kernel/driver: add postqueue_join / postqueue_pop

5 files changed, 30 insertions, 31 deletions

diff --git a/src/kernel/arch/amd64/driver/ps2.c b/src/kernel/arch/amd64/driver/ps2.c
index bac060e..196b890 100644
--- a/src/kernel/arch/amd64/driver/ps2.c
+++ b/src/kernel/arch/amd64/driver/ps2.c
@@ -63,16 +63,10 @@ void ps2_irq(void) {
 		if (!(status & 1)) break; /* read while data available */
 		if (status & (1 << 5)) {
 			ring_put1b((void*)&mouse_backlog, port_in8(PS2));
-			if (mouse_queue) {
-				accept(mouse_queue);
-				mouse_queue = mouse_queue->postqueue_next;
-			}
+			postqueue_pop(&mouse_queue, accept);
 		} else {
 			ring_put1b((void*)&kb_backlog, port_in8(PS2));
-			if (kb_queue) {
-				accept(kb_queue);
-				kb_queue = kb_queue->postqueue_next;
-			}
+			postqueue_pop(&kb_queue, accept);
 		}
 	}
 }
@@ -85,10 +79,7 @@ enum {
 
 static void read_backlog(struct vfs_request *req, ring_t *r, struct vfs_request **queue) {
 	if (ring_used(r) == 0) {
-		/* nothing to read, join queue */
-		assert(!req->postqueue_next);
-		while (*queue) queue = &(*queue)->postqueue_next;
-		*queue = req;
+		postqueue_join(queue, req);
 	} else if (req->caller) {
 		int len = req->output.len;
 		if (len < 0) len = 0;
diff --git a/src/kernel/arch/amd64/driver/rtl8139.c b/src/kernel/arch/amd64/driver/rtl8139.c
index 05a0f70..eb07494 100644
--- a/src/kernel/arch/amd64/driver/rtl8139.c
+++ b/src/kernel/arch/amd64/driver/rtl8139.c
@@ -1,4 +1,5 @@
 #include <kernel/arch/amd64/driver/rtl8139.h>
+#include <kernel/arch/amd64/driver/util.h>
 #include <kernel/arch/amd64/pci.h>
 #include <kernel/arch/amd64/port_io.h>
 #include <kernel/mem/virt.h>
@@ -94,10 +95,7 @@ void rtl8139_irq(void) {
 	/* bit 0 of cmd - Rx Buffer Empty
 	 * not a do while() because sometimes the bit is empty on IRQ. no clue why. */
 	while (!(port_in8(iobase + CMD) & 1)) {
-		if (blocked_on) {
-			accept(blocked_on);
-			blocked_on = blocked_on->postqueue_next;
-		} else {
+		if (!postqueue_pop(&blocked_on, accept)) {
 			rx_irq_enable(false);
 			break;
 		}
@@ -177,12 +175,7 @@ static void accept(struct vfs_request *req) {
 		case VFSOP_READ:
 			ret = try_rx(req->caller->pages, req->output.buf, req->output.len);
 			if (ret == WAIT) {
-				// TODO this is a pretty common pattern in drivers, try to make it unneeded
-				// TODO those asserts should actually be regular panic checks
-				assert(!req->postqueue_next);
-				struct vfs_request **slot = &blocked_on;
-				while (*slot) slot = &(*slot)->postqueue_next;
-				*slot = req;
+				postqueue_join(&blocked_on, req);
 				rx_irq_enable(true);
 			} else {
 				vfsreq_finish_short(req, ret);
diff --git a/src/kernel/arch/amd64/driver/serial.c b/src/kernel/arch/amd64/driver/serial.c
index 9ddb355..2b0812b 100644
--- a/src/kernel/arch/amd64/driver/serial.c
+++ b/src/kernel/arch/amd64/driver/serial.c
@@ -1,4 +1,5 @@
 #include <kernel/arch/amd64/driver/serial.h>
+#include <kernel/arch/amd64/driver/util.h>
 #include <kernel/arch/amd64/interrupts/irq.h>
 #include <kernel/arch/amd64/port_io.h>
 #include <kernel/mem/virt.h>
@@ -43,10 +44,7 @@ void serial_preinit(void) {
 
 void serial_irq(void) {
 	ring_put1b((void*)&backlog, port_in8(COM1));
-	if (blocked_on) {
-		accept(blocked_on);
-		blocked_on = blocked_on->postqueue_next;
-	}
+	postqueue_pop(&blocked_on, accept);
 }
 
 
@@ -71,11 +69,7 @@ static void accept(struct vfs_request *req) {
 			break;
 		case VFSOP_READ:
 			if (ring_used((void*)&backlog) == 0) {
-				/* nothing to read, join queue */
-				assert(!req->postqueue_next);
-				struct vfs_request **slot = &blocked_on;
-				while (*slot) slot = &(*slot)->postqueue_next;
-				*slot = req;
+				postqueue_join(&blocked_on, req);
 			} else if (req->caller) {
 				ret = ring_to_virt((void*)&backlog, req->caller->pages, req->output.buf, req->output.len);
 				// TODO output.len can overflow here
diff --git a/src/kernel/arch/amd64/driver/util.c b/src/kernel/arch/amd64/driver/util.c
index 11aecca..4eeaa0d 100644
--- a/src/kernel/arch/amd64/driver/util.c
+++ b/src/kernel/arch/amd64/driver/util.c
@@ -15,3 +15,20 @@ int req_readcopy(struct vfs_request *req, const void *buf, size_t len) {
 	/* read errors are ignored. TODO write a spec */
 	return req->output.len;
 }
+
+void postqueue_join(struct vfs_request **queue, struct vfs_request *req) {
+	if (req->postqueue_next)
+		panic_invalid_state();
+
+	while (*queue)
+		queue = &(*queue)->postqueue_next;
+	*queue = req;
+}
+
+bool postqueue_pop(struct vfs_request **queue, void (*accept)(struct vfs_request *)) {
+	struct vfs_request *req = *queue;
+	if (req == NULL) return false;
+	*queue = req->postqueue_next;
+	accept(req);
+	return true;
+}
diff --git a/src/kernel/arch/amd64/driver/util.h b/src/kernel/arch/amd64/driver/util.h
index c91605c..d89992a 100644
--- a/src/kernel/arch/amd64/driver/util.h
+++ b/src/kernel/arch/amd64/driver/util.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <stdbool.h>
 #include <stddef.h>
 
 struct vfs_request;
@@ -10,3 +11,6 @@ int req_readcopy(struct vfs_request *req, const void *buf, size_t len);
 	(req->input.kern && \
 	 req->input.len == plen && \
 	 memcmp(req->input.buf_kern, path, plen) == 0)
+
+void postqueue_join(struct vfs_request **queue, struct vfs_request *req);
+bool postqueue_pop(struct vfs_request **queue, void (*accept)(struct vfs_request *));