Commit 176d23a7 authored by Oded Gabbay's avatar Oded Gabbay
Browse files

habanalabs: disable IRQ in user interrupts spinlock 



Because this spinlock is taken in an interrupt handler, we must use
the spin_lock_irqsave/irqrestore version to disable the interrupts
on the local CPU. Otherwise, we can have a potential deadlock (if
the interrupt handler is scheduled to run on the same cpu that the
code who took the lock was running on).

Signed-off-by: default avatarOded Gabbay <ogabbay@kernel.org>
parent 71731090

drivers/misc/habanalabs/common/command_submission.c

+13 −12
Original line number Diff line number Diff line
@@ -923,13 +923,14 @@ static void 
wake_pending_user_interrupt_threads(struct hl_user_interrupt *interrupt)

{

	struct hl_user_pending_interrupt *pend;

	unsigned long flags;



	spin_lock(&interrupt->wait_list_lock);

	spin_lock_irqsave(&interrupt->wait_list_lock, flags);

	list_for_each_entry(pend, &interrupt->wait_list_head, wait_list_node) {

		pend->fence.error = -EIO;

		complete_all(&pend->fence.completion);

	}

	spin_unlock(&interrupt->wait_list_lock);

	spin_unlock_irqrestore(&interrupt->wait_list_lock, flags);

}



void hl_release_pending_user_interrupts(struct hl_device *hdev)
@@ -2714,9 +2715,9 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx, 
{

	struct hl_user_pending_interrupt *pend;

	struct hl_user_interrupt *interrupt;

	unsigned long timeout;

	long completion_rc;

	unsigned long timeout, flags;

	u32 completion_value;

	long completion_rc;

	int rc = 0;



	if (timeout_us == U32_MAX)
@@ -2739,7 +2740,7 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx, 
	else

		interrupt = &hdev->user_interrupt[interrupt_offset];



	spin_lock(&interrupt->wait_list_lock);

	spin_lock_irqsave(&interrupt->wait_list_lock, flags);

	if (!hl_device_operational(hdev, NULL)) {

		rc = -EPERM;

		goto unlock_and_free_fence;
@@ -2765,7 +2766,7 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx, 
	 * handler to monitor

	 */

	list_add_tail(&pend->wait_list_node, &interrupt->wait_list_head);

	spin_unlock(&interrupt->wait_list_lock);

	spin_unlock_irqrestore(&interrupt->wait_list_lock, flags);



wait_again:

	/* Wait for interrupt handler to signal completion */
@@ -2777,12 +2778,12 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx, 
	 * If comparison fails, keep waiting until timeout expires

	 */

	if (completion_rc > 0) {

		spin_lock(&interrupt->wait_list_lock);

		spin_lock_irqsave(&interrupt->wait_list_lock, flags);



		if (copy_from_user(&completion_value,

				u64_to_user_ptr(user_address), 4)) {



			spin_unlock(&interrupt->wait_list_lock);

			spin_unlock_irqrestore(&interrupt->wait_list_lock, flags);



			dev_err(hdev->dev,

				"Failed to copy completion value from user\n");
@@ -2792,13 +2793,13 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx, 
		}



		if (completion_value >= target_value) {

			spin_unlock(&interrupt->wait_list_lock);

			spin_unlock_irqrestore(&interrupt->wait_list_lock, flags);

			*status = CS_WAIT_STATUS_COMPLETED;

		} else {

			reinit_completion(&pend->fence.completion);

			timeout = completion_rc;



			spin_unlock(&interrupt->wait_list_lock);

			spin_unlock_irqrestore(&interrupt->wait_list_lock, flags);

			goto wait_again;

		}

	} else if (completion_rc == -ERESTARTSYS) {
@@ -2812,11 +2813,11 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx, 
	}



remove_pending_user_interrupt:

	spin_lock(&interrupt->wait_list_lock);

	spin_lock_irqsave(&interrupt->wait_list_lock, flags);

	list_del(&pend->wait_list_node);



unlock_and_free_fence:

	spin_unlock(&interrupt->wait_list_lock);

	spin_unlock_irqrestore(&interrupt->wait_list_lock, flags);

	kfree(pend);

	hl_ctx_put(ctx);