| From eb16b3e0447da998d9b745fde650ffac33e79443 Mon Sep 17 00:00:00 2001 |
| From: Tomonori Sakita <tomonori.sakita@sord.co.jp> |
| Date: Fri, 25 Jan 2019 11:02:22 +0900 |
| Subject: net: altera_tse: fix msgdma_tx_completion on non-zero fill_level case |
| |
| [ Upstream commit 6571ebce112a21ec9be68ef2f53b96fcd41fd81b ] |
| |
| If fill_level was not zero and status was not BUSY, |
| result of "tx_prod - tx_cons - inuse" might be zero. |
| Subtracting 1 unconditionally results invalid negative return value |
| on this case. |
| Make sure not to return an negative value. |
| |
| Signed-off-by: Tomonori Sakita <tomonori.sakita@sord.co.jp> |
| Signed-off-by: Atsushi Nemoto <atsushi.nemoto@sord.co.jp> |
| Reviewed-by: Dalon L Westergreen <dalon.westergreen@linux.intel.com> |
| Acked-by: Thor Thayer <thor.thayer@linux.intel.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| drivers/net/ethernet/altera/altera_msgdma.c | 3 ++- |
| 1 file changed, 2 insertions(+), 1 deletion(-) |
| |
| diff --git a/drivers/net/ethernet/altera/altera_msgdma.c b/drivers/net/ethernet/altera/altera_msgdma.c |
| index 0fb986ba3290..0ae723f75341 100644 |
| --- a/drivers/net/ethernet/altera/altera_msgdma.c |
| +++ b/drivers/net/ethernet/altera/altera_msgdma.c |
| @@ -145,7 +145,8 @@ u32 msgdma_tx_completions(struct altera_tse_private *priv) |
| & 0xffff; |
| |
| if (inuse) { /* Tx FIFO is not empty */ |
| - ready = priv->tx_prod - priv->tx_cons - inuse - 1; |
| + ready = max_t(int, |
| + priv->tx_prod - priv->tx_cons - inuse - 1, 0); |
| } else { |
| /* Check for buffered last packet */ |
| status = csrrd32(priv->tx_dma_csr, msgdma_csroffs(status)); |
| -- |
| 2.19.1 |
| |
