Re: [PATCH v3 04/06] 9p fid refcount: add p9_fid_get/put wrappers

From: Christian Schoenebeck
Date: Wed Jun 15 2022 - 09:00:53 EST

Next message: syzbot: "Re: [syzbot] KASAN: stack-out-of-bounds Read in __show_regs"
Previous message: Peng Fan (OSS): "[PATCH V2 1/2] dt-bindings: mailbox: imx-mu: add RST channel"
In reply to: Dominique Martinet: "[PATCH v3 04/06] 9p fid refcount: add p9_fid_get/put wrappers"
Next in thread: Dominique Martinet: "Re: [PATCH v3 04/06] 9p fid refcount: add p9_fid_get/put wrappers"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

On Mittwoch, 15. Juni 2022 05:16:45 CEST Dominique Martinet wrote:
> I was recently reminded that it is not clear that p9_client_clunk()
> was actually just decrementing refcount and clunking only when that
> reaches zero: make it clear through a set of helpers.
>
> This will also allow instrumenting refcounting better for debugging
> next patch
>
> Link:
> https://lkml.kernel.org/r/20220612085330.1451496-5-asmadeus@xxxxxxxxxxxxx
> Reviewed-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Dominique Martinet <asmadeus@xxxxxxxxxxxxx>
> ---
> v1 -> v2: p9_fid_get/put are now static inline in .h
> v2 -> v3: fix commit message and add comment to helpers
>
> fs/9p/fid.c | 18 ++++++++--------
> fs/9p/fid.h | 2 +-
> fs/9p/vfs_addr.c | 4 ++--
> fs/9p/vfs_dentry.c | 4 ++--
> fs/9p/vfs_dir.c | 2 +-
> fs/9p/vfs_file.c | 4 ++--
> fs/9p/vfs_inode.c | 48 ++++++++++++++++++++---------------------
> fs/9p/vfs_inode_dotl.c | 42 ++++++++++++++++++------------------
> fs/9p/vfs_super.c | 6 +++---
> fs/9p/xattr.c | 8 +++----
> include/net/9p/client.h | 28 ++++++++++++++++++++++++
> net/9p/client.c | 15 +++----------
> 12 files changed, 100 insertions(+), 81 deletions(-)
>
> diff --git a/fs/9p/fid.c b/fs/9p/fid.c
> index e8fad28fc5bd..d792499349c4 100644
> --- a/fs/9p/fid.c
> +++ b/fs/9p/fid.c
> @@ -56,7 +56,7 @@ static struct p9_fid *v9fs_fid_find_inode(struct inode
> *inode, kuid_t uid) h = (struct hlist_head *)&inode->i_private;
> hlist_for_each_entry(fid, h, ilist) {
> if (uid_eq(fid->uid, uid)) {
> - refcount_inc(&fid->count);
> + p9_fid_get(fid);
> ret = fid;
> break;
> }
> @@ -104,7 +104,7 @@ static struct p9_fid *v9fs_fid_find(struct dentry
> *dentry, kuid_t uid, int any) hlist_for_each_entry(fid, h, dlist) {
> if (any || uid_eq(fid->uid, uid)) {
> ret = fid;
> - refcount_inc(&ret->count);
> + p9_fid_get(ret);
> break;
> }
> }
> @@ -172,7 +172,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct
> dentry *dentry, old_fid = fid;
>
> fid = p9_client_walk(old_fid, 1, &dentry->d_name.name, 1);
> - p9_client_clunk(old_fid);
> + p9_fid_put(old_fid);
> goto fid_out;
> }
> up_read(&v9ses->rename_sem);
> @@ -194,7 +194,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct
> dentry *dentry, if (IS_ERR(root_fid))
> return root_fid;
>
> - refcount_inc(&root_fid->count);
> + p9_fid_get(root_fid);
> v9fs_fid_add(dentry->d_sb->s_root, root_fid);
> }
> /* If we are root ourself just return that */
> @@ -225,7 +225,7 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct
> dentry *dentry, old_fid == root_fid /* clone */);
> /* non-cloning walk will return the same fid */
> if (fid != old_fid) {
> - p9_client_clunk(old_fid);
> + p9_fid_put(old_fid);
> old_fid = fid;
> }
> if (IS_ERR(fid)) {
> @@ -240,11 +240,11 @@ static struct p9_fid *v9fs_fid_lookup_with_uid(struct
> dentry *dentry, spin_lock(&dentry->d_lock);
> if (d_unhashed(dentry)) {
> spin_unlock(&dentry->d_lock);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> fid = ERR_PTR(-ENOENT);
> } else {
> __add_fid(dentry, fid);
