netdev - [PATCH v2 net-next 03/12] net: mscc: ocelot: better error handling in ocelot_xtr_irq

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Date:   Sun, 14 Feb 2021 00:37:52 +0200
From:   Vladimir Oltean <olteanv@...il.com>
To:     "David S . Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>, netdev@...r.kernel.org
Cc:     Andrew Lunn <andrew@...n.ch>,
        Florian Fainelli <f.fainelli@...il.com>,
        Vivien Didelot <vivien.didelot@...il.com>,
        Richard Cochran <richardcochran@...il.com>,
        Claudiu Manoil <claudiu.manoil@....com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Vladimir Oltean <vladimir.oltean@....com>,
        Maxim Kochetkov <fido_max@...ox.ru>,
        UNGLinuxDriver@...rochip.com
Subject: [PATCH v2 net-next 03/12] net: mscc: ocelot: better error handling in ocelot_xtr_irq_handler

From: Vladimir Oltean <vladimir.oltean@....com>

The ocelot_rx_frame_word() function can return a negative error code,
however this isn't being checked for consistently. Errors being ignored
have not been seen in practice though.

Also, some constructs can be simplified by using "goto" instead of
repeated "break" statements.

Signed-off-by: Vladimir Oltean <vladimir.oltean@....com>
---
Changes in v2:
None.

 drivers/net/ethernet/mscc/ocelot_vsc7514.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/drivers/net/ethernet/mscc/ocelot_vsc7514.c b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
index d19efbe6ffd3..b075dc13354a 100644
--- a/drivers/net/ethernet/mscc/ocelot_vsc7514.c
+++ b/drivers/net/ethernet/mscc/ocelot_vsc7514.c
@@ -619,12 +619,9 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 		for (i = 0; i < OCELOT_TAG_LEN / 4; i++) {
 			err = ocelot_rx_frame_word(ocelot, grp, true, &ifh[i]);
 			if (err != 4)
-				break;
+				goto out;
 		}
 
-		if (err != 4)
-			break;
-
 		/* At this point the IFH was read correctly, so it is safe to
 		 * presume that there is no error. The err needs to be reset
 		 * otherwise a frame could come in CPU queue between the while
@@ -645,7 +642,7 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 		if (unlikely(!skb)) {
 			netdev_err(dev, "Unable to allocate sk_buff\n");
 			err = -ENOMEM;
-			break;
+			goto out;
 		}
 		buf_len = info.len - ETH_FCS_LEN;
 		buf = (u32 *)skb_put(skb, buf_len);
@@ -653,12 +650,21 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 		len = 0;
 		do {
 			sz = ocelot_rx_frame_word(ocelot, grp, false, &val);
+			if (sz < 0) {
+				err = sz;
+				goto out;
+			}
 			*buf++ = val;
 			len += sz;
 		} while (len < buf_len);
 
 		/* Read the FCS */
 		sz = ocelot_rx_frame_word(ocelot, grp, false, &val);
+		if (sz < 0) {
+			err = sz;
+			goto out;
+		}
+
 		/* Update the statistics if part of the FCS was read before */
 		len -= ETH_FCS_LEN - sz;
 
@@ -667,11 +673,6 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 			*buf = val;
 		}
 
-		if (sz < 0) {
-			err = sz;
-			break;
-		}
-
 		if (ocelot->ptp) {
 			ocelot_ptp_gettime64(&ocelot->ptp_info, &ts);
 
@@ -701,6 +702,7 @@ static irqreturn_t ocelot_xtr_irq_handler(int irq, void *arg)
 		dev->stats.rx_packets++;
 	}
 
+out:
 	if (err < 0)
 		while (ocelot_read(ocelot, QS_XTR_DATA_PRESENT) & BIT(grp))
 			ocelot_read_rix(ocelot, QS_XTR_RD, grp);
-- 
2.25.1