llseek: automatically add .llseek fop

All file_operations should get a .llseek operation so we can make
nonseekable_open the default for future file operations without a
.llseek pointer.

The three cases that we can automatically detect are no_llseek, seq_lseek
and default_llseek. For cases where we can we can automatically prove that
the file offset is always ignored, we use noop_llseek, which maintains
the current behavior of not returning an error from a seek.

New drivers should normally not use noop_llseek but instead use no_llseek
and call nonseekable_open at open time.  Existing drivers can be converted
to do the same when the maintainer knows for certain that no user code
relies on calling seek on the device file.

The generated code is often incorrectly indented and right now contains
comments that clarify for each added line why a specific variant was
chosen. In the version that gets submitted upstream, the comments will
be gone and I will manually fix the indentation, because there does not
seem to be a way to do that using coccinelle.

Some amount of new code is currently sitting in linux-next that should get
the same modifications, which I will do at the end of the merge window.

Many thanks to Julia Lawall for helping me learn to write a semantic
patch that does all this.

===== begin semantic patch =====
// This adds an llseek= method to all file operations,
// as a preparation for making no_llseek the default.
//
// The rules are
// - use no_llseek explicitly if we do nonseekable_open
// - use seq_lseek for sequential files
// - use default_llseek if we know we access f_pos
// - use noop_llseek if we know we don't access f_pos,
//   but we still want to allow users to call lseek
//
@ open1 exists @
identifier nested_open;
@@
nested_open(...)
{
<+...
nonseekable_open(...)
...+>
}

@ open exists@
identifier open_f;
identifier i, f;
identifier open1.nested_open;
@@
int open_f(struct inode *i, struct file *f)
{
<+...
(
nonseekable_open(...)
|
nested_open(...)
)
...+>
}

@ read disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
<+...
(
   *off = E
|
   *off += E
|
   func(..., off, ...)
|
   E = *off
)
...+>
}

@ read_no_fpos disable optional_qualifier exists @
identifier read_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t read_f(struct file *f, char *p, size_t s, loff_t *off)
{
... when != off
}

@ write @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
expression E;
identifier func;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
<+...
(
  *off = E
|
  *off += E
|
  func(..., off, ...)
|
  E = *off
)
...+>
}

@ write_no_fpos @
identifier write_f;
identifier f, p, s, off;
type ssize_t, size_t, loff_t;
@@
ssize_t write_f(struct file *f, const char *p, size_t s, loff_t *off)
{
... when != off
}

@ fops0 @
identifier fops;
@@
struct file_operations fops = {
 ...
};

@ has_llseek depends on fops0 @
identifier fops0.fops;
identifier llseek_f;
@@
struct file_operations fops = {
...
 .llseek = llseek_f,
...
};

@ has_read depends on fops0 @
identifier fops0.fops;
identifier read_f;
@@
struct file_operations fops = {
...
 .read = read_f,
...
};

@ has_write depends on fops0 @
identifier fops0.fops;
identifier write_f;
@@
struct file_operations fops = {
...
 .write = write_f,
...
};

@ has_open depends on fops0 @
identifier fops0.fops;
identifier open_f;
@@
struct file_operations fops = {
...
 .open = open_f,
...
};

// use no_llseek if we call nonseekable_open
////////////////////////////////////////////
@ nonseekable1 depends on !has_llseek && has_open @
identifier fops0.fops;
identifier nso ~= "nonseekable_open";
@@
struct file_operations fops = {
...  .open = nso, ...
+.llseek = no_llseek, /* nonseekable */
};

@ nonseekable2 depends on !has_llseek @
identifier fops0.fops;
identifier open.open_f;
@@
struct file_operations fops = {
...  .open = open_f, ...
+.llseek = no_llseek, /* open uses nonseekable */
};

