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Subject[PATCH 5.4 093/104] net/sonic: Improve receive descriptor status flag check
Date
From: Finn Thain <fthain@telegraphics.com.au>

commit 94b166349503957079ef5e7d6f667f157aea014a upstream.

After sonic_tx_timeout() calls sonic_init(), it can happen that
sonic_rx() will subsequently encounter a receive descriptor with no
flags set. Remove the comment that says that this can't happen.

When giving a receive descriptor to the SONIC, clear the descriptor
status field. That way, any rx descriptor with flags set can only be
a newly received packet.

Don't process a descriptor without the LPKT bit set. The buffer is
still in use by the SONIC.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/net/ethernet/natsemi/sonic.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)

--- a/drivers/net/ethernet/natsemi/sonic.c
+++ b/drivers/net/ethernet/natsemi/sonic.c
@@ -434,7 +434,6 @@ static int index_from_addr(struct sonic_
static void sonic_rx(struct net_device *dev)
{
struct sonic_local *lp = netdev_priv(dev);
- int status;
int entry = lp->cur_rx;
int prev_entry = lp->eol_rx;

@@ -445,9 +444,10 @@ static void sonic_rx(struct net_device *
u16 bufadr_l;
u16 bufadr_h;
int pkt_len;
+ u16 status = sonic_rda_get(dev, entry, SONIC_RD_STATUS);

- status = sonic_rda_get(dev, entry, SONIC_RD_STATUS);
- if (status & SONIC_RCR_PRX) {
+ /* If the RD has LPKT set, the chip has finished with the RB */
+ if ((status & SONIC_RCR_PRX) && (status & SONIC_RCR_LPKT)) {
u32 addr = (sonic_rda_get(dev, entry,
SONIC_RD_PKTPTR_H) << 16) |
sonic_rda_get(dev, entry, SONIC_RD_PKTPTR_L);
@@ -495,10 +495,6 @@ static void sonic_rx(struct net_device *
bufadr_h = (unsigned long)new_laddr >> 16;
sonic_rra_put(dev, i, SONIC_RR_BUFADR_L, bufadr_l);
sonic_rra_put(dev, i, SONIC_RR_BUFADR_H, bufadr_h);
- } else {
- /* This should only happen, if we enable accepting broken packets. */
- }
- if (status & SONIC_RCR_LPKT) {
/*
* this was the last packet out of the current receive buffer
* give the buffer back to the SONIC
@@ -511,12 +507,11 @@ static void sonic_rx(struct net_device *
__func__);
SONIC_WRITE(SONIC_ISR, SONIC_INT_RBE); /* clear the flag */
}
- } else
- printk(KERN_ERR "%s: rx desc without RCR_LPKT. Shouldn't happen !?\n",
- dev->name);
+ }
/*
* give back the descriptor
*/
+ sonic_rda_put(dev, entry, SONIC_RD_STATUS, 0);
sonic_rda_put(dev, entry, SONIC_RD_IN_USE, 1);

prev_entry = entry;

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