xhci: add xhci_get_virt_ep() helper

In several event handlers we need to find the right endpoint
structure from slot_id and ep_index in the event.

Add a helper for this, check that slot_id and ep_index are valid.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210129130044.206855-6-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2 files changed, 52 insertions, 25 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 28f5245af971..c9c4c559188f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -446,6 +446,26 @@ void xhci_ring_doorbell_for_active_rings(struct xhci_hcd *xhci,
 	ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
 }
 
+static struct xhci_virt_ep *xhci_get_virt_ep(struct xhci_hcd *xhci,
+					     unsigned int slot_id,
+					     unsigned int ep_index)
+{
+	if (slot_id == 0 || slot_id >= MAX_HC_SLOTS) {
+		xhci_warn(xhci, "Invalid slot_id %u\n", slot_id);
+		return NULL;
+	}
+	if (ep_index >= EP_CTX_PER_DEV) {
+		xhci_warn(xhci, "Invalid endpoint index %u\n", ep_index);
+		return NULL;
+	}
+	if (!xhci->devs[slot_id]) {
+		xhci_warn(xhci, "No xhci virt device for slot_id %u\n", slot_id);
+		return NULL;
+	}
+
+	return &xhci->devs[slot_id]->eps[ep_index];
+}
+
 /* Get the right ring for the given slot_id, ep_index and stream_id.
  * If the endpoint supports streams, boundary check the URB's stream ID.
  * If the endpoint doesn't support streams, return the singular endpoint ring.
@@ -456,7 +476,10 @@ struct xhci_ring *xhci_triad_to_transfer_ring(struct xhci_hcd *xhci,
 {
 	struct xhci_virt_ep *ep;
 
-	ep = &xhci->devs[slot_id]->eps[ep_index];
+	ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
+	if (!ep)
+		return NULL;
+
 	/* Common case: no streams */
 	if (!(ep->ep_state & EP_HAS_STREAMS))
 		return ep->ring;
@@ -742,11 +765,14 @@ static void xhci_handle_cmd_stop_ep(struct xhci_hcd *xhci, int slot_id,
 	memset(&deq_state, 0, sizeof(deq_state));
 	ep_index = TRB_TO_EP_INDEX(le32_to_cpu(trb->generic.field[3]));
 
-	vdev = xhci->devs[slot_id];
+	ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
+	if (!ep)
+		return;
+
+	vdev = ep->vdev;
 	ep_ctx = xhci_get_ep_ctx(xhci, vdev->out_ctx, ep_index);
 	trace_xhci_handle_cmd_stop_ep(ep_ctx);
 
-	ep = &xhci->devs[slot_id]->eps[ep_index];
 	last_unlinked_td = list_last_entry(&ep->cancelled_td_list,
 			struct xhci_td, cancelled_td_list);
 
@@ -1064,17 +1090,17 @@ static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
 	unsigned int ep_index;
 	unsigned int stream_id;
 	struct xhci_ring *ep_ring;
-	struct xhci_virt_device *dev;
 	struct xhci_virt_ep *ep;
 	struct xhci_ep_ctx *ep_ctx;
 	struct xhci_slot_ctx *slot_ctx;
 
 	ep_index = TRB_TO_EP_INDEX(le32_to_cpu(trb->generic.field[3]));
 	stream_id = TRB_TO_STREAM_ID(le32_to_cpu(trb->generic.field[2]));
-	dev = xhci->devs[slot_id];
-	ep = &dev->eps[ep_index];
+	ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
+	if (!ep)
+		return;
 
-	ep_ring = xhci_stream_id_to_ring(dev, ep_index, stream_id);
+	ep_ring = xhci_stream_id_to_ring(ep->vdev, ep_index, stream_id);
 	if (!ep_ring) {
 		xhci_warn(xhci, "WARN Set TR deq ptr command for freed stream ID %u\n",
 				stream_id);
@@ -1082,8 +1108,8 @@ static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
 		goto cleanup;
 	}
 
-	ep_ctx = xhci_get_ep_ctx(xhci, dev->out_ctx, ep_index);
-	slot_ctx = xhci_get_slot_ctx(xhci, dev->out_ctx);
+	ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);
+	slot_ctx = xhci_get_slot_ctx(xhci, ep->vdev->out_ctx);
 	trace_xhci_handle_cmd_set_deq(slot_ctx);
 	trace_xhci_handle_cmd_set_deq_ep(ep_ctx);
 
