linux-kernel - [PATCH 3/7] habanalabs: re-init completion object upon retry

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Message-Id: <20210701112717.9540-3-ogabbay@kernel.org>
Date:   Thu,  1 Jul 2021 14:27:13 +0300
From:   Oded Gabbay <ogabbay@...nel.org>
To:     linux-kernel@...r.kernel.org
Subject: [PATCH 3/7] habanalabs: re-init completion object upon retry

In case user interrupt arrived but the completion value is less than
the target value, we want to retry the wait.

However, before the retry we must reinitialize the completion object,
under spin-lock, so the wait function won't exit immediately because
the completion object is already completed (from the previous
interrupt).

Signed-off-by: Oded Gabbay <ogabbay@...nel.org>
---
 drivers/misc/habanalabs/common/command_submission.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/misc/habanalabs/common/command_submission.c b/drivers/misc/habanalabs/common/command_submission.c
index 80c60fb41bbc..12f20446e99a 100644
--- a/drivers/misc/habanalabs/common/command_submission.c
+++ b/drivers/misc/habanalabs/common/command_submission.c
@@ -2046,7 +2046,8 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx,
 		goto unlock_and_free_fence;
 	}
 
-	if (copy_from_user(&completion_value, u64_to_user_ptr(user_address), 4)) {
+	if (copy_from_user(&completion_value, u64_to_user_ptr(user_address),
+									4)) {
 		dev_err(hdev->dev,
 			"Failed to copy completion value from user\n");
 		rc = -EFAULT;
@@ -2077,18 +2078,28 @@ 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);
+
 		if (copy_from_user(&completion_value,
 				u64_to_user_ptr(user_address), 4)) {
+
+			spin_unlock(&interrupt->wait_list_lock);
+
 			dev_err(hdev->dev,
 				"Failed to copy completion value from user\n");
 			rc = -EFAULT;
+
 			goto remove_pending_user_interrupt;
 		}
 
 		if (completion_value >= target_value) {
+			spin_unlock(&interrupt->wait_list_lock);
 			*status = CS_WAIT_STATUS_COMPLETED;
 		} else {
+			reinit_completion(&pend->fence.completion);
 			timeout = completion_rc;
+
+			spin_unlock(&interrupt->wait_list_lock);
 			goto wait_again;
 		}
 	} else {
-- 
2.25.1