A NULL pointer dereference is possible for the argument ring->buf_pool
which is passed to xgene_enet_free_desc_ring(), as ring could be NULL.

And now since NULL pointers are being checked for before the calls to
xgene_enet_free_desc_ring(), might as well take advantage of them and
not call the function if the argument would be NULL.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NIyappan Subramanian <isubramanian@apm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

xgene_enet_get_ring_size() returns a negative value in case of an error,
but its only caller in xgene_enet_create_desc_ring() currently uses the
return value directly as u32. Instead, check for a negative value first and
error out in case. Also move the call to xgene_enet_get_ring_size() before
devm_kzalloc() so we don't need to free anything in the error path.

This fixes the following issue reported by the Coverity Scanner:

** CID 1231336:  Improper use of negative value  (NEGATIVE_RETURNS)
/drivers/net/ethernet/apm/xgene/xgene_enet_main.c: 596 in xgene_enet_create_desc_ring()
Signed-off-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch adds network driver for APM X-Gene SoC ethernet.
Signed-off-by: NIyappan Subramanian <isubramanian@apm.com>
Signed-off-by: NRavi Patel <rapatel@apm.com>
Signed-off-by: NKeyur Chudgar <kchudgar@apm.com>
Signed-off-by: NDean Nelson <dnelson@redhat.com>
Reviewed-by: NTobias Klauser <tklauser@distanz.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>