[PATCH][next] RDMA/cm: Avoid -Wflex-array-member-not-at-end warning

[Gustavo A. R. Silva]

-Wflex-array-member-not-at-end is coming in GCC-14, and we are getting
ready to enable it globally.

Use the `struct_group_tagged()` helper to separate the flexible array
from the rest of the members in flexible `struct cm_work`, and avoid
embedding the flexible-array member in `struct cm_timewait_info`.

Also, use `container_of()` to retrieve a pointer to the flexible
structure.

So, with these changes, fix the following warning:
drivers/infiniband/core/cm.c:196:24: warning: structure containing a flexible 
array member is not at the end of another structure 
[-Wflex-array-member-not-at-end]

Signed-off-by: Gustavo A. R. Silva <gustavo...@kernel.org>
---
 drivers/infiniband/core/cm.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index bf0df6ee4f78..80c87085499c 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -182,18 +182,21 @@ struct cm_av {
 };
 
 struct cm_work {
-       struct delayed_work work;
-       struct list_head list;
-       struct cm_port *port;
-       struct ib_mad_recv_wc *mad_recv_wc;     /* Received MADs */
-       __be32 local_id;                        /* Established / timewait */
-       __be32 remote_id;
-       struct ib_cm_event cm_event;
+       /* New members must be added within the struct_group() macro below. */
+       struct_group_tagged(cm_work_hdr, hdr,
+               struct delayed_work work;
+               struct list_head list;
+               struct cm_port *port;
+               struct ib_mad_recv_wc *mad_recv_wc;     /* Received MADs */
+               __be32 local_id;                        /* Established / 
timewait */
+               __be32 remote_id;
+               struct ib_cm_event cm_event;
+       );
        struct sa_path_rec path[];
 };
 
 struct cm_timewait_info {
-       struct cm_work work;
+       struct cm_work_hdr work;
        struct list_head list;
        struct rb_node remote_qp_node;
        struct rb_node remote_id_node;
@@ -3440,7 +3443,7 @@ static int cm_timewait_handler(struct cm_work *work)
        struct cm_timewait_info *timewait_info;
        struct cm_id_private *cm_id_priv;
 
-       timewait_info = container_of(work, struct cm_timewait_info, work);
+       timewait_info = container_of(&work->hdr, struct cm_timewait_info, work);
        spin_lock_irq(&cm.lock);
        list_del(&timewait_info->list);
        spin_unlock_irq(&cm.lock);
-- 
2.34.1