2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
|
* linux/fs/fifo.c
|
|
|
|
|
*
|
|
|
|
|
* written by Paul H. Hargrove
|
|
|
|
|
*
|
|
|
|
|
* Fixes:
|
|
|
|
|
* 10-06-1999, AV: fixed OOM handling in fifo_open(), moved
|
|
|
|
|
* initialization there, switched to external
|
|
|
|
|
* allocation of pipe_inode_info.
|
|
|
|
|
*/
|
|
|
|
|
|
|
|
|
|
#include <linux/mm.h>
|
|
|
|
|
#include <linux/fs.h>
|
Detach sched.h from mm.h
First thing mm.h does is including sched.h solely for can_do_mlock() inline
function which has "current" dereference inside. By dealing with can_do_mlock()
mm.h can be detached from sched.h which is good. See below, why.
This patch
a) removes unconditional inclusion of sched.h from mm.h
b) makes can_do_mlock() normal function in mm/mlock.c
c) exports can_do_mlock() to not break compilation
d) adds sched.h inclusions back to files that were getting it indirectly.
e) adds less bloated headers to some files (asm/signal.h, jiffies.h) that were
getting them indirectly
Net result is:
a) mm.h users would get less code to open, read, preprocess, parse, ... if
they don't need sched.h
b) sched.h stops being dependency for significant number of files:
on x86_64 allmodconfig touching sched.h results in recompile of 4083 files,
after patch it's only 3744 (-8.3%).
Cross-compile tested on
all arm defconfigs, all mips defconfigs, all powerpc defconfigs,
alpha alpha-up
arm
i386 i386-up i386-defconfig i386-allnoconfig
ia64 ia64-up
m68k
mips
parisc parisc-up
powerpc powerpc-up
s390 s390-up
sparc sparc-up
sparc64 sparc64-up
um-x86_64
x86_64 x86_64-up x86_64-defconfig x86_64-allnoconfig
as well as my two usual configs.
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-21 05:22:52 +08:00
|
|
|
#include <linux/sched.h>
|
2005-04-17 06:20:36 +08:00
|
|
|
#include <linux/pipe_fs_i.h>
|
|
|
|
|
|
fifo: Do not restart open() if it already found a partner
If a parent and child process open the two ends of a fifo, and the
child immediately exits, the parent may receive a SIGCHLD before its
open() returns. In that case, we need to make sure that open() will
return successfully after the SIGCHLD handler returns, instead of
throwing EINTR or being restarted. Otherwise, the restarted open()
would incorrectly wait for a second partner on the other end.
The following test demonstrates the EINTR that was wrongly thrown from
the parent’s open(). Change .sa_flags = 0 to .sa_flags = SA_RESTART
to see a deadlock instead, in which the restarted open() waits for a
second reader that will never come. (On my systems, this happens
pretty reliably within about 5 to 500 iterations. Others report that
it manages to loop ~forever sometimes; YMMV.)
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define CHECK(x) do if ((x) == -1) {perror(#x); abort();} while(0)
void handler(int signum) {}
int main()
{
struct sigaction act = {.sa_handler = handler, .sa_flags = 0};
CHECK(sigaction(SIGCHLD, &act, NULL));
CHECK(mknod("fifo", S_IFIFO | S_IRWXU, 0));
for (;;) {
int fd;
pid_t pid;
putc('.', stderr);
CHECK(pid = fork());
if (pid == 0) {
CHECK(fd = open("fifo", O_RDONLY));
_exit(0);
}
CHECK(fd = open("fifo", O_WRONLY));
CHECK(close(fd));
CHECK(waitpid(pid, NULL, 0));
}
}
This is what I suspect was causing the Git test suite to fail in
t9010-svn-fe.sh:
http://bugs.debian.org/678852
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-16 05:14:25 +08:00
|
|
|
static int wait_for_partner(struct inode* inode, unsigned int *cnt)
|
2005-04-17 06:20:36 +08:00
|
|
|
{
|
|
|
|
|
int cur = *cnt;
|
2006-04-10 21:18:35 +08:00
|
|
|
|
|
|
|
|
while (cur == *cnt) {
|
|
|
|
|
pipe_wait(inode->i_pipe);
|
|
|
|
|
if (signal_pending(current))
|
2005-04-17 06:20:36 +08:00
|
|
|
break;
|
|
|
|
|
}
|
fifo: Do not restart open() if it already found a partner
If a parent and child process open the two ends of a fifo, and the
child immediately exits, the parent may receive a SIGCHLD before its
open() returns. In that case, we need to make sure that open() will
return successfully after the SIGCHLD handler returns, instead of
throwing EINTR or being restarted. Otherwise, the restarted open()
would incorrectly wait for a second partner on the other end.