> - refcount_inc(&fid->count);
> + p9_fid_get(fid);
> spin_unlock(&dentry->d_lock);
> }
> }
> @@ -301,7 +301,7 @@ struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
> fid = clone_fid(ofid);
> if (IS_ERR(fid))
> goto error_out;
> - p9_client_clunk(ofid);
> + p9_fid_put(ofid);
> /*
> * writeback fid will only be used to write back the
> * dirty pages. We always request for the open fid in read-write
> @@ -310,7 +310,7 @@ struct p9_fid *v9fs_writeback_fid(struct dentry *dentry)
> */
> err = p9_client_open(fid, O_RDWR);
> if (err < 0) {
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> fid = ERR_PTR(err);
> goto error_out;
> }
> diff --git a/fs/9p/fid.h b/fs/9p/fid.h
> index f7f33509e169..3168dfad510e 100644
> --- a/fs/9p/fid.h
> +++ b/fs/9p/fid.h
> @@ -29,7 +29,7 @@ static inline struct p9_fid *v9fs_fid_clone(struct dentry
> *dentry) return fid;
>
> nfid = clone_fid(fid);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return nfid;
> }
> #endif
> diff --git a/fs/9p/vfs_addr.c b/fs/9p/vfs_addr.c
> index 7f924e671e3e..c5f71eeb28b6 100644
> --- a/fs/9p/vfs_addr.c
> +++ b/fs/9p/vfs_addr.c
> @@ -70,7 +70,7 @@ static int v9fs_init_request(struct netfs_io_request
> *rreq, struct file *file)
>
> BUG_ON(!fid);
>
> - refcount_inc(&fid->count);
> + p9_fid_get(fid);
> rreq->netfs_priv = fid;
> return 0;
> }
> @@ -83,7 +83,7 @@ static void v9fs_free_request(struct netfs_io_request
> *rreq) {
> struct p9_fid *fid = rreq->netfs_priv;
>
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> }
>
> /**
> diff --git a/fs/9p/vfs_dentry.c b/fs/9p/vfs_dentry.c
> index 1c609e99d280..f89f01734587 100644
> --- a/fs/9p/vfs_dentry.c
> +++ b/fs/9p/vfs_dentry.c
> @@ -54,7 +54,7 @@ static void v9fs_dentry_release(struct dentry *dentry)
> p9_debug(P9_DEBUG_VFS, " dentry: %pd (%p)\n",
> dentry, dentry);
> hlist_for_each_safe(p, n, (struct hlist_head *)&dentry->d_fsdata)
> - p9_client_clunk(hlist_entry(p, struct p9_fid, dlist));
> + p9_fid_put(hlist_entry(p, struct p9_fid, dlist));
> dentry->d_fsdata = NULL;
> }
>
> @@ -85,7 +85,7 @@ static int v9fs_lookup_revalidate(struct dentry *dentry,
> unsigned int flags) retval = v9fs_refresh_inode_dotl(fid, inode);
> else
> retval = v9fs_refresh_inode(fid, inode);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> if (retval == -ENOENT)
> return 0;
> diff --git a/fs/9p/vfs_dir.c b/fs/9p/vfs_dir.c
> index 958680f7f23e..000fbaae9b18 100644
> --- a/fs/9p/vfs_dir.c
> +++ b/fs/9p/vfs_dir.c
> @@ -218,7 +218,7 @@ int v9fs_dir_release(struct inode *inode, struct file
> *filp) spin_lock(&inode->i_lock);
> hlist_del(&fid->ilist);
> spin_unlock(&inode->i_lock);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> }
>
> if ((filp->f_mode & FMODE_WRITE)) {
> diff --git a/fs/9p/vfs_file.c b/fs/9p/vfs_file.c
> index 2573c08f335c..8276f3af35d7 100644
> --- a/fs/9p/vfs_file.c
> +++ b/fs/9p/vfs_file.c
> @@ -63,7 +63,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
>
> err = p9_client_open(fid, omode);
> if (err < 0) {
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return err;
> }
> if ((file->f_flags & O_APPEND) &&
> @@ -98,7 +98,7 @@ int v9fs_file_open(struct inode *inode, struct file *file)
> v9fs_open_fid_add(inode, fid);
> return 0;
> out_error:
> - p9_client_clunk(file->private_data);
> + p9_fid_put(file->private_data);
> file->private_data = NULL;
> return err;
> }
> diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
> index 3d8297714772..bde18776f0c7 100644
> --- a/fs/9p/vfs_inode.c
> +++ b/fs/9p/vfs_inode.c
> @@ -400,7 +400,7 @@ void v9fs_evict_inode(struct inode *inode)
