[PATCH AUTOSEL 4.20 32/72] net: altera_tse: fix msgdma_tx_completion on non-zero fill_level case
From: Sasha Levin <sashal@kernel.org>
Date: 2019-02-23 21:32:37
Also in:
lkml, stable
Subsystem:
altera triple speed ethernet driver, networking drivers, the rest · Maintainers:
Boon Khai Ng, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
From: Tomonori Sakita <redacted> [ 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 <redacted> Signed-off-by: Atsushi Nemoto <redacted> Reviewed-by: Dalon L Westergreen <redacted> Acked-by: Thor Thayer <redacted> 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 0fb986ba32905..0ae723f753417 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