sysfs: prepare open path for unified regular / bin file handling

sysfs bin file handling will be merged into the regular file support.
This patch prepares the open path.

This patch updates sysfs_open_file() such that it can handle both
regular and bin files.

This is a preparation and the new bin file path isn't used yet.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 02797a1..417d005 100644 (file)
--- a/fs/sysfs/file.c
+++ b/fs/sysfs/file.c
@@ -610,38 +610,40 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
        struct sysfs_dirent *attr_sd = file->f_path.dentry->d_fsdata;
        struct kobject *kobj = attr_sd->s_parent->s_dir.kobj;
        struct sysfs_open_file *of;
-       const struct sysfs_ops *ops;
+       bool has_read, has_write;
        int error = -EACCES;
 
        /* need attr_sd for attr and ops, its parent for kobj */
        if (!sysfs_get_active(attr_sd))
                return -ENODEV;
 
-       /* every kobject with an attribute needs a ktype assigned */
-       ops = sysfs_file_ops(attr_sd);
-       if (WARN(!ops, KERN_ERR
-                "missing sysfs attribute operations for kobject: %s\n",
-                kobject_name(kobj)))
-               goto err_out;
+       if (sysfs_is_bin(attr_sd)) {
+               struct bin_attribute *battr = attr_sd->s_bin_attr.bin_attr;
 
-       /* File needs write support.
-        * The inode's perms must say it's ok,
-        * and we must have a store method.
-        */
-       if (file->f_mode & FMODE_WRITE) {
-               if (!(inode->i_mode & S_IWUGO) || !ops->store)
-                       goto err_out;
-       }
+               has_read = battr->read || battr->mmap;
+               has_write = battr->write || battr->mmap;
+       } else {
+               const struct sysfs_ops *ops = sysfs_file_ops(attr_sd);
 
-       /* File needs read support.
-        * The inode's perms must say it's ok, and we there
-        * must be a show method for it.
-        */
-       if (file->f_mode & FMODE_READ) {
-               if (!(inode->i_mode & S_IRUGO) || !ops->show)
+               /* every kobject with an attribute needs a ktype assigned */
+               if (WARN(!ops, KERN_ERR
+                        "missing sysfs attribute operations for kobject: %s\n",
+                        kobject_name(kobj)))
                        goto err_out;
+
+               has_read = ops->show;
+               has_write = ops->store;
        }
 
+       /* check perms and supported operations */
+       if ((file->f_mode & FMODE_WRITE) &&
+           (!(inode->i_mode & S_IWUGO) || !has_write))
+               goto err_out;
+
+       if ((file->f_mode & FMODE_READ) &&
+           (!(inode->i_mode & S_IRUGO) || !has_read))
+               goto err_out;
+
        /* allocate a sysfs_open_file for the file */
        error = -ENOMEM;
        of = kzalloc(sizeof(struct sysfs_open_file), GFP_KERNEL);
@@ -653,11 +655,14 @@ static int sysfs_open_file(struct inode *inode, struct file *file)
        of->file = file;
 
        /*
-        * Always instantiate seq_file even if read access is not
-        * implemented or requested.  This unifies private data access and
-        * most files are readable anyway.
+        * Always instantiate seq_file even if read access doesn't use
+        * seq_file or is not requested.  This unifies private data access
+        * and readable regular files are the vast majority anyway.
         */
-       error = single_open(file, sysfs_seq_show, of);
+       if (sysfs_is_bin(attr_sd))
+               error = single_open(file, NULL, of);
+       else
+               error = single_open(file, sysfs_seq_show, of);
        if (error)
                goto err_free;
 
@@ -807,6 +812,9 @@ const struct file_operations sysfs_bin_operations = {
        .write          = sysfs_write_file,
        .llseek         = generic_file_llseek,
        .mmap           = sysfs_bin_mmap,
+       .open           = sysfs_open_file,
+       .release        = sysfs_release,
+       .poll           = sysfs_poll,
 };
 
 int sysfs_add_file_mode_ns(struct sysfs_dirent *dir_sd,