accel/habanalabs: add info when FD released while device still in use

When user closes the device file descriptor, it is checked whether the
device is still in use, and a message is printed if it is.
To make this message more informative, add to this print also the reason
due to which the device is considered as in use.
The possible reasons which are checked for now are active CS and
exported dma-buf.

Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <ogabbay@kernel.org>
Signed-off-by: Oded Gabbay <ogabbay@kernel.org>
Reviewed-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>

1 files changed, 48 insertions, 3 deletions

diff --git a/drivers/accel/habanalabs/common/device.c b/drivers/accel/habanalabs/common/device.c
index 194c282d7e55..b8c74185eabd 100644
--- a/drivers/accel/habanalabs/common/device.c
+++ b/drivers/accel/habanalabs/common/device.c
@@ -492,6 +492,52 @@ int hl_hpriv_put(struct hl_fpriv *hpriv)
 	return kref_put(&hpriv->refcount, hpriv_release);
 }
 
+static void compose_device_in_use_info(char **buf, size_t *buf_size, const char *fmt, ...)
+{
+	struct va_format vaf;
+	va_list args;
+	int size;
+
+	va_start(args, fmt);
+	vaf.fmt = fmt;
+	vaf.va = &args;
+
+	size = snprintf(*buf, *buf_size, "%pV", &vaf);
+	if (size >= *buf_size)
+		size = *buf_size;
+
+	*buf += size;
+	*buf_size -= size;
+
+	va_end(args);
+}
+
+static void print_device_in_use_info(struct hl_device *hdev, const char *message)
+{
+	u32 active_cs_num, dmabuf_export_cnt;
+	char buf[64], *buf_ptr = buf;
+	size_t buf_size = sizeof(buf);
+	bool unknown_reason = true;
+
+	active_cs_num = hl_get_active_cs_num(hdev);
+	if (active_cs_num) {
+		unknown_reason = false;
+		compose_device_in_use_info(&buf_ptr, &buf_size, " [%u active CS]", active_cs_num);
+	}
+
+	dmabuf_export_cnt = atomic_read(&hdev->dmabuf_export_cnt);
+	if (dmabuf_export_cnt) {
+		unknown_reason = false;
+		compose_device_in_use_info(&buf_ptr, &buf_size, " [%u exported dma-buf]",
+						dmabuf_export_cnt);
+	}
+
+	if (unknown_reason)
+		compose_device_in_use_info(&buf_ptr, &buf_size, " [unknown reason]");
+
+	dev_notice(hdev->dev, "%s%s\n", message, buf);
+}
+
 /*
  * hl_device_release - release function for habanalabs device
  *
@@ -519,12 +565,11 @@ static int hl_device_release(struct inode *inode, struct file *filp)
 	hdev->compute_ctx_in_release = 1;
 
 	if (!hl_hpriv_put(hpriv)) {
-		dev_notice(hdev->dev, "User process closed FD but device still in use\n");
+		print_device_in_use_info(hdev, "User process closed FD but device still in use");
 		hl_device_reset(hdev, HL_DRV_RESET_HARD);
 	}
 
-	hdev->last_open_session_duration_jif =
-		jiffies - hdev->last_successful_open_jif;
+	hdev->last_open_session_duration_jif = jiffies - hdev->last_successful_open_jif;
 
 	return 0;
 }