usb: host: ehci-sched: add comment about find_tt() not returning error

Add a comment explaining why find_tt() will not return error even though
find_tt() is checking for NULL and other errors.

Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Link: https://lore.kernel.org/r/20201011205008.24369-1-sudipm.mukherjee@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c
index 6dfb242..0f85aa9 100644 (file)
--- a/drivers/usb/host/ehci-sched.c
+++ b/drivers/usb/host/ehci-sched.c
@@ -244,6 +244,12 @@ static void reserve_release_intr_bandwidth(struct ehci_hcd *ehci,
 
        /* FS/LS bus bandwidth */
        if (tt_usecs) {
+               /*
+                * find_tt() will not return any error here as we have
+                * already called find_tt() before calling this function
+                * and checked for any error return. The previous call
+                * would have created the data structure.
+                */
                tt = find_tt(qh->ps.udev);
                if (sign > 0)
                        list_add_tail(&qh->ps.ps_list, &tt->ps_list);
@@ -1337,6 +1343,12 @@ static void reserve_release_iso_bandwidth(struct ehci_hcd *ehci,
                        }
                }
 
+               /*
+                * find_tt() will not return any error here as we have
+                * already called find_tt() before calling this function
+                * and checked for any error return. The previous call
+                * would have created the data structure.
+                */
                tt = find_tt(stream->ps.udev);
                if (sign > 0)
                        list_add_tail(&stream->ps.ps_list, &tt->ps_list);