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linux/drivers/media/dvb/firewire/firedtv-ci.c
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

260 lines
5.7 KiB
C
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/*
* FireDTV driver (formerly known as FireSAT)
*
* Copyright (C) 2004 Andreas Monitzer <andy@monitzer.com>
* Copyright (C) 2008 Henrik Kurelid <henrik@kurelid.se>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*/
#include <linux/device.h>
#include <linux/dvb/ca.h>
#include <linux/fs.h>
#include <linux/module.h>
#include <dvbdev.h>
#include "firedtv.h"
#define EN50221_TAG_APP_INFO_ENQUIRY 0x9f8020
#define EN50221_TAG_CA_INFO_ENQUIRY 0x9f8030
#define EN50221_TAG_CA_PMT 0x9f8032
#define EN50221_TAG_ENTER_MENU 0x9f8022
static int fdtv_ca_ready(struct firedtv_tuner_status *stat)
{
return stat->ca_initialization_status == 1 &&
stat->ca_error_flag == 0 &&
stat->ca_dvb_flag == 1 &&
stat->ca_module_present_status == 1;
}
static int fdtv_get_ca_flags(struct firedtv_tuner_status *stat)
{
int flags = 0;
if (stat->ca_module_present_status == 1)
flags |= CA_CI_MODULE_PRESENT;
if (stat->ca_initialization_status == 1 &&
stat->ca_error_flag == 0 &&
stat->ca_dvb_flag == 1)
flags |= CA_CI_MODULE_READY;
return flags;
}
static int fdtv_ca_reset(struct firedtv *fdtv)
{
return avc_ca_reset(fdtv) ? -EFAULT : 0;
}
static int fdtv_ca_get_caps(void *arg)
{
struct ca_caps *cap = arg;
cap->slot_num = 1;
cap->slot_type = CA_CI;
cap->descr_num = 1;
cap->descr_type = CA_ECD;
return 0;
}
static int fdtv_ca_get_slot_info(struct firedtv *fdtv, void *arg)
{
struct firedtv_tuner_status stat;
struct ca_slot_info *slot = arg;
if (avc_tuner_status(fdtv, &stat))
return -EFAULT;
if (slot->num != 0)
return -EFAULT;
slot->type = CA_CI;
slot->flags = fdtv_get_ca_flags(&stat);
return 0;
}
static int fdtv_ca_app_info(struct firedtv *fdtv, void *arg)
{
struct ca_msg *reply = arg;
return avc_ca_app_info(fdtv, reply->msg, &reply->length) ? -EFAULT : 0;
}
static int fdtv_ca_info(struct firedtv *fdtv, void *arg)
{
struct ca_msg *reply = arg;
return avc_ca_info(fdtv, reply->msg, &reply->length) ? -EFAULT : 0;
}
static int fdtv_ca_get_mmi(struct firedtv *fdtv, void *arg)
{
struct ca_msg *reply = arg;
return avc_ca_get_mmi(fdtv, reply->msg, &reply->length) ? -EFAULT : 0;
}
static int fdtv_ca_get_msg(struct firedtv *fdtv, void *arg)
{
struct firedtv_tuner_status stat;
int err;
switch (fdtv->ca_last_command) {
case EN50221_TAG_APP_INFO_ENQUIRY:
err = fdtv_ca_app_info(fdtv, arg);
break;
case EN50221_TAG_CA_INFO_ENQUIRY:
err = fdtv_ca_info(fdtv, arg);
break;
default:
if (avc_tuner_status(fdtv, &stat))
err = -EFAULT;
else if (stat.ca_mmi == 1)
err = fdtv_ca_get_mmi(fdtv, arg);
else {
dev_info(fdtv->device, "unhandled CA message 0x%08x\n",
fdtv->ca_last_command);
err = -EFAULT;
}
}
