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Commit b406777e authored by Lars Ellenberg's avatar Lars Ellenberg Committed by Philipp Reisner
Browse files

drbd: introduce completion_ref and kref to struct drbd_request 



cherry-picked and adapted from drbd 9 devel branch

completion_ref will count pending events necessary for completion.
kref is for destruction.

This only introduces these new members of struct drbd_request,
a followup patch will make actual use of them.

Signed-off-by: default avatarPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: default avatarLars Ellenberg <lars.ellenberg@linbit.com>
parent 5df69ece

drivers/block/drbd/drbd_int.h

+5 −0
Original line number Original line Diff line number Diff line
@@ -577,6 +577,11 @@ struct drbd_request { 
	struct bio *master_bio;       /* master bio pointer */

	struct bio *master_bio;       /* master bio pointer */

	unsigned long rq_state; /* see comments above _req_mod() */

	unsigned long rq_state; /* see comments above _req_mod() */

	unsigned long start_time;

	unsigned long start_time;



	/* once it hits 0, we may complete the master_bio */

	atomic_t completion_ref;

	/* once it hits 0, we may destroy this drbd_request object */

	struct kref kref;

};

};





struct drbd_epoch {

struct drbd_epoch {

drivers/block/drbd/drbd_req.c

+19 −14
Original line number Original line Diff line number Diff line
@@ -85,17 +85,15 @@ static struct drbd_request *drbd_req_new(struct drbd_conf *mdev, 
	INIT_LIST_HEAD(&req->tl_requests);

	INIT_LIST_HEAD(&req->tl_requests);

	INIT_LIST_HEAD(&req->w.list);

	INIT_LIST_HEAD(&req->w.list);





	atomic_set(&req->completion_ref, 1);

	kref_init(&req->kref);

	return req;

	return req;

}

}





static void drbd_req_free(struct drbd_request *req)

static void drbd_req_destroy(struct kref *kref)

{

	mempool_free(req, drbd_request_mempool);

}



/* rw is bio_data_dir(), only READ or WRITE */

static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const int rw)

{

{

	struct drbd_request *req = container_of(kref, struct drbd_request, kref);

	struct drbd_conf *mdev = req->w.mdev;

	const unsigned long s = req->rq_state;

	const unsigned long s = req->rq_state;





	/* remove it from the transfer log.

	/* remove it from the transfer log.
@@ -109,7 +107,7 @@ static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const 
	/* if it was a write, we may have to set the corresponding

	/* if it was a write, we may have to set the corresponding

	 * bit(s) out-of-sync first. If it had a local part, we need to

	 * bit(s) out-of-sync first. If it had a local part, we need to

	 * release the reference to the activity log. */

	 * release the reference to the activity log. */

	if (rw == WRITE) {

	if (s & RQ_WRITE) {

		/* Set out-of-sync unless both OK flags are set

		/* Set out-of-sync unless both OK flags are set

		 * (local only or remote failed).

		 * (local only or remote failed).

		 * Other places where we set out-of-sync:

		 * Other places where we set out-of-sync:
@@ -146,7 +144,7 @@ static void _req_is_done(struct drbd_conf *mdev, struct drbd_request *req, const 
	if (s & RQ_POSTPONED)

	if (s & RQ_POSTPONED)

		drbd_restart_request(req);

		drbd_restart_request(req);

	else

	else

		drbd_req_free(req);

		mempool_free(req, drbd_request_mempool);

}

}





static void wake_all_senders(struct drbd_tconn *tconn) {

static void wake_all_senders(struct drbd_tconn *tconn) {
@@ -196,12 +194,10 @@ static 
void req_may_be_done(struct drbd_request *req)

void req_may_be_done(struct drbd_request *req)

{

{

	const unsigned long s = req->rq_state;

	const unsigned long s = req->rq_state;

	struct drbd_conf *mdev = req->w.mdev;

	int rw = req->rq_state & RQ_WRITE ? WRITE : READ;





	/* req->master_bio still present means: Not yet completed.

	/* req->master_bio still present means: Not yet completed.

	 *

	 *

	 * Unless this is RQ_POSTPONED, which will cause _req_is_done() to

	 * Unless this is RQ_POSTPONED, which will cause drbd_req_destroy() to

	 * queue it on the retry workqueue instead of destroying it.

	 * queue it on the retry workqueue instead of destroying it.

	 */

	 */

	if (req->master_bio && !(s & RQ_POSTPONED))

	if (req->master_bio && !(s & RQ_POSTPONED))
@@ -216,7 +212,7 @@ void req_may_be_done(struct drbd_request *req) 
		/* this is disconnected (local only) operation,

		/* this is disconnected (local only) operation,

		 * or protocol A, B, or C P_BARRIER_ACK,

		 * or protocol A, B, or C P_BARRIER_ACK,

		 * or killed from the transfer log due to connection loss. */

		 * or killed from the transfer log due to connection loss. */

		_req_is_done(mdev, req, rw);

		kref_put(&req->kref, drbd_req_destroy);

	}

	}

	/* else: network part and not DONE yet. that is

	/* else: network part and not DONE yet. that is

	 * protocol A, B, or C, barrier ack still pending... */

	 * protocol A, B, or C, barrier ack still pending... */
@@ -250,6 +246,15 @@ void req_may_be_completed(struct drbd_request *req, struct bio_and_error *m) 
	if (s & RQ_NET_PENDING)

	if (s & RQ_NET_PENDING)

		return;

		return;





	/* FIXME

	 * instead of all the RQ_FLAGS, actually use the completion_ref

	 * to decide if this is ready to be completed. */

	if (req->master_bio) {

		int complete = atomic_dec_and_test(&req->completion_ref);

		D_ASSERT(complete != 0);

	} else

		D_ASSERT(atomic_read(&req->completion_ref) == 0);



	if (req->master_bio) {

	if (req->master_bio) {

		int rw = bio_rw(req->master_bio);

		int rw = bio_rw(req->master_bio);
@@ -1113,7 +1118,7 @@ struct drbd_request *find_oldest_request(struct drbd_tconn *tconn) 
	 * and find the oldest not yet completed request */

	 * and find the oldest not yet completed request */

	struct drbd_request *r;

	struct drbd_request *r;

	list_for_each_entry(r, &tconn->transfer_log, tl_requests) {

	list_for_each_entry(r, &tconn->transfer_log, tl_requests) {

		if (r->rq_state & (RQ_NET_PENDING|RQ_LOCAL_PENDING))

		if (atomic_read(&r->completion_ref))

			return r;

			return r;

	}

	}

	return NULL;

	return NULL;