* [PATCH v3 0/1] binder: return pending info for frozen async txns
@ 2022-11-23 20:16 Li Li
2022-11-23 20:16 ` [PATCH v3 1/1] " Li Li
0 siblings, 1 reply; 3+ messages in thread
From: Li Li @ 2022-11-23 20:16 UTC (permalink / raw)
To: dualli, gregkh, arve, tkjos, maco, joel, brauner, cmllamas,
surenb, arnd, masahiroy, devel, linux-kernel, hridya, smoreland
Cc: kernel-team
From: Li Li <dualli@google.com>
User applications need to know if their binder transactions reach a
frozen process or not. For sync binder calls, Linux kernel already
has a dedicated return value BR_FROZEN_REPLY, indicating this sync
binder transaction will be rejected (similar to BR_DEAD_REPLY) as the
target process is frozen. But for async binder calls, the user space
application doesn't have a way to know if the target process is frozen.
This patch adds a new return value, BR_TRANSACTION_PENDING_FROZEN, to
fix this issue. Similar to BR_TRANSACTION_COMPLETE, it means the async
binder transaction has been put in the queue of the target process, but
it's waiting for the target process to be unfrozen.
v1: checkpatch.pl --strict passed
v2: protect proc->is_frozen with lock, fix typo in comments
v3: rename BR_TRANSACTION_PENDING to BR_TRANSACTION_PENDING_FROZEN to
signify the frozen scenario and avoid potential confusion
Li Li (1):
binder: return pending info for frozen async txns
drivers/android/binder.c | 32 +++++++++++++++++++++++------
drivers/android/binder_internal.h | 3 ++-
include/uapi/linux/android/binder.h | 7 ++++++-
3 files changed, 34 insertions(+), 8 deletions(-)
--
2.38.1.584.g0f3c55d4c2-goog
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH v3 1/1] binder: return pending info for frozen async txns
2022-11-23 20:16 [PATCH v3 0/1] binder: return pending info for frozen async txns Li Li
@ 2022-11-23 20:16 ` Li Li
2022-11-24 2:25 ` Carlos Llamas
0 siblings, 1 reply; 3+ messages in thread
From: Li Li @ 2022-11-23 20:16 UTC (permalink / raw)
To: dualli, gregkh, arve, tkjos, maco, joel, brauner, cmllamas,
surenb, arnd, masahiroy, devel, linux-kernel, hridya, smoreland
Cc: kernel-team
From: Li Li <dualli@google.com>
An async transaction to a frozen process will still be successfully
put in the queue. But this pending async transaction won't be processed
until the target process is unfrozen at an unspecified time in the
future. Pass this important information back to the user space caller
by returning BR_TRANSACTION_PENDING_FROZEN.
Signed-off-by: Li Li <dualli@google.com>
---
drivers/android/binder.c | 32 +++++++++++++++++++++++------
drivers/android/binder_internal.h | 3 ++-
include/uapi/linux/android/binder.h | 7 ++++++-
3 files changed, 34 insertions(+), 8 deletions(-)
diff --git a/drivers/android/binder.c b/drivers/android/binder.c
index 880224ec6abb..acd53147d5d1 100644
--- a/drivers/android/binder.c
+++ b/drivers/android/binder.c
@@ -2728,7 +2728,10 @@ binder_find_outdated_transaction_ilocked(struct binder_transaction *t,
*
* Return: 0 if the transaction was successfully queued
* BR_DEAD_REPLY if the target process or thread is dead
- * BR_FROZEN_REPLY if the target process or thread is frozen
+ * BR_FROZEN_REPLY if the target process or thread is frozen and
+ * the sync transaction was rejected
+ * BR_TRANSACTION_PENDING_FROZEN if the target process is frozen
+ * and the async transaction was successfully queued
*/
static int binder_proc_transaction(struct binder_transaction *t,
struct binder_proc *proc,
@@ -2738,6 +2741,7 @@ static int binder_proc_transaction(struct binder_transaction *t,
bool oneway = !!(t->flags & TF_ONE_WAY);
bool pending_async = false;
struct binder_transaction *t_outdated = NULL;
+ bool frozen = false;
BUG_ON(!node);
binder_node_lock(node);
@@ -2751,15 +2755,16 @@ static int binder_proc_transaction(struct binder_transaction *t,
