gve: Fix XDP TX completion handling when counters overflow

In gve_clean_xdp_done, the driver processes the TX completions based on
a 32-bit NIC counter and a 32-bit completion counter stored in the tx
queue.

Fix the for loop so that the counter wraparound is handled correctly.

Fixes: 75eaae158b1b ("gve: Add XDP DROP and TX support for GQI-QPL format")
Signed-off-by: Joshua Washington <joshwash@google.com>
Signed-off-by: Praveen Kaligineedi <pkaligineedi@google.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20240716171041.1561142-1-pkaligineedi@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/google/gve/gve_tx.c b/drivers/net/ethernet/google/gve/gve_tx.c
index 24a64ec1073e24191a46fa3d9d5e5f3724c2e586..e7fb7d6d283df192709e40bad552c07075240f2e 100644 (file)
--- a/drivers/net/ethernet/google/gve/gve_tx.c
+++ b/drivers/net/ethernet/google/gve/gve_tx.c
@@ -158,15 +158,16 @@ static int gve_clean_xdp_done(struct gve_priv *priv, struct gve_tx_ring *tx,
                              u32 to_do)
 {
        struct gve_tx_buffer_state *info;
-       u32 clean_end = tx->done + to_do;
        u64 pkts = 0, bytes = 0;
        size_t space_freed = 0;
        u32 xsk_complete = 0;
        u32 idx;
+       int i;
 
-       for (; tx->done < clean_end; tx->done++) {
+       for (i = 0; i < to_do; i++) {
                idx = tx->done & tx->mask;
                info = &tx->info[idx];
+               tx->done++;
 
                if (unlikely(!info->xdp.size))
                        continue;