Re: [PATCH] USB and Driver Core patches for 2.6.10

Greg KH
2005-01-08T07:49:32Z

ChangeSet 1.1938.444.22, 2004/12/21 10:37:07-08:00, jbarnes@engr.sgi.com

[PATCH] sysfs: add mmap support to struct bin_attribute files

This patch adds an mmap method and some more error checking to struct
bin_attribute--good for things like exporting PCI resources directly. I
wasn't sure about the return values for the case where an attribute is
missing a given method, and it looks like mm.h can't be included in sysfs.h,
so I had to forward declare struct vm_area_struct. Other than that, it works
fine for my test cases.

Signed-off-by: Jesse Barnes <jbarnes@sgi.com>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

fs/sysfs/bin.c | 27 +++++++++++++++++++++++++--
include/linux/sysfs.h | 6 ++++++
2 files changed, 31 insertions(+), 2 deletions(-)

diff -Nru a/fs/sysfs/bin.c b/fs/sysfs/bin.c
--- a/fs/sysfs/bin.c 2005-01-07 15:41:17 -08:00
+++ b/fs/sysfs/bin.c 2005-01-07 15:41:17 -08:00
@@ -1,5 +1,9 @@
/*
* bin.c - binary file operations for sysfs.
+ *
+ * Copyright (c) 2003 Patrick Mochel
+ * Copyright (c) 2003 Matthew Wilcox
+ * Copyright (c) 2004 Silicon Graphics, Inc.
*/

#undef DEBUG
@@ -20,6 +24,9 @@
struct bin_attribute * attr = to_bin_attr(dentry);
struct kobject * kobj = to_kobj(dentry->d_parent);

+ if (!attr->read)
+ return -EINVAL;
+
return attr->read(kobj, buffer, off, count);
}

@@ -63,6 +70,9 @@
struct bin_attribute *attr = to_bin_attr(dentry);
struct kobject *kobj = to_kobj(dentry->d_parent);

+ if (!attr->write)
+ return -EINVAL;
+
return attr->write(kobj, buffer, offset, count);
}

@@ -92,6 +102,18 @@
return count;
}

+static int mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct dentry *dentry = file->f_dentry;
+ struct bin_attribute *attr = to_bin_attr(dentry);
+ struct kobject *kobj = to_kobj(dentry->d_parent);
+
+ if (!attr->mmap)
+ return -EINVAL;
+
+ return attr->mmap(kobj, attr, vma);
+}
+
static int open(struct inode * inode, struct file * file)
{
struct kobject *kobj = sysfs_get_kobject(file->f_dentry->d_parent);
@@ -107,9 +129,9 @@
goto Done;

error = -EACCES;
- if ((file->f_mode & FMODE_WRITE) && !attr->write)
+ if ((file->f_mode & FMODE_WRITE) && !(attr->write || attr->mmap))
goto Error;
- if ((file->f_mode & FMODE_READ) && !attr->read)
+ if ((file->f_mode & FMODE_READ) && !(attr->read || attr->mmap))
goto Error;

error = -ENOMEM;
@@ -144,6 +166,7 @@
struct file_operations bin_fops = {
.read = read,
.write = write,
+ .mmap = mmap,
.llseek = generic_file_llseek,
.open = open,
.release = release,
diff -Nru a/include/linux/sysfs.h b/include/linux/sysfs.h
--- a/include/linux/sysfs.h 2005-01-07 15:41:17 -08:00
+++ b/include/linux/sysfs.h 2005-01-07 15:41:17 -08:00
@@ -2,6 +2,7 @@
* sysfs.h - definitions for the device driver filesystem
*
* Copyright (c) 2001,2002 Patrick Mochel
+ * Copyright (c) 2004 Silicon Graphics, Inc.
*
* Please see Documentation/filesystems/sysfs.txt for more information.
*/
@@ -47,11 +48,16 @@

#define attr_name(_attr) (_attr).attr.name

+struct vm_area_struct;
+
struct bin_attribute {
struct attribute attr;
size_t size;
+ void *private;
ssize_t (*read)(struct kobject *, char *, loff_t, size_t);
ssize_t (*write)(struct kobject *, char *, loff_t, size_t);
+ int (*mmap)(struct kobject *, struct bin_attribute *attr,
+ struct vm_area_struct *vma);
};

struct sysfs_ops {