The following test demonstrates the EINTR that was wrongly thrown from
the parent’s open(). Change .sa_flags = 0 to .sa_flags = SA_RESTART
to see a deadlock instead, in which the restarted open() waits for a
second reader that will never come. (On my systems, this happens
pretty reliably within about 5 to 500 iterations. Others report that
it manages to loop ~forever sometimes; YMMV.)
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define CHECK(x) do if ((x) == -1) {perror(#x); abort();} while(0)
void handler(int signum) {}
int main()
{
struct sigaction act = {.sa_handler = handler, .sa_flags = 0};
CHECK(sigaction(SIGCHLD, &act, NULL));
CHECK(mknod("fifo", S_IFIFO | S_IRWXU, 0));
for (;;) {
int fd;
pid_t pid;
putc('.', stderr);
CHECK(pid = fork());
if (pid == 0) {
CHECK(fd = open("fifo", O_RDONLY));
_exit(0);
}
CHECK(fd = open("fifo", O_WRONLY));
CHECK(close(fd));
CHECK(waitpid(pid, NULL, 0));
}
}
This is what I suspect was causing the Git test suite to fail in
t9010-svn-fe.sh:
http://bugs.debian.org/678852
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-16 05:14:25 +08:00
|
|
|
return cur == *cnt ? -ERESTARTSYS : 0;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static void wake_up_partner(struct inode* inode)
|
|
|
|
|
{
|
2006-04-11 19:53:10 +08:00
|
|
|
wake_up_interruptible(&inode->i_pipe->wait);
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
|
|
|
|
|
static int fifo_open(struct inode *inode, struct file *filp)
|
|
|
|
|
{
|
2006-04-11 19:53:33 +08:00
|
|
|
struct pipe_inode_info *pipe;
|
2005-04-17 06:20:36 +08:00
|
|
|
int ret;
|
|
|
|
|
|
2006-04-11 19:53:10 +08:00
|
|
|
mutex_lock(&inode->i_mutex);
|
2006-04-11 19:53:33 +08:00
|
|
|
pipe = inode->i_pipe;
|
|
|
|
|
if (!pipe) {
|
2005-04-17 06:20:36 +08:00
|
|
|
ret = -ENOMEM;
|
2006-04-11 19:53:33 +08:00
|
|
|
pipe = alloc_pipe_info(inode);
|
|
|
|
|
if (!pipe)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_nocleanup;
|
2006-04-11 19:53:33 +08:00
|
|
|
inode->i_pipe = pipe;
|
2005-04-17 06:20:36 +08:00
|
|
|
}
|
|
|
|
|
filp->f_version = 0;
|
|
|
|
|
|
|
|
|
|
/* We can only do regular read/write on fifos */
|
|
|
|
|
filp->f_mode &= (FMODE_READ | FMODE_WRITE);
|
|
|
|
|
|
|
|
|
|
switch (filp->f_mode) {
|
2008-09-03 03:28:45 +08:00
|
|
|
case FMODE_READ:
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
|
* O_RDONLY
|
|
|
|
|
* POSIX.1 says that O_NONBLOCK means return with the FIFO
|
|
|
|
|
* opened, even when there is no process writing the FIFO.