// use seq_lseek for sequential files
/////////////////////////////////////
@ seq depends on !has_llseek @
identifier fops0.fops;
identifier sr ~= "seq_read";
@@
struct file_operations fops = {
...  .read = sr, ...
+.llseek = seq_lseek, /* we have seq_read */
};

// use default_llseek if there is a readdir
///////////////////////////////////////////
@ fops1 depends on !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier readdir_e;
@@
// any other fop is used that changes pos
struct file_operations fops = {
... .readdir = readdir_e, ...
+.llseek = default_llseek, /* readdir is present */
};

// use default_llseek if at least one of read/write touches f_pos
/////////////////////////////////////////////////////////////////
@ fops2 depends on !fops1 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read.read_f;
@@
// read fops use offset
struct file_operations fops = {
... .read = read_f, ...
+.llseek = default_llseek, /* read accesses f_pos */
};

@ fops3 depends on !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write.write_f;
@@
// write fops use offset
struct file_operations fops = {
... .write = write_f, ...
+	.llseek = default_llseek, /* write accesses f_pos */
};

// Use noop_llseek if neither read nor write accesses f_pos
///////////////////////////////////////////////////////////

@ fops4 depends on !fops1 && !fops2 && !fops3 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
identifier write_no_fpos.write_f;
@@
// write fops use offset
struct file_operations fops = {
...
 .write = write_f,
 .read = read_f,
...
+.llseek = noop_llseek, /* read and write both use no f_pos */
};

@ depends on has_write && !has_read && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier write_no_fpos.write_f;
@@
struct file_operations fops = {
... .write = write_f, ...
+.llseek = noop_llseek, /* write uses no f_pos */
};

@ depends on has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
identifier read_no_fpos.read_f;
@@
struct file_operations fops = {
... .read = read_f, ...
+.llseek = noop_llseek, /* read uses no f_pos */
};

@ depends on !has_read && !has_write && !fops1 && !fops2 && !has_llseek && !nonseekable1 && !nonseekable2 && !seq @
identifier fops0.fops;
@@
struct file_operations fops = {
...
+.llseek = noop_llseek, /* no read or write fn */
};
===== End semantic patch =====

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Julia Lawall <julia@diku.dk>
Cc: Christoph Hellwig <hch@infradead.org>

37 files changed, 47 insertions, 5 deletions

diff --git a/drivers/char/apm-emulation.c b/drivers/char/apm-emulation.c
index 033e1505fca..5ffa6904ea6 100644
--- a/drivers/char/apm-emulation.c
+++ b/drivers/char/apm-emulation.c
@@ -402,6 +402,7 @@ static const struct file_operations apm_bios_fops = {
 	.unlocked_ioctl	= apm_ioctl,
 	.open		= apm_open,
 	.release	= apm_release,
+	.llseek		= noop_llseek,
 };
 
 static struct miscdevice apm_device = {
diff --git a/drivers/char/bfin-otp.c b/drivers/char/bfin-otp.c
index 836d4f0a876..44660f1c484 100644
--- a/drivers/char/bfin-otp.c
+++ b/drivers/char/bfin-otp.c
@@ -222,6 +222,7 @@ static const struct file_operations bfin_otp_fops = {
 	.unlocked_ioctl = bfin_otp_ioctl,
 	.read           = bfin_otp_read,
 	.write          = bfin_otp_write,
+	.llseek		= default_llseek,
 };
 
 static struct miscdevice bfin_otp_misc_device = {
diff --git a/drivers/char/briq_panel.c b/drivers/char/briq_panel.c
index d5fa113afe3..f6718f05dad 100644
--- a/drivers/char/briq_panel.c
+++ b/drivers/char/briq_panel.c
@@ -186,6 +186,7 @@ static const struct file_operations briq_panel_fops = {
 	.write		= briq_panel_write,
 	.open		= briq_panel_open,
 	.release	= briq_panel_release,
+	.llseek		= noop_llseek,
 };
 
 static struct miscdevice briq_panel_miscdev = {
diff --git a/drivers/char/bsr.c b/drivers/char/bsr.c
index 91917133ae0..a4a6c2f044b 100644
--- a/drivers/char/bsr.c
+++ b/drivers/char/bsr.c
@@ -155,6 +155,7 @@ static const struct file_operations bsr_fops = {
 	.owner = THIS_MODULE,
 	.mmap  = bsr_mmap,
 	.open  = bsr_open,
+	.llseek = noop_llseek,
 };
 
 static void bsr_cleanup_devs(void)
diff --git a/drivers/char/cs5535_gpio.c b/drivers/char/cs5535_gpio.c
index 4d830dc482e..0cf1e5fad9a 100644
--- a/drivers/char/cs5535_gpio.c
+++ b/drivers/char/cs5535_gpio.c
@@ -169,7 +169,8 @@ static const struct file_operations cs5535_gpio_fops = {
 	.owner	= THIS_MODULE,
 	.write	= cs5535_gpio_write,
 	.read	= cs5535_gpio_read,
-	.open	= cs5535_gpio_open
+	.open	= cs5535_gpio_open,
+	.llseek = no_llseek,
 };
 
 static int __init cs5535_gpio_init(void)
diff --git a/drivers/char/ds1302.c b/drivers/char/ds1302.c
index 170693c93c7..4f7aa364167 100644
--- a/drivers/char/ds1302.c
+++ b/drivers/char/ds1302.c
@@ -288,6 +288,7 @@ get_rtc_status(char *buf)
 static const struct file_operations rtc_fops = {
 	.owner		= THIS_MODULE,
 	.unlocked_ioctl	= rtc_ioctl,
+	.llseek		= noop_llseek,
 };
 
 /* Probe for the chip by writing something to its RAM and try reading it back. */
diff --git a/drivers/char/ds1620.c b/drivers/char/ds1620.c
index dbee8688f75..50462b63e51 100644
--- a/drivers/char/ds1620.c
+++ b/drivers/char/ds1620.c
@@ -357,6 +357,7 @@ static const struct file_operations ds1620_fops = {
 	.open		= ds1620_open,
 	.read		= ds1620_read,
 	.unlocked_ioctl	= ds1620_unlocked_ioctl,
+	.llseek		= no_llseek,
 };
 
 static struct miscdevice ds1620_miscdev = {
diff --git a/drivers/char/dsp56k.c b/drivers/char/dsp56k.c
index 8a1b28a10ef..353be4707d9 100644
--- a/drivers/char/dsp56k.c
+++ b/drivers/char/dsp56k.c
@@ -482,6 +482,7 @@ static const struct file_operations dsp56k_fops = {
 	.unlocked_ioctl	= dsp56k_ioctl,
 	.open		= dsp56k_open,
 	.release	= dsp56k_release,
+	.llseek		= noop_llseek,
 };
 
 
diff --git a/drivers/char/dtlk.c b/drivers/char/dtlk.c
index e3859d4eaea..007eca3ed77 100644
--- a/drivers/char/dtlk.c
+++ b/drivers/char/dtlk.c
@@ -105,6 +105,7 @@ static const struct file_operations dtlk_fops =
 	.unlocked_ioctl	= dtlk_ioctl,
 	.open		= dtlk_open,
 	.release	= dtlk_release,
+	.llseek		= no_llseek,
 };
 
 /* local prototypes */
diff --git a/drivers/char/genrtc.c b/drivers/char/genrtc.c
index b6c2cc167c1..eaa0e4264e1 100644
--- a/drivers/char/genrtc.c
+++ b/drivers/char/genrtc.c
@@ -497,6 +497,7 @@ static const struct file_operations gen_rtc_fops = {
 	.unlocked_ioctl	= gen_rtc_unlocked_ioctl,
 	.open		= gen_rtc_open,
 	.release	= gen_rtc_release,
+	.llseek		= noop_llseek,
 };
 
 static struct miscdevice rtc_gen_dev =
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c
index 3d9c61e5acb..788da05190c 100644
--- a/drivers/char/hw_random/core.c
+++ b/drivers/char/hw_random/core.c
@@ -170,6 +170,7 @@ static const struct file_operations rng_chrdev_ops = {
 	.owner		= THIS_MODULE,
 	.open		= rng_dev_open,
 	.read		= rng_dev_read,
+	.llseek		= noop_llseek,
 };
 
 static struct miscdevice rng_miscdev = {
diff --git a/drivers/char/ip2/ip2main.c b/drivers/char/ip2/ip2main.c
index d4b71e8d0d2..2e49e515d8e 100644
--- a/drivers/char/ip2/ip2main.c
+++ b/drivers/char/ip2/ip2main.c
@@ -236,6 +236,7 @@ static const struct file_operations ip2_ipl = {
 	.write		= ip2_ipl_write,
 	.unlocked_ioctl	= ip2_ipl_ioctl,
 	.open		= ip2_ipl_open,
+	.llseek		= noop_llseek,
 }; 
 
 static unsigned long irq_counter;
diff --git a/drivers/char/ipmi/ipmi_devintf.c b/drivers/char/ipmi/ipmi_devintf.c
index d8ec92a3898..c6709d6b0fd 100644
--- a/drivers/char/ipmi/ipmi_devintf.c
+++ b/drivers/char/ipmi/ipmi_devintf.c
@@ -850,6 +850,7 @@ static const struct file_operations ipmi_fops = {
 	.release	= ipmi_release,
 	.fasync		= ipmi_fasync,
 	.poll		= ipmi_poll,
+	.llseek		= noop_llseek,
 };
 
 #define DEVICE_NAME     "ipmidev"
diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 654d566ca57..da041f88f64 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -909,6 +909,7 @@ static const struct file_operations ipmi_wdog_fops = {
 	.open    = ipmi_open,
 	.release = ipmi_close,
 	.fasync  = ipmi_fasync,
+	.llseek  = no_llseek,
 };
 
 static struct miscdevice ipmi_wdog_miscdev = {
diff --git a/drivers/char/istallion.c b/drivers/char/istallion.c
index be28391adb7..667abd23ad6 100644
--- a/drivers/char/istallion.c
+++ b/drivers/char/istallion.c
@@ -704,6 +704,7 @@ static const struct file_operations	stli_fsiomem = {
 	.read		= stli_memread,
 	.write		= stli_memwrite,
 	.unlocked_ioctl	= stli_memioctl,
+	.llseek		= default_llseek,
 };
 
 /*****************************************************************************/
diff --git a/drivers/char/lp.c b/drivers/char/lp.c
index 938a3a27388..d2344117eaf 100644
--- a/drivers/char/lp.c
+++ b/drivers/char/lp.c
@@ -748,6 +748,7 @@ static const struct file_operations lp_fops = {
 #ifdef CONFIG_PARPORT_1284
 	.read		= lp_read,
 #endif
+	.llseek		= noop_llseek,
 };
 
 /* --- support for console on the line printer ----------------- */
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index a398ecdbd75..8ebd232132f 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -804,6 +804,7 @@ static const struct file_operations full_fops = {
 static const struct file_operations oldmem_fops = {
 	.read	= read_oldmem,
 	.open	= open_oldmem,
+	.llseek = default_llseek,
 };
 #endif
 
@@ -830,6 +831,7 @@ static ssize_t kmsg_write(struct file *file, const char __user *buf,
 
 static const struct file_operations kmsg_fops = {
 	.write = kmsg_write,
+	.llseek = noop_llseek,
 };
 
 static const struct memdev {
@@ -881,6 +883,7 @@ static int memory_open(struct inode *inode, struct file *filp)
 
 static const struct file_operations memory_fops = {
 	.open = memory_open,
+	.llseek = noop_llseek,
 };
 
 static char *mem_devnode(struct device *dev, mode_t *mode)
diff --git a/drivers/char/misc.c b/drivers/char/misc.c
index abdafd48898..778273c9324 100644
--- a/drivers/char/misc.c
+++ b/drivers/char/misc.c
@@ -162,6 +162,7 @@ static struct class *misc_class;
 static const struct file_operations misc_fops = {
 	.owner		= THIS_MODULE,
 	.open		= misc_open,
+	.llseek		= noop_llseek,
 };
 
