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>

1 files changed, 33 insertions, 25 deletions

diff --git a/fs/sysfs/file.c b/fs/sysfs/file.c
index 02797a134cf8..417d005955d9 100644
--- 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,