clone) {
@@ -1224,7 +1222,6 @@ int p9_client_open(struct p9_fid *fid, int mode)
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P, ">>> %s fid %d mode %d\n",
 		 p9_is_proto_dotl(clnt) ? "TLOPEN" : "TOPEN", fid->fid, mode);
-	err = 0;
 
 	if (fid->mode != -1)
 		return -EINVAL;
@@ -1262,7 +1259,7 @@ EXPORT_SYMBOL(p9_client_open);
 int p9_client_create_dotl(struct p9_fid *ofid, const char *name, u32 flags,
 			  u32 mode, kgid_t gid, struct p9_qid *qid)
 {
-	int err = 0;
+	int err;
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 	int iounit;
@@ -1314,7 +1311,6 @@ int p9_client_fcreate(struct p9_fid *fid, const char *name, u32 perm, int mode,
 
 	p9_debug(P9_DEBUG_9P, ">>> TCREATE fid %d name %s perm %d mode %d\n",
 		 fid->fid, name, perm, mode);
-	err = 0;
 	clnt = fid->clnt;
 
 	if (fid->mode != -1)
@@ -1350,7 +1346,7 @@ EXPORT_SYMBOL(p9_client_fcreate);
 int p9_client_symlink(struct p9_fid *dfid, const char *name,
 		      const char *symtgt, kgid_t gid, struct p9_qid *qid)
 {
-	int err = 0;
+	int err;
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
@@ -1402,13 +1398,12 @@ EXPORT_SYMBOL(p9_client_link);
 
 int p9_client_fsync(struct p9_fid *fid, int datasync)
 {
-	int err;
+	int err = 0;
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
 	p9_debug(P9_DEBUG_9P, ">>> TFSYNC fid %d datasync:%d\n",
 		 fid->fid, datasync);
-	err = 0;
 	clnt = fid->clnt;
 
 	req = p9_client_rpc(clnt, P9_TFSYNC, "dd", fid->fid, datasync);
@@ -1428,7 +1423,7 @@ EXPORT_SYMBOL(p9_client_fsync);
 
 int p9_client_clunk(struct p9_fid *fid)
 {
-	int err;
+	int err = 0;
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 	int retries = 0;
@@ -1436,7 +1431,6 @@ int p9_client_clunk(struct p9_fid *fid)
 again:
 	p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
 		 fid->fid, retries);
-	err = 0;
 	clnt = fid->clnt;
 
 	req = p9_client_rpc(clnt, P9_TCLUNK, "d", fid->fid);
@@ -1465,12 +1459,11 @@ EXPORT_SYMBOL(p9_client_clunk);
 
 int p9_client_remove(struct p9_fid *fid)
 {
-	int err;
+	int err = 0;
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
 	p9_debug(P9_DEBUG_9P, ">>> TREMOVE fid %d\n", fid->fid);
-	err = 0;
 	clnt = fid->clnt;
 
 	req = p9_client_rpc(clnt, P9_TREMOVE, "d", fid->fid);
@@ -1680,7 +1673,6 @@ struct p9_wstat *p9_client_stat(struct p9_fid *fid)
 	if (!ret)
 		return ERR_PTR(-ENOMEM);
 
-	err = 0;
 	clnt = fid->clnt;
 
 	req = p9_client_rpc(clnt, P9_TSTAT, "d", fid->fid);
@@ -1733,7 +1725,6 @@ struct p9_stat_dotl *p9_client_getattr_dotl(struct p9_fid *fid,
 	if (!ret)
 		return ERR_PTR(-ENOMEM);
 
-	err = 0;
 	clnt = fid->clnt;
 
 	req = p9_client_rpc(clnt, P9_TGETATTR, "dq", fid->fid, request_mask);
@@ -1812,11 +1803,10 @@ static int p9_client_statsize(struct p9_wstat *wst, int proto_version)
 
 int p9_client_wstat(struct p9_fid *fid, struct p9_wstat *wst)
 {
-	int err;
+	int err = 0;
 	struct p9_req_t *req;
 	struct p9_client *clnt;
 
-	err = 0;
 	clnt = fid->clnt;
 	wst->size = p9_client_statsize(wst, clnt->proto_version);
 	p9_debug(P9_DEBUG_9P, ">>> TWSTAT fid %d\n",
@@ -1851,11 +1841,10 @@ EXPORT_SYMBOL(p9_client_wstat);
 
 int p9_client_setattr(struct p9_fid *fid, struct p9_iattr_dotl *p9attr)
 {
-	int err;
+	int err = 0;
 	struct p9_req_t *req;
 	struct p9_client *clnt;
 
-	err = 0;
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P, ">>> TSETATTR fid %d\n", fid->fid);
 	p9_debug(P9_DEBUG_9P, "    valid=%x mode=%x uid=%d gid=%d size=%lld\n",
@@ -1887,7 +1876,6 @@ int p9_client_statfs(struct p9_fid *fid, struct p9_rstatfs *sb)
 	struct p9_req_t *req;
 	struct p9_client *clnt;
 
