[PATCH 16/19] xhci: split free interrupter into separate remove and free parts

[Mathias Nyman <mathias.nyman@linux.intel.com>]

The current function that both removes and frees an interrupter isn't
optimal when using several interrupters. The array of interrupters need
to be protected with a lock while removing interrupters, but the default
xhci spin lock can't be used while freeing the interrupters event ring
segment table as dma_free_coherent() should be called with IRQs enabled.

There is no need to free the interrupter under the lock, so split this
code into separate unlocked free part, and a lock protected remove part.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-mem.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 4d0b1c0e61a8..62116586848b 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1807,22 +1807,13 @@ static int xhci_alloc_erst(struct xhci_hcd *xhci,
 }
 
 static void
-xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
+xhci_remove_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
 {
-	struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
-	size_t erst_size;
 	u32 tmp;
 
 	if (!ir)
 		return;
 
-	erst_size = sizeof(struct xhci_erst_entry) * ir->erst.num_entries;
-	if (ir->erst.entries)
-		dma_free_coherent(dev, erst_size,
-				  ir->erst.entries,
-				  ir->erst.erst_dma_addr);
-	ir->erst.entries = NULL;
-
 	/*
 	 * Clean out interrupter registers except ERSTBA. Clearing either the
 	 * low or high 32 bits of ERSTBA immediately causes the controller to
@@ -1835,10 +1826,28 @@ xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
 
 		xhci_write_64(xhci, ERST_EHB, &ir->ir_set->erst_dequeue);
 	}
+}
+
+static void
+xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
+{
+	struct device *dev = xhci_to_hcd(xhci)->self.sysdev;
+	size_t erst_size;
+
+	if (!ir)
+		return;
+
+	erst_size = sizeof(struct xhci_erst_entry) * ir->erst.num_entries;
+	if (ir->erst.entries)
+		dma_free_coherent(dev, erst_size,
+				  ir->erst.entries,
+				  ir->erst.erst_dma_addr);
+	ir->erst.entries = NULL;
 
-	/* free interrrupter event ring */
+	/* free interrupter event ring */
 	if (ir->event_ring)
 		xhci_ring_free(xhci, ir->event_ring);
+
 	ir->event_ring = NULL;
 
 	kfree(ir);
@@ -1851,6 +1860,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)
 
 	cancel_delayed_work_sync(&xhci->cmd_timer);
 
+	xhci_remove_interrupter(xhci, xhci->interrupter);
 	xhci_free_interrupter(xhci, xhci->interrupter);
 	xhci->interrupter = NULL;
 	xhci_dbg_trace(xhci, trace_xhci_dbg_init, "Freed primary event ring");
-- 
2.25.1