usb: dwc2: remove WARN in dwc2_hcd_save_data_toggle

The WARN() in dwc2_hcd_save_data_toggle() was introduced in
commit 62943b7dfa35 ("usb: dwc2: host: fix the data toggle error in
full speed descriptor dma"), it looks like the WARN() is to ensure
proper usage of dwc2_hcd_save_data_toggle(): either qtd is provided
for control eps or qh is provided for non-control eps. This check is
good even if there's no such improper usage in current code. But the
WARN() usage in driver is discouraged nowadays: imagine there is an
improper usage, then kernel panic due to warn if 'panic_on_warn' is
enabled.

While emitting the err msg for improper usage is still valueable, so
let's replace the WARN with check and dev_err().

At the same time, it looks a bit strange we check !chan after
dereference of this pointer with
"if (chan->ep_type != USB_ENDPOINT_XFER_CONTROL)".

In fact, when entering the dwc2_hcd_save_data_toggle(), the chan won't
be NULL, because its caller or indirect caller has ensured this,
specifically, it's checked with below line in dwc2_hc_n_intr()

if (!chan) {
    dev_err(hsotg->dev, "## hc_ptr_array for channel is NULL ##\n");
    return;
}

This addresses the following issue reported by klocwork tool:
  - Suspicious dereference of pointer 'chan' before NULL check at
    line 518

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Link: https://patch.msgid.link/20260520133711.14410-1-jszhang@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c
index 5c7538d498dd1194d9d328511f583b40c557cd5e..f380275ac696a1ea6997a08fd99c0ba2c62c1c95 100644 (file)
--- a/drivers/usb/dwc2/hcd_intr.c
+++ b/drivers/usb/dwc2/hcd_intr.c
@@ -515,18 +515,20 @@ void dwc2_hcd_save_data_toggle(struct dwc2_hsotg *hsotg,
        u32 pid = (hctsiz & TSIZ_SC_MC_PID_MASK) >> TSIZ_SC_MC_PID_SHIFT;
 
        if (chan->ep_type != USB_ENDPOINT_XFER_CONTROL) {
-               if (WARN(!chan || !chan->qh,
-                        "chan->qh must be specified for non-control eps\n"))
+               if (!chan->qh) {
+                       dev_err(hsotg->dev, "chan->qh must be specified for non-control eps\n");
                        return;
+               }
 
                if (pid == TSIZ_SC_MC_PID_DATA0)
                        chan->qh->data_toggle = DWC2_HC_PID_DATA0;
                else
                        chan->qh->data_toggle = DWC2_HC_PID_DATA1;
        } else {
-               if (WARN(!qtd,
-                        "qtd must be specified for control eps\n"))
+               if (!qtd) {
+                       dev_err(hsotg->dev, "qtd must be specified for control eps\n");
                        return;
+               }
 
                if (pid == TSIZ_SC_MC_PID_DATA0)
                        qtd->data_toggle = DWC2_HC_PID_DATA0;