fdtv->ca_last_command = 0;
return err;
}
static int fdtv_ca_pmt(struct firedtv *fdtv, void *arg)
{
struct ca_msg *msg = arg;
int data_pos;
int data_length;
int i;
data_pos = 4;
if (msg->msg[3] & 0x80) {
data_length = 0;
for (i = 0; i < (msg->msg[3] & 0x7f); i++)
data_length = (data_length << 8) + msg->msg[data_pos++];
} else {
data_length = msg->msg[3];
}
return avc_ca_pmt(fdtv, &msg->msg[data_pos], data_length) ? -EFAULT : 0;
}
static int fdtv_ca_send_msg(struct firedtv *fdtv, void *arg)
{
struct ca_msg *msg = arg;
int err;
/* Do we need a semaphore for this? */
fdtv->ca_last_command =
(msg->msg[0] << 16) + (msg->msg[1] << 8) + msg->msg[2];
switch (fdtv->ca_last_command) {
case EN50221_TAG_CA_PMT:
err = fdtv_ca_pmt(fdtv, arg);
break;
case EN50221_TAG_APP_INFO_ENQUIRY:
/* handled in ca_get_msg */
err = 0;
break;
case EN50221_TAG_CA_INFO_ENQUIRY:
/* handled in ca_get_msg */
err = 0;
break;
case EN50221_TAG_ENTER_MENU:
err = avc_ca_enter_menu(fdtv);
break;
default:
dev_err(fdtv->device, "unhandled CA message 0x%08x\n",
fdtv->ca_last_command);
err = -EFAULT;
}
return err;
}
static int fdtv_ca_ioctl(struct file *file, unsigned int cmd, void *arg)
{
struct dvb_device *dvbdev = file->private_data;
struct firedtv *fdtv = dvbdev->priv;
struct firedtv_tuner_status stat;
int err;
switch (cmd) {
case CA_RESET:
err = fdtv_ca_reset(fdtv);
break;
case CA_GET_CAP:
err = fdtv_ca_get_caps(arg);
break;
case CA_GET_SLOT_INFO:
err = fdtv_ca_get_slot_info(fdtv, arg);
break;
case CA_GET_MSG:
err = fdtv_ca_get_msg(fdtv, arg);
break;
case CA_SEND_MSG:
err = fdtv_ca_send_msg(fdtv, arg);
break;
default:
dev_info(fdtv->device, "unhandled CA ioctl %u\n", cmd);
err = -EOPNOTSUPP;
}
/* FIXME Is this necessary? */
avc_tuner_status(fdtv, &stat);
return err;
}
static unsigned int fdtv_ca_io_poll(struct file *file, poll_table *wait)
{
return POLLIN;
}
static const struct file_operations fdtv_ca_fops = {
.owner = THIS_MODULE,
.unlocked_ioctl = dvb_generic_ioctl,
.open = dvb_generic_open,
.release = dvb_generic_release,
.poll = fdtv_ca_io_poll,
.llseek = noop_llseek,
};
static struct dvb_device fdtv_ca = {
.users = 1,
.readers = 1,
.writers = 1,
.fops = &fdtv_ca_fops,
.kernel_ioctl = fdtv_ca_ioctl,
};
int fdtv_ca_register(struct firedtv *fdtv)
{
struct firedtv_tuner_status stat;
int err;
if (avc_tuner_status(fdtv, &stat))
return -EINVAL;
if (!fdtv_ca_ready(&stat))
return -EFAULT;
err = dvb_register_device(&fdtv->adapter, &fdtv->cadev,
&fdtv_ca, fdtv, DVB_DEVICE_CA);
if (stat.ca_application_info == 0)
dev_err(fdtv->device, "CaApplicationInfo is not set\n");
if (stat.ca_date_time_request == 1)
avc_ca_get_time_date(fdtv, &fdtv->ca_time_interval);
return err;
}
void fdtv_ca_release(struct firedtv *fdtv)
{
if (fdtv->cadev)
dvb_unregister_device(fdtv->cadev);
}
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