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[82.69.66.36]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-45d9ec3ac86sm46855162f8f.14.2026.05.19.10.35.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 19 May 2026 10:35:34 -0700 (PDT) Date: Tue, 19 May 2026 18:35:32 +0100 From: David Laight To: Hongling Zeng Cc: ericvh@kernel.org, lucho@ionkov.net, asmadeus@codewreck.org, linux_oss@crudebyte.com, v9fs@lists.linux.dev, linux-kernel@vger.kernel.org, zhongling0719@126.com Subject: Re: [PATCH v1] 9p: Fix mkdir to return NULL on success Message-ID: <20260519183532.04e8e8f2@pumpkin> In-Reply-To: <20260511061830.38373-1-zenghongling@kylinos.cn> References: <20260511061830.38373-1-zenghongling@kylinos.cn> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; arm-unknown-linux-gnueabihf) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Mon, 11 May 2026 14:18:30 +0800 Hongling Zeng wrote: > When mkdir succeeds, v9fs_vfs_mkdir_dotl() and v9fs_vfs_mkdir() return > ERR_PTR(0) which is incorrect. They should return NULL instead for > success and ERR_PTR() only with negative error codes for failure. > > Return NULL instead of passing to ERR_PTR while err is zero > Fixes smatch warnings: > fs/9p/vfs_inode_dotl.c:420 v9fs_vfs_mkdir_dotl() warn: passing zero to 'ERR_PTR' > fs/9p/vfs_inode.c:695 v9fs_vfs_mkdir() warn: passing zero to 'ERR_PTR' > > This change does not alter the runtime behavior since ERR_PTR(0) and NULL > are equivalent. However, it improves code readability and silences static > analyzer warnings. > > Fixes: 88d5baf69082 ("Change inode_operations.mkdir to return struct dentry *") > Acked-by: Christian Schoenebeck > Signed-off-by: Hongling Zeng > > --- > change inv1: > - Add clarification in commit message that this is not a functional > change, as suggested by Christian Schoenebeck. > - Add acked-by. > --- > --- > fs/9p/vfs_inode.c | 5 ++--- > fs/9p/vfs_inode_dotl.c | 4 ++-- > 2 files changed, 4 insertions(+), 5 deletions(-) > > diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c > index d1508b1fe109..d2d18c796b58 100644 > --- a/fs/9p/vfs_inode.c > +++ b/fs/9p/vfs_inode.c > @@ -672,13 +672,12 @@ v9fs_vfs_create(struct mnt_idmap *idmap, struct inode *dir, > static struct dentry *v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, > struct dentry *dentry, umode_t mode) > { > - int err; > + int err = 0; > u32 perm; > struct p9_fid *fid; > struct v9fs_session_info *v9ses; > > p9_debug(P9_DEBUG_VFS, "name %pd\n", dentry); > - err = 0; > v9ses = v9fs_inode2v9ses(dir); > perm = unixmode2p9mode(v9ses, mode | S_IFDIR); > fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD); > @@ -692,7 +691,7 @@ static struct dentry *v9fs_vfs_mkdir(struct mnt_idmap *idmap, struct inode *dir, > > if (fid) > p9_fid_put(fid); > - return ERR_PTR(err); > + return err ? ERR_PTR(err) : NULL; > } That function is odd, it ends: fid = v9fs_create(v9ses, dir, dentry, NULL, perm, P9_OREAD); if (IS_ERR(fid)) { err = PTR_ERR(fid); fid = NULL; A 'return' here would solve the mess later on. } else { inc_nlink(dir); v9fs_invalidate_inode_attr(dir); } Can v9fs_create() even return NULL? In any case p9_fid_put() already contains an (inline) check for both NULL and IS_ERR() so the 'if (fid)' and 'fid == NULL' (above) are pointless. if (fid) p9_fid_put(fid); return ERR_PTR(err); -- David > > /** > diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c > index 71796a89bcf4..83a52a85ce08 100644 > --- a/fs/9p/vfs_inode_dotl.c > +++ b/fs/9p/vfs_inode_dotl.c > @@ -349,7 +349,7 @@ static struct dentry *v9fs_vfs_mkdir_dotl(struct mnt_idmap *idmap, > struct inode *dir, struct dentry *dentry, > umode_t omode) > { > - int err; > + int err = 0; > struct v9fs_session_info *v9ses; > struct p9_fid *fid = NULL, *dfid = NULL; > kgid_t gid; > @@ -412,7 +412,7 @@ static struct dentry *v9fs_vfs_mkdir_dotl(struct mnt_idmap *idmap, > p9_fid_put(fid); > v9fs_put_acl(dacl, pacl); > p9_fid_put(dfid); > - return ERR_PTR(err); > + return err ? ERR_PTR(err) : NULL; > } > > static int