On Sat, Oct 21, 2017 at 3:23 AM, Felix Kuehling <Felix.Kuehling at amd.com> wrote:
> Cleaned up the code while resolving some potential bugs and
> inconsistencies in the process.
>
> Clean-ups:
> * Remove enum kfd_event_wait_result, which duplicates
> KFD_IOC_EVENT_RESULT definitions
> * alloc_event_waiters can be called without holding p->event_mutex
> * Return an error code from copy_signaled_event_data instead of bool
> * Clean up error handling code paths to minimize duplication in
> kfd_wait_on_events
>
> Fixes:
> * Consistently return an error code from kfd_wait_on_events and set
> wait_result to KFD_IOC_WAIT_RESULT_FAIL in all failure cases.
> * Always call free_waiters while holding p->event_mutex
> * copy_signaled_event_data might sleep. Don't call it while the task state
> is TASK_INTERRUPTIBLE.
>
> Signed-off-by: Felix Kuehling <Felix.Kuehling at amd.com>
> ---
> drivers/gpu/drm/amd/amdkfd/kfd_chardev.c | 5 +--
> drivers/gpu/drm/amd/amdkfd/kfd_events.c | 71 ++++++++++++++------------------
> drivers/gpu/drm/amd/amdkfd/kfd_priv.h | 8 +---
> 3 files changed, 32 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> index 0ef82b2..a25321f 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_chardev.c
> @@ -835,15 +835,12 @@ static int kfd_ioctl_wait_events(struct file *filp, struct kfd_process *p,
> void *data)
> {
> struct kfd_ioctl_wait_events_args *args = data;
> - enum kfd_event_wait_result wait_result;
> int err;
>
> err = kfd_wait_on_events(p, args->num_events,
> (void __user *)args->events_ptr,
> (args->wait_for_all != 0),
> - args->timeout, &wait_result);
> -
> - args->wait_result = wait_result;
> + args->timeout, &args->wait_result);
>
> return err;
> }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_events.c b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> index c6d9572..5bb88b74 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_events.c
> @@ -668,7 +668,7 @@ static bool test_event_condition(bool all, uint32_t num_events,
> * Copy event specific data, if defined.
> * Currently only memory exception events have additional data to copy to user
> */
> -static bool copy_signaled_event_data(uint32_t num_events,
> +static int copy_signaled_event_data(uint32_t num_events,
> struct kfd_event_waiter *event_waiters,
> struct kfd_event_data __user *data)
> {
> @@ -686,11 +686,11 @@ static bool copy_signaled_event_data(uint32_t num_events,
> src = &event->memory_exception_data;
> if (copy_to_user(dst, src,
> sizeof(struct kfd_hsa_memory_exception_data)))
> - return false;
> + return -EFAULT;
> }
> }
>
> - return true;
> + return 0;
>
> }
>
> @@ -727,7 +727,7 @@ static void free_waiters(uint32_t num_events, struct kfd_event_waiter *waiters)
> int kfd_wait_on_events(struct kfd_process *p,
> uint32_t num_events, void __user *data,
> bool all, uint32_t user_timeout_ms,
> - enum kfd_event_wait_result *wait_result)
> + uint32_t *wait_result)
> {
> struct kfd_event_data __user *events =
> (struct kfd_event_data __user *) data;
> @@ -737,18 +737,18 @@ int kfd_wait_on_events(struct kfd_process *p,
> struct kfd_event_waiter *event_waiters = NULL;
> long timeout = user_timeout_to_jiffies(user_timeout_ms);
>
> + event_waiters = alloc_event_waiters(num_events);
> + if (!event_waiters) {
> + ret = -ENOMEM;
> + goto out;
> + }
> +
> mutex_lock(&p->event_mutex);
>
> /* Set to something unreasonable - this is really
> * just a bool for now.
