sysfs, kernfs: add sysfs_dirent->s_attr.size

sysfs sets the size of regular files unconditionally at PAGE_SIZE and
takes the size of bin files from bin_attribute.  The latter is a
pretty bad interface which forces bin_attribute users to create a
separate copy of bin_attribute for each instance of the file -
e.g. pci resource files.

Add sysfs_dirent->s_attr.size so that the size can be specified
separately.  This unifies inode init paths of ATTR and BIN_ATTR
identical and allows for generic size handling for kernfs.

Unfortunately, this grows the size of sysfs_dirent by sizeof(loff_t).

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

1 files changed, 1 insertions, 7 deletions

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index 4c463dabfc6a..037a8925f56e 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -254,8 +254,6 @@ int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
 
 static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
 {
-        struct bin_attribute *bin_attr;
-
         inode->i_private = sysfs_get(sd);
         inode->i_mapping->a_ops = &sysfs_aops;
         inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
@@ -271,12 +269,8 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
                 inode->i_fop = &sysfs_dir_operations;
                 break;
         case SYSFS_KOBJ_ATTR:
-                inode->i_size = PAGE_SIZE;
-                inode->i_fop = &kernfs_file_operations;
-                break;
         case SYSFS_KOBJ_BIN_ATTR:
-                bin_attr = sd->priv;
-                inode->i_size = bin_attr->size;
+                inode->i_size = sd->s_attr.size;
                 inode->i_fop = &kernfs_file_operations;
                 break;
         case SYSFS_KOBJ_LINK: