kernel-fxtec-pro1x/drivers/staging
Arnd Bergmann 6038f373a3 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>
2010-10-15 15:53:27 +02:00
..
adis16255 Staging: adis16255: missing spacess in log messages added 2010-06-18 15:16:20 -07:00
asus_oled Staging: asus_oled: asus_oled.c: Checkpatch cleanup 2010-05-11 11:35:30 -07:00
batman-adv Staging: batman-adv: Don't write in not allocated packet_buff 2010-08-23 18:15:38 -07:00
comedi llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
crystalhd llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
cx25821 Staging: Merge staging-next into Linus's tree 2010-08-05 14:18:03 -07:00
cxt1e1 Staging: cxt1e1: remove code guarded by GENERIC_HDLC_VERSION 2010-06-18 15:20:59 -07:00
dream llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
dt3155v4l Staging: dt3155v4l: correcting a pointer mismatch bug and cleanups 2010-06-18 16:50:04 -07:00
easycap staging: Pushdown bkl to easycap ioctl handlers 2010-08-09 03:28:40 +02:00
echo staging: trivial: fix typo "seperate" 2010-05-14 13:16:10 -07:00
et131x Staging: et131x: Small format/style tidyups 2010-06-17 16:08:45 -07:00
frontier llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
go7007 i2c: Remove all i2c_set_clientdata(client, NULL) in drivers 2010-06-03 11:33:58 +02:00
hv staging: hv: Fixed lockup problem with bounce_buffer scatter list 2010-09-03 17:37:15 -07:00
iio llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
line6 Staging: line6: needs to select SND_PCM 2010-07-28 08:20:55 -07:00
lirc llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
memrar llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
mrst-touchscreen Staging: mrst-touchscreen: fix dereferencing free memory 2010-06-30 08:18:14 -07:00
msm staging: msm: remove video drivers for obsolete platforms 2010-07-26 15:39:31 -07:00
octeon Staging: octeon: depends on NETDEVICES 2010-09-03 17:37:16 -07:00
otus Staging: comedi : fix brace coding style issue in wwrap.c 2010-08-02 18:27:42 -07:00
panel llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
phison Staging: phison: depends on ATA_BMDMA 2010-06-04 13:38:57 -07:00
pohmelfs fs: fs_struct rwlock to spinlock 2010-08-18 08:35:46 -04:00
quatech_usb2 Staging: quatech_usb2: remove unused qt2_box_flush function 2010-08-02 18:25:27 -07:00
quickstart Staging: quickstart: depends on INPUT 2010-08-02 18:12:46 -07:00
rt2860 Staging: rt2870sta: Add more device IDs from vendor drivers 2010-09-03 17:37:15 -07:00
rt2870 Staging: rt2870: Allow building on ARM 2010-05-11 11:35:55 -07:00
rtl8187se param: remove unnecessary writable charp 2010-08-11 23:04:27 +09:30
rtl8192e param: remove unnecessary writable charp 2010-08-11 23:04:27 +09:30
rtl8192su param: remove unnecessary writable charp 2010-08-11 23:04:27 +09:30
rtl8192u Staging: Merge staging-next into Linus's tree 2010-08-05 14:18:03 -07:00
samsung-laptop backlight: Allow properties to be passed at registration 2010-03-16 19:47:54 +00:00
serqt_usb2 Staging: serqt_usb2: fix space coding style issue in serqt_usb2.c 2010-05-11 11:35:54 -07:00
slicoss Staging: slicoss: Remove net_device_stats from the driver's private 2010-08-02 18:25:26 -07:00
sm7xx staging: sm7xx: Fixup of the section mismatch 2010-07-22 14:32:59 -07:00
solo6x10 Staging: solo: add delay.h header 2010-07-08 13:57:58 -07:00
spectra Staging: spectra: depend on X86_MRST 2010-09-03 17:37:16 -07:00
ti-st Staging: ti-st: update TODO 2010-08-02 18:28:40 -07:00
tidspbridge llseek: automatically add .llseek fop 2010-10-15 15:53:27 +02:00
tm6000 V4L/DVB: tm6000-input: Make checkpatch.pl happy 2010-08-02 15:29:35 -03:00
udlfb Merge git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging-2.6 2010-05-21 15:26:46 -07:00
usbip USB: convert usb_hcd bitfields into atomic flags 2010-08-10 14:35:37 -07:00
vme Staging: autoconvert trivial BKL users to private mutex 2010-07-22 11:10:29 -07:00
vt6655 Staging: vt6655: replace BOOL with in kernel bool 2010-08-02 18:17:57 -07:00
vt6656 staging: vt6656: removed NTSTATUS definition 2010-08-02 18:19:04 -07:00
winbond Staging: Merge staging-next into Linus's tree 2010-08-05 14:18:03 -07:00
wlags49_h2 Merge git://git.kernel.org/pub/scm/linux/kernel/git/brodo/pcmcia-2.6 2010-08-06 12:25:06 -07:00
wlags49_h25 Staging: wlags49_h2, wlags49_h25: fixed Kconfig dependencies 2010-06-04 13:38:57 -07:00
wlan-ng Staging: wlan-ng: Explicitly set some fields in cfg80211 interface 2010-09-03 17:37:16 -07:00
xgifb Staging: xgifb: increase VBIOS_VER_MAX_LENGTH to 5 2010-06-22 14:33:36 -07:00
zram Staging: zram: free device memory when init fails 2010-09-03 17:37:15 -07:00
Kconfig Staging: sep: remove driver 2010-08-23 18:15:38 -07:00
Makefile Staging: sep: remove driver 2010-08-23 18:15:38 -07:00
staging.c Staging: workaround build system bug 2008-10-13 14:32:52 -07:00