debugfs: convert to debugfs_file_get() and -put()

Convert all calls to the now obsolete debugfs_use_file_start() and
debugfs_use_file_finish() from the debugfs core itself to the new
debugfs_file_get() and debugfs_file_put() API.

Fixes: 49d200deaa68 ("debugfs: prevent access to removed files' private data")
Signed-off-by: Nicolai Stange <nicstange@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 50 insertions, 56 deletions

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 08511678b782..d3a972b45ff0 100644
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -155,15 +155,12 @@ EXPORT_SYMBOL_GPL(debugfs_file_put);
 
 static int open_proxy_open(struct inode *inode, struct file *filp)
 {
-        const struct dentry *dentry = F_DENTRY(filp);
+        struct dentry *dentry = F_DENTRY(filp);
         const struct file_operations *real_fops = NULL;
-        int srcu_idx, r;
+        int r = 0;
 
-        r = debugfs_use_file_start(dentry, &srcu_idx);
-        if (r) {
-                r = -ENOENT;
-                goto out;
-        }
+        if (debugfs_file_get(dentry))
+                return -ENOENT;
 
         real_fops = debugfs_real_fops(filp);
         real_fops = fops_get(real_fops);
@@ -180,7 +177,7 @@ static int open_proxy_open(struct inode *inode, struct file *filp)
                 r = real_fops->open(inode, filp);
 
 out:
-        debugfs_use_file_finish(srcu_idx);
+        debugfs_file_put(dentry);
         return r;
 }
 
@@ -194,16 +191,16 @@ const struct file_operations debugfs_open_proxy_file_operations = {
 #define FULL_PROXY_FUNC(name, ret_type, filp, proto, args)              \
 static ret_type full_proxy_ ## name(proto)                              \
 {                                                                       \
-        const struct dentry *dentry = F_DENTRY(filp);                   \
+        struct dentry *dentry = F_DENTRY(filp);                 \
         const struct file_operations *real_fops =                       \
                 debugfs_real_fops(filp);                                \
-        int srcu_idx;                                                   \
         ret_type r;                                                     \
                                                                         \
-        r = debugfs_use_file_start(dentry, &srcu_idx);                  \
-        if (likely(!r))                                         \
-                r = real_fops->name(args);                              \
-        debugfs_use_file_finish(srcu_idx);                              \
+        r = debugfs_file_get(dentry);                                   \
+        if (unlikely(r))                                                \
+                return r;                                               \
+        r = real_fops->name(args);                                      \
+        debugfs_file_put(dentry);                                       \
         return r;                                                       \
 }
 
@@ -228,18 +225,15 @@ FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
 static unsigned int full_proxy_poll(struct file *filp,
                                 struct poll_table_struct *wait)
 {
-        const struct dentry *dentry = F_DENTRY(filp);
         const struct file_operations *real_fops = debugfs_real_fops(filp);
-        int srcu_idx;
+        struct dentry *dentry = F_DENTRY(filp);
         unsigned int r = 0;
 
-        if (debugfs_use_file_start(dentry, &srcu_idx)) {
-                debugfs_use_file_finish(srcu_idx);
+        if (debugfs_file_get(dentry))
                 return POLLHUP;
-        }
 
         r = real_fops->poll(filp, wait);
-        debugfs_use_file_finish(srcu_idx);
+        debugfs_file_put(dentry);
         return r;
 }
 
@@ -283,16 +277,13 @@ static void __full_proxy_fops_init(struct file_operations *proxy_fops,
 
 static int full_proxy_open(struct inode *inode, struct file *filp)
 {
-        const struct dentry *dentry = F_DENTRY(filp);
+        struct dentry *dentry = F_DENTRY(filp);
         const struct file_operations *real_fops = NULL;
         struct file_operations *proxy_fops = NULL;
-        int srcu_idx, r;
+        int r = 0;
 
-        r = debugfs_use_file_start(dentry, &srcu_idx);
-        if (r) {
-                r = -ENOENT;
-                goto out;
-        }
+        if (debugfs_file_get(dentry))
+                return -ENOENT;
 
         real_fops = debugfs_real_fops(filp);
         real_fops = fops_get(real_fops);
@@ -330,7 +321,7 @@ free_proxy:
         kfree(proxy_fops);
         fops_put(real_fops);
 out:
-        debugfs_use_file_finish(srcu_idx);
+        debugfs_file_put(dentry);
         return r;
 }
 
