[PATCH] sysfs variable size files, lost dget, ...

[Manuel Estrada Sainz]

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 Hi,

 While working on request_firmware() interface, I found some trouble
 with sysfs and Greg said that you are the one to send this patches:

  - sysfs-bin-flexible-size.diff:
	Make dynamically sized files possible.  And return the right
	value on successful write.

  - sysfs-bin-lost-dget.diff:
	I was having trouble when calling request_firmware() from a work
	queue, and after a little investigations it seams that this dget
	got lost along the way. Adding it back fixed the issue.
	Or am I causing a dentry leak now?

  - sysfs-bin-header.diff:
	I guess that I am the first user of sysfs's binary interface :-)

 Thanks

 	Manuel

-- 
--- Manuel Estrada Sainz <[e-mail]>
                         <[e-mail]>
			 <[e-mail]>
------------------------ <[e-mail]> -------------------
Let us have the serenity to accept the things we cannot change, courage to
change the things we can, and wisdom to know the difference.

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diff --exclude=CVS -urN linux-2.5.orig/fs/sysfs/bin.c linux-2.5.mine/fs/sysfs/bin.c
--- linux-2.5.orig/fs/sysfs/bin.c	2003-05-17 20:44:03.000000000 +0200
+++ linux-2.5.mine/fs/sysfs/bin.c	2003-05-17 14:53:01.000000000 +0200
@@ -30,10 +30,15 @@
 	loff_t offs = *off;
 	int ret;
 
-	if (offs > size)
-		return 0;
-	if (offs + count > size)
-		count = size - offs;
+	if (count > PAGE_SIZE)
+		count = PAGE_SIZE;
+
+	if(size){
+		if (offs > size)
+			return 0;
+		if (offs + count > size)
+			count = size - offs;
+	}
 
 	ret = fill_read(dentry, buffer, offs, count);
 	if (ret < 0) 
@@ -69,10 +74,14 @@
 	loff_t offs = *off;
 	int ret;
 
-	if (offs > size)
-		return 0;
-	if (offs + count > size)
-		count = size - offs;
+	if (count > PAGE_SIZE)
+		count = PAGE_SIZE;
+	if (size) {
+		if (offs > size)
+			return 0;
+		if (offs + count > size)
+			count = size - offs;
+	}
 
 	ret = -EFAULT;
 	if (copy_from_user(buffer + offs, userbuf, count))
@@ -81,7 +90,7 @@
 	count = flush_write(dentry, buffer, offs, count);
 	if (count > 0)
 		*off = offs + count;
-	ret = 0;
+	ret = count;
  Done:
 	return ret;
 }
@@ -102,7 +111,7 @@
 		goto Done;
 
 	error = -ENOMEM;
-	file->private_data = kmalloc(attr->size, GFP_KERNEL);
+	file->private_data = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!file->private_data)
 		goto Done;
 

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Index: include/linux/sysfs.h
===================================================================
RCS file: /home/cvs/linux-2.5/include/linux/sysfs.h,v
retrieving revision 1.9
diff -u -r1.9 sysfs.h
--- include/linux/sysfs.h	15 May 2003 23:50:23 -0000	1.9
+++ include/linux/sysfs.h	21 May 2003 13:49:29 -0000
@@ -23,6 +23,9 @@
 	ssize_t (*write)(struct kobject *, char *, loff_t, size_t);
 };
 
+int sysfs_create_bin_file(struct kobject * kobj, struct bin_attribute * attr);
+int sysfs_remove_bin_file(struct kobject * kobj, struct bin_attribute * attr);
+
 struct sysfs_ops {
 	ssize_t	(*show)(struct kobject *, struct attribute *,char *);
 	ssize_t	(*store)(struct kobject *,struct attribute *,const char *, size_t);

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diff --exclude=CVS -urN linux-2.5.orig/fs/sysfs/inode.c linux-2.5.mine/fs/sysfs/inode.c
--- linux-2.5.orig/fs/sysfs/inode.c	2003-05-17 20:44:03.000000000 +0200
+++ linux-2.5.mine/fs/sysfs/inode.c	2003-05-17 20:30:34.000000000 +0200
@@ -60,9 +60,10 @@
  Proceed:
 	if (init)
 		error = init(inode);
-	if (!error)
+	if (!error){
 		d_instantiate(dentry, inode);
-	else
+		dget(dentry); /* Extra count - pin the dentry in core */
+	} else
 		iput(inode);
  Done:
 	return error;

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