[PATCH 6/8] IB/hns: Replace counting semaphore event_sem with wait condition

[Binoy Jayan]

Counting semaphores are going away in the future, so replace the semaphore
hns_roce_cmdq::event_sem with an open-coded implementation.

Signed-off-by: Binoy Jayan <binoy.ja...@linaro.org>
---
 drivers/infiniband/hw/hns/hns_roce_cmd.c    | 16 ++++++++++++----
 drivers/infiniband/hw/hns/hns_roce_device.h |  3 ++-
 include/rdma/ib_sa.h                        |  5 +++++
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_cmd.c 
b/drivers/infiniband/hw/hns/hns_roce_cmd.c
index 1421fdb..3e76717 100644
--- a/drivers/infiniband/hw/hns/hns_roce_cmd.c
+++ b/drivers/infiniband/hw/hns/hns_roce_cmd.c
@@ -248,10 +248,14 @@ static int hns_roce_cmd_mbox_wait(struct hns_roce_dev 
*hr_dev, u64 in_param,
 {
        int ret = 0;
 
-       down(&hr_dev->cmd.event_sem);
+       wait_event(hr_dev->cmd.event_sem.wq,
+                  atomic_add_unless(&hr_dev->cmd.event_sem.count, -1, 0));
+
        ret = __hns_roce_cmd_mbox_wait(hr_dev, in_param, out_param,
                                       in_modifier, op_modifier, op, timeout);
-       up(&hr_dev->cmd.event_sem);
+
+       if (atomic_inc_return(&hr_dev->cmd.event_sem.count) == 1)
+               wake_up(&hr_dev->cmd.event_sem.wq);
 
        return ret;
 }
@@ -313,7 +317,9 @@ int hns_roce_cmd_use_events(struct hns_roce_dev *hr_dev)
        hr_cmd->context[hr_cmd->max_cmds - 1].next = -1;
        hr_cmd->free_head = 0;
 
-       sema_init(&hr_cmd->event_sem, hr_cmd->max_cmds);
+       init_waitqueue_head(&hr_cmd->event_sem.wq);
+       atomic_set(&hr_cmd->event_sem.count, hr_cmd->max_cmds);
+
        spin_lock_init(&hr_cmd->context_lock);
 
        hr_cmd->token_mask = CMD_TOKEN_MASK;
@@ -332,7 +338,9 @@ void hns_roce_cmd_use_polling(struct hns_roce_dev *hr_dev)
        hr_cmd->use_events = 0;
 
        for (i = 0; i < hr_cmd->max_cmds; ++i)
-               down(&hr_cmd->event_sem);
+               wait_event(hr_cmd->event_sem.wq,
+                          atomic_add_unless(
+                          &hr_dev->cmd.event_sem.count, -1, 0));
 
        kfree(hr_cmd->context);
        mutex_unlock(&hr_cmd->poll_mutex);
diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h 
b/drivers/infiniband/hw/hns/hns_roce_device.h
index 2afe075..6aed04a 100644
--- a/drivers/infiniband/hw/hns/hns_roce_device.h
+++ b/drivers/infiniband/hw/hns/hns_roce_device.h
@@ -34,6 +34,7 @@
 #define _HNS_ROCE_DEVICE_H
 
 #include <rdma/ib_verbs.h>
+#include <rdma/ib_sa.h>
 #include <linux/mutex.h>
 
 #define DRV_NAME "hns_roce"
@@ -364,7 +365,7 @@ struct hns_roce_cmdq {
        * Event mode: cmd register mutex protection,
        * ensure to not exceed max_cmds and user use limit region
        */
-       struct semaphore        event_sem;
+       struct ib_semaphore     event_sem;
        int                     max_cmds;
        spinlock_t              context_lock;
        int                     free_head;
diff --git a/include/rdma/ib_sa.h b/include/rdma/ib_sa.h
index 5ee7aab..1901042 100644
--- a/include/rdma/ib_sa.h
+++ b/include/rdma/ib_sa.h
@@ -291,6 +291,11 @@ struct ib_sa_service_rec {
 #define IB_SA_GUIDINFO_REC_GID6                IB_SA_COMP_MASK(10)
 #define IB_SA_GUIDINFO_REC_GID7                IB_SA_COMP_MASK(11)
 
+struct ib_semaphore {
+       wait_queue_head_t wq;
+       atomic_t count;
+};
+
 struct ib_sa_guidinfo_rec {
        __be16  lid;
        u8      block_num;
-- 
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