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Subject[RFC PATCH 5/X] ptrace: mv task_struct->ptrace ptrace_task->pt_flags, kill ptrace_link()
Move task_struct->ptrace into ptrace_task->pt_flags and change the users
accordingly.

Also, kill ptrace_link(). The only caller is ptrace_init_task(), and with
the recent changes we can check "is it traced" earlier, because ->pt_flags
was already initialized by alloc_ptrace_task().

include/linux/sched.h | 1 -
include/linux/ptrace.h | 21 ++++++---------------
kernel/ptrace.c | 16 ++++++++--------
3 files changed, 14 insertions(+), 24 deletions(-)
--- PTRACE/include/linux/sched.h~5_MV_FLAGS 2009-05-24 22:14:41.000000000 +0200
+++ PTRACE/include/linux/sched.h 2009-05-24 23:10:47.000000000 +0200
@@ -1119,7 +1119,6 @@ struct task_struct {
void *stack;
atomic_t usage;
unsigned int flags; /* per process flags, defined below */
- unsigned int ptrace;

int lock_depth; /* BKL lock depth */

--- PTRACE/include/linux/ptrace.h~5_MV_FLAGS 2009-05-24 22:15:08.000000000 +0200
+++ PTRACE/include/linux/ptrace.h 2009-05-24 22:37:50.000000000 +0200
@@ -51,10 +51,6 @@
#ifdef __KERNEL__
/*
* Ptrace flags
- *
- * The owner ship rules for task->ptrace which holds the ptrace
- * flags is simple. When a task is running it owns it's task->ptrace
- * flags. When the a task is stopped the ptracer owns task->ptrace.
*/

#define PT_PTRACED 0x00000001
@@ -80,6 +76,7 @@
#include <linux/sched.h> /* For struct task_struct. */

struct ptrace_task {
+ unsigned long pt_flags;
};

extern int alloc_ptrace_task(struct task_struct *child);
@@ -119,15 +116,10 @@ static inline int ptrace_reparented(stru
*/
static inline int task_ptrace(struct task_struct *task)
{
- return task->ptrace;
+ return unlikely(task->ptrace_task) ?
+ task->ptrace_task->pt_flags : 0;
}

-static inline void ptrace_link(struct task_struct *child,
- struct task_struct *new_parent)
-{
- if (unlikely(task_ptrace(child)))
- __ptrace_link(child, new_parent);
-}
static inline void ptrace_unlink(struct task_struct *child)
{
if (unlikely(task_ptrace(child)))
@@ -173,10 +165,9 @@ static inline void ptrace_init_task(stru
INIT_LIST_HEAD(&child->ptrace_entry);
INIT_LIST_HEAD(&child->ptraced);
child->parent = child->real_parent;
- child->ptrace = 0;
- if (unlikely(child->ptrace_task)) {
- child->ptrace = current->ptrace;
- ptrace_link(child, current->parent);
+ if (unlikely(child->ptrace_task) && task_ptrace(current)) {
+ child->ptrace_task->pt_flags = task_ptrace(current);
+ __ptrace_link(child, current->parent);
}
}

--- PTRACE/kernel/ptrace.c~5_MV_FLAGS 2009-05-24 22:14:41.000000000 +0200
+++ PTRACE/kernel/ptrace.c 2009-05-24 23:09:13.000000000 +0200
@@ -81,7 +81,7 @@ void __ptrace_unlink(struct task_struct
{
BUG_ON(!task_ptrace(child));

- child->ptrace = 0;
+ child->ptrace_task->pt_flags = 0;
child->parent = child->real_parent;
list_del_init(&child->ptrace_entry);

@@ -227,9 +227,9 @@ int ptrace_attach(struct task_struct *ta
if (task_ptrace(task))
goto unlock_tasklist;

- task->ptrace = PT_PTRACED;
+ task->ptrace_task->pt_flags = PT_PTRACED;
if (capable(CAP_SYS_PTRACE))
- task->ptrace |= PT_PTRACE_CAP;
+ task->ptrace_task->pt_flags |= PT_PTRACE_CAP;

__ptrace_link(task, current);
send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
@@ -267,7 +267,7 @@ int ptrace_traceme(void)
* pretend ->real_parent untraces us right after return.
*/
if (!ret && !(current->real_parent->flags & PF_EXITING)) {
- current->ptrace = PT_PTRACED;
+ current->ptrace_task->pt_flags = PT_PTRACED;
__ptrace_link(current, current->real_parent);
}
}
@@ -425,7 +425,7 @@ int ptrace_writedata(struct task_struct
return copied;
}

-static int ptrace_setoptions(struct task_struct *child, long data)
+static int ptrace_setoptions(struct ptrace_task *ptrace_task, long data)
{
unsigned int new_flags = 0;

@@ -450,8 +450,8 @@ static int ptrace_setoptions(struct task
if (data & PTRACE_O_TRACEEXIT)
new_flags |= PT_TRACE_EXIT;

- child->ptrace &= ~PT_TRACE_MASK;
- child->ptrace |= new_flags;
+ ptrace_task->pt_flags &= ~PT_TRACE_MASK;
+ ptrace_task->pt_flags |= new_flags;
return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
}

@@ -563,7 +563,7 @@ int ptrace_request(struct task_struct *c
case PTRACE_OLDSETOPTIONS:
#endif
case PTRACE_SETOPTIONS:
- ret = ptrace_setoptions(child, data);
+ ret = ptrace_setoptions(child->ptrace_task, data);
break;
case PTRACE_GETEVENTMSG:
ret = put_user(child->ptrace_message, (unsigned long __user *) data);


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