From bbf125500724befb010fee2f8f658f32512d8585 Mon Sep 17 00:00:00 2001
From: Thomas Schoebel-Theuer <mars@box>
Date: Tue, 18 Oct 2022 18:48:42 +0200
Subject: [PATCH] aio: v3 obey CONFIG_MARS_CANNOT_USE_AIO_ANYMORE

---
 kernel/mars.h             |  9 +++++++--
 kernel/mars_aio.c         | 17 ++++++++++++++++-
 kernel/mars_aio.h         |  3 +++
 kernel/sy_old/mars_proc.c |  4 ++++
 4 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/kernel/mars.h b/kernel/mars.h
index aa4c878d..0ea2fbca 100644
--- a/kernel/mars.h
+++ b/kernel/mars.h
@@ -473,6 +473,10 @@ extern const struct generic_brick_type *_qio_brick_type;
 extern const struct generic_brick_type *_aio_brick_type;
 extern const struct generic_brick_type *_sio_brick_type;
 
+#if defined(CONFIG_MARS_CANNOT_USE_AIO_ANYMORE) /* starting with kernel v5.10 */
+#define ENABLE_MARS_QIO
+#else /* !defined(CONFIG_MARS_CANNOT_USE_AIO_ANYMORE) */
+/* QIO may only work for kernels 5.1 <= $to_check <= 5.9 but Frankensteins are unknown */
 #if defined(IOCB_NOWAIT)			&&			\
 	/* see dde0c2e79848298cc25621ad080d47f94dbd7cce */		\
 	defined(IOCB_DSYNC)			&&			\
@@ -481,15 +485,16 @@ extern const struct generic_brick_type *_sio_brick_type;
 	!defined(CONFIG_MARS_PREFER_SIO)	&&			\
 	1
 #define ENABLE_MARS_QIO
-#else
+#else /* check whether AIO can be used in addition at kernels < v5.10 */
 #if !defined(CONFIG_MARS_PREFER_SIO)		&&			\
 	(defined(MARS_HAS_PREPATCH)		||			\
 	 defined(MARS_HAS_PREPATCH_V2)		||			\
 	 defined(MARS_HAS_PREPATCH_V3a)		||			\
-	 1)
+	 0) /* When there is no prepatch, AIO cannot work anymore */
 #define ENABLE_MARS_AIO
 #endif
 #endif
+#endif /* !CONFIG_MARS_CANNOT_USE_AIO_ANYMORE */
 
 #if defined(ENABLE_MARS_QIO)
 # define any_io_brick_type qio_brick_type
diff --git a/kernel/mars_aio.c b/kernel/mars_aio.c
index f551ee3b..aafac7ad 100644
--- a/kernel/mars_aio.c
+++ b/kernel/mars_aio.c
@@ -23,13 +23,14 @@
 
 /* HISTORIC - please avoid this ASAP
  */
+#include <linux/module.h>
+#if !defined(CONFIG_MARS_CANNOT_USE_AIO_ANYMORE)
 
 //#define BRICK_DEBUGGING
 #define MARS_DEBUGGING
 //#define IO_DEBUGGING
 
 #include <linux/kernel.h>
-#include <linux/module.h>
 #include <linux/version.h>
 #include <linux/string.h>
 #include <linux/list.h>
@@ -1438,3 +1439,17 @@ void exit_mars_aio(void)
 	MARS_DBG("exit_aio()\n");
 	aio_unregister_brick_type();
 }
+
+#else /* !CONFIG_MARS_CANNOT_USE_AIO_ANYMORE */
+
+int __init init_mars_aio(void)
+{
+	/* empty */
+	return 0;
+}
+
+void exit_mars_aio(void)
+{
+}
+
+#endif /* !CONFIG_MARS_CANNOT_USE_AIO_ANYMORE */
diff --git a/kernel/mars_aio.h b/kernel/mars_aio.h
index 32a2bfea..8723c797 100644
--- a/kernel/mars_aio.h
+++ b/kernel/mars_aio.h
@@ -25,6 +25,8 @@
  */
 #ifndef MARS_AIO_H
 #define MARS_AIO_H
+#include <linux/module.h>
+#if !defined(CONFIG_MARS_CANNOT_USE_AIO_ANYMORE)
 
 #include <linux/aio.h>
 #include <linux/syscalls.h>
@@ -124,4 +126,5 @@ struct aio_output {
 
 MARS_TYPES(aio);
 
+#endif /* !CONFIG_MARS_CANNOT_USE_AIO_ANYMORE */
 #endif
diff --git a/kernel/sy_old/mars_proc.c b/kernel/sy_old/mars_proc.c
index 057b1420..3b034606 100644
--- a/kernel/sy_old/mars_proc.c
+++ b/kernel/sy_old/mars_proc.c
@@ -533,10 +533,12 @@ struct ctl_table io_tuning_table[] = {
 	THRESHOLD_ENTRIES(&bio_submit_threshold, "bio_submit"),
 	THRESHOLD_ENTRIES(&bio_io_threshold[0],  "bio_io_r"),
 	THRESHOLD_ENTRIES(&bio_io_threshold[1],  "bio_io_w"),
+#if !defined(CONFIG_MARS_CANNOT_USE_AIO_ANYMORE)
 	THRESHOLD_ENTRIES(&aio_submit_threshold, "aio_submit"),
 	THRESHOLD_ENTRIES(&aio_io_threshold[0],  "aio_io_r"),
 	THRESHOLD_ENTRIES(&aio_io_threshold[1],  "aio_io_w"),
 	THRESHOLD_ENTRIES(&aio_sync_threshold,   "aio_sync"),
+#endif /* !CONFIG_MARS_CANNOT_USE_AIO_ANYMORE */
 	INT_ENTRY("if_nr_requests", if_nr_requests, 0600),
 #if defined(MARS_HAS_BIO_IO_ACCT) || defined(MARS_HAS_GENERIC_BLK_ACCOUNTING)
 	INT_ENTRY("if_io_acct", mars_io_acct, 0600),
@@ -620,7 +622,9 @@ struct ctl_table mars_table[] = {
 	INT_ENTRY("show_statistics_server", server_show_statist,  0600),
 	INT_ENTRY("show_connections",     global_show_connections, 0600),
 #endif
+#if !defined(CONFIG_MARS_CANNOT_USE_AIO_ANYMORE)
 	INT_ENTRY("aio_sync_mode",        aio_sync_mode,          0600),
+#endif /* !CONFIG_MARS_CANNOT_USE_AIO_ANYMORE */
 #ifdef CONFIG_MARS_DEBUG
 	INT_ENTRY("debug_crash_mode",     mars_crash_mode,        0600),
 	INT_ENTRY("debug_hang_mode",      mars_hang_mode,         0600),