> */
> - *wait_result = KFD_WAIT_TIMEOUT;
> -
> - event_waiters = alloc_event_waiters(num_events);
> - if (!event_waiters) {
> - ret = -ENOMEM;
> - goto fail;
> - }
> + *wait_result = KFD_IOC_WAIT_RESULT_TIMEOUT;
>
> for (i = 0; i < num_events; i++) {
> struct kfd_event_data event_data;
> @@ -756,23 +756,21 @@ int kfd_wait_on_events(struct kfd_process *p,
> if (copy_from_user(&event_data, &events[i],
> sizeof(struct kfd_event_data))) {
> ret = -EFAULT;
> - goto fail;
> + goto out_unlock;
> }
>
> ret = init_event_waiter_get_status(p, &event_waiters[i],
> event_data.event_id, i);
> if (ret)
> - goto fail;
> + goto out_unlock;
> }
>
> /* Check condition once. */
> if (test_event_condition(all, num_events, event_waiters)) {
> - if (copy_signaled_event_data(num_events,
> - event_waiters, events))
> - *wait_result = KFD_WAIT_COMPLETE;
> - else
> - *wait_result = KFD_WAIT_ERROR;
> - free_waiters(num_events, event_waiters);
> + *wait_result = KFD_IOC_WAIT_RESULT_COMPLETE;
> + ret = copy_signaled_event_data(num_events,
> + event_waiters, events);
> + goto out_unlock;
> } else {
> /* Add to wait lists if we need to wait. */
> for (i = 0; i < num_events; i++)
> @@ -781,12 +779,6 @@ int kfd_wait_on_events(struct kfd_process *p,
>
> mutex_unlock(&p->event_mutex);
>
> - /* Return if all waits were already satisfied. */
> - if (*wait_result != KFD_WAIT_TIMEOUT) {
> - __set_current_state(TASK_RUNNING);
> - return ret;
> - }
> -
> while (true) {
> if (fatal_signal_pending(current)) {
> ret = -EINTR;
> @@ -818,16 +810,12 @@ int kfd_wait_on_events(struct kfd_process *p,
> set_current_state(TASK_INTERRUPTIBLE);
>
> if (test_event_condition(all, num_events, event_waiters)) {
> - if (copy_signaled_event_data(num_events,
> - event_waiters, events))
> - *wait_result = KFD_WAIT_COMPLETE;
> - else
> - *wait_result = KFD_WAIT_ERROR;
> + *wait_result = KFD_IOC_WAIT_RESULT_COMPLETE;
> break;
> }
>
> if (timeout <= 0) {
> - *wait_result = KFD_WAIT_TIMEOUT;
> + *wait_result = KFD_IOC_WAIT_RESULT_TIMEOUT;
> break;
> }
>
> @@ -835,19 +823,20 @@ int kfd_wait_on_events(struct kfd_process *p,
> }
> __set_current_state(TASK_RUNNING);
>
> + /* copy_signaled_event_data may sleep. So this has to happen
> + * after the task state is set back to RUNNING.
> + */
> + if (!ret && *wait_result == KFD_IOC_WAIT_RESULT_COMPLETE)
> + ret = copy_signaled_event_data(num_events,
> + event_waiters, events);
> +
> mutex_lock(&p->event_mutex);
> +out_unlock:
> free_waiters(num_events, event_waiters);
> mutex_unlock(&p->event_mutex);
> -
> - return ret;
> -
> -fail:
> - if (event_waiters)
> - free_waiters(num_events, event_waiters);
> -
> - mutex_unlock(&p->event_mutex);
> -
> - *wait_result = KFD_WAIT_ERROR;
> +out:
> + if (ret)
> + *wait_result = KFD_IOC_WAIT_RESULT_FAIL;
>
> return ret;
> }
> diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> index 1a483a7..d3cf53a 100644
> --- a/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> +++ b/drivers/gpu/drm/amd/amdkfd/kfd_priv.h
> @@ -726,19 +726,13 @@ uint64_t kfd_get_number_elems(struct kfd_dev *kfd);
> extern const struct kfd_event_interrupt_class event_interrupt_class_cik;
> extern const struct kfd_device_global_init_class device_global_init_class_cik;
>
> -enum kfd_event_wait_result {
> - KFD_WAIT_COMPLETE,
> - KFD_WAIT_TIMEOUT,
> - KFD_WAIT_ERROR
> -};
> -
> void kfd_event_init_process(struct kfd_process *p);
> void kfd_event_free_process(struct kfd_process *p);
> int kfd_event_mmap(struct kfd_process *process, struct vm_area_struct *vma);
> int kfd_wait_on_events(struct kfd_process *p,
> uint32_t num_events, void __user *data,
> bool all, uint32_t user_timeout_ms,
> - enum kfd_event_wait_result *wait_result);
> + uint32_t *wait_result);
> void kfd_signal_event_interrupt(unsigned int pasid, uint32_t partial_id,
> uint32_t valid_id_bits);
> void kfd_signal_iommu_event(struct kfd_dev *dev,
> --
> 2.7.4
>
This patch is:
Acked-by: Oded Gabbay <oded.gabbay at gmail.com>
