[PATCH] xip: reduce code duplication

This patch reworks filemap_xip.c with the goal to reduce code duplication
from mm/filemap.c.  It applies agains 2.6.12-rc6-mm1.  Instead of
implementing the aio functions, this one implements the synchronous
read/write functions only.  For readv and writev, the generic fallback is
used.  For aio, we rely on the application doing the fallback.  Since our
"synchronous" function does memcpy immediately anyway, there is no
performance difference between using the fallbacks or implementing each
operation.

Signed-off-by: Carsten Otte <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

fs/ext2/file.c

@@ -58,17 +58,13 @@ struct file_operations ext2_file_operations = {
 #ifdef CONFIG_EXT2_FS_XIP
 struct file_operations ext2_xip_file_operations = {
 	.llseek		= generic_file_llseek,
-	.read		= do_sync_read,
-	.write		= do_sync_write,
-	.aio_read	= xip_file_aio_read,
-	.aio_write	= xip_file_aio_write,
+	.read		= xip_file_read,
+	.write		= xip_file_write,
 	.ioctl		= ext2_ioctl,
 	.mmap		= xip_file_mmap,
 	.open		= generic_file_open,
 	.release	= ext2_release_file,
 	.fsync		= ext2_sync_file,
-	.readv		= xip_file_readv,
-	.writev		= xip_file_writev,
 	.sendfile	= xip_file_sendfile,
 };
 #endif

include/linux/fs.h

@@ -1500,18 +1500,14 @@ extern int generic_file_open(struct inode * inode, struct file * filp);
 extern int nonseekable_open(struct inode * inode, struct file * filp);
 
 #ifdef CONFIG_FS_XIP
-extern ssize_t xip_file_aio_read(struct kiocb *iocb, char __user *buf,
-				 size_t count, loff_t pos);
-extern ssize_t xip_file_readv(struct file *filp, const struct iovec *iov,
-			      unsigned long nr_segs, loff_t *ppos);
+extern ssize_t xip_file_read(struct file *filp, char __user *buf, size_t len,
+			     loff_t *ppos);
 extern ssize_t xip_file_sendfile(struct file *in_file, loff_t *ppos,
 				 size_t count, read_actor_t actor,
 				 void *target);
 extern int xip_file_mmap(struct file * file, struct vm_area_struct * vma);
-extern ssize_t xip_file_aio_write(struct kiocb *iocb, const char __user *buf,
-				  size_t count, loff_t pos);
-extern ssize_t xip_file_writev(struct file *file, const struct iovec *iov,
-			       unsigned long nr_segs, loff_t *ppos);
+extern ssize_t xip_file_write(struct file *filp, const char __user *buf,
+			      size_t len, loff_t *ppos);
 extern int xip_truncate_page(struct address_space *mapping, loff_t from);
 #else
 static inline int xip_truncate_page(struct address_space *mapping, loff_t from)

mm/filemap.h

@@ -15,7 +15,7 @@
 #include <linux/config.h>
 #include <asm/uaccess.h>
 
-extern size_t
+size_t
 __filemap_copy_from_user_iovec(char *vaddr,
 			       const struct iovec *iov,
 			       size_t base,