| Message ID | 20220316083744.GB30941@kili (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 58e06d05d43a9e37e121edabaada00a9d844444c |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net-next] net: stmmac: clean up impossible condition | expand |
Hello: This patch was applied to netdev/net-next.git (master) by Paolo Abeni <pabeni@redhat.com>: On Wed, 16 Mar 2022 11:37:44 +0300 you wrote: > This code works but it has a static checker warning: > > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:1687 init_dma_rx_desc_rings() > warn: always true condition '(queue >= 0) => (0-u32max >= 0)' > > Obviously, it makes no sense to check if an unsigned int is >= 0. What > prevents this code from being a forever loop is that later there is a > separate check for if (queue == 0). > > [...] Here is the summary with links: - [net-next] net: stmmac: clean up impossible condition https://git.kernel.org/netdev/net-next/c/58e06d05d43a You are awesome, thank you!
diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c index cf4e077d21ff..932f444d0d68 100644 --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -1668,7 +1668,7 @@ static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags) { struct stmmac_priv *priv = netdev_priv(dev); u32 rx_count = priv->plat->rx_queues_to_use; - u32 queue; + int queue; int ret; /* RX INITIALIZATION */ @@ -1695,9 +1695,6 @@ static int init_dma_rx_desc_rings(struct net_device *dev, gfp_t flags) rx_q->buf_alloc_num = 0; rx_q->xsk_pool = NULL; - if (queue == 0) - break; - queue--; }
This code works but it has a static checker warning: drivers/net/ethernet/stmicro/stmmac/stmmac_main.c:1687 init_dma_rx_desc_rings() warn: always true condition '(queue >= 0) => (0-u32max >= 0)' Obviously, it makes no sense to check if an unsigned int is >= 0. What prevents this code from being a forever loop is that later there is a separate check for if (queue == 0). The "queue" variable is less than MTL_MAX_RX_QUEUES (8) so it can easily fit in an int type. Any larger value for "queue" would lead to an array overflow when we assign "rx_q = &priv->rx_queue[queue]". Fixes: de0b90e52a11 ("net: stmmac: rearrange RX and TX desc init into per-queue basis") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> --- This code is old so the patch could apply to net, but it's a cleanup and not a bugfix. drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-)