From dc021c0469e061f5a7c0db78a8692ab54e33bc73 Mon Sep 17 00:00:00 2001
From: kamkow1 <kamkow256@gmail.com>
Date: Sat, 21 Feb 2026 15:52:31 +0100
Subject: [PATCH] Use a ring buffer for mail

---
 kernel/proc/mail.c     | 24 +++++++++++-------------
 kernel/proc/mail.h     | 11 +++++++++--
 kernel/proc/resource.c |  5 +++++
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/kernel/proc/mail.c b/kernel/proc/mail.c
index d979e78..cedb57d 100644
--- a/kernel/proc/mail.c
+++ b/kernel/proc/mail.c
@@ -1,5 +1,6 @@
 #include <libk/list.h>
 #include <libk/minmax.h>
+#include <libk/ringbuffer.h>
 #include <libk/std.h>
 #include <libk/string.h>
 #include <mm/liballoc.h>
@@ -15,10 +16,7 @@ void proc_cleanup_resource_mail (struct proc_resource* resource, struct reschedu
 
   spin_lock (&mail->resource->lock);
 
-  if (mail->pending_mesg != NULL)
-    free (mail->pending_mesg);
-
-  mail->pending_mesg_size = 0;
+  ringbuffer_fini (&mail->ringbuffer);
 
   spin_lock (&mail->send_sq.lock);
 
@@ -45,7 +43,7 @@ void proc_mail_send (struct proc* proc, struct proc_mail* mail, struct reschedul
   spin_lock (&mail->resource->lock);
 
   /* mail full */
-  if (mail->pending_mesg != NULL) {
+  if (mail->ringbuffer.count == mail->ringbuffer.capacity) {
     proc_sq_suspend (proc, &mail->send_sq, &mail->resource->lock, rctx);
     return;
   }
@@ -83,9 +81,9 @@ void proc_mail_send (struct proc* proc, struct proc_mail* mail, struct reschedul
   /* mail is empty and nobody is waiting */
   void* mesg = malloc (data_size);
   if (mesg != NULL) {
-    mail->pending_mesg = mesg;
-    memcpy (mail->pending_mesg, data, data_size);
-    mail->pending_mesg_size = data_size;
+    memcpy (mesg, data, data_size);
+    struct mail_packet packet = {.packet_buffer = mesg, .packet_size = data_size};
+    ringbuffer_push (struct mail_packet, &mail->ringbuffer, packet);
   }
 
   spin_unlock (&mail->resource->lock);
@@ -101,11 +99,11 @@ void proc_mail_receive (struct proc* proc, struct proc_mail* mail, struct resche
   spin_lock (&mail->resource->lock);
 
   /* consume mesg if available */
-  if (mail->pending_mesg != NULL) {
-    memcpy (recv_buffer, mail->pending_mesg, min (recv_size, mail->pending_mesg_size));
-    free (mail->pending_mesg);
-    mail->pending_mesg = NULL;
-    mail->pending_mesg_size = 0;
+  if (mail->ringbuffer.count > 0) {
+    struct mail_packet packet;
+    ringbuffer_pop (struct mail_packet, &mail->ringbuffer, &packet);
+    memcpy (recv_buffer, packet.packet_buffer, min (recv_size, packet.packet_size));
+    free (packet.packet_buffer);
 
     /* check for suspended sender */
     spin_lock (&mail->send_sq.lock);
diff --git a/kernel/proc/mail.h b/kernel/proc/mail.h
index 29cc9f7..d2fc949 100644
--- a/kernel/proc/mail.h
+++ b/kernel/proc/mail.h
@@ -2,21 +2,28 @@
 #define _KERNEL_PROC_MAIL_H
 
 #include <libk/list.h>
+#include <libk/ringbuffer.h>
 #include <libk/std.h>
 #include <proc/suspension_q.h>
 
+#define PROC_MAIL_MAX 1024
+
 struct proc;
 struct proc_resource;
 struct cpu;
 struct reschedule_ctx;
 
+struct mail_packet {
+  void* packet_buffer;
+  size_t packet_size;
+};
+
 struct proc_mail {
   struct proc_resource* resource;
 
   struct proc_suspension_q send_sq;
   struct proc_suspension_q recv_sq;
-  void* pending_mesg;
-  size_t pending_mesg_size;
+  struct ringbuffer ringbuffer;
 };
 
 void proc_cleanup_resource_mail (struct proc_resource* resource, struct reschedule_ctx* rctx);
diff --git a/kernel/proc/resource.c b/kernel/proc/resource.c
index a7c9bdf..0cc8b06 100644
--- a/kernel/proc/resource.c
+++ b/kernel/proc/resource.c
@@ -69,6 +69,11 @@ struct proc_resource* proc_create_resource_mail (struct procgroup* procgroup, in
   resource->rid = rid;
   resource->type = PR_MAIL;
 
+  if (!ringbuffer_init (&resource->u.mail.ringbuffer, PROC_MAIL_MAX, sizeof (struct mail_packet))) {
+    free (resource);
+    return NULL;
+  }
+
   spin_lock (&procgroup->lock);
   rbtree_insert (struct proc_resource, &procgroup->resource_tree, &resource->resource_tree_link,
                  resource_tree_link, rid);