[PATCH] 2.5.4-pre1: further llseek cleanup (2/3)

This is the second patch of three implementing further llseek cleanups,
against 2.5.4-pre1.  It does not depend on the other patches.

This patch cleans up various code and quite nicely removes much more
code than it adds.  Specifically:

- remove static lseek method which merely reimplements
  the standard no_llseek in the following seven files:
  hci_vhci.c, ite8172.c, nec_vrc5477.c, auerswald.c,
  pipe.c, netlink_dev.c, and socket.c

- remove fs/ufs/file.c::ufs_file_lseek -- Al says it is
  reimplementing generic_file_llseek, so let's use that
  instead (the comment about 32-bit sizes shouldn't be
  an issue, the generic method checks size)

- include smp_lock.h in 3 files missed from previous
  'remove bkl' patch

- Documentation/filesystem/Locking update

Please, apply.

	Robert Love

Documentation/filesystems/Locking

@@ -237,7 +237,10 @@ writev:		no
 
 ->llseek() locking has moved from llseek to the individual llseek
 implementations.  If your fs is not using generic_file_llseek, you
-need to acquire and release the BKL in your ->llseek().
+need to acquire and release the appropriate locks in your ->llseek().
+For many filesystems, it is probably safe to acquire the inode
+semaphore.  Note some filesystems (i.e. remote ones) provide no
+protection for i_size so you will need to use the BKL.
 
 ->open() locking is in-transit: big lock partially moved into the methods.
 The only exception is ->open() in the instances of file_operations that never

drivers/bluetooth/hci_vhci.c

@@ -221,11 +221,6 @@ static ssize_t hci_vhci_chr_read(struct file * file, char * buf, size_t count, l
 	return ret;
 }
 
-static loff_t hci_vhci_chr_lseek(struct file * file, loff_t offset, int origin)
-{
-	return -ESPIPE;
-}
-
 static int hci_vhci_chr_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned long arg)
 {
 	return -EINVAL;
@@ -296,7 +291,7 @@ static int hci_vhci_chr_close(struct inode *inode, struct file *file)
 
 static struct file_operations hci_vhci_fops = {
 	owner:	THIS_MODULE,	
-	llseek:	hci_vhci_chr_lseek,
+	llseek:	no_lseek,
 	read:	hci_vhci_chr_read,
 	write:	hci_vhci_chr_write,
 	poll:	hci_vhci_chr_poll,

drivers/sound/ite8172.c

@@ -824,12 +824,6 @@ static void it8172_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 
 /* --------------------------------------------------------------------- */
 
-static loff_t it8172_llseek(struct file *file, loff_t offset, int origin)
-{
-    return -ESPIPE;
-}
-
-
 static int it8172_open_mixdev(struct inode *inode, struct file *file)
 {
     int minor = MINOR(inode->i_rdev);
@@ -870,7 +864,7 @@ static int it8172_ioctl_mixdev(struct inode *inode, struct file *file,
 
 static /*const*/ struct file_operations it8172_mixer_fops = {
     owner:	THIS_MODULE,
-    llseek:	it8172_llseek,
+    llseek:	no_llseek,
     ioctl:	it8172_ioctl_mixdev,
     open:	it8172_open_mixdev,
     release:	it8172_release_mixdev,
@@ -1633,7 +1627,7 @@ static int it8172_release(struct inode *inode, struct file *file)
 
 static /*const*/ struct file_operations it8172_audio_fops = {
     owner:	THIS_MODULE,
-    llseek:	it8172_llseek,
+    llseek:	no_llseek,
     read:	it8172_read,
     write:	it8172_write,
     poll:	it8172_poll,

drivers/sound/nec_vrc5477.c

@@ -805,12 +805,6 @@ static void vrc5477_ac97_interrupt(int irq, void *dev_id, struct pt_regs *regs)
 
