Counting semaphores are going away in the future, so replace the semaphore
mthca_cmd::event_sem with a conditional wait_event.

Signed-off-by: Binoy Jayan <binoy.ja...@linaro.org>
---
 drivers/infiniband/hw/hns/hns_roce_cmd.c    | 46 ++++++++++++++++++++---------
 drivers/infiniband/hw/hns/hns_roce_device.h |  2 +-
 2 files changed, 33 insertions(+), 15 deletions(-)

diff --git a/drivers/infiniband/hw/hns/hns_roce_cmd.c 
b/drivers/infiniband/hw/hns/hns_roce_cmd.c
index 51a0675..12ef3d8 100644
--- a/drivers/infiniband/hw/hns/hns_roce_cmd.c
+++ b/drivers/infiniband/hw/hns/hns_roce_cmd.c
@@ -189,6 +189,34 @@ void hns_roce_cmd_event(struct hns_roce_dev *hr_dev, u16 
token, u8 status,
        complete(&context->done);
 }
 
+static inline struct hns_roce_cmd_context *
+hns_roce_try_get_context(struct hns_roce_cmdq *cmd)
+{
+       struct hns_roce_cmd_context *context = NULL;
+
+       spin_lock(&cmd->context_lock);
+
+       if (cmd->free_head < 0)
+               goto out;
+
+       context = &cmd->context[cmd->free_head];
+       context->token += cmd->token_mask + 1;
+       cmd->free_head = context->next;
+out:
+       spin_unlock(&cmd->context_lock);
+       return context;
+}
+
+/* wait for and acquire a free context */
+static inline struct hns_roce_cmd_context *
+hns_roce_get_free_context(struct hns_roce_cmdq *cmd)
+{
+       struct hns_roce_cmd_context *context;
+
+       wait_event(cmd->wq, (context = hns_roce_try_get_context(cmd)));
+       return context;
+}
+
 /* this should be called with "use_events" */
 static int __hns_roce_cmd_mbox_wait(struct hns_roce_dev *hr_dev, u64 in_param,
                                    u64 out_param, unsigned long in_modifier,
@@ -200,13 +228,7 @@ static int __hns_roce_cmd_mbox_wait(struct hns_roce_dev 
*hr_dev, u64 in_param,
        struct hns_roce_cmd_context *context;
        int ret = 0;
 
-       spin_lock(&cmd->context_lock);
-       WARN_ON(cmd->free_head < 0);
-       context = &cmd->context[cmd->free_head];
-       context->token += cmd->token_mask + 1;
-       cmd->free_head = context->next;
-       spin_unlock(&cmd->context_lock);
-
+       context = hns_roce_get_free_context(cmd);
        init_completion(&context->done);
 
        ret = hns_roce_cmd_mbox_post_hw(hr_dev, in_param, out_param,
@@ -238,6 +260,7 @@ static int __hns_roce_cmd_mbox_wait(struct hns_roce_dev 
*hr_dev, u64 in_param,
        context->next = cmd->free_head;
        cmd->free_head = context - cmd->context;
        spin_unlock(&cmd->context_lock);
+       wake_up(&cmd->wq);
 
        return ret;
 }
@@ -248,10 +271,8 @@ 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);
        ret = __hns_roce_cmd_mbox_wait(hr_dev, in_param, out_param,
                                       in_modifier, op_modifier, op, timeout);
-       up(&hr_dev->cmd.event_sem);
 
        return ret;
 }
@@ -313,7 +334,7 @@ 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->wq);
        spin_lock_init(&hr_cmd->context_lock);
 
        hr_cmd->token_mask = CMD_TOKEN_MASK;
@@ -325,12 +346,9 @@ int hns_roce_cmd_use_events(struct hns_roce_dev *hr_dev)
 void hns_roce_cmd_use_polling(struct hns_roce_dev *hr_dev)
 {
        struct hns_roce_cmdq *hr_cmd = &hr_dev->cmd;
-       int i;
 
        hr_cmd->use_events = 0;
-
-       for (i = 0; i < hr_cmd->max_cmds; ++i)
-               down(&hr_cmd->event_sem);
+       hr_cmd->free_head = -1;
 
        kfree(hr_cmd->context);
 }
diff --git a/drivers/infiniband/hw/hns/hns_roce_device.h 
b/drivers/infiniband/hw/hns/hns_roce_device.h
index 2afe075..ac95f52 100644
--- a/drivers/infiniband/hw/hns/hns_roce_device.h
+++ b/drivers/infiniband/hw/hns/hns_roce_device.h
@@ -364,7 +364,7 @@ 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;
+       wait_queue_head_t       wq;
        int                     max_cmds;
        spinlock_t              context_lock;
        int                     free_head;
-- 
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