 /**
diff --git a/drivers/char/mmtimer.c b/drivers/char/mmtimer.c
index ea7c99fa978..1c4070ced06 100644
--- a/drivers/char/mmtimer.c
+++ b/drivers/char/mmtimer.c
@@ -72,6 +72,7 @@ static const struct file_operations mmtimer_fops = {
 	.owner = THIS_MODULE,
 	.mmap =	mmtimer_mmap,
 	.unlocked_ioctl = mmtimer_ioctl,
+	.llseek = noop_llseek,
 };
 
 /*
diff --git a/drivers/char/mspec.c b/drivers/char/mspec.c
index ecb89d798e3..966a95bc974 100644
--- a/drivers/char/mspec.c
+++ b/drivers/char/mspec.c
@@ -316,7 +316,8 @@ uncached_mmap(struct file *file, struct vm_area_struct *vma)
 
 static const struct file_operations fetchop_fops = {
 	.owner = THIS_MODULE,
-	.mmap = fetchop_mmap
+	.mmap = fetchop_mmap,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice fetchop_miscdev = {
@@ -327,7 +328,8 @@ static struct miscdevice fetchop_miscdev = {
 
 static const struct file_operations cached_fops = {
 	.owner = THIS_MODULE,
-	.mmap = cached_mmap
+	.mmap = cached_mmap,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice cached_miscdev = {
@@ -338,7 +340,8 @@ static struct miscdevice cached_miscdev = {
 
 static const struct file_operations uncached_fops = {
 	.owner = THIS_MODULE,
-	.mmap = uncached_mmap
+	.mmap = uncached_mmap,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice uncached_miscdev = {
diff --git a/drivers/char/mwave/mwavedd.c b/drivers/char/mwave/mwavedd.c
index a4ec50c9507..0464822eac5 100644
--- a/drivers/char/mwave/mwavedd.c
+++ b/drivers/char/mwave/mwavedd.c
@@ -479,7 +479,8 @@ static const struct file_operations mwave_fops = {
 	.write		= mwave_write,
 	.unlocked_ioctl	= mwave_ioctl,
 	.open		= mwave_open,
-	.release	= mwave_close
+	.release	= mwave_close,
+	.llseek		= default_llseek,
 };
 
 
diff --git a/drivers/char/nwbutton.c b/drivers/char/nwbutton.c
index 2604246501e..8994ce32e6c 100644
--- a/drivers/char/nwbutton.c
+++ b/drivers/char/nwbutton.c
@@ -182,6 +182,7 @@ static int button_read (struct file *filp, char __user *buffer,
 static const struct file_operations button_fops = {
 	.owner		= THIS_MODULE,
 	.read		= button_read,
+	.llseek		= noop_llseek,
 };
 
 /* 
diff --git a/drivers/char/pc8736x_gpio.c b/drivers/char/pc8736x_gpio.c
index 8ecbcc174c1..b304ec05250 100644
--- a/drivers/char/pc8736x_gpio.c
+++ b/drivers/char/pc8736x_gpio.c
@@ -234,6 +234,7 @@ static const struct file_operations pc8736x_gpio_fileops = {
 	.open	= pc8736x_gpio_open,
 	.write	= nsc_gpio_write,
 	.read	= nsc_gpio_read,
+	.llseek = no_llseek,
 };
 
