usb: dwc3: debug: fix string position formatting mixup with ret and len

commit b32196e35bd7bbc8038db1aba1fbf022dc469b6a upstream.

Currently the string formatting is mixing up the offset of ret and
len. Re-work the code to use just len, remove ret and use scnprintf
instead of snprintf and len position accumulation where required.
Remove the -ve return check since scnprintf never returns a failure
-ve size. Also break overly long lines to clean up checkpatch
warnings.

Addresses-Coverity: ("Unused value")
Fixes: 1381a5113caf ("usb: dwc3: debug: purge usage of strcat")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210095139.328711-1-colin.king@canonical.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/dwc3/debug.h b/drivers/usb/dwc3/debug.h
index 9baabed87d61b84eb7febb5753d0b342d7724e48..f2c97058a00b8ef9a7098c1fb100248c19cb81f1 100644 (file)
--- a/drivers/usb/dwc3/debug.h
+++ b/drivers/usb/dwc3/debug.h
@@ -256,86 +256,77 @@ static inline const char *dwc3_ep_event_string(char *str, size_t size,
        u8 epnum = event->endpoint_number;
        size_t len;
        int status;
-       int ret;
 
-       ret = snprintf(str, size, "ep%d%s: ", epnum >> 1,
+       len = scnprintf(str, size, "ep%d%s: ", epnum >> 1,
                        (epnum & 1) ? "in" : "out");
-       if (ret < 0)
-               return "UNKNOWN";
 
        status = event->status;
 
        switch (event->endpoint_event) {
        case DWC3_DEPEVT_XFERCOMPLETE:
-               len = strlen(str);
-               snprintf(str + len, size - len, "Transfer Complete (%c%c%c)",
+               len += scnprintf(str + len, size - len,
+                               "Transfer Complete (%c%c%c)",
                                status & DEPEVT_STATUS_SHORT ? 'S' : 's',
                                status & DEPEVT_STATUS_IOC ? 'I' : 'i',
                                status & DEPEVT_STATUS_LST ? 'L' : 'l');
 
-               len = strlen(str);
-
                if (epnum <= 1)
-                       snprintf(str + len, size - len, " [%s]",
+                       scnprintf(str + len, size - len, " [%s]",
                                        dwc3_ep0_state_string(ep0state));
                break;
        case DWC3_DEPEVT_XFERINPROGRESS:
-               len = strlen(str);
-
-               snprintf(str + len, size - len, "Transfer In Progress [%d] (%c%c%c)",
+               scnprintf(str + len, size - len,
+                               "Transfer In Progress [%d] (%c%c%c)",
                                event->parameters,
                                status & DEPEVT_STATUS_SHORT ? 'S' : 's',
                                status & DEPEVT_STATUS_IOC ? 'I' : 'i',
                                status & DEPEVT_STATUS_LST ? 'M' : 'm');
                break;
        case DWC3_DEPEVT_XFERNOTREADY:
-               len = strlen(str);
-
-               snprintf(str + len, size - len, "Transfer Not Ready [%d]%s",
+               len += scnprintf(str + len, size - len,
+                               "Transfer Not Ready [%d]%s",
                                event->parameters,
                                status & DEPEVT_STATUS_TRANSFER_ACTIVE ?
                                " (Active)" : " (Not Active)");
 
-               len = strlen(str);
-
                /* Control Endpoints */
                if (epnum <= 1) {
                        int phase = DEPEVT_STATUS_CONTROL_PHASE(event->status);
 
                        switch (phase) {
                        case DEPEVT_STATUS_CONTROL_DATA:
-                               snprintf(str + ret, size - ret,
+                               scnprintf(str + len, size - len,
                                                " [Data Phase]");
                                break;
                        case DEPEVT_STATUS_CONTROL_STATUS:
-                               snprintf(str + ret, size - ret,
+                               scnprintf(str + len, size - len,
                                                " [Status Phase]");
                        }
                }
                break;
        case DWC3_DEPEVT_RXTXFIFOEVT:
-               snprintf(str + ret, size - ret, "FIFO");
+               scnprintf(str + len, size - len, "FIFO");
                break;
        case DWC3_DEPEVT_STREAMEVT:
                status = event->status;
 
                switch (status) {
                case DEPEVT_STREAMEVT_FOUND:
-                       snprintf(str + ret, size - ret, " Stream %d Found",
+                       scnprintf(str + len, size - len, " Stream %d Found",
                                        event->parameters);
                        break;
                case DEPEVT_STREAMEVT_NOTFOUND:
                default:
-                       snprintf(str + ret, size - ret, " Stream Not Found");
+                       scnprintf(str + len, size - len, " Stream Not Found");
                        break;
                }
 
                break;
        case DWC3_DEPEVT_EPCMDCMPLT:
-               snprintf(str + ret, size - ret, "Endpoint Command Complete");
+               scnprintf(str + len, size - len, "Endpoint Command Complete");
                break;
        default:
-               snprintf(str, size, "UNKNOWN");
+               scnprintf(str + len, size - len, "UNKNOWN");
        }
 
        return str;