net: smc91c111: gate can_receive() on rx FIFO having a slot

Return false from can_receive() when the FIFO doesn't have a free RX
slot. This fixes a bug in the current code where the allocated buffer
is freed before the fifo pop, triggering a premature flush of queued RX
packets. It also will handle a corner case, where the guest manually
frees the allocated buffer before popping the rx FIFO (hence it is not
enough to just delay the flush_queued_packets()).

Reported-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Signed-off-by: Peter Crosthwaite <crosthwaite.peter@gmail.com>
Reviewed-by: Fam Zheng <famz@redhat.com>
Tested-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Message-id: 97bfdfc5cbce0bd5e0cbbbff35ce7a1bf6f8603d.1441873621.git.crosthwaite.peter@gmail.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Peter Crosthwaite 2015-09-10 21:23:57 -07:00 committed by Stefan Hajnoczi
parent 8d06b14927
commit e62cb54cd5

View File

@ -129,7 +129,8 @@ static int smc91c111_can_receive(smc91c111_state *s)
if ((s->rcr & RCR_RXEN) == 0 || (s->rcr & RCR_SOFT_RST)) {
return 1;
}
if (s->allocated == (1 << NUM_PACKETS) - 1) {
if (s->allocated == (1 << NUM_PACKETS) - 1 ||
s->rx_fifo_len == NUM_PACKETS) {
return 0;
}
return 1;
@ -182,6 +183,7 @@ static void smc91c111_pop_rx_fifo(smc91c111_state *s)
} else {
s->int_level &= ~INT_RCV;
}
smc91c111_flush_queued_packets(s);
smc91c111_update(s);
}