 static void __init pc8736x_init_shadow(void)
diff --git a/drivers/char/pcmcia/cm4000_cs.c b/drivers/char/pcmcia/cm4000_cs.c
index ec73d9f6d9e..c99f6997e5e 100644
--- a/drivers/char/pcmcia/cm4000_cs.c
+++ b/drivers/char/pcmcia/cm4000_cs.c
@@ -1880,6 +1880,7 @@ static const struct file_operations cm4000_fops = {
 	.unlocked_ioctl	= cmm_ioctl,
 	.open	= cmm_open,
 	.release= cmm_close,
+	.llseek = no_llseek,
 };
 
 static struct pcmcia_device_id cm4000_ids[] = {
diff --git a/drivers/char/pcmcia/cm4040_cs.c b/drivers/char/pcmcia/cm4040_cs.c
index 815cde1d057..9ecc58baa8f 100644
--- a/drivers/char/pcmcia/cm4040_cs.c
+++ b/drivers/char/pcmcia/cm4040_cs.c
@@ -650,6 +650,7 @@ static const struct file_operations reader_fops = {
 	.open		= cm4040_open,
 	.release	= cm4040_close,
 	.poll		= cm4040_poll,
+	.llseek		= no_llseek,
 };
 
 static struct pcmcia_device_id cm4040_ids[] = {
diff --git a/drivers/char/random.c b/drivers/char/random.c
index caef35a4689..5a1aa64f4e7 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1165,6 +1165,7 @@ const struct file_operations random_fops = {
 	.poll  = random_poll,
 	.unlocked_ioctl = random_ioctl,
 	.fasync = random_fasync,
+	.llseek = noop_llseek,
 };
 
 const struct file_operations urandom_fops = {
@@ -1172,6 +1173,7 @@ const struct file_operations urandom_fops = {
 	.write = random_write,
 	.unlocked_ioctl = random_ioctl,
 	.fasync = random_fasync,
+	.llseek = noop_llseek,
 };
 
 /***************************************************************
diff --git a/drivers/char/rio/rio_linux.c b/drivers/char/rio/rio_linux.c
index d58c2eb07f0..1e87a93164b 100644
--- a/drivers/char/rio/rio_linux.c
+++ b/drivers/char/rio/rio_linux.c
@@ -241,6 +241,7 @@ static struct real_driver rio_real_driver = {
 static const struct file_operations rio_fw_fops = {
 	.owner = THIS_MODULE,
 	.unlocked_ioctl = rio_fw_ioctl,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice rio_fw_device = {
diff --git a/drivers/char/scx200_gpio.c b/drivers/char/scx200_gpio.c
index 99e5272e3c5..0bc135b9b16 100644
--- a/drivers/char/scx200_gpio.c
+++ b/drivers/char/scx200_gpio.c
@@ -67,6 +67,7 @@ static const struct file_operations scx200_gpio_fileops = {
 	.read    = nsc_gpio_read,
 	.open    = scx200_gpio_open,
 	.release = scx200_gpio_release,
+	.llseek  = no_llseek,
 };
 
 static struct cdev scx200_gpio_cdev;  /* use 1 cdev for all pins */
diff --git a/drivers/char/snsc.c b/drivers/char/snsc.c
index 32b74de18f5..444ce17ac72 100644
--- a/drivers/char/snsc.c
+++ b/drivers/char/snsc.c
@@ -357,6 +357,7 @@ static const struct file_operations scdrv_fops = {
 	.poll =		scdrv_poll,
 	.open =		scdrv_open,
 	.release =	scdrv_release,
+	.llseek =	noop_llseek,
 };
 
 static struct class *snsc_class;
diff --git a/drivers/char/stallion.c b/drivers/char/stallion.c
index f2167f8e5aa..8ef16490810 100644
--- a/drivers/char/stallion.c
+++ b/drivers/char/stallion.c
@@ -608,6 +608,7 @@ static unsigned int	sc26198_baudtable[] = {
 static const struct file_operations	stl_fsiomem = {
 	.owner		= THIS_MODULE,
 	.unlocked_ioctl	= stl_memioctl,
+	.llseek		= noop_llseek,
 };
 