|
|
|
|
|
*/
|
2008-07-01 20:16:09 +08:00
|
|
|
filp->f_op = &read_pipefifo_fops;
|
2006-04-11 19:53:33 +08:00
|
|
|
pipe->r_counter++;
|
|
|
|
|
if (pipe->readers++ == 0)
|
2005-04-17 06:20:36 +08:00
|
|
|
wake_up_partner(inode);
|
|
|
|
|
|
2006-04-11 19:53:33 +08:00
|
|
|
if (!pipe->writers) {
|
2005-04-17 06:20:36 +08:00
|
|
|
if ((filp->f_flags & O_NONBLOCK)) {
|
|
|
|
|
/* suppress POLLHUP until we have
|
|
|
|
|
* seen a writer */
|
2006-04-11 19:53:33 +08:00
|
|
|
filp->f_version = pipe->w_counter;
|
2011-02-23 23:51:05 +08:00
|
|
|
} else {
|
fifo: Do not restart open() if it already found a partner
If a parent and child process open the two ends of a fifo, and the
child immediately exits, the parent may receive a SIGCHLD before its
open() returns. In that case, we need to make sure that open() will
return successfully after the SIGCHLD handler returns, instead of
throwing EINTR or being restarted. Otherwise, the restarted open()
would incorrectly wait for a second partner on the other end.
The following test demonstrates the EINTR that was wrongly thrown from
the parent’s open(). Change .sa_flags = 0 to .sa_flags = SA_RESTART
to see a deadlock instead, in which the restarted open() waits for a
second reader that will never come. (On my systems, this happens
pretty reliably within about 5 to 500 iterations. Others report that
it manages to loop ~forever sometimes; YMMV.)
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define CHECK(x) do if ((x) == -1) {perror(#x); abort();} while(0)
void handler(int signum) {}
int main()
{
struct sigaction act = {.sa_handler = handler, .sa_flags = 0};
CHECK(sigaction(SIGCHLD, &act, NULL));
CHECK(mknod("fifo", S_IFIFO | S_IRWXU, 0));
for (;;) {
int fd;
pid_t pid;
putc('.', stderr);
CHECK(pid = fork());
if (pid == 0) {
CHECK(fd = open("fifo", O_RDONLY));
_exit(0);
}
CHECK(fd = open("fifo", O_WRONLY));
CHECK(close(fd));
CHECK(waitpid(pid, NULL, 0));
}
}
This is what I suspect was causing the Git test suite to fail in
t9010-svn-fe.sh:
http://bugs.debian.org/678852
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-16 05:14:25 +08:00
|
|
|
if (wait_for_partner(inode, &pipe->w_counter))
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_rd;
|
|
|
|
|
}
|
|
|
|
|
}
|
|
|
|
|
break;
|
|
|
|
|
|
2008-09-03 03:28:45 +08:00
|
|
|
case FMODE_WRITE:
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
|
* O_WRONLY
|
|
|
|
|
* POSIX.1 says that O_NONBLOCK means return -1 with
|
|
|
|
|
* errno=ENXIO when there is no process reading the FIFO.
|
|
|
|
|
*/
|
|
|
|
|
ret = -ENXIO;
|
2006-04-11 19:53:33 +08:00
|
|
|
if ((filp->f_flags & O_NONBLOCK) && !pipe->readers)
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err;
|
|
|
|
|
|
2008-07-01 20:16:09 +08:00
|
|
|
filp->f_op = &write_pipefifo_fops;
|
2006-04-11 19:53:33 +08:00
|
|
|
pipe->w_counter++;
|
|
|
|
|
if (!pipe->writers++)
|
2005-04-17 06:20:36 +08:00
|
|
|
wake_up_partner(inode);
|
|
|
|
|
|
2006-04-11 19:53:33 +08:00
|
|
|
if (!pipe->readers) {
|
fifo: Do not restart open() if it already found a partner
If a parent and child process open the two ends of a fifo, and the
child immediately exits, the parent may receive a SIGCHLD before its
open() returns. In that case, we need to make sure that open() will
return successfully after the SIGCHLD handler returns, instead of
throwing EINTR or being restarted. Otherwise, the restarted open()
would incorrectly wait for a second partner on the other end.
The following test demonstrates the EINTR that was wrongly thrown from
the parent’s open(). Change .sa_flags = 0 to .sa_flags = SA_RESTART
to see a deadlock instead, in which the restarted open() waits for a
second reader that will never come. (On my systems, this happens
pretty reliably within about 5 to 500 iterations. Others report that
it manages to loop ~forever sometimes; YMMV.)