> fscache_relinquish_cookie(v9fs_inode_cookie(v9inode), false);
> /* clunk the fid stashed in writeback_fid */
> if (v9inode->writeback_fid) {
> - p9_client_clunk(v9inode->writeback_fid);
> + p9_fid_put(v9inode->writeback_fid);
> v9inode->writeback_fid = NULL;
> }
> }
> @@ -569,7 +569,7 @@ static int v9fs_remove(struct inode *dir, struct dentry
> *dentry, int flags) if (v9fs_proto_dotl(v9ses))
> retval = p9_client_unlinkat(dfid, dentry->d_name.name,
>
v9fs_at_to_dotl_flags(flags));
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> if (retval == -EOPNOTSUPP) {
> /* Try the one based on path */
> v9fid = v9fs_fid_clone(dentry);
> @@ -633,14 +633,14 @@ v9fs_create(struct v9fs_session_info *v9ses, struct
> inode *dir, if (IS_ERR(ofid)) {
> err = PTR_ERR(ofid);
> p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> return ERR_PTR(err);
> }
>
> err = p9_client_fcreate(ofid, name, perm, mode, extension);
> if (err < 0) {
> p9_debug(P9_DEBUG_VFS, "p9_client_fcreate failed %d\n",
err);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> goto error;
> }
>
> @@ -652,7 +652,7 @@ v9fs_create(struct v9fs_session_info *v9ses, struct
> inode *dir, p9_debug(P9_DEBUG_VFS,
> "p9_client_walk failed %d\n", err);
> fid = NULL;
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> goto error;
> }
> /*
> @@ -663,20 +663,20 @@ v9fs_create(struct v9fs_session_info *v9ses, struct
> inode *dir, err = PTR_ERR(inode);
> p9_debug(P9_DEBUG_VFS,
> "inode creation failed %d\n", err);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> goto error;
> }
> v9fs_fid_add(dentry, fid);
> d_instantiate(dentry, inode);
> }
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> return ofid;
> error:
> if (ofid)
> - p9_client_clunk(ofid);
> + p9_fid_put(ofid);
>
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> return ERR_PTR(err);
> }
> @@ -708,7 +708,7 @@ v9fs_vfs_create(struct user_namespace *mnt_userns,
> struct inode *dir, return PTR_ERR(fid);
>
> v9fs_invalidate_inode_attr(dir);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> return 0;
> }
> @@ -744,7 +744,7 @@ static int v9fs_vfs_mkdir(struct user_namespace
> *mnt_userns, struct inode *dir, }
>
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> return err;
> }
> @@ -785,7 +785,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct
> dentry *dentry, */
> name = dentry->d_name.name;
> fid = p9_client_walk(dfid, 1, &name, 1);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> if (fid == ERR_PTR(-ENOENT))
> inode = NULL;
> else if (IS_ERR(fid))
> @@ -808,7 +808,7 @@ struct dentry *v9fs_vfs_lookup(struct inode *dir, struct
> dentry *dentry, else if (!IS_ERR(res))
> v9fs_fid_add(res, fid);
> else
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> }
> return res;
> }
> @@ -891,7 +891,7 @@ v9fs_vfs_atomic_open(struct inode *dir, struct dentry
> *dentry,
>
> error:
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> goto out;
> }
>
> @@ -959,7 +959,7 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns,
> struct inode *old_dir, dfid = v9fs_parent_fid(old_dentry);
> olddirfid = clone_fid(dfid);
> if (dfid && !IS_ERR(dfid))
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
>
> if (IS_ERR(olddirfid)) {
> retval = PTR_ERR(olddirfid);
> @@ -968,7 +968,7 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns,
> struct inode *old_dir,
>
> dfid = v9fs_parent_fid(new_dentry);
> newdirfid = clone_fid(dfid);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
>
> if (IS_ERR(newdirfid)) {
> retval = PTR_ERR(newdirfid);
> @@ -1020,13 +1020,13 @@ v9fs_vfs_rename(struct user_namespace *mnt_userns,
