atl1: fix oops when changing tx/rx ring params

Commit 3f5a2a713aad28480d86b0add00c68484b54febc zeroes out the statistics
message block (SMB) and coalescing message block (CMB) when adapter ring
resources are freed.  This is desirable behavior, but, as a side effect,
the commit leads to an oops when atl1_set_ringparam() attempts to alter
the number of rx or tx elements in the ring buffer (by using ethtool
-G, for example).  We don't want SMB or CMB to change during this
operation.

Modify atl1_set_ringparam() to preserve SMB and CMB when changing ring
parameters.

Cc: stable@kernel.org
Signed-off-by: Jay Cliburn <jcliburn@gmail.com>
Reported-by: Tõnu Raitviir <jussuf@linux.ee>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/atlx/atl1.c b/drivers/net/atlx/atl1.c
index 53363108994ee93bed670940b0eb91170a389456..3acf5123a6efa8c0e21d76b7deb487a76d21ea3e 100644 (file)
--- a/drivers/net/atlx/atl1.c
+++ b/drivers/net/atlx/atl1.c
@@ -3504,6 +3504,8 @@ static int atl1_set_ringparam(struct net_device *netdev,
        struct atl1_rfd_ring rfd_old, rfd_new;
        struct atl1_rrd_ring rrd_old, rrd_new;
        struct atl1_ring_header rhdr_old, rhdr_new;
+       struct atl1_smb smb;
+       struct atl1_cmb cmb;
        int err;
 
        tpd_old = adapter->tpd_ring;
@@ -3544,11 +3546,19 @@ static int atl1_set_ringparam(struct net_device *netdev,
                adapter->rrd_ring = rrd_old;
                adapter->tpd_ring = tpd_old;
                adapter->ring_header = rhdr_old;
+               /*
+                * Save SMB and CMB, since atl1_free_ring_resources
+                * will clear them.
+                */
+               smb = adapter->smb;
+               cmb = adapter->cmb;
                atl1_free_ring_resources(adapter);
                adapter->rfd_ring = rfd_new;
                adapter->rrd_ring = rrd_new;
                adapter->tpd_ring = tpd_new;
                adapter->ring_header = rhdr_new;
+               adapter->smb = smb;
+               adapter->cmb = cmb;
 
                err = atl1_up(adapter);
                if (err)