kernel: start cleaning up VfsRequest

* I'm being more strict about the linked list state to hopefully ensure
  I'm not leaking any references.
* vfsreq_create was renamed to vfsreq_dispatchcopy as that name feels more
  clear. It copies its argument, and dispatches it.
* Requests for user backends are now handled more like requests for kernel
  backends - there's an accept() function that accepts a request.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/kernel/arch/amd64/driver/util.c b/src/kernel/arch/amd64/driver/util.c
index 0f0ee34..2b33849 100644
--- a/src/kernel/arch/amd64/driver/util.c
+++ b/src/kernel/arch/amd64/driver/util.c
@@ -26,6 +26,7 @@ bool postqueue_pop(VfsReq **queue, void (*accept)(VfsReq *)) {
 	VfsReq *req = *queue;
 	if (req == NULL) return false;
 	*queue = req->postqueue_next;
+	req->postqueue_next = NULL;
 	accept(req);
 	return true;
 }
@@ -45,6 +46,7 @@ void postqueue_ringreadall(VfsReq **queue, ring_t *r) {
 	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);