[PATCH v2 net-next 01/10] net: eth: altera: tse_start_xmit ignores tx_buffer call response
From: <hidden>
Date: 2018-12-13 17:52:43
Subsystem:
altera triple speed ethernet driver, networking drivers, the rest · Maintainers:
Boon Khai Ng, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Dalon Westergreen <redacted>
The return from tx_buffer call in tse_start_xmit is
inapropriately ignored. tse_buffer calls should return
0 for success or NETDEV_TX_BUSY. tse_start_xmit should
return not report a successful transmit when the tse_buffer
call returns an error condition.
In addition to the above, the msgdma and sgdma do not return
the same value on success or failure. The sgdma_tx_buffer
returned 0 on failure and a positive number of transmitted
packets on success. Given that it only ever sends 1 packet,
this made no sense. The msgdma implementation msgdma_tx_buffer
returns 0 on success.
-> Don't ignore the return from tse_buffer calls
-> Fix sgdma tse_buffer call to return 0 on success
and NETDEV_TX_BUSY on failure.
Signed-off-by: Dalon Westergreen <redacted>
---
drivers/net/ethernet/altera/altera_sgdma.c | 14 ++++++++------
drivers/net/ethernet/altera/altera_tse_main.c | 4 +++-
2 files changed, 11 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/altera/altera_sgdma.c b/drivers/net/ethernet/altera/altera_sgdma.c
index 88ef67a998b4..eb47b9b820bb 100644
--- a/drivers/net/ethernet/altera/altera_sgdma.c
+++ b/drivers/net/ethernet/altera/altera_sgdma.c@@ -15,6 +15,7 @@ */ #include <linux/list.h> +#include <linux/netdevice.h> #include "altera_utils.h" #include "altera_tse.h" #include "altera_sgdmahw.h"
@@ -170,10 +171,11 @@ void sgdma_clear_txirq(struct altera_tse_private *priv) SGDMA_CTRLREG_CLRINT); } -/* transmits buffer through SGDMA. Returns number of buffers - * transmitted, 0 if not possible. - * - * tx_lock is held by the caller +/* transmits buffer through SGDMA. + * original behavior returned the number of transmitted packets (always 1) & + * returned 0 on error. This differs from the msgdma. the calling function + * will now actually look at the code, so from now, 0 is good and return + * NETDEV_TX_BUSY when busy. */ int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) {
@@ -185,7 +187,7 @@ int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) /* wait 'til the tx sgdma is ready for the next transmit request */ if (sgdma_txbusy(priv)) - return 0; + return NETDEV_TX_BUSY; sgdma_setup_descrip(cdesc, /* current descriptor */ ndesc, /* next descriptor */
@@ -202,7 +204,7 @@ int sgdma_tx_buffer(struct altera_tse_private *priv, struct tse_buffer *buffer) /* enqueue the request to the pending transmit queue */ queue_tx(priv, buffer); - return 1; + return 0; }
diff --git a/drivers/net/ethernet/altera/altera_tse_main.c b/drivers/net/ethernet/altera/altera_tse_main.c
index baca8f704a45..dcb330129e23 100644
--- a/drivers/net/ethernet/altera/altera_tse_main.c
+++ b/drivers/net/ethernet/altera/altera_tse_main.c@@ -606,7 +606,9 @@ static int tse_start_xmit(struct sk_buff *skb, struct net_device *dev) buffer->dma_addr = dma_addr; buffer->len = nopaged_len; - priv->dmaops->tx_buffer(priv, buffer); + ret = priv->dmaops->tx_buffer(priv, buffer); + if (ret) + goto out; skb_tx_timestamp(skb);
--
2.19.2