mlx4_core: Fix crash on uninitialized priv->cmd.slave_sem

On an SR-IOV master device, __mlx4_init_one() calls mlx4_init_hca()
before mlx4_multi_func_init().  However, for unlucky configurations,
mlx4_init_hca() might call mlx4_SENSE_PORT() (via mlx4_dev_cap()), and
that calls mlx4_cmd_imm() with MLX4_CMD_WRAPPED set.

However, on a multifunction device with MLX4_CMD_WRAPPED, __mlx4_cmd()
calls into mlx4_slave_cmd(), and that immediately tries to do

	down(&priv->cmd.slave_sem);

but priv->cmd.slave_sem isn't initialized until mlx4_multi_func_init()
(which we haven't called yet).  The next thing it tries to do is access
priv->mfunc.vhcr, but that hasn't been allocated yet.

Fix this by moving the initialization of slave_sem and vhcr up into
mlx4_cmd_init(). Also, since slave_sem is really just being used as a
mutex, convert it into a slave_cmd_mutex.

Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4.h b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
index 4b1fbd84a68f..71eed05426ec 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4.h
@@ -513,9 +513,9 @@ struct mlx4_cmd {
         struct pci_pool        *pool;
         void __iomem           *hcr;
         struct mutex            hcr_mutex;
+        struct mutex            slave_cmd_mutex;
         struct semaphore        poll_sem;
         struct semaphore        event_sem;
-        struct semaphore        slave_sem;
         int                     max_cmds;
         spinlock_t              context_lock;
         int                     free_head;