@@ -1136,7 +1162,7 @@ static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
 			/* Update the ring's dequeue segment and dequeue pointer
 			 * to reflect the new position.
 			 */
-			update_ring_for_set_deq_completion(xhci, dev,
+			update_ring_for_set_deq_completion(xhci, ep->vdev,
 				ep_ring, ep_index);
 		} else {
 			xhci_warn(xhci, "Mismatch between completed Set TR Deq Ptr command & xHCI internal state.\n");
@@ -1146,9 +1172,9 @@ static void xhci_handle_cmd_set_deq(struct xhci_hcd *xhci, int slot_id,
 	}
 
 cleanup:
-	dev->eps[ep_index].ep_state &= ~SET_DEQ_PENDING;
-	dev->eps[ep_index].queued_deq_seg = NULL;
-	dev->eps[ep_index].queued_deq_ptr = NULL;
+	ep->ep_state &= ~SET_DEQ_PENDING;
+	ep->queued_deq_seg = NULL;
+	ep->queued_deq_ptr = NULL;
 	/* Restart any rings with pending URBs */
 	ring_doorbell_for_active_rings(xhci, slot_id, ep_index);
 }
@@ -1156,13 +1182,16 @@ cleanup:
 static void xhci_handle_cmd_reset_ep(struct xhci_hcd *xhci, int slot_id,
 		union xhci_trb *trb, u32 cmd_comp_code)
 {
-	struct xhci_virt_device *vdev;
+	struct xhci_virt_ep *ep;
 	struct xhci_ep_ctx *ep_ctx;
 	unsigned int ep_index;
 
 	ep_index = TRB_TO_EP_INDEX(le32_to_cpu(trb->generic.field[3]));
-	vdev = xhci->devs[slot_id];
-	ep_ctx = xhci_get_ep_ctx(xhci, vdev->out_ctx, ep_index);
+	ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
+	if (!ep)
+		return;
+
+	ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);
 	trace_xhci_handle_cmd_reset_ep(ep_ctx);
 
 	/* This command will only fail if the endpoint wasn't halted,
@@ -1190,7 +1219,7 @@ static void xhci_handle_cmd_reset_ep(struct xhci_hcd *xhci, int slot_id,
 		xhci_ring_cmd_db(xhci);
 	} else {
 		/* Clear our internal halted state */
-		xhci->devs[slot_id]->eps[ep_index].ep_state &= ~EP_HALTED;
+		ep->ep_state &= ~EP_HALTED;
 	}
 
 	/* if this was a soft reset, then restart */
@@ -2313,7 +2342,6 @@ finish_td:
 static int handle_tx_event(struct xhci_hcd *xhci,
 		struct xhci_transfer_event *event)
 {
-	struct xhci_virt_device *xdev;
 	struct xhci_virt_ep *ep;
 	struct xhci_ring *ep_ring;
 	unsigned int slot_id;
@@ -2334,16 +2362,14 @@ static int handle_tx_event(struct xhci_hcd *xhci,
 	trb_comp_code = GET_COMP_CODE(le32_to_cpu(event->transfer_len));
 	ep_trb_dma = le64_to_cpu(event->buffer);
 
-	xdev = xhci->devs[slot_id];
-	if (!xdev) {
-		xhci_err(xhci, "ERROR Transfer event pointed to bad slot %u\n",
-			 slot_id);
+	ep = xhci_get_virt_ep(xhci, slot_id, ep_index);
+	if (!ep) {
+		xhci_err(xhci, "ERROR Invalid Transfer event\n");
 		goto err_out;
 	}
 
-	ep = &xdev->eps[ep_index];
 	ep_ring = xhci_dma_to_transfer_ring(ep, ep_trb_dma);
-	ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
+	ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep_index);
 
 	if (GET_EP_CTX_STATE(ep_ctx) == EP_STATE_DISABLED) {
 		xhci_err(xhci,
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 123ccdd3fea5..a9862f1083ad 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -995,6 +995,7 @@ struct xhci_interval_bw_table {
 	unsigned int		ss_bw_out;
 };
 
+#define EP_CTX_PER_DEV		31
 
 struct xhci_virt_device {
 	int				slot_id;
@@ -1010,7 +1011,7 @@ struct xhci_virt_device {
 	struct xhci_container_ctx       *out_ctx;
 	/* Used for addressing devices and configuration changes */
 	struct xhci_container_ctx       *in_ctx;
-	struct xhci_virt_ep		eps[31];
+	struct xhci_virt_ep		eps[EP_CTX_PER_DEV];
 	u8				fake_port;
 	u8				real_port;
 	struct xhci_interval_bw_table	*bw_table;