wifi: mt76: dma: do not increment queue head if mt76_dma_add_buf fails

Do not increment queue head if mt76_dma_add_buf fails for Wireless
Ethernet Dispatcher rx queues.

Fixes: cd372b8c99c5 ("wifi: mt76: add WED RX support to mt76_dma_{add,get}_buf")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
(cherry picked from commit fe13dad8992be0b26c1be390bcd111acf9892c17)
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230113105848.34642-1-nbd@nbd.name

diff --git a/drivers/net/wireless/mediatek/mt76/dma.c b/drivers/net/wireless/mediatek/mt76/dma.c
index f795548..c058a02 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/dma.c
+++ b/drivers/net/wireless/mediatek/mt76/dma.c
@@ -212,14 +212,14 @@ mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
 {
        struct mt76_queue_entry *entry;
        struct mt76_desc *desc;
-       u32 ctrl;
        int i, idx = -1;
+       u32 ctrl, next;
 
        for (i = 0; i < nbufs; i += 2, buf += 2) {
                u32 buf0 = buf[0].addr, buf1 = 0;
 
                idx = q->head;
-               q->head = (q->head + 1) % q->ndesc;
+               next = (q->head + 1) % q->ndesc;
 
                desc = &q->desc[idx];
                entry = &q->entry[idx];
@@ -239,8 +239,8 @@ mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
                               MT_DMA_CTL_TO_HOST;
                } else {
                        if (txwi) {
-                               q->entry[q->head].txwi = DMA_DUMMY_DATA;
-                               q->entry[q->head].skip_buf0 = true;
+                               q->entry[next].txwi = DMA_DUMMY_DATA;
+                               q->entry[next].skip_buf0 = true;
                        }
 
                        if (buf[0].skip_unmap)
@@ -271,6 +271,7 @@ mt76_dma_add_buf(struct mt76_dev *dev, struct mt76_queue *q,
                WRITE_ONCE(desc->info, cpu_to_le32(info));
                WRITE_ONCE(desc->ctrl, cpu_to_le32(ctrl));
 
+               q->head = next;
                q->queued++;
        }