debugfs: split short and full proxy wrappers, kill debugfs_real_fops()

All users outside of fs/debugfs/file.c are gone, in there we can just
fully split the wrappers for full and short cases and be done with that.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://lore.kernel.org/r/20250702212419.GG3406663@ZenIV
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/debugfs/file.c b/fs/debugfs/file.c
index 69e9ddcb113dfe370cc96d3d80689cd587db6eca..77784091a10fc170db94c8b01d0f1431a7d05c26 100644 (file)
--- a/fs/debugfs/file.c
+++ b/fs/debugfs/file.c
@@ -53,23 +53,6 @@ const void *debugfs_get_aux(const struct file *file)
 }
 EXPORT_SYMBOL_GPL(debugfs_get_aux);
 
-const struct file_operations *debugfs_real_fops(const struct file *filp)
-{
-       struct debugfs_fsdata *fsd = F_DENTRY(filp)->d_fsdata;
-
-       if (!fsd) {
-               /*
-                * Urgh, we've been called w/o a protecting
-                * debugfs_file_get().
-                */
-               WARN_ON(1);
-               return NULL;
-       }
-
-       return fsd->real_fops;
-}
-EXPORT_SYMBOL_GPL(debugfs_real_fops);
-
 enum dbgfs_get_mode {
        DBGFS_GET_ALREADY,
        DBGFS_GET_REGULAR,
@@ -302,15 +285,13 @@ static int debugfs_locked_down(struct inode *inode,
 static int open_proxy_open(struct inode *inode, struct file *filp)
 {
        struct dentry *dentry = F_DENTRY(filp);
-       const struct file_operations *real_fops = NULL;
+       const struct file_operations *real_fops = DEBUGFS_I(inode)->real_fops;
        int r;
 
        r = __debugfs_file_get(dentry, DBGFS_GET_REGULAR);
        if (r)
                return r == -EIO ? -ENOENT : r;
 
-       real_fops = debugfs_real_fops(filp);
-
        r = debugfs_locked_down(inode, filp, real_fops);
        if (r)
                goto out;
@@ -352,7 +333,6 @@ static ret_type full_proxy_ ## name(proto)                          \
 {                                                                      \
        struct dentry *dentry = F_DENTRY(filp);                         \
        struct debugfs_fsdata *fsd = dentry->d_fsdata;                  \
-       const struct file_operations *real_fops;                        \
        ret_type r;                                                     \
                                                                        \
        if (!(fsd->methods & bit))                                      \
@@ -360,14 +340,13 @@ static ret_type full_proxy_ ## name(proto)                                \
        r = debugfs_file_get(dentry);                                   \
        if (unlikely(r))                                                \
                return r;                                               \
-       real_fops = debugfs_real_fops(filp);                            \
-       r = real_fops->name(args);                                      \
+       r = fsd->real_fops->name(args);                                 \
        debugfs_file_put(dentry);                                       \
        return r;                                                       \
 }
 
-#define FULL_PROXY_FUNC_BOTH(name, ret_type, filp, proto, args, bit, ret)      \
-static ret_type full_proxy_ ## name(proto)                             \
+#define SHORT_PROXY_FUNC(name, ret_type, filp, proto, args, bit, ret)  \
+static ret_type short_proxy_ ## name(proto)                            \
 {                                                                      \
        struct dentry *dentry = F_DENTRY(filp);                         \
        struct debugfs_fsdata *fsd = dentry->d_fsdata;                  \
@@ -378,27 +357,38 @@ static ret_type full_proxy_ ## name(proto)                                \
        r = debugfs_file_get(dentry);                                   \
        if (unlikely(r))                                                \
                return r;                                               \
-       if (fsd->real_fops)                                             \
-               r = fsd->real_fops->name(args);                         \
-       else                                                            \
-               r = fsd->short_fops->name(args);                        \
+       r = fsd->short_fops->name(args);                                \
        debugfs_file_put(dentry);                                       \
        return r;                                                       \
 }
 
-FULL_PROXY_FUNC_BOTH(llseek, loff_t, filp,
-                    PROTO(struct file *filp, loff_t offset, int whence),
-                    ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
+SHORT_PROXY_FUNC(llseek, loff_t, filp,
+               PROTO(struct file *filp, loff_t offset, int whence),
+               ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
 