 /* --------------------------------------------------------------------- */
 
-static loff_t vrc5477_ac97_llseek(struct file *file, loff_t offset, int origin)
-{
-	return -ESPIPE;
-}
-
-
 static int vrc5477_ac97_open_mixdev(struct inode *inode, struct file *file)
 {
 	int minor = MINOR(inode->i_rdev);
@@ -852,7 +846,7 @@ static int vrc5477_ac97_ioctl_mixdev(struct inode *inode, struct file *file,
 
 static /*const*/ struct file_operations vrc5477_ac97_mixer_fops = {
 	owner:		THIS_MODULE,
-	llseek:		vrc5477_ac97_llseek,
+	llseek:		no_llseek,
 	ioctl:		vrc5477_ac97_ioctl_mixdev,
 	open:		vrc5477_ac97_open_mixdev,
 	release:	vrc5477_ac97_release_mixdev,
@@ -1618,7 +1612,7 @@ static int vrc5477_ac97_release(struct inode *inode, struct file *file)
 
 static /*const*/ struct file_operations vrc5477_ac97_audio_fops = {
 	owner:	THIS_MODULE,
-	llseek:		vrc5477_ac97_llseek,
+	llseek:		no_llseek,
 	read:		vrc5477_ac97_read,
 	write:		vrc5477_ac97_write,
 	poll:		vrc5477_ac97_poll,

drivers/usb/auerswald.c

@@ -1553,15 +1553,6 @@ static int auerchar_ioctl (struct inode *inode, struct file *file, unsigned int
 	return ret;
 }
 
-
-/* Seek is not supported */
-static loff_t auerchar_llseek (struct file *file, loff_t offset, int origin)
-{
-        dbg ("auerchar_seek");
-        return -ESPIPE;
-}
-
-
 /* Read data from the device */
 static ssize_t auerchar_read (struct file *file, char *buf, size_t count, loff_t * ppos)
 {
@@ -1843,7 +1834,7 @@ static int auerchar_release (struct inode *inode, struct file *file)
 static struct file_operations auerswald_fops =
 {
 	owner:		THIS_MODULE,
-	llseek:		auerchar_llseek,
+	llseek:		no_llseek,
 	read:		auerchar_read,
 	write:          auerchar_write,
 	ioctl:		auerchar_ioctl,

fs/hfs/file_cap.c

@@ -24,6 +24,7 @@
 #include <linux/hfs_fs_sb.h>
 #include <linux/hfs_fs_i.h>
 #include <linux/hfs_fs.h>
+#include <linux/smp_lock.h>
 
 /*================ Forward declarations ================*/
 static loff_t      cap_info_llseek(struct file *, loff_t,

fs/hfs/file_hdr.c

@@ -29,6 +29,7 @@
 #include <linux/hfs_fs_sb.h>
 #include <linux/hfs_fs_i.h>
 #include <linux/hfs_fs.h>
+#include <linux/smp_lock.h>
 
 /* prodos types */
 #define PRODOSI_FTYPE_DIR   0x0F

fs/ncpfs/file.c

@@ -18,6 +18,7 @@
 #include <linux/locks.h>
 #include <linux/slab.h>
 #include <linux/vmalloc.h>
+#include <linux/smp_lock.h>
 
 #include <linux/ncp_fs.h>
 #include "ncplib_kernel.h"

fs/pipe.c

@@ -246,12 +246,6 @@ pipe_write(struct file *filp, const char *buf, size_t count, loff_t *ppos)
 	return -EPIPE;
 }
 
-static loff_t
-pipe_lseek(struct file *file, loff_t offset, int orig)
-{
-	return -ESPIPE;
-}
-
 static ssize_t
 bad_pipe_r(struct file *filp, char *buf, size_t count, loff_t *ppos)
 {
@@ -381,7 +375,7 @@ pipe_rdwr_open(struct inode *inode, struct file *filp)
  * are also used in linux/fs/fifo.c to do operations on FIFOs.
  */
 struct file_operations read_fifo_fops = {
-	llseek:		pipe_lseek,
+	llseek:		no_llseek,
 	read:		pipe_read,
 	write:		bad_pipe_w,
 	poll:		fifo_poll,
@@ -391,7 +385,7 @@ struct file_operations read_fifo_fops = {
 };
 
 struct file_operations write_fifo_fops = {
-	llseek:		pipe_lseek,
+	llseek:		no_llseek,
 	read:		bad_pipe_r,
 	write:		pipe_write,
 	poll:		fifo_poll,
@@ -401,7 +395,7 @@ struct file_operations write_fifo_fops = {
 };
 
 struct file_operations rdwr_fifo_fops = {
-	llseek:		pipe_lseek,
+	llseek:		no_llseek,
 	read:		pipe_read,
 	write:		pipe_write,
 	poll:		fifo_poll,
@@ -411,7 +405,7 @@ struct file_operations rdwr_fifo_fops = {
 };
 
