Current way to set FR_WAITING in fuse_simple_background:
fuse_simple_background
	if (args->force)
		fuse_request_alloc
		/* need to increase num_waiting before request is queued */
	else
		fuse_get_req
			atomic_inc(&fc->num_waiting);
			__set_bit(FR_WAITING, &req->flags);

	fuse_request_queue_background
		if (!test_bit(FR_WAITING, &req->flags)
			__set_bit(FR_WAITING, &req->flags);
			atomic_inc(&fc->num_waiting);

We only need to increase num_waiting for force allocated reqeust in
fuse_request_queue_background. Simply increase num_waiting in force block
to remove unnecessary test_bit(FR_WAITING).
This patch also makes it more intuitive to remove FR_WATING usage in next
commit.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
---
 fs/fuse/dev.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index 1a8f82f478cb..59e1357d4880 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -528,10 +528,6 @@ static bool fuse_request_queue_background(struct fuse_req *req)
 	bool queued = false;
 
 	WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
-	if (!test_bit(FR_WAITING, &req->flags)) {
-		__set_bit(FR_WAITING, &req->flags);
-		atomic_inc(&fc->num_waiting);
-	}
 	__set_bit(FR_ISREPLY, &req->flags);
 	spin_lock(&fc->bg_lock);
 	if (likely(fc->connected)) {
@@ -553,10 +549,14 @@ int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
 	struct fuse_req *req;
 
 	if (args->force) {
+		struct fuse_conn *fc = fm->fc;
+
 		WARN_ON(!args->nocreds);
 		req = fuse_request_alloc(fm, gfp_flags);
 		if (!req)
 			return -ENOMEM;
+		atomic_inc(&fc->num_waiting);
+		__set_bit(FR_WAITING, &req->flags);
 		__set_bit(FR_BACKGROUND, &req->flags);
 	} else {
 		WARN_ON(args->nocreds);
-- 
2.30.0

On 9/4/23 16:30, Kemeng Shi wrote:
> Current way to set FR_WAITING in fuse_simple_background:
> fuse_simple_background
> 	if (args->force)
> 		fuse_request_alloc
> 		/* need to increase num_waiting before request is queued */
> 	else
> 		fuse_get_req
> 			atomic_inc(&fc->num_waiting);
> 			__set_bit(FR_WAITING, &req->flags);
> 
> 	fuse_request_queue_background
> 		if (!test_bit(FR_WAITING, &req->flags)
> 			__set_bit(FR_WAITING, &req->flags);
> 			atomic_inc(&fc->num_waiting);
> 
> We only need to increase num_waiting for force allocated reqeust in
> fuse_request_queue_background. Simply increase num_waiting in force block
> to remove unnecessary test_bit(FR_WAITING).
> This patch also makes it more intuitive to remove FR_WATING usage in next
> commit.

Very minor nit 'FR_WAITING'. The patch looks good to me.

> 
> Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
> ---
>   fs/fuse/dev.c | 8 ++++----
>   1 file changed, 4 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
> index 1a8f82f478cb..59e1357d4880 100644
> --- a/fs/fuse/dev.c
> +++ b/fs/fuse/dev.c
> @@ -528,10 +528,6 @@ static bool fuse_request_queue_background(struct fuse_req *req)
>   	bool queued = false;
>   
>   	WARN_ON(!test_bit(FR_BACKGROUND, &req->flags));
> -	if (!test_bit(FR_WAITING, &req->flags)) {
> -		__set_bit(FR_WAITING, &req->flags);
> -		atomic_inc(&fc->num_waiting);
> -	}
>   	__set_bit(FR_ISREPLY, &req->flags);
>   	spin_lock(&fc->bg_lock);
>   	if (likely(fc->connected)) {
> @@ -553,10 +549,14 @@ int fuse_simple_background(struct fuse_mount *fm, struct fuse_args *args,
>   	struct fuse_req *req;
>   
>   	if (args->force) {
> +		struct fuse_conn *fc = fm->fc;
> +
>   		WARN_ON(!args->nocreds);
>   		req = fuse_request_alloc(fm, gfp_flags);
>   		if (!req)
>   			return -ENOMEM;
> +		atomic_inc(&fc->num_waiting);
> +		__set_bit(FR_WAITING, &req->flags);
>   		__set_bit(FR_BACKGROUND, &req->flags);
>   	} else {
>   		WARN_ON(args->nocreds);