From 9889b47b5216bdcd301e2b63baf71683bcbb22af Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Sat, 3 Sep 2022 14:56:05 +0200
Subject: driver/ps2,serial: handle all pending reads at the same time

---
 src/kernel/arch/amd64/driver/util.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

(limited to 'src/kernel/arch/amd64/driver/util.c')

diff --git a/src/kernel/arch/amd64/driver/util.c b/src/kernel/arch/amd64/driver/util.c
index 4eeaa0d..b8895b8 100644
--- a/src/kernel/arch/amd64/driver/util.c
+++ b/src/kernel/arch/amd64/driver/util.c
@@ -32,3 +32,25 @@ bool postqueue_pop(struct vfs_request **queue, void (*accept)(struct vfs_request
 	accept(req);
 	return true;
 }
+
+void postqueue_ringreadall(struct vfs_request **queue, ring_t *r) {
+	struct vfs_request *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);
+
+	for (req = *queue; req; req = req->postqueue_next) {
+		size_t ret = min(mlen, req->output.len);
+		assert(req->type == VFSOP_READ);
+		if (req->caller)
+			virt_cpy_to(req->caller->pages, req->output.buf, tmp, ret);
+		vfsreq_finish_short(req, ret);
+	}
+	*queue = NULL;
+}
-- 
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