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Subjectnet: thunder: change q_len's type to handle max ring size
The Cavium thunder nicvf driver supports rx/tx rings of up to 65536 entries per.
The number of entires are stored in the q_len member of struct q_desc_mem. The
problem is that q_len being a u16, results in 65536 becoming 0.

In getting pointers to descriptors in the rings, the driver uses q_len minus 1
as a mask after incrementing the pointer, in order to go back to the beginning
and not go past the end of the ring.

With the q_len set to 0 the mask is no longer correct and the driver does go
beyond the end of the ring, causing various ills. Usually the first thing that
shows up is a "NETDEV WATCHDOG: enP2p1s0f1 (nicvf): transmit queue 7 timed out"

This patch remedies the problem by changing q_len to a u32.

Signed-off-by: Dean Nelson <>
drivers/net/ethernet/cavium/thunder/nicvf_queues.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.h b/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
index 7d1e4e2aaad0..ce1eed7a6d63 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
@@ -213,7 +213,7 @@ struct rx_tx_queue_stats {
struct q_desc_mem {
dma_addr_t dma;
u64 size;
- u16 q_len;
+ u32 q_len;
dma_addr_t phys_base;
void *base;
void *unalign_base;
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