net/mlx5: Reorder completion before putting command entry in cmd_work_handler

net/mlx5: Reorder completion before putting command entry in cmd_work_handler

Assuming callback != NULL && !page_queue, cmd_work_handler takes
command entry with refcnt == 1 from mlx5_cmd_invoke.
If either semaphore timeout or index allocation error happens,
it does final cmd_ent_put(ent). To avoid access to freed memory,
notify slotted completion before cmd_ent_put.

This is theoretical issue found by Svace static analyser.

Cc: stable@vger.kernel.org
Fixes: 485d65e135712 ("net/mlx5: Add a timeout to acquire the command queue semaphore")
Fixes: 0e2909c6bec90 ("net/mlx5: Fix variable not being completed when function returns")
Signed-off-by: Nikolay Kuratov <kniv@yandex-team.ru>
Reviewed-by: Md Haris Iqbal <haris.iqbal@linux.dev>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Acked-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260526162932.501584-1-kniv@yandex-team.ru
Signed-off-by: Paolo Abeni <pabeni@redhat.com>