 struct file_operations read_pipe_fops = {
-	llseek:		pipe_lseek,
+	llseek:		no_llseek,
 	read:		pipe_read,
 	write:		bad_pipe_w,
 	poll:		pipe_poll,
@@ -421,7 +415,7 @@ struct file_operations read_pipe_fops = {
 };
 
 struct file_operations write_pipe_fops = {
-	llseek:		pipe_lseek,
+	llseek:		no_llseek,
 	read:		bad_pipe_r,
 	write:		pipe_write,
 	poll:		pipe_poll,
@@ -431,7 +425,7 @@ struct file_operations write_pipe_fops = {
 };
 
 struct file_operations rdwr_pipe_fops = {
-	llseek:		pipe_lseek,
+	llseek:		no_llseek,
 	read:		pipe_read,
 	write:		pipe_write,
 	poll:		pipe_poll,

fs/ufs/file.c

@@ -37,47 +37,13 @@
 #include <linux/pagemap.h>
 #include <linux/smp_lock.h>
 
-/*
- * Make sure the offset never goes beyond the 32-bit mark..
- */
-static long long ufs_file_lseek(
-	struct file *file,
-	long long offset,
-	int origin )
-{
-	long long retval;
-	struct inode *inode = file->f_dentry->d_inode;
-
-	lock_kernel();
-
-	switch (origin) {
-		case 2:
-			offset += inode->i_size;
-			break;
-		case 1:
-			offset += file->f_pos;
-	}
-	retval = -EINVAL;
-	/* make sure the offset fits in 32 bits */
-	if (((unsigned long long) offset >> 32) == 0) {
-		if (offset != file->f_pos) {
-			file->f_pos = offset;
-			file->f_reada = 0;
-			file->f_version = ++event;
-		}
-		retval = offset;
-	}
-	unlock_kernel();
-	return retval;
-}
-
 /*
  * We have mostly NULL's here: the current defaults are ok for
  * the ufs filesystem.
  */
  
 struct file_operations ufs_file_operations = {
-	llseek:		ufs_file_lseek,
+	llseek:		generic_file_llseek,
 	read:		generic_file_read,
 	write:		generic_file_write,
 	mmap:		generic_file_mmap,

net/netlink/netlink_dev.c

@@ -98,11 +98,6 @@ static ssize_t netlink_read(struct file * file, char * buf,
 	return sock_recvmsg(sock, &msg, count, msg.msg_flags);
 }
 
-static loff_t netlink_lseek(struct file * file, loff_t offset, int origin)
-{
-	return -ESPIPE;
-}
-
 static int netlink_open(struct inode * inode, struct file * file)
 {
 	unsigned int minor = minor(inode->i_rdev);
@@ -166,7 +161,7 @@ static int netlink_ioctl(struct inode *inode, struct file *file,
 
 static struct file_operations netlink_fops = {
 	owner:		THIS_MODULE,
-	llseek:		netlink_lseek,
+	llseek:		no_llseek,
 	read:		netlink_read,
 	write:		netlink_write,
 	poll:		netlink_poll,

net/socket.c

@@ -86,7 +86,6 @@
 #include <linux/netfilter.h>
 
 static int sock_no_open(struct inode *irrelevant, struct file *dontcare);
-static loff_t sock_lseek(struct file *file, loff_t offset, int whence);
 static ssize_t sock_read(struct file *file, char *buf,
 			 size_t size, loff_t *ppos);
 static ssize_t sock_write(struct file *file, const char *buf,
@@ -113,7 +112,7 @@ static ssize_t sock_sendpage(struct file *file, struct page *page,
  */
 
 static struct file_operations socket_file_ops = {
-	llseek:		sock_lseek,
+	llseek:		no_llseek,
 	read:		sock_read,
 	write:		sock_write,
 	poll:		sock_poll,
@@ -559,15 +558,6 @@ int sock_recvmsg(struct socket *sock, struct msghdr *msg, int size, int flags)
 }
 
 
-/*
- *	Sockets are not seekable.
- */
-
-static loff_t sock_lseek(struct file *file, loff_t offset, int whence)
-{
-	return -ESPIPE;
-}
-
 /*
  *	Read data from a socket. ubuf is a user mode pointer. We make sure the user
  *	area ubuf...ubuf+size-1 is writable before asking the protocol.