ceph: eliminate req->r_wait_for_completion from ceph_mds_request

...and instead just pass the wait function on the stack.

Make ceph_mdsc_wait_request non-static, and add an argument for wait for
completion. Then have ceph_lock_message call ceph_mdsc_submit_request,
and ceph_mdsc_wait_request and pass in the pointer to
ceph_lock_wait_for_completion.

While we're in there, rearrange some fields in ceph_mds_request, so we
save a total of 24 bytes per.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
---
 fs/ceph/locks.c      |  8 ++++----
 fs/ceph/mds_client.c | 11 ++++++-----
 fs/ceph/mds_client.h |  9 +++++----
 3 files changed, 15 insertions(+), 13 deletions(-)

v2: actually change ceph_mdsc_do_request to ceph_mdsc_submit_request

On 2/4/22 2:38 AM, Jeff Layton wrote:
> ...and instead just pass the wait function on the stack.
>
> Make ceph_mdsc_wait_request non-static, and add an argument for wait for
> completion. Then have ceph_lock_message call ceph_mdsc_submit_request,
> and ceph_mdsc_wait_request and pass in the pointer to
> ceph_lock_wait_for_completion.
>
> While we're in there, rearrange some fields in ceph_mds_request, so we
> save a total of 24 bytes per.
>
> Signed-off-by: Jeff Layton <jlayton@kernel.org>
> ---
>   fs/ceph/locks.c      |  8 ++++----
>   fs/ceph/mds_client.c | 11 ++++++-----
>   fs/ceph/mds_client.h |  9 +++++----
>   3 files changed, 15 insertions(+), 13 deletions(-)
>
> v2: actually change ceph_mdsc_do_request to ceph_mdsc_submit_request
>
> diff --git a/fs/ceph/locks.c b/fs/ceph/locks.c
> index d1f154aec249..3e2843e86e27 100644
> --- a/fs/ceph/locks.c
> +++ b/fs/ceph/locks.c
> @@ -111,10 +111,10 @@ static int ceph_lock_message(u8 lock_type, u16 operation, struct inode *inode,
>   	req->r_args.filelock_change.length = cpu_to_le64(length);
>   	req->r_args.filelock_change.wait = wait;
>   
> -	if (wait)
> -		req->r_wait_for_completion = ceph_lock_wait_for_completion;
> -
> -	err = ceph_mdsc_do_request(mdsc, inode, req);
> +	err = ceph_mdsc_submit_request(mdsc, inode, req);
> +	if (!err)
> +		err = ceph_mdsc_wait_request(mdsc, req, wait ?
> +					ceph_lock_wait_for_completion : NULL);
>   	if (!err && operation == CEPH_MDS_OP_GETFILELOCK) {
>   		fl->fl_pid = -le64_to_cpu(req->r_reply_info.filelock_reply->pid);
>   		if (CEPH_LOCK_SHARED == req->r_reply_info.filelock_reply->type)
> diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
> index 5937cbfafd31..72ba22de2b46 100644
> --- a/fs/ceph/mds_client.c
> +++ b/fs/ceph/mds_client.c
> @@ -2974,15 +2974,16 @@ int ceph_mdsc_submit_request(struct ceph_mds_client *mdsc, struct inode *dir,
>   	return err;
>   }
>   
> -static int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
> -				  struct ceph_mds_request *req)
> +int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
> +			   struct ceph_mds_request *req,
> +			   ceph_mds_request_wait_callback_t wait_func)
>   {
>   	int err;
>   
>   	/* wait */
>   	dout("do_request waiting\n");
> -	if (!req->r_timeout && req->r_wait_for_completion) {
> -		err = req->r_wait_for_completion(mdsc, req);
> +	if (wait_func) {
> +		err = wait_func(mdsc, req);
>   	} else {
>   		long timeleft = wait_for_completion_killable_timeout(
>   					&req->r_completion,
> @@ -3039,7 +3040,7 @@ int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
>   	/* issue */
>   	err = ceph_mdsc_submit_request(mdsc, dir, req);
>   	if (!err)
> -		err = ceph_mdsc_wait_request(mdsc, req);
> +		err = ceph_mdsc_wait_request(mdsc, req, NULL);
>   	dout("do_request %p done, result %d\n", req, err);
>   	return err;
>   }
> diff --git a/fs/ceph/mds_client.h b/fs/ceph/mds_client.h
> index 97c7f7bfa55f..ab12f3ce81a3 100644
> --- a/fs/ceph/mds_client.h
> +++ b/fs/ceph/mds_client.h
> @@ -274,8 +274,8 @@ struct ceph_mds_request {
>   
>   	union ceph_mds_request_args r_args;
>   	int r_fmode;        /* file mode, if expecting cap */
> -	const struct cred *r_cred;
>   	int r_request_release_offset;
> +	const struct cred *r_cred;
>   	struct timespec64 r_stamp;
>   
>   	/* for choosing which mds to send this request to */
> @@ -296,12 +296,11 @@ struct ceph_mds_request {
>   	struct ceph_msg  *r_reply;
>   	struct ceph_mds_reply_info_parsed r_reply_info;
>   	int r_err;
> -
> +	u32               r_readdir_offset;
>   
>   	struct page *r_locked_page;
>   	int r_dir_caps;
>   	int r_num_caps;
> -	u32               r_readdir_offset;
>   
>   	unsigned long r_timeout;  /* optional.  jiffies, 0 is "wait forever" */
>   	unsigned long r_started;  /* start time to measure timeout against */
> @@ -329,7 +328,6 @@ struct ceph_mds_request {
>   	struct completion r_completion;
>   	struct completion r_safe_completion;
>   	ceph_mds_request_callback_t r_callback;
> -	ceph_mds_request_wait_callback_t r_wait_for_completion;
>   	struct list_head  r_unsafe_item;  /* per-session unsafe list item */
>   
>   	long long	  r_dir_release_cnt;
> @@ -507,6 +505,9 @@ ceph_mdsc_create_request(struct ceph_mds_client *mdsc, int op, int mode);
>   extern int ceph_mdsc_submit_request(struct ceph_mds_client *mdsc,
>   				    struct inode *dir,
>   				    struct ceph_mds_request *req);
> +int ceph_mdsc_wait_request(struct ceph_mds_client *mdsc,
> +			struct ceph_mds_request *req,
> +			ceph_mds_request_wait_callback_t wait_func);
>   extern int ceph_mdsc_do_request(struct ceph_mds_client *mdsc,
>   				struct inode *dir,
>   				struct ceph_mds_request *req);

LGTM.

Reviewed-by: Xiubo Li <xiubli@redhat.com>