binder_inner_proc_lock(proc);
if (proc->is_frozen) {
+ frozen = true;
proc->sync_recv |= !oneway;
proc->async_recv |= oneway;
}
- if ((proc->is_frozen && !oneway) || proc->is_dead ||
+ if ((frozen && !oneway) || proc->is_dead ||
(thread && thread->is_dead)) {
binder_inner_proc_unlock(proc);
binder_node_unlock(node);
- return proc->is_frozen ? BR_FROZEN_REPLY : BR_DEAD_REPLY;
+ return frozen ? BR_FROZEN_REPLY : BR_DEAD_REPLY;
}
if (!thread && !pending_async)
@@ -2770,7 +2775,7 @@ static int binder_proc_transaction(struct binder_transaction *t,
} else if (!pending_async) {
binder_enqueue_work_ilocked(&t->work, &proc->todo);
} else {
- if ((t->flags & TF_UPDATE_TXN) && proc->is_frozen) {
+ if ((t->flags & TF_UPDATE_TXN) && frozen) {
t_outdated = binder_find_outdated_transaction_ilocked(t,
&node->async_todo);
if (t_outdated) {
@@ -2807,6 +2812,9 @@ static int binder_proc_transaction(struct binder_transaction *t,
binder_stats_deleted(BINDER_STAT_TRANSACTION);
}
+ if (oneway && frozen)
+ return BR_TRANSACTION_PENDING_FROZEN;
+
return 0;
}
@@ -3607,9 +3615,17 @@ static void binder_transaction(struct binder_proc *proc,
} else {
BUG_ON(target_node == NULL);
BUG_ON(t->buffer->async_transaction != 1);
- binder_enqueue_thread_work(thread, tcomplete);
return_error = binder_proc_transaction(t, target_proc, NULL);
- if (return_error)
+ /*
+ * Let the caller know when async transaction reaches a frozen
+ * process and is put in a pending queue, waiting for the target
+ * process to be unfrozen.
+ */
+ if (return_error == BR_TRANSACTION_PENDING_FROZEN)
+ tcomplete->type = BINDER_WORK_TRANSACTION_PENDING;
+ binder_enqueue_thread_work(thread, tcomplete);
+ if (return_error &&
+ return_error != BR_TRANSACTION_PENDING_FROZEN)
goto err_dead_proc_or_thread;
}
if (target_thread)
@@ -4440,10 +4456,13 @@ static int binder_thread_read(struct binder_proc *proc,
binder_stat_br(proc, thread, cmd);
} break;
case BINDER_WORK_TRANSACTION_COMPLETE:
+ case BINDER_WORK_TRANSACTION_PENDING:
case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT: {
if (proc->oneway_spam_detection_enabled &&
w->type == BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT)
cmd = BR_ONEWAY_SPAM_SUSPECT;
+ else if (w->type == BINDER_WORK_TRANSACTION_PENDING)
+ cmd = BR_TRANSACTION_PENDING_FROZEN;
else
cmd = BR_TRANSACTION_COMPLETE;
binder_inner_proc_unlock(proc);
@@ -6170,6 +6189,7 @@ static const char * const binder_return_strings[] = {
"BR_FAILED_REPLY",
"BR_FROZEN_REPLY",
"BR_ONEWAY_SPAM_SUSPECT",
+ "BR_TRANSACTION_PENDING_FROZEN"
};
static const char * const binder_command_strings[] = {
diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
index abe19d88c6ec..28ef5b3704b1 100644
--- a/drivers/android/binder_internal.h
+++ b/drivers/android/binder_internal.h
@@ -133,7 +133,7 @@ enum binder_stat_types {
};
struct binder_stats {
- atomic_t br[_IOC_NR(BR_ONEWAY_SPAM_SUSPECT) + 1];
+ atomic_t br[_IOC_NR(BR_TRANSACTION_PENDING_FROZEN) + 1];
atomic_t bc[_IOC_NR(BC_REPLY_SG) + 1];
atomic_t obj_created[BINDER_STAT_COUNT];
atomic_t obj_deleted[BINDER_STAT_COUNT];
@@ -152,6 +152,7 @@ struct binder_work {
enum binder_work_type {
BINDER_WORK_TRANSACTION = 1,
BINDER_WORK_TRANSACTION_COMPLETE,
+ BINDER_WORK_TRANSACTION_PENDING,
BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT,
BINDER_WORK_RETURN_ERROR,
BINDER_WORK_NODE,
diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
index e72e4de8f452..5f636b5afcd7 100644
--- a/include/uapi/linux/android/binder.h
+++ b/include/uapi/linux/android/binder.h
@@ -450,7 +450,7 @@ enum binder_driver_return_protocol {
BR_FROZEN_REPLY = _IO('r', 18),
/*
- * The target of the last transaction (either a bcTRANSACTION or
+ * The target of the last sync transaction (either a bcTRANSACTION or
* a bcATTEMPT_ACQUIRE) is frozen. No parameters.
