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Subject[PATCH v16 01/12] nsfs: clean-up ns_get_path() signature to return int
Date
ns_get_path() and ns_get_path_cb() only ever return either NULL or an
ERR_PTR. It is far more idiomatic to simply return an integer, and it
makes all of the callers of ns_get_path() more straightforward to read.

Fixes: e149ed2b805f ("take the targets of /proc/*/ns/* symlinks to separate fs")
Signed-off-by: Aleksa Sarai <cyphar@cyphar.com>
---
fs/nsfs.c | 29 ++++++++++++++---------------
fs/proc/namespaces.c | 6 +++---
include/linux/proc_ns.h | 4 ++--
kernel/bpf/offload.c | 12 ++++++------
kernel/events/core.c | 2 +-
5 files changed, 26 insertions(+), 27 deletions(-)

diff --git a/fs/nsfs.c b/fs/nsfs.c
index a0431642c6b5..f3d2833c5781 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -52,7 +52,7 @@ static void nsfs_evict(struct inode *inode)
ns->ops->put(ns);
}

-static void *__ns_get_path(struct path *path, struct ns_common *ns)
+static int __ns_get_path(struct path *path, struct ns_common *ns)
{
struct vfsmount *mnt = nsfs_mnt;
struct dentry *dentry;
@@ -71,13 +71,13 @@ static void *__ns_get_path(struct path *path, struct ns_common *ns)
got_it:
path->mnt = mntget(mnt);
path->dentry = dentry;
- return NULL;
+ return 0;
slow:
rcu_read_unlock();
inode = new_inode_pseudo(mnt->mnt_sb);
if (!inode) {
ns->ops->put(ns);
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
}
inode->i_ino = ns->inum;
inode->i_mtime = inode->i_atime = inode->i_ctime = current_time(inode);
@@ -89,7 +89,7 @@ static void *__ns_get_path(struct path *path, struct ns_common *ns)
dentry = d_alloc_anon(mnt->mnt_sb);
if (!dentry) {
iput(inode);
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
}
d_instantiate(dentry, inode);
dentry->d_fsdata = (void *)ns->ops;
@@ -98,23 +98,22 @@ static void *__ns_get_path(struct path *path, struct ns_common *ns)
d_delete(dentry); /* make sure ->d_prune() does nothing */
dput(dentry);
cpu_relax();
- return ERR_PTR(-EAGAIN);
+ return -EAGAIN;
}
goto got_it;
}

-void *ns_get_path_cb(struct path *path, ns_get_path_helper_t *ns_get_cb,
+int ns_get_path_cb(struct path *path, ns_get_path_helper_t *ns_get_cb,
void *private_data)
{
- void *ret;
+ int ret;

do {
struct ns_common *ns = ns_get_cb(private_data);
if (!ns)
- return ERR_PTR(-ENOENT);
-
+ return -ENOENT;
ret = __ns_get_path(path, ns);
- } while (ret == ERR_PTR(-EAGAIN));
+ } while (ret == -EAGAIN);

return ret;
}
@@ -131,7 +130,7 @@ static struct ns_common *ns_get_path_task(void *private_data)
return args->ns_ops->get(args->task);
}

-void *ns_get_path(struct path *path, struct task_struct *task,
+int ns_get_path(struct path *path, struct task_struct *task,
const struct proc_ns_operations *ns_ops)
{
struct ns_get_path_task_args args = {
@@ -147,7 +146,7 @@ int open_related_ns(struct ns_common *ns,
{
struct path path = {};
struct file *f;
- void *err;
+ int err;
int fd;

fd = get_unused_fd_flags(O_CLOEXEC);
@@ -164,11 +163,11 @@ int open_related_ns(struct ns_common *ns,
}

err = __ns_get_path(&path, relative);
- } while (err == ERR_PTR(-EAGAIN));
+ } while (err == -EAGAIN);

- if (IS_ERR(err)) {
+ if (err) {
put_unused_fd(fd);
- return PTR_ERR(err);
+ return err;
}

f = dentry_open(&path, O_RDONLY, current_cred());
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index dd2b35f78b09..08dd94df1a66 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -42,14 +42,14 @@ static const char *proc_ns_get_link(struct dentry *dentry,
const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
struct task_struct *task;
struct path ns_path;
- void *error = ERR_PTR(-EACCES);
+ int error = -EACCES;

if (!dentry)
return ERR_PTR(-ECHILD);

task = get_proc_task(inode);
if (!task)
- return error;
+ return ERR_PTR(-EACCES);

if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
error = ns_get_path(&ns_path, task, ns_ops);
@@ -57,7 +57,7 @@ static const char *proc_ns_get_link(struct dentry *dentry,
nd_jump_link(&ns_path);
}
put_task_struct(task);
- return error;
+ return ERR_PTR(error);
}

static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index d31cb6215905..aed366b4795c 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -76,10 +76,10 @@ static inline int ns_alloc_inum(struct ns_common *ns)

extern struct file *proc_ns_fget(int fd);
#define get_proc_ns(inode) ((struct ns_common *)(inode)->i_private)
-extern void *ns_get_path(struct path *path, struct task_struct *task,
+extern int ns_get_path(struct path *path, struct task_struct *task,
const struct proc_ns_operations *ns_ops);
typedef struct ns_common *ns_get_path_helper_t(void *);
-extern void *ns_get_path_cb(struct path *path, ns_get_path_helper_t ns_get_cb,
+extern int ns_get_path_cb(struct path *path, ns_get_path_helper_t ns_get_cb,
void *private_data);

extern int ns_get_name(char *buf, size_t size, struct task_struct *task,
diff --git a/kernel/bpf/offload.c b/kernel/bpf/offload.c
index ba635209ae9a..a2253a044f90 100644
--- a/kernel/bpf/offload.c
+++ b/kernel/bpf/offload.c
@@ -302,14 +302,14 @@ int bpf_prog_offload_info_fill(struct bpf_prog_info *info,
struct inode *ns_inode;
struct path ns_path;
char __user *uinsns;
- void *res;
+ int res;
u32 ulen;

res = ns_get_path_cb(&ns_path, bpf_prog_offload_info_fill_ns, &args);
- if (IS_ERR(res)) {
+ if (res) {
if (!info->ifindex)
return -ENODEV;
- return PTR_ERR(res);
+ return res;
}

down_read(&bpf_devs_lock);
@@ -526,13 +526,13 @@ int bpf_map_offload_info_fill(struct bpf_map_info *info, struct bpf_map *map)
};
struct inode *ns_inode;
struct path ns_path;
- void *res;
+ int res;

res = ns_get_path_cb(&ns_path, bpf_map_offload_info_fill_ns, &args);
- if (IS_ERR(res)) {
+ if (res) {
if (!info->ifindex)
return -ENODEV;
- return PTR_ERR(res);
+ return res;
}

ns_inode = ns_path.dentry->d_inode;
diff --git a/kernel/events/core.c b/kernel/events/core.c
index aec8dba2bea4..39c5711e868a 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7258,7 +7258,7 @@ static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
{
struct path ns_path;
struct inode *ns_inode;
- void *error;
+ int error;

error = ns_get_path(&ns_path, task, ns_ops);
if (!error) {
--
2.24.0
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