Commit Graph

24 Commits

Author SHA1 Message Date
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
Arnd Bergmann
d9d2e9d5c9 lirc: make chardev nonseekable
There does not seem to be a need for lirc to
allow seeking on the file descriptor, so let's
just disallow this before users start relying
on it.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
2010-09-16 10:33:16 +02:00
Maxim Levitsky
9ea53b74df V4L/DVB: STAGING: remove lirc_ene0100 driver
Add latest unported version of this driver to media/IR.
Next patch will port it to ir core.

Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-08 23:43:00 -03:00
Jarod Wilson
2c1101d5ae V4L/DVB: IR: put newly ported streamzap driver in proper home
Moves drivers/staging/lirc/lirc_streamzap.c to
drivers/media/IR/streamzap.c, along with making the requisite Kconfig
and Makefile changes.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-08 23:42:58 -03:00
Jarod Wilson
8e9e606400 V4L/DVB: staging/lirc: port lirc_streamzap to ir-core
This ports lirc_streamzap.c over to ir-core in-place, to be followed by
a patch moving the driver over to drivers/media/IR/streamzap.c and
enabling the proper Kconfig bits.

Presently, the in-kernel keymap doesn't work, as the stock Streamzap
remote uses an RC-5-like, but not-quite-RC-5 protocol, which the
in-kernel RC-5 decoder doesn't cope with. The remote can be used right
now with the lirc bridge driver though, and other remotes (at least an
RC-6(A) MCE remote) work perfectly with the driver.

I'll take a look at making the existing RC-5 decoder cope with this odd
duck, possibly implement another standalone decoder engine, or just
throw up my hands and say "meh, use lirc"... But the driver itself
should be perfectly sound.

Remaining items on the streamzap TODO list:
- add LIRC_SET_REC_TIMEOUT-alike support
- add LIRC_GET_M{AX,IN}_TIMEOUT-alike support
- add LIRC_GET_REC_RESOLUTION-alike support

All of the above should be trivial to add. There are patches pending to
add this support to ir-core from Maxim Levitsky, and I'll take care of
these once his patches get integrated. None of them are currently
essential though.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-08 23:42:58 -03:00
Jarod Wilson
82ce67bf26 V4L/DVB: staging/lirc: fix non-CONFIG_MODULES build horkage
Fix when CONFIG_MODULES is not enabled:

drivers/staging/lirc/lirc_parallel.c:243: error: implicit declaration of function 'module_refcount'
drivers/staging/lirc/lirc_it87.c:150: error: implicit declaration of function 'module_refcount'
drivers/built-in.o: In function `it87_probe':
lirc_it87.c:(.text+0x4079b0): undefined reference to `init_chrdev'
lirc_it87.c:(.text+0x4079cc): undefined reference to `drop_chrdev'
drivers/built-in.o: In function `lirc_it87_exit':
lirc_it87.c:(.exit.text+0x38a5): undefined reference to `drop_chrdev'

Its a quick hack and untested beyond building, since I don't have the
hardware, but it should do the trick.

Acked-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-08 23:42:57 -03:00
Janne Grunau
efce8ca3c5 V4L/DVB: staging/lirc: fix Kconfig dependencies
Signed-off-by: Janne Grunau <j@jannau.net>
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-08 23:42:57 -03:00
Mauro Carvalho Chehab
0f9313ad06 V4L/DVB: staging/lirc: CodingStyle cleanups
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:35 -03:00
Jarod Wilson
14f184e6d1 V4L/DVB: staging/lirc: wire up Kconfig and Makefile bits
Make the bits under staging/lirc/ buildable, and add a TODO note.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:34 -03:00
Jarod Wilson
69b1214c2c V4L/DVB: staging/lirc: add lirc_zilog driver
Commonly found on several Hauppauge video capture devices.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:33 -03:00
Jarod Wilson
44abf0d9b4 V4L/DVB: staging/lirc: add lirc_ttusbir driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:32 -03:00
Jarod Wilson
19770693c3 V4L/DVB: staging/lirc: add lirc_streamzap driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:31 -03:00
Jarod Wilson
404f3e956b V4L/DVB: staging/lirc: add lirc_sir driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:30 -03:00
Jarod Wilson
1beef3c1c6 V4L/DVB: staging/lirc: add lirc_serial driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:29 -03:00
Jarod Wilson
c5ac457117 V4L/DVB: staging/lirc: add lirc_sasem driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:28 -03:00
Jarod Wilson
805a896665 V4L/DVB: staging/lirc: add lirc_parallel driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:27 -03:00
Jarod Wilson
c147f9078a V4L/DVB: staging/lirc: add lirc_it87 driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:26 -03:00
Jarod Wilson
85cb01afc8 V4L/DVB: staging/lirc: add lirc_ite8709 driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:25 -03:00
Jarod Wilson
4cb613aea4 V4L/DVB: staging/lirc: add lirc_imon driver
Nb: this is a very trimmed-down lirc_imon, which only supports the
oldest generation of imon devices that don't do onboard signal decoding
like the most recent generation imon devices -- those are now supported
by the ir-core imon driver.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:24 -03:00
Jarod Wilson
eedaf1ae7c V4L/DVB: staging/lirc: add lirc_igorplugusb driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:23 -03:00
Mauro Carvalho Chehab
35f168d10f V4L/DVB: staging: Add an specific TODO note for lirc_i2c
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:23 -03:00
Jarod Wilson
085ffd08aa V4L/DVB: staging/lirc: add lirc_i2c driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:22 -03:00
Jarod Wilson
9119fddb77 V4L/DVB: staging/lirc: add lirc_ene0100 driver
[mchehab@redhat.com: fixed a few WARNING: please, no space before tabs]
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:21 -03:00
Jarod Wilson
d10d634143 V4L/DVB: staging/lirc: add lirc_bt829 driver
Signed-off-by: Jarod Wilson <jarod@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
2010-08-02 16:43:19 -03:00