*/
@@ -460,6 +460,11 @@ enum binder_driver_return_protocol {
* asynchronous transaction makes the allocated async buffer size exceed
* detection threshold. No parameters.
*/
+
+ BR_TRANSACTION_PENDING_FROZEN = _IO('r', 20),
+ /*
+ * The target of the last async transaction is frozen. No parameters.
+ */
};
enum binder_driver_command_protocol {
--
2.38.1.584.g0f3c55d4c2-goog
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v3 1/1] binder: return pending info for frozen async txns
2022-11-23 20:16 ` [PATCH v3 1/1] " Li Li
@ 2022-11-24 2:25 ` Carlos Llamas
0 siblings, 0 replies; 3+ messages in thread
From: Carlos Llamas @ 2022-11-24 2:25 UTC (permalink / raw)
To: Li Li
Cc: dualli, gregkh, arve, tkjos, maco, joel, brauner, surenb, arnd,
masahiroy, devel, linux-kernel, hridya, smoreland, kernel-team
On Wed, Nov 23, 2022 at 12:16:54PM -0800, Li Li wrote:
> From: Li Li <dualli@google.com>
>
> An async transaction to a frozen process will still be successfully
> put in the queue. But this pending async transaction won't be processed
> until the target process is unfrozen at an unspecified time in the
> future. Pass this important information back to the user space caller
> by returning BR_TRANSACTION_PENDING_FROZEN.
>
> Signed-off-by: Li Li <dualli@google.com>
> ---
> drivers/android/binder.c | 32 +++++++++++++++++++++++------
> drivers/android/binder_internal.h | 3 ++-
> include/uapi/linux/android/binder.h | 7 ++++++-
> 3 files changed, 34 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/android/binder.c b/drivers/android/binder.c
> index 880224ec6abb..acd53147d5d1 100644
> --- a/drivers/android/binder.c
> +++ b/drivers/android/binder.c
> @@ -2728,7 +2728,10 @@ binder_find_outdated_transaction_ilocked(struct binder_transaction *t,
> *
> * Return: 0 if the transaction was successfully queued
> * BR_DEAD_REPLY if the target process or thread is dead
> - * BR_FROZEN_REPLY if the target process or thread is frozen
> + * BR_FROZEN_REPLY if the target process or thread is frozen and
> + * the sync transaction was rejected
> + * BR_TRANSACTION_PENDING_FROZEN if the target process is frozen
> + * and the async transaction was successfully queued
> */
> static int binder_proc_transaction(struct binder_transaction *t,
> struct binder_proc *proc,
> @@ -2738,6 +2741,7 @@ static int binder_proc_transaction(struct binder_transaction *t,
> bool oneway = !!(t->flags & TF_ONE_WAY);
> bool pending_async = false;
> struct binder_transaction *t_outdated = NULL;
> + bool frozen = false;
>
> BUG_ON(!node);
> binder_node_lock(node);
> @@ -2751,15 +2755,16 @@ static int binder_proc_transaction(struct binder_transaction *t,
>
> binder_inner_proc_lock(proc);
> if (proc->is_frozen) {
> + frozen = true;
> proc->sync_recv |= !oneway;
> proc->async_recv |= oneway;
> }
>
> - if ((proc->is_frozen && !oneway) || proc->is_dead ||
> + if ((frozen && !oneway) || proc->is_dead ||
> (thread && thread->is_dead)) {
> binder_inner_proc_unlock(proc);
> binder_node_unlock(node);
> - return proc->is_frozen ? BR_FROZEN_REPLY : BR_DEAD_REPLY;
> + return frozen ? BR_FROZEN_REPLY : BR_DEAD_REPLY;
> }
>
> if (!thread && !pending_async)
> @@ -2770,7 +2775,7 @@ static int binder_proc_transaction(struct binder_transaction *t,
> } else if (!pending_async) {
> binder_enqueue_work_ilocked(&t->work, &proc->todo);
> } else {
> - if ((t->flags & TF_UPDATE_TXN) && proc->is_frozen) {
> + if ((t->flags & TF_UPDATE_TXN) && frozen) {
> t_outdated = binder_find_outdated_transaction_ilocked(t,
> &node->async_todo);
> if (t_outdated) {
> @@ -2807,6 +2812,9 @@ static int binder_proc_transaction(struct binder_transaction *t,
> binder_stats_deleted(BINDER_STAT_TRANSACTION);
> }
>
> + if (oneway && frozen)
> + return BR_TRANSACTION_PENDING_FROZEN;
> +
> return 0;
> }
>
> @@ -3607,9 +3615,17 @@ static void binder_transaction(struct binder_proc *proc,
> } else {
> BUG_ON(target_node == NULL);
> BUG_ON(t->buffer->async_transaction != 1);
> - binder_enqueue_thread_work(thread, tcomplete);
> return_error = binder_proc_transaction(t, target_proc, NULL);
> - if (return_error)
> + /*
> + * Let the caller know when async transaction reaches a frozen
> + * process and is put in a pending queue, waiting for the target
> + * process to be unfrozen.