> struct inode *old_dir, d_move(old_dentry, new_dentry);
> }
> up_write(&v9ses->rename_sem);
> - p9_client_clunk(newdirfid);
> + p9_fid_put(newdirfid);
>
> clunk_olddir:
> - p9_client_clunk(olddirfid);
> + p9_fid_put(olddirfid);
>
> done:
> - p9_client_clunk(oldfid);
> + p9_fid_put(oldfid);
> return retval;
> }
>
> @@ -1060,7 +1060,7 @@ v9fs_vfs_getattr(struct user_namespace *mnt_userns,
> const struct path *path, return PTR_ERR(fid);
>
> st = p9_client_stat(fid);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> if (IS_ERR(st))
> return PTR_ERR(st);
>
> @@ -1136,7 +1136,7 @@ static int v9fs_vfs_setattr(struct user_namespace
> *mnt_userns, retval = p9_client_wstat(fid, &wstat);
>
> if (use_dentry)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> if (retval < 0)
> return retval;
> @@ -1261,7 +1261,7 @@ static const char *v9fs_vfs_get_link(struct dentry
> *dentry, return ERR_CAST(fid);
>
> st = p9_client_stat(fid);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> if (IS_ERR(st))
> return ERR_CAST(st);
>
> @@ -1308,7 +1308,7 @@ static int v9fs_vfs_mkspecial(struct inode *dir,
> struct dentry *dentry, return PTR_ERR(fid);
>
> v9fs_invalidate_inode_attr(dir);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return 0;
> }
>
> @@ -1364,7 +1364,7 @@ v9fs_vfs_link(struct dentry *old_dentry, struct inode
> *dir, v9fs_refresh_inode(oldfid, d_inode(old_dentry));
> v9fs_invalidate_inode_attr(dir);
> }
> - p9_client_clunk(oldfid);
> + p9_fid_put(oldfid);
> return retval;
> }
>
> diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
> index b6eb1160296c..09b124fe349c 100644
> --- a/fs/9p/vfs_inode_dotl.c
> +++ b/fs/9p/vfs_inode_dotl.c
> @@ -274,7 +274,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct
> dentry *dentry, if (IS_ERR(ofid)) {
> err = PTR_ERR(ofid);
> p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> goto out;
> }
>
> @@ -286,7 +286,7 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct
> dentry *dentry, if (err) {
> p9_debug(P9_DEBUG_VFS, "Failed to get acl values in creat
%d\n",
> err);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> goto error;
> }
> err = p9_client_create_dotl(ofid, name,
v9fs_open_to_dotl_flags(flags),
> @@ -294,14 +294,14 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct
> dentry *dentry, if (err < 0) {
> p9_debug(P9_DEBUG_VFS, "p9_client_open_dotl failed in
creat %d\n",
> err);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> goto error;
> }
> v9fs_invalidate_inode_attr(dir);
>
> /* instantiate inode and assign the unopened fid to the dentry */
> fid = p9_client_walk(dfid, 1, &name, 1);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> if (IS_ERR(fid)) {
> err = PTR_ERR(fid);
> p9_debug(P9_DEBUG_VFS, "p9_client_walk failed %d\n", err);
> @@ -358,10 +358,10 @@ v9fs_vfs_atomic_open_dotl(struct inode *dir, struct
> dentry *dentry,
>
> error:
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> err_clunk_old_fid:
> if (ofid)
> - p9_client_clunk(ofid);
> + p9_fid_put(ofid);
> goto out;
> }
>
> @@ -458,9 +458,9 @@ static int v9fs_vfs_mkdir_dotl(struct user_namespace
> *mnt_userns, v9fs_invalidate_inode_attr(dir);
> error:
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> v9fs_put_acl(dacl, pacl);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> return err;
> }
>
> @@ -489,7 +489,7 @@ v9fs_vfs_getattr_dotl(struct user_namespace *mnt_userns,
> */
>
> st = p9_client_getattr_dotl(fid, P9_STATS_ALL);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> if (IS_ERR(st))
> return PTR_ERR(st);
>
> @@ -603,7 +603,7 @@ int v9fs_vfs_setattr_dotl(struct user_namespace
