linux-kernel - [PATCH 03/12] eeprom_read()/eeprom_write() should update ppos instead of file->f

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Date:	Fri,  9 Apr 2010 16:00:46 +0200
From:	Jan Blunck <jblunck@...e.de>
To:	Linux-Kernel Mailinglist <linux-kernel@...r.kernel.org>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Arnd Bergmann <arnd@...db.de>, Alan Cox <alan@...ux.intel.com>,
	Jan Blunck <jblunck@...e.de>
Subject: [PATCH 03/12] eeprom_read()/eeprom_write() should update ppos instead of file->f_pos

eeprom_read()/eeprom_write() modify file->f_pos directly instead of the
ppos given. The VFS later updates the file->f_pos and overwrites it with
the unchanged value of ppos. Since nothing touches the struct file in
eeprom_read()/eeprom_write() now, the on stack allocated struct file in
eeprom_read_buf()/eeprom_write_buf() can be removed as well.

Signed-off-by: Jan Blunck <jblunck@...e.de>
---
 arch/cris/arch-v10/drivers/eeprom.c |   34 +++++++++++++---------------------
 1 files changed, 13 insertions(+), 21 deletions(-)

diff --git a/arch/cris/arch-v10/drivers/eeprom.c b/arch/cris/arch-v10/drivers/eeprom.c
index 1f2ae90..68d9e88 100644
--- a/arch/cris/arch-v10/drivers/eeprom.c
+++ b/arch/cris/arch-v10/drivers/eeprom.c
@@ -439,20 +439,18 @@ static loff_t eeprom_lseek(struct file * file, loff_t offset, int orig)
 
 static int eeprom_read_buf(loff_t addr, char * buf, int count)
 {
-  struct file f;
-
-  f.f_pos = addr;
-  return eeprom_read(&f, buf, count, &addr);
+  return eeprom_read(NULL, buf, count, &addr);
 }
 
 
 
 /* Reads data from eeprom. */
 
-static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t *off)
+static ssize_t eeprom_read(struct file * file, char * buf, size_t count,
+			   loff_t *ppos)
 {
   int read=0;
-  unsigned long p = file->f_pos;
+  loff_t p = *ppos;
 
   unsigned char page;
 
@@ -498,11 +496,9 @@ static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t
 
   /* go on with the actual read */
   read = read_from_eeprom( buf, count);
-  
+
   if(read > 0)
-  {
-    file->f_pos += read;
-  }
+    *ppos += read;
 
   eeprom.busy--;
   wake_up_interruptible(&eeprom.wait_q);
@@ -513,18 +509,14 @@ static ssize_t eeprom_read(struct file * file, char * buf, size_t count, loff_t
 
 static int eeprom_write_buf(loff_t addr, const char * buf, int count)
 {
-  struct file f;
-
-  f.f_pos = addr;
-  
-  return eeprom_write(&f, buf, count, &addr);
+  return eeprom_write(NULL, buf, count, &addr);
 }
 
 
 /* Writes data to eeprom. */
 
 static ssize_t eeprom_write(struct file * file, const char * buf, size_t count,
-                            loff_t *off)
+			    loff_t *ppos)
 {
   int i, written, restart=1;
   unsigned long p;
@@ -543,9 +535,9 @@ static ssize_t eeprom_write(struct file * file, const char * buf, size_t count,
   {
     restart = 0;
     written = 0;
-    p = file->f_pos;
-   
-    
+    p = *ppos;
+
+
     while( (written < count) && (p < eeprom.size))
     {
       /* address the eeprom */
@@ -671,10 +663,10 @@ static ssize_t eeprom_write(struct file * file, const char * buf, size_t count,
 
   eeprom.busy--;
   wake_up_interruptible(&eeprom.wait_q);
-  if (written == 0 && file->f_pos >= eeprom.size){
+  if (written == 0 && *ppos >= eeprom.size){
     return -ENOSPC;
   }
-  file->f_pos += written;
+  *ppos += written;
   return written;
 }
 
-- 
1.6.4.2

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