shinys000114/linux
1
0
Fork 0
mirror of https://github.com/hardkernel/linux.git synced 2026-06-05 02:21:52 +09:00
Code Issues Packages Projects Releases Wiki Activity

net: stmmac: Prevent RX starvation in stmmac_napi_poll()

Browse Source 
[ Upstream commit fa0be0a43f ]

Currently, TX is given a budget which is consumed by stmmac_tx_clean()
and stmmac_rx() is given the remaining non-consumed budget.

This is wrong and in case we are sending a large number of packets this
can starve RX because remaining budget will be low.

Let's give always the same budget for RX and TX clean.

While at it, check if we missed any interrupts while we were in NAPI
callback by looking at DMA interrupt status.

Cc: Joao Pinto <jpinto@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Jose Abreu
2019-01-09 10:06:00 +01:00
committed by Greg Kroah-Hartman
parent 2406055411
commit 1b8742ba98
1 changed files with 14 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

27
drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
View File

@@ -3522,27 +3522,28 @@ static int stmmac_napi_poll(struct napi_struct *napi, int budget)
struct stmmac_channel *ch =
container_of(napi, struct stmmac_channel, napi);
struct stmmac_priv *priv = ch->priv_data;
int work_done = 0, work_rem = budget;
int work_done, rx_done = 0, tx_done = 0;
u32 chan = ch->index;
priv->xstats.napi_poll++;
if (ch->has_tx) {
int done = stmmac_tx_clean(priv, work_rem, chan);
if (ch->has_tx)
tx_done = stmmac_tx_clean(priv, budget, chan);
if (ch->has_rx)
rx_done = stmmac_rx(priv, budget, chan);
work_done += done;
work_rem -= done;
}
work_done = max(rx_done, tx_done);
work_done = min(work_done, budget);
if (ch->has_rx) {
int done = stmmac_rx(priv, work_rem, chan);
if (work_done < budget && napi_complete_done(napi, work_done)) {
int stat;
work_done += done;
work_rem -= done;
}
if (work_done < budget && napi_complete_done(napi, work_done))
stmmac_enable_dma_irq(priv, priv->ioaddr, chan);
stat = stmmac_dma_interrupt_status(priv, priv->ioaddr,
&priv->xstats, chan);
if (stat && napi_reschedule(napi))
stmmac_disable_dma_irq(priv, priv->ioaddr, chan);
}
return work_done;
}