[PATCH] i3c: master: dw: fix deadlock

[Jisheng Zhang]

In dw_i3c_master_irq_handler(), we already have gotten
&master->xferqueue.lock, if we try to get the same lock again in
dw_i3c_master_dequeue_xfer(), deadlock happens.

We fix this issue by introduing dw_i3c_master_dequeue_xfer_locked()
which does all what dw_i3c_master_dequeue_xfer() does without trying
to lock &master->xferqueue.lock.

Signed-off-by: Jisheng Zhang <jisheng.zh...@synaptics.com>
---
 drivers/i3c/master/dw-i3c-master.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/i3c/master/dw-i3c-master.c 
b/drivers/i3c/master/dw-i3c-master.c
index f8c00b94817f..bb03079fbade 100644
--- a/drivers/i3c/master/dw-i3c-master.c
+++ b/drivers/i3c/master/dw-i3c-master.c
@@ -419,12 +419,9 @@ static void dw_i3c_master_enqueue_xfer(struct 
dw_i3c_master *master,
        spin_unlock_irqrestore(&master->xferqueue.lock, flags);
 }
 
-static void dw_i3c_master_dequeue_xfer(struct dw_i3c_master *master,
-                                      struct dw_i3c_xfer *xfer)
+static void dw_i3c_master_dequeue_xfer_locked(struct dw_i3c_master *master,
+                                             struct dw_i3c_xfer *xfer)
 {
-       unsigned long flags;
-
-       spin_lock_irqsave(&master->xferqueue.lock, flags);
        if (master->xferqueue.cur == xfer) {
                u32 status;
 
@@ -439,6 +436,15 @@ static void dw_i3c_master_dequeue_xfer(struct 
dw_i3c_master *master,
        } else {
                list_del_init(&xfer->node);
        }
+}
+
+static void dw_i3c_master_dequeue_xfer(struct dw_i3c_master *master,
+                                      struct dw_i3c_xfer *xfer)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&master->xferqueue.lock, flags);
+       dw_i3c_master_dequeue_xfer_locked(master, xfer);
        spin_unlock_irqrestore(&master->xferqueue.lock, flags);
 }
 
@@ -494,7 +500,7 @@ static void dw_i3c_master_end_xfer_locked(struct 
dw_i3c_master *master, u32 isr)
        complete(&xfer->comp);
 
        if (ret < 0) {
-               dw_i3c_master_dequeue_xfer(master, xfer);
+               dw_i3c_master_dequeue_xfer_locked(master, xfer);
                writel(readl(master->regs + DEVICE_CTRL) | DEV_CTRL_RESUME,
                       master->regs + DEVICE_CTRL);
        }
-- 
2.20.1