Fix compilation on Linux up to v5.4

[elmcan.git] / module / can327.c

diff --git a/module/can327.c b/module/can327.c
index aba198651476e1fe79f30ecdf4398e773e0d2c8d..fc99dea652f6f22170f76176042bcad4beb425d4 100644 (file)
--- a/module/can327.c
+++ b/module/can327.c
@@ -682,10 +682,9 @@ static void elm327_drop_bytes(struct can327 *elm, size_t i)
        elm->rxfill -= i;
 }
 
-static void elm327_parse_rxbuf(struct can327 *elm)
+static void elm327_parse_rxbuf(struct can327 *elm, size_t first_new_char_idx)
 {
-       size_t len;
-       int i;
+       size_t len, pos;
 
        lockdep_assert_held(&elm->lock);
 
@@ -696,20 +695,20 @@ static void elm327_parse_rxbuf(struct can327 *elm)
 
        case ELM327_STATE_GETDUMMYCHAR:
                /* Wait for 'y' or '>' */
-               for (i = 0; i < elm->rxfill; i++) {
-                       if (elm->rxbuf[i] == ELM327_DUMMY_CHAR) {
+               for (pos = 0; pos < elm->rxfill; pos++) {
+                       if (elm->rxbuf[pos] == ELM327_DUMMY_CHAR) {
                                elm327_send(elm, "\r", 1);
                                elm->state = ELM327_STATE_GETPROMPT;
-                               i++;
+                               pos++;
                                break;
-                       } else if (elm327_is_ready_char(elm->rxbuf[i])) {
+                       } else if (elm327_is_ready_char(elm->rxbuf[pos])) {
                                elm327_send(elm, ELM327_DUMMY_STRING, 1);
-                               i++;
+                               pos++;
                                break;
                        }
                }
 
-               elm327_drop_bytes(elm, i);
+               elm327_drop_bytes(elm, pos);
                break;
 
        case ELM327_STATE_GETPROMPT:
@@ -722,7 +721,7 @@ static void elm327_parse_rxbuf(struct can327 *elm)
 
        case ELM327_STATE_RECEIVING:
                /* Find <CR> delimiting feedback lines. */
-               len = 0;
+               len = first_new_char_idx;
                while (len < elm->rxfill && elm->rxbuf[len] != '\r')
                        len++;
 
@@ -756,13 +755,23 @@ static void elm327_parse_rxbuf(struct can327 *elm)
 
                        /* More data to parse? */
                        if (elm->rxfill)
-                               elm327_parse_rxbuf(elm);
+                               elm327_parse_rxbuf(elm, 0);
                }
        }
 }
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(5,10,0)
 /* Dummy needed to use can_rx_offload */
+#if LINUX_VERSION_CODE < KERNEL_VERSION(5,5,0)
+static unsigned int *can327_mailbox_read(struct can_rx_offload *offload,
+                                        struct can_frame *cf,
+                                        u32 *timestamp, unsigned int n)
+{
+       WARN_ON_ONCE(1); /* This function is a dummy, so don't call it! */
+
+       return -ENOBUFS;
+}
+#else /* Since 4e9c9484b085 (included in v5.5) */
 static struct sk_buff *can327_mailbox_read(struct can_rx_offload *offload,
                                           unsigned int n, u32 *timestamp,
                                           bool drop)
@@ -772,6 +781,7 @@ static struct sk_buff *can327_mailbox_read(struct can_rx_offload *offload,
        return ERR_PTR(-ENOBUFS);
 }
 #endif
+#endif
 
 static int can327_netdev_open(struct net_device *dev)
 {
@@ -935,12 +945,18 @@ static void can327_ldisc_rx(struct tty_struct *tty,
 #endif
 {
        struct can327 *elm = (struct can327 *)tty->disc_data;
+       size_t first_new_char_idx;
 
        if (elm->uart_side_failure)
                return;
 
        spin_lock_bh(&elm->lock);
 
+       /* Store old rxfill, so elm327_parse_rxbuf() will have
+        * the option of skipping already checked characters.
+        */
+       first_new_char_idx = elm->rxfill;
+
        while (count-- && elm->rxfill < ELM327_SIZE_RXBUF) {
                if (fp && *fp++) {
                        netdev_err(elm->dev, "Error in received character stream. Check your wiring.");
@@ -985,7 +1001,7 @@ static void can327_ldisc_rx(struct tty_struct *tty,
                return;
        }
 
-       elm327_parse_rxbuf(elm);
+       elm327_parse_rxbuf(elm, first_new_char_idx);
        spin_unlock_bh(&elm->lock);
 }