-FULL_PROXY_FUNC_BOTH(read, ssize_t, filp,
-                    PROTO(struct file *filp, char __user *buf, size_t size,
-                          loff_t *ppos),
-                    ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
+FULL_PROXY_FUNC(llseek, loff_t, filp,
+               PROTO(struct file *filp, loff_t offset, int whence),
+               ARGS(filp, offset, whence), HAS_LSEEK, -ESPIPE);
 
-FULL_PROXY_FUNC_BOTH(write, ssize_t, filp,
-                    PROTO(struct file *filp, const char __user *buf,
-                          size_t size, loff_t *ppos),
-                    ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
+SHORT_PROXY_FUNC(read, ssize_t, filp,
+               PROTO(struct file *filp, char __user *buf, size_t size,
+                       loff_t *ppos),
+               ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
+
+FULL_PROXY_FUNC(read, ssize_t, filp,
+               PROTO(struct file *filp, char __user *buf, size_t size,
+                       loff_t *ppos),
+               ARGS(filp, buf, size, ppos), HAS_READ, -EINVAL);
+
+SHORT_PROXY_FUNC(write, ssize_t, filp,
+               PROTO(struct file *filp, const char __user *buf,
+                       size_t size, loff_t *ppos),
+               ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
+
+FULL_PROXY_FUNC(write, ssize_t, filp,
+               PROTO(struct file *filp, const char __user *buf,
+                       size_t size, loff_t *ppos),
+               ARGS(filp, buf, size, ppos), HAS_WRITE, -EINVAL);
 
 FULL_PROXY_FUNC(unlocked_ioctl, long, filp,
                PROTO(struct file *filp, unsigned int cmd, unsigned long arg),
@@ -410,22 +400,21 @@ static __poll_t full_proxy_poll(struct file *filp,
        struct dentry *dentry = F_DENTRY(filp);
        struct debugfs_fsdata *fsd = dentry->d_fsdata;
        __poll_t r = 0;
-       const struct file_operations *real_fops;
 
        if (!(fsd->methods & HAS_POLL))
                return DEFAULT_POLLMASK;
        if (debugfs_file_get(dentry))
                return EPOLLHUP;
 
-       real_fops = debugfs_real_fops(filp);
-       r = real_fops->poll(filp, wait);
+       r = fsd->real_fops->poll(filp, wait);
        debugfs_file_put(dentry);
        return r;
 }
 
-static int full_proxy_release(struct inode *inode, struct file *filp)
+static int full_proxy_release(struct inode *inode, struct file *file)
 {
-       const struct file_operations *real_fops = debugfs_real_fops(filp);
+       struct debugfs_fsdata *fsd = F_DENTRY(file)->d_fsdata;
+       const struct file_operations *real_fops = fsd->real_fops;
        int r = 0;
 
        /*
@@ -435,7 +424,7 @@ static int full_proxy_release(struct inode *inode, struct file *filp)
         * ->i_private is still being meaningful here.
         */
        if (real_fops->release)
-               r = real_fops->release(inode, filp);
+               r = real_fops->release(inode, file);
 
        fops_put(real_fops);
        return r;
@@ -517,9 +506,9 @@ static int full_proxy_open_short(struct inode *inode, struct file *filp)
 
 const struct file_operations debugfs_full_short_proxy_file_operations = {
        .open = full_proxy_open_short,
-       .llseek = full_proxy_llseek,
-       .read = full_proxy_read,
-       .write = full_proxy_write,
+       .llseek = short_proxy_llseek,
+       .read = short_proxy_read,
+       .write = short_proxy_write,
 };
 
 ssize_t debugfs_attr_read(struct file *file, char __user *buf,

diff --git a/include/linux/debugfs.h b/include/linux/debugfs.h
index fa2568b4380da0f03ec2261cb863d074d6a33efa..a420152105d09ef1ef48e7a1c3d848ebbbde9c9d 100644 (file)
--- a/include/linux/debugfs.h
+++ b/include/linux/debugfs.h
@@ -162,7 +162,6 @@ void debugfs_remove(struct dentry *dentry);
 
 void debugfs_lookup_and_remove(const char *name, struct dentry *parent);
 
-const struct file_operations *debugfs_real_fops(const struct file *filp);
 const void *debugfs_get_aux(const struct file *file);
 
 int debugfs_file_get(struct dentry *dentry);
@@ -329,7 +328,6 @@ static inline void debugfs_lookup_and_remove(const char *name,
                                             struct dentry *parent)
 { }
 
-const struct file_operations *debugfs_real_fops(const struct file *filp);
 void *debugfs_get_aux(const struct file *file);
 
 static inline int debugfs_file_get(struct dentry *dentry)