[PATCH] workqueue: Correct declaration of cpu_pwq in struct workqueue_struct

From: Uros Bizjak
Date: Mon Aug 05 2024 - 03:30:51 EST


cpu_pwq is used in various percpu functions that expect variable in
__percpu address space. Correct the declaration of cpu_pwq to

struct pool_workqueue __rcu * __percpu *cpu_pwq

to declare the variable as __percpu pointer.

The patch also fixes following sparse errors:

workqueue.c:380:37: warning: duplicate [noderef]
workqueue.c:380:37: error: multiple address spaces given: __rcu & __percpu
workqueue.c:2271:15: error: incompatible types in comparison expression (different address spaces):
workqueue.c:2271:15: struct pool_workqueue [noderef] __rcu *
workqueue.c:2271:15: struct pool_workqueue [noderef] __percpu *

and uncovers a couple of exisiting "incorrect type in assignment"
warnings (from __rcu address space), which this patch does not address.

Found by GCC's named address space checks.

There were no changes in the resulting object files.

Signed-off-by: Uros Bizjak <ubizjak@xxxxxxxxx>
Cc: Tejun Heo <tj@xxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
---
kernel/workqueue.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 1745ca788ede..32729a2e93af 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -377,7 +377,7 @@ struct workqueue_struct {

/* hot fields used during command issue, aligned to cacheline */
unsigned int flags ____cacheline_aligned; /* WQ: WQ_* flags */
- struct pool_workqueue __percpu __rcu **cpu_pwq; /* I: per-cpu pwqs */
+ struct pool_workqueue __rcu * __percpu *cpu_pwq; /* I: per-cpu pwqs */
struct wq_node_nr_active *node_nr_active[]; /* I: per-node nr_active */
};

--
2.45.2