linux-kernel - [PATCH v16 08/50] xhci: Don't check if the event ring is valid before every event TRB

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Date: Thu, 15 Feb 2024 19:58:41 -0800
From: Wesley Cheng <quic_wcheng@...cinc.com>
To: <srinivas.kandagatla@...aro.org>, <mathias.nyman@...el.com>,
        <perex@...ex.cz>, <conor+dt@...nel.org>, <corbet@....net>,
        <lgirdwood@...il.com>, <andersson@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <gregkh@...uxfoundation.org>,
        <Thinh.Nguyen@...opsys.com>, <broonie@...nel.org>,
        <bgoswami@...cinc.com>, <tiwai@...e.com>, <robh+dt@...nel.org>,
        <konrad.dybcio@...aro.org>
CC: <linux-kernel@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-sound@...r.kernel.org>, <linux-usb@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <alsa-devel@...a-project.org>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Wesley Cheng <quic_wcheng@...cinc.com>
Subject: [PATCH v16 08/50] xhci: Don't check if the event ring is valid before every event TRB

From: Mathias Nyman <mathias.nyman@...ux.intel.com>

Check if the event ring exists and is valid once when the event handler
is called, not before every individual event TRB.

At this point the interrupter is valid, so no need to check that.

Change-Id: I2d69fc39c194d8fa93afd0a1cf3e209b929cee43
Signed-off-by: Mathias Nyman <mathias.nyman@...ux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.com>
---
 drivers/usb/host/xhci-ring.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 275164dc449d..d31599d46b92 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2972,12 +2972,6 @@ static int xhci_handle_event(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
 	union xhci_trb *event;
 	u32 trb_type;
 
-	/* Event ring hasn't been allocated yet. */
-	if (!ir || !ir->event_ring || !ir->event_ring->dequeue) {
-		xhci_err(xhci, "ERROR interrupter not ready\n");
-		return -ENOMEM;
-	}
-
 	event = ir->event_ring->dequeue;
 
 	if (!unhandled_event_trb(ir->event_ring))
@@ -3081,6 +3075,12 @@ static int xhci_handle_events(struct xhci_hcd *xhci, struct xhci_interrupter *ir
 
 	xhci_clear_interrupt_pending(xhci, ir);
 
+	/* Event ring hasn't been allocated yet. */
+	if (!ir->event_ring || !ir->event_ring->dequeue) {
+		xhci_err(xhci, "ERROR interrupter event ring not ready\n");
+		return -ENOMEM;
+	}
+
 	if (xhci->xhc_state & XHCI_STATE_DYING ||
 	    xhci->xhc_state & XHCI_STATE_HALTED) {
 		xhci_dbg(xhci, "xHCI dying, ignoring interrupt. Shouldn't IRQs be disabled?\n");