diff options
| author | Tomonori Sakita <tomonori.sakita@sord.co.jp> | 2019-01-25 11:02:22 +0900 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2019-01-27 10:39:07 -0800 |
| commit | 6571ebce112a21ec9be68ef2f53b96fcd41fd81b (patch) | |
| tree | 8347f592ace98ab4338dd84538c8acf049ddc206 | |
| parent | 63346650c1a94a92be61a57416ac88c0a47c4327 (diff) | |
| download | linux-6571ebce112a21ec9be68ef2f53b96fcd41fd81b.tar.bz2 | |
net: altera_tse: fix msgdma_tx_completion on non-zero fill_level case
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>
| -rw-r--r-- | drivers/net/ethernet/altera/altera_msgdma.c | 3 |
1 files changed, 2 insertions, 1 deletions
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)); |