evie/android_kernel_oneplus_msm8998
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msm: ipa: Fix the problem with nested sleeping primitives

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prepare_to_wait() will enqueue the thread on the given queue
and put it into the given execution state,
which is TASK_INTERRUPTIBLE.

Further processing in function, calls  mutex_lock(),
will go into a new version of the going-to-sleep code,
changing the task state.

That, of course, may well interfere with the outer
sleeping code.

So, nesting of sleeping primitives in this way is discouraged.

And new warning was added to point out this kind of nesting.

Fix the nesting of sleeping primitives with the new solution
provide in linux kernel.

Change-Id: Id1a5f64472cd2d63e679706c6482db98f89ec765
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>
This commit is contained in:
Mohammed Javid 2017-06-29 11:35:19 +05:30
parent 823d04d683
commit 50989c54d6
2 changed files with 8 additions and 10 deletions
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8
drivers/platform/msm/ipa/ipa_v2/ipa_intf.c
View file

@ -541,15 +541,15 @@ ssize_t ipa_read(struct file *filp, char __user *buf, size_t count,
char __user *start;
struct ipa_push_msg *msg = NULL;
int ret;
DEFINE_WAIT(wait);
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int locked;
start = buf;
add_wait_queue(&ipa_ctx->msg_waitq, &wait);
while (1) {
mutex_lock(&ipa_ctx->msg_lock);
locked = 1;
prepare_to_wait(&ipa_ctx->msg_waitq, &wait, TASK_INTERRUPTIBLE);
if (!list_empty(&ipa_ctx->msg_list)) {
msg = list_first_entry(&ipa_ctx->msg_list,
struct ipa_push_msg, link);
@ -601,10 +601,10 @@ ssize_t ipa_read(struct file *filp, char __user *buf, size_t count,
locked = 0;
mutex_unlock(&ipa_ctx->msg_lock);
schedule();
wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
finish_wait(&ipa_ctx->msg_waitq, &wait);
remove_wait_queue(&ipa_ctx->msg_waitq, &wait);
if (start != buf && ret != -EFAULT)
ret = buf - start;

10
drivers/platform/msm/ipa/ipa_v3/ipa_intf.c
View file

@ -546,17 +546,15 @@ ssize_t ipa3_read(struct file *filp, char __user *buf, size_t count,
char __user *start;
struct ipa3_push_msg *msg = NULL;
int ret;
DEFINE_WAIT(wait);
DEFINE_WAIT_FUNC(wait, woken_wake_function);
int locked;
start = buf;
add_wait_queue(&ipa3_ctx->msg_waitq, &wait);
while (1) {
mutex_lock(&ipa3_ctx->msg_lock);
locked = 1;
prepare_to_wait(&ipa3_ctx->msg_waitq,
&wait,
TASK_INTERRUPTIBLE);
if (!list_empty(&ipa3_ctx->msg_list)) {
msg = list_first_entry(&ipa3_ctx->msg_list,
@ -609,10 +607,10 @@ ssize_t ipa3_read(struct file *filp, char __user *buf, size_t count,
locked = 0;
mutex_unlock(&ipa3_ctx->msg_lock);
schedule();
wait_woken(&wait, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
finish_wait(&ipa3_ctx->msg_waitq, &wait);
remove_wait_queue(&ipa3_ctx->msg_waitq, &wait);
if (start != buf && ret != -EFAULT)
ret = buf - start;