[PATCH 02/40] proc: simplify proc_register calling conventions

From: Christoph Hellwig
Date: Wed Apr 25 2018 - 11:49:24 EST


Return registered entry on success, return NULL on failure and free the
passed in entry. Also expose it in internal.h as we'll start using it
in proc_net.c soon.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
fs/proc/generic.c | 44 ++++++++++++++++++--------------------------
fs/proc/internal.h | 2 ++
2 files changed, 20 insertions(+), 26 deletions(-)

diff --git a/fs/proc/generic.c b/fs/proc/generic.c
index 2078e70e1595..bd8480ff0d35 100644
--- a/fs/proc/generic.c
+++ b/fs/proc/generic.c
@@ -346,13 +346,12 @@ static const struct inode_operations proc_dir_inode_operations = {
.setattr = proc_notify_change,
};

-static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp)
+/* returns the registered entry, or frees dp and returns NULL on failure */
+struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
+ struct proc_dir_entry *dp)
{
- int ret;
-
- ret = proc_alloc_inum(&dp->low_ino);
- if (ret)
- return ret;
+ if (proc_alloc_inum(&dp->low_ino))
+ goto out_free_entry;

write_lock(&proc_subdir_lock);
dp->parent = dir;
@@ -360,12 +359,16 @@ static int proc_register(struct proc_dir_entry * dir, struct proc_dir_entry * dp
WARN(1, "proc_dir_entry '%s/%s' already registered\n",
dir->name, dp->name);
write_unlock(&proc_subdir_lock);
- proc_free_inum(dp->low_ino);
- return -EEXIST;
+ goto out_free_inum;
}
write_unlock(&proc_subdir_lock);

- return 0;
+ return dp;
+out_free_inum:
+ proc_free_inum(dp->low_ino);
+out_free_entry:
+ pde_free(dp);
+ return NULL;
}

static struct proc_dir_entry *__proc_create(struct proc_dir_entry **parent,
@@ -443,10 +446,7 @@ struct proc_dir_entry *proc_symlink(const char *name,
if (ent->data) {
strcpy((char*)ent->data,dest);
ent->proc_iops = &proc_link_inode_operations;
- if (proc_register(parent, ent) < 0) {
- pde_free(ent);
- ent = NULL;
- }
+ ent = proc_register(parent, ent);
} else {
pde_free(ent);
ent = NULL;
@@ -470,11 +470,9 @@ struct proc_dir_entry *proc_mkdir_data(const char *name, umode_t mode,
ent->proc_fops = &proc_dir_operations;
ent->proc_iops = &proc_dir_inode_operations;
parent->nlink++;
- if (proc_register(parent, ent) < 0) {
- pde_free(ent);
+ ent = proc_register(parent, ent);
+ if (!ent)
parent->nlink--;
- ent = NULL;
- }
}
return ent;
}
@@ -505,11 +503,9 @@ struct proc_dir_entry *proc_create_mount_point(const char *name)
ent->proc_fops = NULL;
ent->proc_iops = NULL;
parent->nlink++;
- if (proc_register(parent, ent) < 0) {
- pde_free(ent);
+ ent = proc_register(parent, ent);
+ if (!ent)
parent->nlink--;
- ent = NULL;
- }
}
return ent;
}
@@ -539,11 +535,7 @@ struct proc_dir_entry *proc_create_data(const char *name, umode_t mode,
pde->proc_fops = proc_fops;
pde->data = data;
pde->proc_iops = &proc_file_inode_operations;
- if (proc_register(parent, pde) < 0)
- goto out_free;
- return pde;
-out_free:
- pde_free(pde);
+ return proc_register(parent, pde);
out:
return NULL;
}
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index 0f1692e63cb6..488e67490312 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -162,6 +162,8 @@ extern bool proc_fill_cache(struct file *, struct dir_context *, const char *, i
/*
* generic.c
*/
+struct proc_dir_entry *proc_register(struct proc_dir_entry *dir,
+ struct proc_dir_entry *dp);
extern struct dentry *proc_lookup(struct inode *, struct dentry *, unsigned int);
struct dentry *proc_lookup_de(struct inode *, struct dentry *, struct proc_dir_entry *);
extern int proc_readdir(struct file *, struct dir_context *);
--
2.17.0