| Message ID | 20170418062135.76698-1-gthelen@google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Apr 17, 2017 at 11:21:35PM -0700, Greg Thelen wrote: > gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized > 'mpt' variable: > drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper': > drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized] > mpt->mtt = mtt; > > I think this warning is a false complaint. mpt is only used when > mr_res_start_move_to() return zero, and in all such cases it initializes > mpt. > But apparently gcc cannot see that. > > Initialize mpt to avoid the warning. > > Signed-off-by: Greg Thelen <gthelen@google.com> > --- It looks like other callers of mr_res_start_move_to() have the same "uninitialized" variable. Thanks
Leon Romanovsky <leon@kernel.org> wrote: > [ Unknown signature status ] > On Mon, Apr 17, 2017 at 11:21:35PM -0700, Greg Thelen wrote: >> gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized >> 'mpt' variable: >> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper': >> drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized] >> mpt->mtt = mtt; >> >> I think this warning is a false complaint. mpt is only used when >> mr_res_start_move_to() return zero, and in all such cases it initializes >> mpt. >> But apparently gcc cannot see that. >> >> Initialize mpt to avoid the warning. >> >> Signed-off-by: Greg Thelen <gthelen@google.com> >> --- > > It looks like other callers of mr_res_start_move_to() have the same > "uninitialized" variable. > > Thanks The above is the only mellanox warning I see. So gcc is able to better analyze the other callsites.
From: Greg Thelen <gthelen@google.com> Date: Mon, 17 Apr 2017 23:21:35 -0700 > gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized > 'mpt' variable: > drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper': > drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized] > mpt->mtt = mtt; > > I think this warning is a false complaint. mpt is only used when > mr_res_start_move_to() return zero, and in all such cases it initializes > mpt. But apparently gcc cannot see that. > > Initialize mpt to avoid the warning. > > Signed-off-by: Greg Thelen <gthelen@google.com> Appied to net-next.
diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c index d8d5d161b8c7..4aa29ee93013 100644 --- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c @@ -2749,7 +2749,7 @@ int mlx4_SW2HW_MPT_wrapper(struct mlx4_dev *dev, int slave, int err; int index = vhcr->in_modifier; struct res_mtt *mtt; - struct res_mpt *mpt; + struct res_mpt *mpt = NULL; int mtt_base = mr_get_mtt_addr(inbox->buf) / dev->caps.mtt_entry_sz; int phys; int id;
gcc 4.8.4 complains that mlx4_SW2HW_MPT_wrapper() uses an uninitialized 'mpt' variable: drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_MPT_wrapper': drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:2802:12: warning: 'mpt' may be used uninitialized in this function [-Wmaybe-uninitialized] mpt->mtt = mtt; I think this warning is a false complaint. mpt is only used when mr_res_start_move_to() return zero, and in all such cases it initializes mpt. But apparently gcc cannot see that. Initialize mpt to avoid the warning. Signed-off-by: Greg Thelen <gthelen@google.com> --- drivers/net/ethernet/mellanox/mlx4/resource_tracker.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)