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path: root/kernel/mutex.c

Age	Commit message (Expand)	Author
2011-05-25	lockdep, mutex: provide mutex_lock_nest_lock	Peter Zijlstra
2011-04-24	sched: Get rid of lock_depth	Jonathan Corbet
2011-04-14	mutex: Use p->on_cpu for the adaptive spin	Peter Zijlstra
2011-03-31	Fix common misspellings	Lucas De Marchi
2010-11-26	mutexes, sched: Introduce arch_mutex_cpu_relax()	Gerald Schaefer
2010-09-03	mutex: Fix annotations to include it in kernel-locking docbook	Randy Dunlap
2010-05-19	mutex: Fix optimistic spinning vs. BKL	Tony Breeds
2009-12-03	mutex: Better control mutex adaptive spinning config	Frederic Weisbecker
2009-06-11	Merge branch 'linus' into perfcounters/core	Ingo Molnar
2009-06-10	Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...	Linus Torvalds
2009-05-11	Merge commit 'v2.6.30-rc5' into sched/core	Ingo Molnar
2009-05-06	Merge branch 'core/locking' into perfcounters/core	Ingo Molnar
2009-04-30	mutex: add atomic_dec_and_mutex_lock(), fix	Andrew Morton
2009-04-29	Merge branch 'linus' into perfcounters/core	Ingo Molnar
2009-04-20	sched: remove extra call overhead for schedule()	Peter Zijlstra
2009-04-09	mutex: have non-spinning mutexes on s390 by default	Heiko Carstens
2009-04-06	mutex: drop "inline" from mutex_lock() inside kernel/mutex.c	H. Peter Anvin
2009-01-14	mutex: adaptive spinnning, performance tweaks	Chris Mason
2009-01-14	mutex: implement adaptive spinning	Peter Zijlstra
2009-01-14	mutex: preemption fixes	Peter Zijlstra
2009-01-14	mutex: small cleanup	Peter Zijlstra
2008-11-24	mutex: __used is needed for function referenced only from inline asm	Török Edwin
2008-10-20	lockstat: contend with points	Peter Zijlstra
2008-07-28	locking: fix mutex @key parameter kernel-doc notation	Randy Dunlap
2008-06-10	__mutex_lock_common: use signal_pending_state()	Oleg Nesterov
2008-02-08	kernel: remove fastcall in kernel/*	Harvey Harrison
2007-12-06	Add mutex_lock_killable	Liam R. Howlett
2007-10-11	lockdep: fixup mutex annotations	Peter Zijlstra
2007-07-19	lockstat: measure lock bouncing	Peter Zijlstra
2007-07-19	lockstat: hook into spinlock_t, rwlock_t, rwsem and mutex	Peter Zijlstra
2007-05-09	wrap access to thread_info	Roman Zippel
2006-12-08	[PATCH] lockdep: avoid lockdep warning in md	NeilBrown
2006-07-03	[PATCH] lockdep: prove mutex locking correctness	Ingo Molnar
2006-07-03	[PATCH] lockdep: mutex section binutils workaround	Ingo Molnar
2006-07-03	[PATCH] lockdep: better lock debugging	Ingo Molnar
2006-07-03	[PATCH] lockdep: rename DEBUG_WARN_ON()	Ingo Molnar
2006-06-26	[PATCH] work around ppc64 bootup bug by making mutex-debugging save/restore irqs	Ingo Molnar
2006-01-10	[PATCH] mutex: trivial whitespace cleanups	Ingo Molnar
2006-01-10	[PATCH] mark mutex_lock*() as might_sleep()	Ingo Molnar
2006-01-10	[PATCH] fix i386 mutex fastpath on FRAME_POINTER && !DEBUG_MUTEXES	Ingo Molnar
2006-01-09	[PATCH] mutex subsystem, core	Ingo Molnar

generated by cgit v1.2.3 (git 2.25.1) at 2024-09-02 20:44:52 +0000

/*
 *  linux/fs/read_write.c
 *
 *  Copyright (C) 1991, 1992  Linus Torvalds
 */

#include <linux/slab.h> 
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/file.h>
#include <linux/uio.h>
#include <linux/fsnotify.h>
#include <linux/security.h>
#include <linux/module.h>
#include <linux/syscalls.h>
#include <linux/pagemap.h>
#include <linux/splice.h>
#include "read_write.h"

#include <asm/uaccess.h>
#include <asm/unistd.h>

const struct file_operations generic_ro_fops = {
	.llseek		= generic_file_llseek,
	.read		= do_sync_read,
	.aio_read	= generic_file_aio_read,
	.mmap		= generic_file_readonly_mmap,
	.splice_read	= generic_file_splice_read,
};

EXPORT_SYMBOL(generic_ro_fops);

static inline int unsigned_offsets(struct file *file)
{
	return file->f_mode & FMODE_UNSIGNED_OFFSET;
}

/**
 * generic_file_llseek_unlocked - lockless generic llseek implementation
 * @file:	file structure to seek on
 * @offset:	file offset to seek to
 * @origin:	type of seek
 *
 * Updates the file offset to the value specified by @offset and @origin.
 * Locking must be provided by the caller.
 */
loff_t
generic_file_llseek_unlocked(struct file *file, loff_t offset, int origin)
{
	struct inode *inode = file->f_mapping->host;

	switch (origin) {
	case SEEK_END:
		offset += inode->i_size;
		break;
	case SEEK_CUR:
		/*
		 * Here we special-case the lseek(fd, 0, SEEK_CUR)
		 * position-querying operation.  Avoid rewriting the "same"
		 * f_pos value back to the file because a concurrent read(),
		 * write() or lseek() might have altered it
		 */
		if (offset == 0)
			return file->f_pos;
		offset += file->f_pos;
		break;
	}

	if (offset < 0 && !unsigned_offsets(file))
		return -EINVAL;
	if (offset > inode->i_sb->s_maxbytes)
		return -EINVAL;

	/* Special lock needed here? */
	if (offset != file->f_pos) {
		file->f_pos = offset;
		file->f_version = 0;
	}

	return offset;
}
EXPORT_SYMBOL(generic_file_llseek_unlocked);

/**
 * generic_file_llseek - generic llseek implementation for regular files
 * @file:	file structure to seek on
 * @offset:	file offset to seek to
 * @origin:	type of seek
 *
 * This is a generic implemenation of ->llseek useable for all normal local
 * filesystems.  It just updates the file offset to the value specified by
 * @offset and @origin under i_mutex.
 */
loff_t generic_file_llseek(struct file *file, loff_t offset, int origin)
{
	loff_t rval;

	mutex_lock(&file->f_dentry->d_inode->i_mutex);
	rval = generic_file_llseek_unlocked(file, offset, origin);
	mutex_unlock(&file->f_dentry->d_inode->i_mutex);

	return rval;
}
EXPORT_SYMBOL(generic_file_llseek);

/**
 * noop_llseek - No Operation Performed llseek implementation
 * @file:	file structure to seek on
 * @offset:	file offset to seek to
 * @origin:	type of seek
 *
 * This is an implementation of ->llseek useable for the rare special case when
 * userspace expects the seek to succeed but the (device) file is actually not
 * able to perform the seek. In this case you use noop_llseek() instead of
 * falling back to the default implementation of ->llseek.
 */
loff_t noop_llseek(struct file *file, loff_t offset, int origin)
{
	return file->f_pos;
}
EXPORT_SYMBOL(noop_llseek);

loff_t no_llseek(struct file *file, loff_t offset, int origin)
{
	return -ESPIPE;
}
EXPORT_SYMBOL(no_llseek);

loff_t default_llseek(struct file *file, loff_t offset, int origin)
{
	loff_t retval;

	mutex_lock(&file->f_dentry->d_inode->i_mutex);
	switch (origin) {
		case SEEK_END:
			offset += i_size_read(file->f_path.dentry->d_inode);
			break;
		case SEEK_CUR:
			if (offset == 0) {
				retval = file->f_pos;
				goto out;
			}
			offset += file->f_pos;
	}
	retval = -EINVAL;
	if (offset >= 0 || unsigned_offsets(file)) {
		if (offset != file->f_pos) {
			file->f_pos = offset;
			file->f_version = 0;
		}
		retval = offset;
	}
out:
	mutex_unlock(&file->f_dentry->d_inode->i_mutex);
	return retval;
}
EXPORT_SYMBOL(default_llseek);

loff_t vfs_llseek(struct file *file, loff_t offset, int origin)
{
	loff_t (*fn)(struct file *, loff_t, int);

	fn = no_llseek;
	if (file->f_mode & FMODE_LSEEK) {
		if (file->f_op && file->f_op->llseek)
			fn = file->f_op->llseek;
	}
	return fn(file, offset, origin);
}
EXPORT_SYMBOL(vfs_llseek);

SYSCALL_DEFINE3(lseek, unsigned int, fd, off_t, offset, unsigned int, origin)
{
	off_t retval;
	struct file * file;
	int fput_needed;

	retval = -EBADF;
	file = fget_light(fd, &am