From: Tomonori Sakita <tomonori.sak...@sord.co.jp>
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.sak...@sord.co.jp>
Signed-off-by: Atsushi Nemoto <atsushi.nem...@sord.co.jp>
Reviewed-by: Dalon L Westergreen <dalon.westergr...@linux.intel.com>
---
Changes in v2:
Use max_t instead of just removing the "- 1".
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 0fb986b..0ae723f 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));
--
2.1.4
