From 31d654e6503229c52172d72eaa018e1f274b6d48 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Fri, 6 May 2022 15:00:25 +0200
Subject: kernel: remove the union in `struct handle`

---
 src/kernel/handle.c      | 23 +++++++++--------------
 src/kernel/handle.h      | 12 ++----------
 src/kernel/syscalls.c    | 12 ++++++------
 src/kernel/vfs/request.c |  4 ++--
 4 files changed, 19 insertions(+), 32 deletions(-)

(limited to 'src/kernel')

diff --git a/src/kernel/handle.c b/src/kernel/handle.c
index 103c788..ac8db1f 100644
--- a/src/kernel/handle.c
+++ b/src/kernel/handle.c
@@ -16,22 +16,17 @@ void handle_close(struct handle *h) {
 	assert(h->refcount > 0);
 	if (--(h->refcount) > 0) return;
 
-	switch (h->type) {
-		case HANDLE_FILE:
-			vfsreq_create((struct vfs_request) {
-					.type = VFSOP_CLOSE,
-					.id = h->file.id,
-					.caller = NULL,
-					.backend = h->file.backend,
-				});
-			vfs_backend_refdown(h->file.backend);
-			break;
-		case HANDLE_FS_FRONT:
-			vfs_backend_refdown(h->fs.backend);
-			break;
-		case HANDLE_INVALID: panic_invalid_state();
+	if (h->type == HANDLE_FILE) {
+		vfsreq_create((struct vfs_request) {
+				.type = VFSOP_CLOSE,
+				.id = h->file_id,
+				.caller = NULL,
+				.backend = h->backend,
+			});
 	}
 
+	vfs_backend_refdown(h->backend);
+
 	// TODO sanity check to check if refcount is true. handle_sanity?
 
 	// TODO tests which would catch premature frees
diff --git a/src/kernel/handle.h b/src/kernel/handle.h
index c7a0728..088ff93 100644
--- a/src/kernel/handle.h
+++ b/src/kernel/handle.h
@@ -15,16 +15,8 @@ enum handle_type {
 
 struct handle {
 	enum handle_type type;
-	union {
-		// TODO consolidate backend fields
-		struct {
-			struct vfs_backend *backend;
-			int id;
-		} file;
-		struct {
-			struct vfs_backend *backend;
-		} fs;
-	};
+	struct vfs_backend *backend;
+	int file_id; // only applicable to HANDLE_FILE
 
 	size_t refcount;
 };
diff --git a/src/kernel/syscalls.c b/src/kernel/syscalls.c
index 59358a8..21b9cf2 100644
--- a/src/kernel/syscalls.c
+++ b/src/kernel/syscalls.c
@@ -66,7 +66,7 @@ int _syscall_fork(int flags, handle_t __user *fs_front) {
 
 		child->controlled = backend;
 
-		process_current->handles[front]->fs.backend = backend;
+		process_current->handles[front]->backend = backend;
 
 		if (fs_front) {
 			/* failure ignored. if you pass an invalid pointer to this function,
@@ -144,7 +144,7 @@ int _syscall_mount(handle_t hid, const char __user *path, int len) {
 	if (hid >= 0) { // mounting a real backend?
 		struct handle *handle = process_handle_get(process_current, hid, HANDLE_FS_FRONT);
 		if (!handle) goto fail;
-		backend = handle->fs.backend;
+		backend = handle->backend;
 		backend->refcount++;
 	} // otherwise backend == NULL
 
@@ -178,10 +178,10 @@ int _syscall_read(handle_t handle_num, void __user *buf, size_t len, int offset)
 				.buf = (userptr_t) buf,
 				.len = len,
 			},
-			.id = handle->file.id,
+			.id = handle->file_id,
 			.offset = offset,
 			.caller = process_current,
-			.backend = handle->file.backend,
+			.backend = handle->backend,
 		});
 	return -1; // dummy
 }
@@ -195,10 +195,10 @@ int _syscall_write(handle_t handle_num, const void __user *buf, size_t len, int
 				.buf = (userptr_t) buf,
 				.len = len,
 			},
-			.id = handle->file.id,
+			.id = handle->file_id,
 			.offset = offset,
 			.caller = process_current,
-			.backend = handle->file.backend,
+			.backend = handle->backend,
 		});
 	return -1; // dummy
 }
diff --git a/src/kernel/vfs/request.c b/src/kernel/vfs/request.c
index d6f348a..30c0e77 100644
--- a/src/kernel/vfs/request.c
+++ b/src/kernel/vfs/request.c
@@ -40,9 +40,9 @@ void vfsreq_finish(struct vfs_request *req, int ret) {
 				panic_invalid_state(); // we check for free handles before the open() call
 
 			struct handle *backing = handle_init(HANDLE_FILE);
-			backing->file.backend = req->backend;
+			backing->backend = req->backend;
 			req->backend->refcount++;
-			backing->file.id = ret;
+			backing->file_id = ret;
 			req->caller->handles[handle] = backing;
 			ret = handle;
 		} else {
-- 
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