 static struct class *stallion_class;
diff --git a/drivers/char/sx.c b/drivers/char/sx.c
index 5b24db4ff7f..e53f1686539 100644
--- a/drivers/char/sx.c
+++ b/drivers/char/sx.c
@@ -397,6 +397,7 @@ static struct real_driver sx_real_driver = {
 static const struct file_operations sx_fw_fops = {
 	.owner = THIS_MODULE,
 	.unlocked_ioctl = sx_fw_ioctl,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice sx_fw_device = {
diff --git a/drivers/char/sysrq.c b/drivers/char/sysrq.c
index ef31bb81e84..f3019f53e87 100644
--- a/drivers/char/sysrq.c
+++ b/drivers/char/sysrq.c
@@ -772,6 +772,7 @@ static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
 
 static const struct file_operations proc_sysrq_trigger_operations = {
 	.write		= write_sysrq_trigger,
+	.llseek		= noop_llseek,
 };
 
 static void sysrq_init_procfs(void)
diff --git a/drivers/char/tb0219.c b/drivers/char/tb0219.c
index cad4eb65f13..ad264185eb1 100644
--- a/drivers/char/tb0219.c
+++ b/drivers/char/tb0219.c
@@ -261,6 +261,7 @@ static const struct file_operations tb0219_fops = {
 	.write		= tanbac_tb0219_write,
 	.open		= tanbac_tb0219_open,
 	.release	= tanbac_tb0219_release,
+	.llseek		= no_llseek,
 };
 
 static void tb0219_restart(char *command)
diff --git a/drivers/char/tlclk.c b/drivers/char/tlclk.c
index 80ea6bcfffd..d087532b29d 100644
--- a/drivers/char/tlclk.c
+++ b/drivers/char/tlclk.c
@@ -267,6 +267,7 @@ static const struct file_operations tlclk_fops = {
 	.read = tlclk_read,
 	.open = tlclk_open,
 	.release = tlclk_release,
+	.llseek = noop_llseek,
 
 };
 
diff --git a/drivers/char/toshiba.c b/drivers/char/toshiba.c
index f8bc79f6de3..3d6e9617245 100644
--- a/drivers/char/toshiba.c
+++ b/drivers/char/toshiba.c
@@ -95,6 +95,7 @@ static long tosh_ioctl(struct file *, unsigned int,
 static const struct file_operations tosh_fops = {
 	.owner		= THIS_MODULE,
 	.unlocked_ioctl	= tosh_ioctl,
+	.llseek		= noop_llseek,
 };
 
 static struct miscdevice tosh_device = {
diff --git a/drivers/char/uv_mmtimer.c b/drivers/char/uv_mmtimer.c
index c7072ba14f4..493b47a0d51 100644
--- a/drivers/char/uv_mmtimer.c
+++ b/drivers/char/uv_mmtimer.c
@@ -52,6 +52,7 @@ static const struct file_operations uv_mmtimer_fops = {
 	.owner = THIS_MODULE,
 	.mmap =	uv_mmtimer_mmap,
 	.unlocked_ioctl = uv_mmtimer_ioctl,
+	.llseek = noop_llseek,
 };
 
 /**
diff --git a/drivers/char/xilinx_hwicap/xilinx_hwicap.c b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
index b663d573aad..be6d6fb47cc 100644
--- a/drivers/char/xilinx_hwicap/xilinx_hwicap.c
+++ b/drivers/char/xilinx_hwicap/xilinx_hwicap.c
@@ -567,6 +567,7 @@ static const struct file_operations hwicap_fops = {
 	.read = hwicap_read,
 	.open = hwicap_open,
 	.release = hwicap_release,
+	.llseek = noop_llseek,
 };
 
 static int __devinit hwicap_setup(struct device *dev, int id,