> + */
> + if (return_error == BR_TRANSACTION_PENDING_FROZEN)
> + tcomplete->type = BINDER_WORK_TRANSACTION_PENDING;
> + binder_enqueue_thread_work(thread, tcomplete);
> + if (return_error &&
> + return_error != BR_TRANSACTION_PENDING_FROZEN)
> goto err_dead_proc_or_thread;
> }
> if (target_thread)
> @@ -4440,10 +4456,13 @@ static int binder_thread_read(struct binder_proc *proc,
> binder_stat_br(proc, thread, cmd);
> } break;
> case BINDER_WORK_TRANSACTION_COMPLETE:
> + case BINDER_WORK_TRANSACTION_PENDING:
> case BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT: {
> if (proc->oneway_spam_detection_enabled &&
> w->type == BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT)
> cmd = BR_ONEWAY_SPAM_SUSPECT;
> + else if (w->type == BINDER_WORK_TRANSACTION_PENDING)
> + cmd = BR_TRANSACTION_PENDING_FROZEN;
> else
> cmd = BR_TRANSACTION_COMPLETE;
> binder_inner_proc_unlock(proc);
> @@ -6170,6 +6189,7 @@ static const char * const binder_return_strings[] = {
> "BR_FAILED_REPLY",
> "BR_FROZEN_REPLY",
> "BR_ONEWAY_SPAM_SUSPECT",
> + "BR_TRANSACTION_PENDING_FROZEN"
> };
>
> static const char * const binder_command_strings[] = {
> diff --git a/drivers/android/binder_internal.h b/drivers/android/binder_internal.h
> index abe19d88c6ec..28ef5b3704b1 100644
> --- a/drivers/android/binder_internal.h
> +++ b/drivers/android/binder_internal.h
> @@ -133,7 +133,7 @@ enum binder_stat_types {
> };
>
> struct binder_stats {
> - atomic_t br[_IOC_NR(BR_ONEWAY_SPAM_SUSPECT) + 1];
> + atomic_t br[_IOC_NR(BR_TRANSACTION_PENDING_FROZEN) + 1];
> atomic_t bc[_IOC_NR(BC_REPLY_SG) + 1];
> atomic_t obj_created[BINDER_STAT_COUNT];
> atomic_t obj_deleted[BINDER_STAT_COUNT];
> @@ -152,6 +152,7 @@ struct binder_work {
> enum binder_work_type {
> BINDER_WORK_TRANSACTION = 1,
> BINDER_WORK_TRANSACTION_COMPLETE,
> + BINDER_WORK_TRANSACTION_PENDING,
> BINDER_WORK_TRANSACTION_ONEWAY_SPAM_SUSPECT,
> BINDER_WORK_RETURN_ERROR,
> BINDER_WORK_NODE,
> diff --git a/include/uapi/linux/android/binder.h b/include/uapi/linux/android/binder.h
> index e72e4de8f452..5f636b5afcd7 100644
> --- a/include/uapi/linux/android/binder.h
> +++ b/include/uapi/linux/android/binder.h
> @@ -450,7 +450,7 @@ enum binder_driver_return_protocol {
>
> BR_FROZEN_REPLY = _IO('r', 18),
> /*
> - * The target of the last transaction (either a bcTRANSACTION or
> + * The target of the last sync transaction (either a bcTRANSACTION or
> * a bcATTEMPT_ACQUIRE) is frozen. No parameters.
> */
>
> @@ -460,6 +460,11 @@ enum binder_driver_return_protocol {
> * asynchronous transaction makes the allocated async buffer size exceed
> * detection threshold. No parameters.
> */
> +
> + BR_TRANSACTION_PENDING_FROZEN = _IO('r', 20),
> + /*
> + * The target of the last async transaction is frozen. No parameters.
> + */
> };
>
> enum binder_driver_command_protocol {
> --
> 2.38.1.584.g0f3c55d4c2-goog
>
Thanks!
Acked-by: Carlos Llamas <cmllamas@google.com>
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-11-24 2:25 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-11-23 20:16 [PATCH v3 0/1] binder: return pending info for frozen async txns Li Li
2022-11-23 20:16 ` [PATCH v3 1/1] " Li Li
2022-11-24 2:25 ` Carlos Llamas
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox