[patch 03/13] syslets: generic kernel bits

[Ingo Molnar <mingo@elte.hu>]

From: Ingo Molnar <mingo@elte.hu>

add the kernel generic bits - these are present even if !CONFIG_ASYNC_SUPPORT.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
 fs/exec.c             |    4 ++++
 include/linux/sched.h |   23 ++++++++++++++++++++++-
 kernel/capability.c   |    3 +++
 kernel/exit.c         |    7 +++++++
 kernel/fork.c         |    5 +++++
 kernel/sched.c        |    9 +++++++++
 kernel/sys.c          |   36 ++++++++++++++++++++++++++++++++++++
 7 files changed, 86 insertions(+), 1 deletion(-)

Index: linux/fs/exec.c
===================================================================
--- linux.orig/fs/exec.c
+++ linux/fs/exec.c
@@ -1446,6 +1446,10 @@ static int coredump_wait(int exit_code)
 		tsk->vfork_done = NULL;
 		complete(vfork_done);
 	}
+	/*
+	 * Make sure we exit our async context before waiting:
+	 */
+	async_exit(tsk);
 
 	if (core_waiters)
 		wait_for_completion(&startup_done);
Index: linux/include/linux/sched.h
===================================================================
--- linux.orig/include/linux/sched.h
+++ linux/include/linux/sched.h
@@ -83,12 +83,12 @@ struct sched_param {
 #include <linux/timer.h>
 #include <linux/hrtimer.h>
 #include <linux/task_io_accounting.h>
+#include <linux/async.h>
 
 #include <asm/processor.h>
 
 struct exec_domain;
 struct futex_pi_state;
-
 /*
  * List of flags we want to share for kernel threads,
  * if only because they are not used by them anyway.
@@ -997,6 +997,12 @@ struct task_struct {
 /* journalling filesystem info */
 	void *journal_info;
 
+/* async syscall support: */
+	struct async_thread *at, *async_ready;
+	struct async_head *ah;
+	struct async_thread __at;
+	struct async_head __ah;
+
 /* VM state */
 	struct reclaim_state *reclaim_state;
 
@@ -1053,6 +1059,21 @@ struct task_struct {
 #endif
 };
 
+/*
+ * Is an async syscall being executed currently?
+ */
+#ifdef CONFIG_ASYNC_SUPPORT
+static inline int async_syscall(struct task_struct *t)
+{
+	return t->async_ready != NULL;
+}
+#else /* !CONFIG_ASYNC_SUPPORT */
+static inline int async_syscall(struct task_struct *t)
+{
+	return 0;
+}
+#endif /* !CONFIG_ASYNC_SUPPORT */
+
 static inline pid_t process_group(struct task_struct *tsk)
 {
 	return tsk->signal->pgrp;
Index: linux/kernel/capability.c
===================================================================
--- linux.orig/kernel/capability.c
+++ linux/kernel/capability.c
@@ -176,6 +176,9 @@ asmlinkage long sys_capset(cap_user_head
      int ret;
      pid_t pid;
 
+     if (async_syscall(current))
+             return -ENOSYS;
+
      if (get_user(version, &header->version))
 	     return -EFAULT; 
 
Index: linux/kernel/exit.c
===================================================================
--- linux.orig/kernel/exit.c
+++ linux/kernel/exit.c
@@ -26,6 +26,7 @@
 #include <linux/ptrace.h>
 #include <linux/profile.h>
 #include <linux/mount.h>
+#include <linux/async.h>
 #include <linux/proc_fs.h>
 #include <linux/mempolicy.h>
 #include <linux/taskstats_kern.h>
@@ -889,6 +890,12 @@ fastcall NORET_TYPE void do_exit(long co
 		schedule();
 	}
 
+	/*
+	 * Note: async threads have to exit their context before the MM
+	 * exit (due to the coredumping wait):
+	 */
+	async_exit(tsk);
+
 	tsk->flags |= PF_EXITING;
 
 	if (unlikely(in_atomic()))
Index: linux/kernel/fork.c
===================================================================
--- linux.orig/kernel/fork.c
+++ linux/kernel/fork.c
@@ -22,6 +22,7 @@
 #include <linux/personality.h>
 #include <linux/mempolicy.h>
 #include <linux/sem.h>
+#include <linux/async.h>
 #include <linux/file.h>
 #include <linux/key.h>
 #include <linux/binfmts.h>
@@ -1054,6 +1055,7 @@ static struct task_struct *copy_process(
 
 	p->lock_depth = -1;		/* -1 = no lock */
 	do_posix_clock_monotonic_gettime(&p->start_time);
+	async_init(p);
 	p->security = NULL;
 	p->io_context = NULL;
 	p->io_wait = NULL;
@@ -1621,6 +1623,9 @@ asmlinkage long sys_unshare(unsigned lon
 	struct uts_namespace *uts, *new_uts = NULL;
 	struct ipc_namespace *ipc, *new_ipc = NULL;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	check_unshare_flags(&unshare_flags);
 
 	/* Return -EINVAL for all unsupported flags */
Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -38,6 +38,7 @@
 #include <linux/vmalloc.h>
 #include <linux/blkdev.h>
 #include <linux/delay.h>
+#include <linux/async.h>
 #include <linux/smp.h>
 #include <linux/threads.h>
 #include <linux/timer.h>
@@ -3436,6 +3437,14 @@ asmlinkage void __sched schedule(void)
 	}
 	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
 
+	prev = current;
+	if (unlikely(prev->async_ready)) {
+		if (prev->state && !(preempt_count() & PREEMPT_ACTIVE) &&
+			(!(prev->state & TASK_INTERRUPTIBLE) ||
+				!signal_pending(prev)))
+			__async_schedule(prev);
+	}
+
 need_resched:
 	preempt_disable();
 	prev = current;
Index: linux/kernel/sys.c
===================================================================
--- linux.orig/kernel/sys.c
+++ linux/kernel/sys.c
@@ -933,6 +933,9 @@ asmlinkage long sys_setregid(gid_t rgid,
 	int new_egid = old_egid;
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	retval = security_task_setgid(rgid, egid, (gid_t)-1, LSM_SETID_RE);
 	if (retval)
 		return retval;
@@ -979,6 +982,9 @@ asmlinkage long sys_setgid(gid_t gid)
 	int old_egid = current->egid;
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	retval = security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_ID);
 	if (retval)
 		return retval;
@@ -1049,6 +1055,9 @@ asmlinkage long sys_setreuid(uid_t ruid,
 	int old_ruid, old_euid, old_suid, new_ruid, new_euid;
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	retval = security_task_setuid(ruid, euid, (uid_t)-1, LSM_SETID_RE);
 	if (retval)
 		return retval;
@@ -1112,6 +1121,9 @@ asmlinkage long sys_setuid(uid_t uid)
 	int old_ruid, old_suid, new_suid;
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	retval = security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_ID);
 	if (retval)
 		return retval;
@@ -1152,6 +1164,9 @@ asmlinkage long sys_setresuid(uid_t ruid
 	int old_suid = current->suid;
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	retval = security_task_setuid(ruid, euid, suid, LSM_SETID_RES);
 	if (retval)
 		return retval;
@@ -1206,6 +1221,9 @@ asmlinkage long sys_setresgid(gid_t rgid
 {
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	retval = security_task_setgid(rgid, egid, sgid, LSM_SETID_RES);
 	if (retval)
 		return retval;
@@ -1261,6 +1279,9 @@ asmlinkage long sys_setfsuid(uid_t uid)
 {
 	int old_fsuid;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	old_fsuid = current->fsuid;
 	if (security_task_setuid(uid, (uid_t)-1, (uid_t)-1, LSM_SETID_FS))
 		return old_fsuid;
@@ -1290,6 +1311,9 @@ asmlinkage long sys_setfsgid(gid_t gid)
 {
 	int old_fsgid;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	old_fsgid = current->fsgid;
 	if (security_task_setgid(gid, (gid_t)-1, (gid_t)-1, LSM_SETID_FS))
 		return old_fsgid;
@@ -1365,6 +1389,9 @@ asmlinkage long sys_setpgid(pid_t pid, p
 	struct task_struct *group_leader = current->group_leader;
 	int err = -EINVAL;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	if (!pid)
 		pid = group_leader->pid;
 	if (!pgid)
@@ -1488,6 +1515,9 @@ asmlinkage long sys_setsid(void)
 	pid_t session;
 	int err = -EPERM;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	write_lock_irq(&tasklist_lock);
 
 	/* Fail if I am already a session leader */
@@ -1732,6 +1762,9 @@ asmlinkage long sys_setgroups(int gidset
 	struct group_info *group_info;
 	int retval;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	if (!capable(CAP_SETGID))
 		return -EPERM;
 	if ((unsigned)gidsetsize > NGROUPS_MAX)
@@ -2073,6 +2106,9 @@ asmlinkage long sys_prctl(int option, un
 {
 	long error;
 
+	if (async_syscall(current))
+		return -ENOSYS;
+
 	error = security_task_prctl(option, arg2, arg3, arg4, arg5);
 	if (error)
 		return error;
-
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