usb: musb: jz4740: Prevent lockup when CONFIG_SMP is set

The function dma_controller_irq() locks up the exact same spinlock we
locked before calling it, which obviously resulted in a deadlock when
CONFIG_SMP was enabled. This flew under the radar as none of the boards
supported by this driver needs SMP.

Fixes: 57aadb46bd63 ("usb: musb: jz4740: Add support for DMA")

Cc: stable@vger.kernel.org
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Bin Liu <b-liu@ti.com>
Link: https://lore.kernel.org/r/20200525025049.3400-6-b-liu@ti.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/musb/jz4740.c b/drivers/usb/musb/jz4740.c
index e64dd30..c4fe1f4 100644 (file)
--- a/drivers/usb/musb/jz4740.c
+++ b/drivers/usb/musb/jz4740.c
@@ -30,11 +30,11 @@ static irqreturn_t jz4740_musb_interrupt(int irq, void *__hci)
        irqreturn_t     retval = IRQ_NONE, retval_dma = IRQ_NONE;
        struct musb     *musb = __hci;
 
-       spin_lock_irqsave(&musb->lock, flags);
-
        if (IS_ENABLED(CONFIG_USB_INVENTRA_DMA) && musb->dma_controller)
                retval_dma = dma_controller_irq(irq, musb->dma_controller);
 
+       spin_lock_irqsave(&musb->lock, flags);
+
        musb->int_usb = musb_readb(musb->mregs, MUSB_INTRUSB);
        musb->int_tx = musb_readw(musb->mregs, MUSB_INTRTX);
        musb->int_rx = musb_readw(musb->mregs, MUSB_INTRRX);