From 881be872675e4cff153c27c641980451c4a3f479 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 14 Jul 2024 19:40:31 +0200
Subject: kernel: make the adhoc VfsQueue queues use ReqQueue instead

I'm still not sure if I should use sys/queue.h for this.
But yeah, this is more consistent, and it will also let me switch over to O(1)
insertions later on.
---
 src/kernel/vfs/request.c | 58 ++++++++++++++++++++----------------------------
 1 file changed, 24 insertions(+), 34 deletions(-)

(limited to 'src/kernel/vfs/request.c')

diff --git a/src/kernel/vfs/request.c b/src/kernel/vfs/request.c
index 8f44afb..58e2987 100644
--- a/src/kernel/vfs/request.c
+++ b/src/kernel/vfs/request.c
@@ -52,8 +52,7 @@ vfsreq_dispatchcopy(VfsReq tmpl)
 		vfsreq_finish_short(req, -EINVAL);
 		return;
 	}
-	assert(req->queue_next == NULL);
-	assert(req->postqueue_next == NULL);
+	assert(req->reqqueue_next == NULL);
 
 	if (backend == NULL) {
 		/* null mount - probably never had a real backend */
@@ -111,8 +110,7 @@ vfsreq_finish(VfsReq *req, char __user *stored, long ret, int flags, Proc *handl
 		vfsback_userdown(req->backend);
 	}
 
-	assert(req->queue_next == NULL);
-	assert(req->postqueue_next == NULL);
+	assert(req->reqqueue_next == NULL);
 
 	if (req->caller) {
 		assert(req->caller->state == PS_WAITS4FS);
@@ -134,17 +132,11 @@ vfsback_useraccept(VfsReq *req)
 	backend = req->backend;
 	assert(backend);
 	assert(backend->is_user);
-	if (backend->provhcnt == 0) {
+	if (backend->user.provhcnt == 0) {
 		vfsreq_finish_short(req, -EPIPE);
 		return;
 	} else if (backend->user.handler == NULL) {
-		/* queue the request up */
-		// TODO use postqueue
-		VfsReq **it = &backend->queue;
-		while (*it != NULL) { /* find a free spot in queue */
-			it = &(*it)->queue_next;
-		}
-		*it = req;
+		reqqueue_join(&backend->user.queue, req);
 		return;
 	}
 
@@ -194,8 +186,8 @@ vfsback_useraccept(VfsReq *req)
 static void
 vfsback_checkfree(VfsBackend *b)
 {
-	if (b->usehcnt == 0 && b->provhcnt == 0) {
-		assert(!b->queue);
+	if (b->is_user && b->usehcnt == 0 && b->user.provhcnt == 0) {
+		assert(b->user.queue.head == NULL);
 		kfree(b);
 	}
 }
@@ -227,54 +219,52 @@ void
 vfsback_provdown(VfsBackend *b)
 {
 	assert(b);
-	assert(0 < b->provhcnt);
-	b->provhcnt--;
-	if (b->provhcnt == 0) {
+	assert(b->is_user);
+	assert(0 < b->user.provhcnt);
+	b->user.provhcnt--;
+	if (b->user.provhcnt == 0) {
+		assert(b->is_user);
 		/* discard everything in the queue */
-		VfsReq *q = b->queue;
-		while (q) {
-			VfsReq *q2 = q->queue_next;
-			q->queue_next = NULL;
+		VfsReq *q;
+		while ((q = reqqueue_pop(&b->user.queue))) {
 			vfsreq_finish_short(q, -EPIPE);
-			q = q2;
 		}
-		b->queue = NULL;
 	}
 	vfsback_checkfree(b);
 }
 
 void
-postqueue_init(ReqQueue *q)
+reqqueue_init(ReqQueue *q)
 {
 	q->head = NULL;
 }
 
 void
-postqueue_join(ReqQueue *q, VfsReq *req)
+reqqueue_join(ReqQueue *q, VfsReq *req)
 {
-	if (req->postqueue_next)
+	if (req->reqqueue_next)
 		panic_invalid_state();
 
 	VfsReq **it = &q->head;
 	while (*it != NULL) {
-		it = &(*it)->postqueue_next;
+		it = &(*it)->reqqueue_next;
 	}
 	*it = req;
 }
 
 VfsReq *
-postqueue_pop(ReqQueue *q)
+reqqueue_pop(ReqQueue *q)
 {
 	VfsReq *req = q->head;
 	if (req) {
-		q->head = req->postqueue_next;
-		req->postqueue_next = NULL;
+		q->head = req->reqqueue_next;
+		req->reqqueue_next = NULL;
 	}
 	return req;
 }
 
 void
-postqueue_ringreadall(ReqQueue *q, ring_t *r)
+reqqueue_ringreadall(ReqQueue *q, ring_t *r)
 {
 	VfsReq **queue = &q->head; /* whatever */
 	VfsReq *req;
@@ -283,15 +273,15 @@ postqueue_ringreadall(ReqQueue *q, ring_t *r)
 	if (ring_used(r) == 0) return;
 
 	/* read as much as the biggest request wants */
-	for (req = *queue; req; req = req->postqueue_next)
+	for (req = *queue; req; req = req->reqqueue_next)
 		mlen = max(mlen, req->output.len);
 	mlen = min(mlen, sizeof tmp);
 	mlen = ring_get(r, tmp, mlen);
 
 	while (*queue) {
 		req = *queue;
-		*queue = req->postqueue_next;
-		req->postqueue_next = NULL;
+		*queue = req->reqqueue_next;
+		req->reqqueue_next = NULL;
 
 		size_t ret = min(mlen, req->output.len);
 		assert(req->type == VFSOP_READ);
-- 
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