@@ -341,13 +332,14 @@ const struct file_operations debugfs_full_proxy_file_operations = {
 ssize_t debugfs_attr_read(struct file *file, char __user *buf,
                         size_t len, loff_t *ppos)
 {
+        struct dentry *dentry = F_DENTRY(file);
         ssize_t ret;
-        int srcu_idx;
 
-        ret = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
-        if (likely(!ret))
-                ret = simple_attr_read(file, buf, len, ppos);
-        debugfs_use_file_finish(srcu_idx);
+        ret = debugfs_file_get(dentry);
+        if (unlikely(ret))
+                return ret;
+        ret = simple_attr_read(file, buf, len, ppos);
+        debugfs_file_put(dentry);
         return ret;
 }
 EXPORT_SYMBOL_GPL(debugfs_attr_read);
@@ -355,13 +347,14 @@ EXPORT_SYMBOL_GPL(debugfs_attr_read);
 ssize_t debugfs_attr_write(struct file *file, const char __user *buf,
                          size_t len, loff_t *ppos)
 {
+        struct dentry *dentry = F_DENTRY(file);
         ssize_t ret;
-        int srcu_idx;
 
-        ret = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
-        if (likely(!ret))
-                ret = simple_attr_write(file, buf, len, ppos);
-        debugfs_use_file_finish(srcu_idx);
+        ret = debugfs_file_get(dentry);
+        if (unlikely(ret))
+                return ret;
+        ret = simple_attr_write(file, buf, len, ppos);
+        debugfs_file_put(dentry);
         return ret;
 }
 EXPORT_SYMBOL_GPL(debugfs_attr_write);
@@ -795,14 +788,14 @@ ssize_t debugfs_read_file_bool(struct file *file, char __user *user_buf,
 {
         char buf[3];
         bool val;
-        int r, srcu_idx;
+        int r;
+        struct dentry *dentry = F_DENTRY(file);
 
-        r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
-        if (likely(!r))
-                val = *(bool *)file->private_data;
-        debugfs_use_file_finish(srcu_idx);
-        if (r)
+        r = debugfs_file_get(dentry);
+        if (unlikely(r))
                 return r;
+        val = *(bool *)file->private_data;
+        debugfs_file_put(dentry);
 
         if (val)
                 buf[0] = 'Y';
@@ -820,8 +813,9 @@ ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
         char buf[32];
         size_t buf_size;
         bool bv;
-        int r, srcu_idx;
+        int r;
         bool *val = file->private_data;
+        struct dentry *dentry = F_DENTRY(file);
 
         buf_size = min(count, (sizeof(buf)-1));
         if (copy_from_user(buf, user_buf, buf_size))
@@ -829,12 +823,11 @@ ssize_t debugfs_write_file_bool(struct file *file, const char __user *user_buf,
 
         buf[buf_size] = '\0';
         if (strtobool(buf, &bv) == 0) {
-                r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
-                if (likely(!r))
-                        *val = bv;
-                debugfs_use_file_finish(srcu_idx);
-                if (r)
+                r = debugfs_file_get(dentry);
+                if (unlikely(r))
                         return r;
+                *val = bv;
+                debugfs_file_put(dentry);
         }
 
         return count;
@@ -896,14 +889,15 @@ static ssize_t read_file_blob(struct file *file, char __user *user_buf,
                               size_t count, loff_t *ppos)
 {
         struct debugfs_blob_wrapper *blob = file->private_data;
+        struct dentry *dentry = F_DENTRY(file);
         ssize_t r;
-        int srcu_idx;
 
-        r = debugfs_use_file_start(F_DENTRY(file), &srcu_idx);
-        if (likely(!r))
-                r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
-                                        blob->size);
-        debugfs_use_file_finish(srcu_idx);
+        r = debugfs_file_get(dentry);
+        if (unlikely(r))
+                return r;
+        r = simple_read_from_buffer(user_buf, count, ppos, blob->data,
+                                blob->size);
+        debugfs_file_put(dentry);
         return r;
 }