> *mnt_userns, retval = p9_client_setattr(fid, &p9attr);
> if (retval < 0) {
> if (use_dentry)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return retval;
> }
>
> @@ -619,12 +619,12 @@ int v9fs_vfs_setattr_dotl(struct user_namespace
> *mnt_userns, retval = v9fs_acl_chmod(inode, fid);
> if (retval < 0) {
> if (use_dentry)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return retval;
> }
> }
> if (use_dentry)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> return 0;
> }
> @@ -771,9 +771,9 @@ v9fs_vfs_symlink_dotl(struct user_namespace *mnt_userns,
> struct inode *dir,
>
> error:
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> return err;
> }
>
> @@ -803,14 +803,14 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct
> inode *dir,
>
> oldfid = v9fs_fid_lookup(old_dentry);
> if (IS_ERR(oldfid)) {
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
> return PTR_ERR(oldfid);
> }
>
> err = p9_client_link(dfid, oldfid, dentry->d_name.name);
>
> - p9_client_clunk(dfid);
> - p9_client_clunk(oldfid);
> + p9_fid_put(dfid);
> + p9_fid_put(oldfid);
> if (err < 0) {
> p9_debug(P9_DEBUG_VFS, "p9_client_link failed %d\n", err);
> return err;
> @@ -826,7 +826,7 @@ v9fs_vfs_link_dotl(struct dentry *old_dentry, struct
> inode *dir, return PTR_ERR(fid);
>
> v9fs_refresh_inode_dotl(fid, d_inode(old_dentry));
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> }
> ihold(d_inode(old_dentry));
> d_instantiate(dentry, d_inode(old_dentry));
> @@ -924,9 +924,9 @@ v9fs_vfs_mknod_dotl(struct user_namespace *mnt_userns,
> struct inode *dir, }
> error:
> if (fid)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> v9fs_put_acl(dacl, pacl);
> - p9_client_clunk(dfid);
> + p9_fid_put(dfid);
>
> return err;
> }
> @@ -956,7 +956,7 @@ v9fs_vfs_get_link_dotl(struct dentry *dentry,
> if (IS_ERR(fid))
> return ERR_CAST(fid);
> retval = p9_client_readlink(fid, &target);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> if (retval)
> return ERR_PTR(retval);
> set_delayed_call(done, kfree_link, target);
> diff --git a/fs/9p/vfs_super.c b/fs/9p/vfs_super.c
> index 97e23b4e6982..bf350fad9500 100644
> --- a/fs/9p/vfs_super.c
> +++ b/fs/9p/vfs_super.c
> @@ -190,7 +190,7 @@ static struct dentry *v9fs_mount(struct file_system_type
> *fs_type, int flags, return dget(sb->s_root);
>
> clunk_fid:
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> v9fs_session_close(v9ses);
> free_session:
> kfree(v9ses);
> @@ -203,7 +203,7 @@ static struct dentry *v9fs_mount(struct file_system_type
> *fs_type, int flags, * attached the fid to dentry so it won't get clunked
> * automatically.
> */
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> deactivate_locked_super(sb);
> return ERR_PTR(retval);
> }
> @@ -270,7 +270,7 @@ static int v9fs_statfs(struct dentry *dentry, struct
> kstatfs *buf) }
> res = simple_statfs(dentry, buf);
> done:
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return res;
> }
>
> diff --git a/fs/9p/xattr.c b/fs/9p/xattr.c
> index a824441b95a2..1f9298a4bd42 100644
> --- a/fs/9p/xattr.c
> +++ b/fs/9p/xattr.c
> @@ -44,7 +44,7 @@ ssize_t v9fs_fid_xattr_get(struct p9_fid *fid, const char
> *name, if (err)
> retval = err;
> }
> - p9_client_clunk(attr_fid);
> + p9_fid_put(attr_fid);
> return retval;
> }
>
> @@ -71,7 +71,7 @@ ssize_t v9fs_xattr_get(struct dentry *dentry, const char
> *name, if (IS_ERR(fid))
> return PTR_ERR(fid);
> ret = v9fs_fid_xattr_get(fid, name, buffer, buffer_size);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
>
> return ret;
> }
> @@ -98,7 +98,7 @@ int v9fs_xattr_set(struct dentry *dentry, const char