-	err = 0;
 	clnt = fid->clnt;
 
 	p9_debug(P9_DEBUG_9P, ">>> TSTATFS fid %d\n", fid->fid);
@@ -1921,11 +1909,10 @@ EXPORT_SYMBOL(p9_client_statfs);
 int p9_client_rename(struct p9_fid *fid,
 		     struct p9_fid *newdirfid, const char *name)
 {
-	int err;
+	int err = 0;
 	struct p9_req_t *req;
 	struct p9_client *clnt;
 
-	err = 0;
 	clnt = fid->clnt;
 
 	p9_debug(P9_DEBUG_9P, ">>> TRENAME fid %d newdirfid %d name %s\n",
@@ -1949,11 +1936,10 @@ EXPORT_SYMBOL(p9_client_rename);
 int p9_client_renameat(struct p9_fid *olddirfid, const char *old_name,
 		       struct p9_fid *newdirfid, const char *new_name)
 {
-	int err;
+	int err = 0;
 	struct p9_req_t *req;
 	struct p9_client *clnt;
 
-	err = 0;
 	clnt = olddirfid->clnt;
 
 	p9_debug(P9_DEBUG_9P,
@@ -1986,7 +1972,6 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid *file_fid,
 	struct p9_client *clnt;
 	struct p9_fid *attr_fid;
 
-	err = 0;
 	clnt = file_fid->clnt;
 	attr_fid = p9_fid_create(clnt);
 	if (!attr_fid) {
@@ -2027,14 +2012,13 @@ EXPORT_SYMBOL_GPL(p9_client_xattrwalk);
 int p9_client_xattrcreate(struct p9_fid *fid, const char *name,
 			  u64 attr_size, int flags)
 {
-	int err;
+	int err = 0;
 	struct p9_req_t *req;
 	struct p9_client *clnt;
 
 	p9_debug(P9_DEBUG_9P,
 		 ">>> TXATTRCREATE fid %d name  %s size %llu flag %d\n",
 		 fid->fid, name, attr_size, flags);
-	err = 0;
 	clnt = fid->clnt;
 	req = p9_client_rpc(clnt, P9_TXATTRCREATE, "dsqd",
 			    fid->fid, name, attr_size, flags);
@@ -2063,7 +2047,6 @@ int p9_client_readdir(struct p9_fid *fid, char *data, u32 count, u64 offset)
 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
 		 fid->fid, offset, count);
 
-	err = 0;
 	clnt = fid->clnt;
 
 	rsize = fid->iounit;
@@ -2122,7 +2105,6 @@ int p9_client_mknod_dotl(struct p9_fid *fid, const char *name, int mode,
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
-	err = 0;
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P,
 		 ">>> TMKNOD fid %d name %s mode %d major %d minor %d\n",
@@ -2153,7 +2135,6 @@ int p9_client_mkdir_dotl(struct p9_fid *fid, const char *name, int mode,
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
-	err = 0;
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P, ">>> TMKDIR fid %d name %s mode %d gid %d\n",
 		 fid->fid, name, mode, from_kgid(&init_user_ns, gid));
@@ -2182,7 +2163,6 @@ int p9_client_lock_dotl(struct p9_fid *fid, struct p9_flock *flock, u8 *status)
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
-	err = 0;
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P,
 		 ">>> TLOCK fid %d type %i flags %d start %lld length %lld proc_id %d client_id %s\n",
@@ -2214,7 +2194,6 @@ int p9_client_getlock_dotl(struct p9_fid *fid, struct p9_getlock *glock)
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
-	err = 0;
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P,
 		 ">>> TGETLOCK fid %d, type %i start %lld length %lld proc_id %d client_id %s\n",
@@ -2251,7 +2230,6 @@ int p9_client_readlink(struct p9_fid *fid, char **target)
 	struct p9_client *clnt;
 	struct p9_req_t *req;
 
-	err = 0;
 	clnt = fid->clnt;
 	p9_debug(P9_DEBUG_9P, ">>> TREADLINK fid %d\n", fid->fid);
 

-- 
2.39.2


  parent reply	other threads:[~2023-04-27 11:24 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-27 11:23 [PATCH 0/5] Fix scan-build warnings Dominique Martinet
2023-04-27 11:23 ` [PATCH 1/5] 9p: fix ignored return value in v9fs_dir_release Dominique Martinet
2023-05-02 14:46   ` Simon Horman
2023-05-02 23:32     ` Dominique Martinet
2023-05-03  7:17       ` Simon Horman
2023-04-27 11:23 ` [PATCH 2/5] 9p: virtio: fix unlikely null pointer deref in handle_rerror Dominique Martinet
2023-05-02 15:28   ` Simon Horman
2023-04-27 11:23 ` [PATCH 3/5] 9p: virtio: make sure 'offs' is initialized in zc_request Dominique Martinet
2023-05-02 15:27   ` Simon Horman
2023-04-27 11:23 ` [PATCH 4/5] 9p: virtio: skip incrementing unused variable Dominique Martinet
2023-05-02 15:27   ` Simon Horman
2023-04-27 11:23 ` Dominique Martinet [this message]
2023-05-02 15:26   ` [PATCH 5/5] 9p: remove dead stores (variable set again without being read) Simon Horman

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