This is a note to let you know that I've just added the patch titled
sfc: ensure correct number of XDP queues
to the 5.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sfc-ensure-correct-number-of-xdp-queues.patch
and it can be found in the queue-5.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 67f2fc93c6a444392870f61f512b4ce09a6b8f03
Author: �ñigo Huguet <ihuguet@xxxxxxxxxx>
Date: Tue Jul 13 16:21:28 2021 +0200
sfc: ensure correct number of XDP queues
[ Upstream commit 788bc000d4c2f25232db19ab3a0add0ba4e27671 ]
Commit 99ba0ea616aa ("sfc: adjust efx->xdp_tx_queue_count with the real
number of initialized queues") intended to fix a problem caused by a
round up when calculating the number of XDP channels and queues.
However, this was not the real problem. The real problem was that the
number of XDP TX queues had been reduced to half in
commit e26ca4b53582 ("sfc: reduce the number of requested xdp ev queues"),
but the variable xdp_tx_queue_count had remained the same.
Once the correct number of XDP TX queues is created again in the
previous patch of this series, this also can be reverted since the error
doesn't actually exist.
Only in the case that there is a bug in the code we can have different
values in xdp_queue_number and efx->xdp_tx_queue_count. Because of this,
and per Edward Cree's suggestion, I add instead a WARN_ON to catch if it
happens again in the future.
Note that the number of allocated queues can be higher than the number
of used ones due to the round up, as explained in the existing comment
in the code. That's why we also have to stop increasing xdp_queue_number
beyond efx->xdp_tx_queue_count.
Signed-off-by: �ñigo Huguet <ihuguet@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/ethernet/sfc/efx_channels.c b/drivers/net/ethernet/sfc/efx_channels.c
index 5b71f8a03a6d..bb48a139dd15 100644
--- a/drivers/net/ethernet/sfc/efx_channels.c
+++ b/drivers/net/ethernet/sfc/efx_channels.c
@@ -892,18 +892,20 @@ int efx_set_channels(struct efx_nic *efx)
if (efx_channel_is_xdp_tx(channel)) {
efx_for_each_channel_tx_queue(tx_queue, channel) {
tx_queue->queue = next_queue++;
- netif_dbg(efx, drv, efx->net_dev, "Channel %u TXQ %u is XDP %u, HW %u\n",
- channel->channel, tx_queue->label,
- xdp_queue_number, tx_queue->queue);
+
/* We may have a few left-over XDP TX
* queues owing to xdp_tx_queue_count
* not dividing evenly by EFX_MAX_TXQ_PER_CHANNEL.
* We still allocate and probe those
* TXQs, but never use them.
*/
- if (xdp_queue_number < efx->xdp_tx_queue_count)
+ if (xdp_queue_number < efx->xdp_tx_queue_count) {
+ netif_dbg(efx, drv, efx->net_dev, "Channel %u TXQ %u is XDP %u, HW %u\n",
+ channel->channel, tx_queue->label,
+ xdp_queue_number, tx_queue->queue);
efx->xdp_tx_queues[xdp_queue_number] = tx_queue;
- xdp_queue_number++;
+ xdp_queue_number++;
+ }
}
} else {
efx_for_each_channel_tx_queue(tx_queue, channel) {
@@ -915,8 +917,7 @@ int efx_set_channels(struct efx_nic *efx)
}
}
}
- if (xdp_queue_number)
- efx->xdp_tx_queue_count = xdp_queue_number;
+ WARN_ON(xdp_queue_number != efx->xdp_tx_queue_count);
rc = netif_set_real_num_tx_queues(efx->net_dev, efx->n_tx_channels);
if (rc)
