From 6fe8073de975ad7722043f9173fec068178e2eac Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sun, 14 Jul 2024 19:19:35 +0200
Subject: kernel: rework postqueue

Keeping its old name for now to make things easier for myself.

This might just be replaced by sys/queue.h soon.
---
 src/kernel/vfs/request.c | 59 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

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

diff --git a/src/kernel/vfs/request.c b/src/kernel/vfs/request.c
index d4ea16c..8f44afb 100644
--- a/src/kernel/vfs/request.c
+++ b/src/kernel/vfs/request.c
@@ -242,3 +242,62 @@ vfsback_provdown(VfsBackend *b)
 	}
 	vfsback_checkfree(b);
 }
+
+void
+postqueue_init(ReqQueue *q)
+{
+	q->head = NULL;
+}
+
+void
+postqueue_join(ReqQueue *q, VfsReq *req)
+{
+	if (req->postqueue_next)
+		panic_invalid_state();
+
+	VfsReq **it = &q->head;
+	while (*it != NULL) {
+		it = &(*it)->postqueue_next;
+	}
+	*it = req;
+}
+
+VfsReq *
+postqueue_pop(ReqQueue *q)
+{
+	VfsReq *req = q->head;
+	if (req) {
+		q->head = req->postqueue_next;
+		req->postqueue_next = NULL;
+	}
+	return req;
+}
+
+void
+postqueue_ringreadall(ReqQueue *q, ring_t *r)
+{
+	VfsReq **queue = &q->head; /* whatever */
+	VfsReq *req;
+	char tmp[64];
+	size_t mlen = 0;
+	if (ring_used(r) == 0) return;
+
+	/* read as much as the biggest request wants */
+	for (req = *queue; req; req = req->postqueue_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;
+
+		size_t ret = min(mlen, req->output.len);
+		assert(req->type == VFSOP_READ);
+		if (req->caller) {
+			pcpy_to(req->caller, req->output.buf, tmp, ret);
+		}
+		vfsreq_finish_short(req, ret);
+	}
+}
-- 
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