48c1 100644
--- a/drivers/spi/spi-tegra210-quad.c
+++ b/drivers/spi/spi-tegra210-quad.c
@@ -1393,6 +1393,11 @@ static irqreturn_t handle_cpu_based_xfer(struct tegra_qspi *tqspi)
 	spin_lock_irqsave(&tqspi->lock, flags);
 	t = tqspi->curr_xfer;
 
+	if (!t) {
+		spin_unlock_irqrestore(&tqspi->lock, flags);
+		return IRQ_HANDLED;
+	}
+
 	if (tqspi->tx_status ||  tqspi->rx_status) {
 		tegra_qspi_handle_error(tqspi);
 		complete(&tqspi->xfer_completion);
@@ -1463,6 +1468,11 @@ static irqreturn_t handle_dma_based_xfer(struct tegra_qspi *tqspi)
 	spin_lock_irqsave(&tqspi->lock, flags);
 	t = tqspi->curr_xfer;
 
+	if (!t) {
+		spin_unlock_irqrestore(&tqspi->lock, flags);
+		return IRQ_HANDLED;
+	}
+
 	if (num_errors) {
 		tegra_qspi_dma_unmap_xfer(tqspi, t);
 		tegra_qspi_handle_error(tqspi);
@@ -1501,6 +1511,7 @@ static irqreturn_t handle_dma_based_xfer(struct tegra_qspi *tqspi)
 static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data)
 {
 	struct tegra_qspi *tqspi = context_data;
+	unsigned long flags;
 	u32 status;
 
 	/*
@@ -1518,7 +1529,9 @@ static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data)
 	 * If no transfer is in progress, check if this was a real interrupt
 	 * that the timeout handler already processed, or a spurious one.
 	 */
+	spin_lock_irqsave(&tqspi->lock, flags);
 	if (!tqspi->curr_xfer) {
+		spin_unlock_irqrestore(&tqspi->lock, flags);
 		/* Spurious interrupt - transfer not ready */
 		if (!(status & QSPI_RDY))
 			return IRQ_NONE;
@@ -1535,7 +1548,14 @@ static irqreturn_t tegra_qspi_isr_thread(int irq, void *context_data)
 		tqspi->rx_status = tqspi->status_reg & (QSPI_RX_FIFO_OVF | QSPI_RX_FIFO_UNF);
 
 	tegra_qspi_mask_clear_irq(tqspi);
+	spin_unlock_irqrestore(&tqspi->lock, flags);
 
+	/*
+	 * Lock is released here but handlers safely re-check curr_xfer under
+	 * lock before dereferencing.
+	 * DMA handler also needs to sleep in wait_for_completion_*(), which
+	 * cannot be done while holding spinlock.
+	 */
 	if (!tqspi->is_curr_dma_xfer)
 		return handle_cpu_based_xfer(tqspi);
 
-- 
2.51.0[PATCH 6.18 170/175] spi: tegra210-quad: Protect curr_xfer check in IRQ handlerGreg Kroah-Hartman <gregkh@linuxfoundation.org> undefinedstable@vger.kernel.org undefined undefined undefined undefined undefined undefined undefinedŒq…ėg