| Message ID | 20150514231708.13594.13610.stgit@bhelgaas-glaptop2.roam.corp.google.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
From: Bjorn Helgaas <bhelgaas@google.com> Date: Thu, 14 May 2015 18:17:08 -0500 > With a cross-compiler based on gcc-4.9, I see warnings like the following: > > drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_CQ_wrapper': > drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:3048:10: error: 'cq' may be used uninitialized in this function [-Werror=maybe-uninitialized] > cq->mtt = mtt; > > I think the warning is spurious because we only use cq when > cq_res_start_move_to() returns zero, and it always initializes *cq in that > case. The srq case is similar. But maybe gcc isn't smart enough to figure > that out. > > Initialize cq and srq explicitly to avoid the warnings. > > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Applied. The compiler, generally, is not good at determining use-before-initialized in situations of the form: int x; if (foo) x = whatever; ... if (foo) use(x); -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c index c7f28bf..cdd32f4 100644 --- a/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c +++ b/drivers/net/ethernet/mellanox/mlx4/resource_tracker.c @@ -3187,7 +3187,7 @@ int mlx4_SW2HW_CQ_wrapper(struct mlx4_dev *dev, int slave, int cqn = vhcr->in_modifier; struct mlx4_cq_context *cqc = inbox->buf; int mtt_base = cq_get_mtt_addr(cqc) / dev->caps.mtt_entry_sz; - struct res_cq *cq; + struct res_cq *cq = NULL; struct res_mtt *mtt; err = cq_res_start_move_to(dev, slave, cqn, RES_CQ_HW, &cq); @@ -3223,7 +3223,7 @@ int mlx4_HW2SW_CQ_wrapper(struct mlx4_dev *dev, int slave, { int err; int cqn = vhcr->in_modifier; - struct res_cq *cq; + struct res_cq *cq = NULL; err = cq_res_start_move_to(dev, slave, cqn, RES_CQ_ALLOCATED, &cq); if (err) @@ -3362,7 +3362,7 @@ int mlx4_SW2HW_SRQ_wrapper(struct mlx4_dev *dev, int slave, int err; int srqn = vhcr->in_modifier; struct res_mtt *mtt; - struct res_srq *srq; + struct res_srq *srq = NULL; struct mlx4_srq_context *srqc = inbox->buf; int mtt_base = srq_get_mtt_addr(srqc) / dev->caps.mtt_entry_sz; @@ -3406,7 +3406,7 @@ int mlx4_HW2SW_SRQ_wrapper(struct mlx4_dev *dev, int slave, { int err; int srqn = vhcr->in_modifier; - struct res_srq *srq; + struct res_srq *srq = NULL; err = srq_res_start_move_to(dev, slave, srqn, RES_SRQ_ALLOCATED, &srq); if (err)
With a cross-compiler based on gcc-4.9, I see warnings like the following: drivers/net/ethernet/mellanox/mlx4/resource_tracker.c: In function 'mlx4_SW2HW_CQ_wrapper': drivers/net/ethernet/mellanox/mlx4/resource_tracker.c:3048:10: error: 'cq' may be used uninitialized in this function [-Werror=maybe-uninitialized] cq->mtt = mtt; I think the warning is spurious because we only use cq when cq_res_start_move_to() returns zero, and it always initializes *cq in that case. The srq case is similar. But maybe gcc isn't smart enough to figure that out. Initialize cq and srq explicitly to avoid the warnings. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> --- .../net/ethernet/mellanox/mlx4/resource_tracker.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html