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Subject[PATCH 33/37] binder: use inner lock to protect thread accounting
Date
Use the inner lock to protect thread accounting fields in
proc structure: max_threads, requested_threads,
requested_threads_started and ready_threads.

Signed-off-by: Todd Kjos <tkjos@google.com>
---
drivers/android/binder.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 9d18ca1f7dcc..704540ea3e12 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -498,11 +498,15 @@ enum binder_deferred_state {
* @delivered_death: list of delivered death notification
* (protected by @inner_lock)
* @max_threads: cap on number of binder threads
+ * (protected by @inner_lock)
* @requested_threads: number of binder threads requested but not
* yet started. In current implementation, can
* only be 0 or 1.
+ * (protected by @inner_lock)
* @requested_threads_started: number binder threads started
+ * (protected by @inner_lock)
* @ready_threads: number of threads waiting for proc work
+ * (protected by @inner_lock)
* @tmp_ref: temporary reference to indicate proc is in use
* (protected by @inner_lock)
* @default_priority: default scheduler priority
@@ -3234,6 +3238,7 @@ static int binder_thread_write(struct binder_proc *proc,
binder_debug(BINDER_DEBUG_THREADS,
"%d:%d BC_REGISTER_LOOPER\n",
proc->pid, thread->pid);
+ binder_inner_proc_lock(proc);
if (thread->looper & BINDER_LOOPER_STATE_ENTERED) {
thread->looper |= BINDER_LOOPER_STATE_INVALID;
binder_user_error("%d:%d ERROR: BC_REGISTER_LOOPER called after BC_ENTER_LOOPER\n",
@@ -3247,6 +3252,7 @@ static int binder_thread_write(struct binder_proc *proc,
proc->requested_threads_started++;
}
thread->looper |= BINDER_LOOPER_STATE_REGISTERED;
+ binder_inner_proc_unlock(proc);
break;
case BC_ENTER_LOOPER:
binder_debug(BINDER_DEBUG_THREADS,
@@ -3523,11 +3529,11 @@ static int binder_thread_read(struct binder_proc *proc,
binder_inner_proc_lock(proc);
wait_for_proc_work = thread->transaction_stack == NULL &&
binder_worklist_empty_ilocked(&thread->todo);
+ if (wait_for_proc_work)
+ proc->ready_threads++;
binder_inner_proc_unlock(proc);

thread->looper |= BINDER_LOOPER_STATE_WAITING;
- if (wait_for_proc_work)
- proc->ready_threads++;

binder_unlock(__func__);

@@ -3558,8 +3564,10 @@ static int binder_thread_read(struct binder_proc *proc,

binder_lock(__func__);

+ binder_inner_proc_lock(proc);
if (wait_for_proc_work)
proc->ready_threads--;
+ binder_inner_proc_unlock(proc);
thread->looper &= ~BINDER_LOOPER_STATE_WAITING;

if (ret)
@@ -3849,19 +3857,22 @@ static int binder_thread_read(struct binder_proc *proc,
done:

*consumed = ptr - buffer;
+ binder_inner_proc_lock(proc);
if (proc->requested_threads + proc->ready_threads == 0 &&
proc->requested_threads_started < proc->max_threads &&
(thread->looper & (BINDER_LOOPER_STATE_REGISTERED |
BINDER_LOOPER_STATE_ENTERED)) /* the user-space code fails to */
/*spawn a new thread if we leave this out */) {
proc->requested_threads++;
+ binder_inner_proc_unlock(proc);
binder_debug(BINDER_DEBUG_THREADS,
"%d:%d BR_SPAWN_LOOPER\n",
proc->pid, thread->pid);
if (put_user(BR_SPAWN_LOOPER, (uint32_t __user *)buffer))
return -EFAULT;
binder_stat_br(proc, thread, BR_SPAWN_LOOPER);
- }
+ } else
+ binder_inner_proc_unlock(proc);
return 0;
}

@@ -4241,12 +4252,19 @@ static long binder_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
if (ret)
goto err;
break;
- case BINDER_SET_MAX_THREADS:
- if (copy_from_user(&proc->max_threads, ubuf, sizeof(proc->max_threads))) {
+ case BINDER_SET_MAX_THREADS: {
+ int max_threads;
+
+ if (copy_from_user(&max_threads, ubuf,
+ sizeof(max_threads))) {
ret = -EINVAL;
goto err;
}
+ binder_inner_proc_lock(proc);
+ proc->max_threads = max_threads;
+ binder_inner_proc_unlock(proc);
break;
+ }
case BINDER_SET_CONTEXT_MGR:
ret = binder_ioctl_set_ctx_mgr(filp);
if (ret)
--
2.13.2.725.g09c95d1e9-goog
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