linux-kernel - [PATCH 3/4] habanalabs: remove unnecessary device status check

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Date:   Fri, 20 Aug 2021 18:07:18 +0300
From:   Oded Gabbay <ogabbay@...nel.org>
To:     linux-kernel@...r.kernel.org
Subject: [PATCH 3/4] habanalabs: remove unnecessary device status check

Checking if the device is operational when entering the function to
wait for user interrupt is not something that is useful or necessary.

It is not done in any other wait_for_cs ioctl path.

If the device becomes non-operational during the wait, the reset
function will make sure the process wait is interrupted.

Instead, move the check to the beginning of hl_wait_ioctl(). It will
block any attempt to wait on CS or user interrupt once the device
is already marked as non-operational.

Signed-off-by: Oded Gabbay <ogabbay@...nel.org>
---
 drivers/misc/habanalabs/common/command_submission.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/misc/habanalabs/common/command_submission.c b/drivers/misc/habanalabs/common/command_submission.c
index 8a2f75de6df8..a97bb27ebb90 100644
--- a/drivers/misc/habanalabs/common/command_submission.c
+++ b/drivers/misc/habanalabs/common/command_submission.c
@@ -2741,10 +2741,6 @@ static int _hl_interrupt_wait_ioctl(struct hl_device *hdev, struct hl_ctx *ctx,
 		interrupt = &hdev->user_interrupt[interrupt_offset];
 
 	spin_lock_irqsave(&interrupt->wait_list_lock, flags);
-	if (!hl_device_operational(hdev, NULL)) {
-		rc = -EPERM;
-		goto unlock_and_free_fence;
-	}
 
 	if (copy_from_user(&completion_value, u64_to_user_ptr(user_address),
 									4)) {
@@ -2891,6 +2887,12 @@ int hl_wait_ioctl(struct hl_fpriv *hpriv, void *data)
 	u32 flags = args->in.flags;
 	int rc;
 
+	/* If the device is not operational, no point in waiting for any command submission or
+	 * user interrupt
+	 */
+	if (!hl_device_operational(hpriv->hdev, NULL))
+		return -EPERM;
+
 	if (flags & HL_WAIT_CS_FLAGS_INTERRUPT)
 		rc = hl_interrupt_wait_ioctl(hpriv, data);
 	else if (flags & HL_WAIT_CS_FLAGS_MULTI_CS)
-- 
2.17.1