linux-kernel - [PATCH v9 01/34] xhci: split free interrupter into separate remove and free parts

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Date:   Tue, 17 Oct 2023 13:00:36 -0700
From:   Wesley Cheng <quic_wcheng@...cinc.com>
To:     <mathias.nyman@...el.com>, <gregkh@...uxfoundation.org>,
        <lgirdwood@...il.com>, <broonie@...nel.org>, <perex@...ex.cz>,
        <tiwai@...e.com>, <agross@...nel.org>, <andersson@...nel.org>,
        <konrad.dybcio@...aro.org>, <robh+dt@...nel.org>,
        <krzysztof.kozlowski+dt@...aro.org>, <conor+dt@...nel.org>,
        <srinivas.kandagatla@...aro.org>, <bgoswami@...cinc.com>,
        <Thinh.Nguyen@...opsys.com>
CC:     <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <alsa-devel@...a-project.org>, <linux-arm-msm@...r.kernel.org>,
        <devicetree@...r.kernel.org>,
        Mathias Nyman <mathias.nyman@...ux.intel.com>,
        Wesley Cheng <quic_wcheng@...cinc.com>
Subject: [PATCH v9 01/34] xhci: split free interrupter into separate remove and free parts

From: Mathias Nyman <mathias.nyman@...ux.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@...ux.intel.com>
Signed-off-by: Wesley Cheng <quic_wcheng@...cinc.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 0a37f0d511cf..0994ca9fba44 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1797,23 +1797,14 @@ 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;
 	u64 tmp64;
 	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
@@ -1828,10 +1819,28 @@ xhci_free_interrupter(struct xhci_hcd *xhci, struct xhci_interrupter *ir)
 		tmp64 &= (u64) ERST_PTR_MASK;
 		xhci_write_64(xhci, tmp64, &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);
@@ -1844,6 +1853,7 @@ 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");