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <fcntl.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define CHECK(x) do if ((x) == -1) {perror(#x); abort();} while(0)
void handler(int signum) {}
int main()
{
struct sigaction act = {.sa_handler = handler, .sa_flags = 0};
CHECK(sigaction(SIGCHLD, &act, NULL));
CHECK(mknod("fifo", S_IFIFO | S_IRWXU, 0));
for (;;) {
int fd;
pid_t pid;
putc('.', stderr);
CHECK(pid = fork());
if (pid == 0) {
CHECK(fd = open("fifo", O_RDONLY));
_exit(0);
}
CHECK(fd = open("fifo", O_WRONLY));
CHECK(close(fd));
CHECK(waitpid(pid, NULL, 0));
}
}
This is what I suspect was causing the Git test suite to fail in
t9010-svn-fe.sh:
http://bugs.debian.org/678852
Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2012-07-16 05:14:25 +08:00
|
|
|
if (wait_for_partner(inode, &pipe->r_counter))
|
2005-04-17 06:20:36 +08:00
|
|
|
goto err_wr;
|
|
|
|
|
}
|
|
|
|
|
break;
|
|
|
|
|
|
2008-09-03 03:28:45 +08:00
|
|
|
case FMODE_READ | FMODE_WRITE:
|
2005-04-17 06:20:36 +08:00
|
|
|
/*
|
|
|
|
|
* O_RDWR
|
|
|
|
|
* POSIX.1 leaves this case "undefined" when O_NONBLOCK is set.
|
|
|
|
|
* This implementation will NEVER block on a O_RDWR open, since
|
|
|
|
|
* the process can at least talk to itself.
|
|
|
|
|
*/
|
2008-07-01 20:16:09 +08:00
|
|
|
filp->f_op = &rdwr_pipefifo_fops;
|
2005-04-17 06:20:36 +08:00
|
|
|
|
2006-04-11 19:53:33 +08:00
|
|
|
pipe->readers++;
|
|
|
|
|
pipe->writers++;
|
|
|
|
|
pipe->r_counter++;
|
|
|
|
|
pipe->w_counter++;
|
|
|
|
|
if (pipe->readers == 1 || pipe->writers == 1)
|
2005-04-17 06:20:36 +08:00
|
|
|
wake_up_partner(inode);
|
|
|
|
|
break;
|
|
|
|
|
|
|
|
|
|
default:
|
|
|
|
|
ret = -EINVAL;
|
|
|
|
|
goto err;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/* Ok! */
|
2006-04-11 19:53:10 +08:00
|
|
|
mutex_unlock(&inode->i_mutex);
|
2005-04-17 06:20:36 +08:00
|
|
|
return 0;
|
|
|
|
|
|
|
|
|
|
err_rd:
|
2006-04-11 19:53:33 +08:00
|
|
|
if (!--pipe->readers)
|
|
|
|
|
wake_up_interruptible(&pipe->wait);
|
2005-04-17 06:20:36 +08:00
|
|
|
ret = -ERESTARTSYS;
|
|
|
|
|
goto err;
|
|
|
|
|
|
|
|
|
|
err_wr:
|
2006-04-11 19:53:33 +08:00
|
|
|
if (!--pipe->writers)
|
|
|
|
|
wake_up_interruptible(&pipe->wait);
|
2005-04-17 06:20:36 +08:00
|
|
|
ret = -ERESTARTSYS;
|
|
|
|
|
goto err;
|
|
|
|
|
|
|
|
|
|
err:
|
2006-04-11 19:53:33 +08:00
|
|
|
if (!pipe->readers && !pipe->writers)
|
2005-04-17 06:20:36 +08:00
|
|
|
free_pipe_info(inode);
|
|
|
|
|
|
|
|
|
|
err_nocleanup:
|
2006-04-11 19:53:10 +08:00
|
|
|
mutex_unlock(&inode->i_mutex);
|
2005-04-17 06:20:36 +08:00
|
|
|
return ret;
|
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
/*
|
|
|
|
|
* Dummy default file-operations: the only thing this does
|
|
|
|
|
* is contain the open that then fills in the correct operations
|
|
|
|
|
* depending on the access mode of the file...
|
|
|
|
|
*/
|
2006-03-28 17:56:42 +08:00
|
|
|
const struct file_operations def_fifo_fops = {
|
2008-07-01 20:16:09 +08:00
|
|
|
.open = fifo_open, /* will set read_ or write_pipefifo_fops */
|
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>
2010-08-16 00:52:59 +08:00
|
|
|
.llseek = noop_llseek,
|
2005-04-17 06:20:36 +08:00
|
|
|
};
|