> *name, if (IS_ERR(fid))
> return PTR_ERR(fid);
> ret = v9fs_fid_xattr_set(fid, name, value, value_len, flags);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> return ret;
> }
>
> @@ -128,7 +128,7 @@ int v9fs_fid_xattr_set(struct p9_fid *fid, const char
> *name, retval);
> else
> p9_client_write(fid, 0, &from, &retval);
> - err = p9_client_clunk(fid);
> + err = p9_fid_put(fid);
> if (!retval && err)
> retval = err;
> return retval;
> diff --git a/include/net/9p/client.h b/include/net/9p/client.h
> index ec1d1706f43c..eabb53992350 100644
> --- a/include/net/9p/client.h
> +++ b/include/net/9p/client.h
> @@ -237,6 +237,34 @@ static inline int p9_req_try_get(struct p9_req_t *r)
>
> int p9_req_put(struct p9_req_t *r);
>
> +/* fid reference counting helpers:
> + * - fids used for any length of time should always be referenced through
> + * p9_fid_get(), and released with p9_fid_put()
> + * - v9fs_fid_lookup() or similar will automatically call get for you
> + * and also require a put
> + * - the *_fid_add() helpers will stash the fid in the inode,
> + * at which point it is the responsibility of evict_inode()
> + * to call the put
> + * - the last put will automatically send a clunk to the server
> + */
> +static inline struct p9_fid *p9_fid_get(struct p9_fid *fid)
> +{
> + refcount_inc(&fid->count);
> +
> + return fid;
> +}
> +
> +static inline int p9_fid_put(struct p9_fid *fid)
> +{
> + if (!fid || IS_ERR(fid))
> + return 0;
> +
> + if (!refcount_dec_and_test(&fid->count))
> + return 0;
> +
> + return p9_client_clunk(fid);
> +}
> +
> void p9_client_cb(struct p9_client *c, struct p9_req_t *req, int status);
>
> int p9_parse_header(struct p9_fcall *pdu, int32_t *size, int8_t *type,
> diff --git a/net/9p/client.c b/net/9p/client.c
> index 8bba0d9cf975..f3eb280c7d9d 100644
> --- a/net/9p/client.c
> +++ b/net/9p/client.c
> @@ -1228,7 +1228,7 @@ struct p9_fid *p9_client_walk(struct p9_fid *oldfid,
> uint16_t nwname,
>
> clunk_fid:
> kfree(wqids);
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> fid = NULL;
>
> error:
> @@ -1459,15 +1459,6 @@ int p9_client_clunk(struct p9_fid *fid)
> struct p9_req_t *req;
> int retries = 0;
>
> - if (!fid || IS_ERR(fid)) {
> - pr_warn("%s (%d): Trying to clunk with invalid fid\n",
> - __func__, task_pid_nr(current));
> - dump_stack();
> - return 0;
> - }
> - if (!refcount_dec_and_test(&fid->count))
> - return 0;
> -

I probably would have moved (and that way preserved) that sanity warning to
p9_fid_put(), but anyway LGTM.

Reviewed-by: Christian Schoenebeck <linux_oss@xxxxxxxxxxxxx>

> again:
> p9_debug(P9_DEBUG_9P, ">>> TCLUNK fid %d (try %d)\n",
> fid->fid, retries);
> @@ -1519,7 +1510,7 @@ int p9_client_remove(struct p9_fid *fid)
> p9_tag_remove(clnt, req);
> error:
> if (err == -ERESTARTSYS)
> - p9_client_clunk(fid);
> + p9_fid_put(fid);
> else
> p9_fid_destroy(fid);
> return err;
> @@ -2042,7 +2033,7 @@ struct p9_fid *p9_client_xattrwalk(struct p9_fid
> *file_fid, attr_fid->fid, *attr_size);
> return attr_fid;
> clunk_fid:
> - p9_client_clunk(attr_fid);
> + p9_fid_put(attr_fid);
> attr_fid = NULL;
> error:
> if (attr_fid && attr_fid != file_fid)

Next message: syzbot: "Re: [syzbot] KASAN: stack-out-of-bounds Read in __show_regs"
Previous message: Peng Fan (OSS): "[PATCH V2 1/2] dt-bindings: mailbox: imx-mu: add RST channel"
In reply to: Dominique Martinet: "[PATCH v3 04/06] 9p fid refcount: add p9_fid_get/put wrappers"
Next in thread: Dominique Martinet: "Re: [PATCH v3 04/06] 9p fid refcount: add p9_fid_get/put wrappers"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]