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authorTomonori Sakita <tomonori.sakita@sord.co.jp>2019-01-25 11:02:22 +0900
committerDavid S. Miller <davem@davemloft.net>2019-01-27 10:39:07 -0800
commit6571ebce112a21ec9be68ef2f53b96fcd41fd81b (patch)
tree8347f592ace98ab4338dd84538c8acf049ddc206 /drivers/net/ethernet/altera
parent63346650c1a94a92be61a57416ac88c0a47c4327 (diff)
downloadlinux-6571ebce112a21ec9be68ef2f53b96fcd41fd81b.tar.gz
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>
Diffstat (limited to 'drivers/net/ethernet/altera')
-rw-r--r--drivers/net/ethernet/altera/altera_msgdma.c3
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));