bcm27xx: add support for linux v5.15

Build system: x86_64
Build-tested: bcm2708, bcm2709, bcm2710, bcm2711
Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B

Signed-off-by: Marty Jones <mj8263788@gmail.com>
Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 125 insertions, 0 deletions

diff --git a/target/linux/bcm27xx/patches-5.15/950-0235-zswap-Defer-zswap-initialisation.patch b/target/linux/bcm27xx/patches-5.15/950-0235-zswap-Defer-zswap-initialisation.patch
new file mode 100644
index 0000000000..d9619f1c1d
--- /dev/null
+++ b/target/linux/bcm27xx/patches-5.15/950-0235-zswap-Defer-zswap-initialisation.patch
@@ -0,0 +1,125 @@
+From 42487c7c83a14fd00b69038932baf6373d422b59 Mon Sep 17 00:00:00 2001
+From: Phil Elwell <phil@raspberrypi.com>
+Date: Tue, 5 May 2020 15:23:32 +0100
+Subject: [PATCH] zswap: Defer zswap initialisation
+
+Enabling zswap support in the kernel configuration costs about 1.5MB
+of RAM, even when zswap is not enabled at runtime. This cost can be
+reduced significantly by deferring initialisation (including pool
+creation) until the "enabled" parameter is set to true. There is a
+small cost to this in that some initialisation code has to remain in
+memory after the init phase, just in case they are needed later,
+but the total size increase is negligible.
+
+See: https://github.com/raspberrypi/linux/pull/3432
+
+Signed-off-by: Phil Elwell <phil@raspberrypi.com>
+---
+ mm/zswap.c | 53 +++++++++++++++++++++++++++++------------------------
+ 1 file changed, 29 insertions(+), 24 deletions(-)
+
+--- a/mm/zswap.c
++++ b/mm/zswap.c
+@@ -648,8 +648,9 @@ error:
+ 	return NULL;
+ }
+ 
+-static __init struct zswap_pool *__zswap_pool_create_fallback(void)
++static bool zswap_try_pool_create(void)
+ {
++	struct zswap_pool *pool;
+ 	bool has_comp, has_zpool;
+ 
+ 	has_comp = crypto_has_acomp(zswap_compressor, 0, 0);
+@@ -685,9 +686,21 @@ static __init struct zswap_pool *__zswap
+ 	}
+ 
+ 	if (!has_comp || !has_zpool)
+-		return NULL;
++		return false;
++
++	pool = zswap_pool_create(zswap_zpool_type, zswap_compressor);
+ 
+-	return zswap_pool_create(zswap_zpool_type, zswap_compressor);
++	if (pool) {
++		pr_info("loaded using pool %s/%s\n", pool->tfm_name,
++			zpool_get_type(pool->zpool));
++		list_add(&pool->list, &zswap_pools);
++		zswap_has_pool = true;
++	} else {
++		pr_err("pool creation failed\n");
++		zswap_enabled = false;
++	}
++
++	return zswap_enabled;
+ }
+ 
+ static void zswap_pool_destroy(struct zswap_pool *pool)
+@@ -860,16 +873,19 @@ static int zswap_zpool_param_set(const c
+ static int zswap_enabled_param_set(const char *val,
+ 				   const struct kernel_param *kp)
+ {
++	int ret;
++
+ 	if (zswap_init_failed) {
+ 		pr_err("can't enable, initialization failed\n");
+ 		return -ENODEV;
+ 	}
+-	if (!zswap_has_pool && zswap_init_started) {
+-		pr_err("can't enable, no pool configured\n");
+-		return -ENODEV;
+-	}
+ 
+-	return param_set_bool(val, kp);
++	ret = param_set_bool(val, kp);
++	if (!ret && zswap_enabled && zswap_init_started && !zswap_has_pool)
++		if (!zswap_try_pool_create())
++			ret = -ENODEV;
++
++	return ret;
+ }
+ 
+ /*********************************
+@@ -1436,7 +1452,6 @@ static int __init zswap_debugfs_init(voi
+ **********************************/
+ static int __init init_zswap(void)
+ {
+-	struct zswap_pool *pool;
+ 	int ret;
+ 
+ 	zswap_init_started = true;
+@@ -1460,29 +1475,19 @@ static int __init init_zswap(void)
+ 	if (ret)
+ 		goto hp_fail;
+ 
+-	pool = __zswap_pool_create_fallback();
+-	if (pool) {
+-		pr_info("loaded using pool %s/%s\n", pool->tfm_name,
+-			zpool_get_type(pool->zpool));
+-		list_add(&pool->list, &zswap_pools);
+-		zswap_has_pool = true;
+-	} else {
+-		pr_err("pool creation failed\n");
+-		zswap_enabled = false;
+-	}
+-
+ 	shrink_wq = create_workqueue("zswap-shrink");
+ 	if (!shrink_wq)
+-		goto fallback_fail;
++		goto hp_fail;
+ 
+ 	frontswap_register_ops(&zswap_frontswap_ops);
+ 	if (zswap_debugfs_init())
+ 		pr_warn("debugfs initialization failed\n");
++
++	if (zswap_enabled)
++		zswap_try_pool_create();
++
+ 	return 0;
+ 
+-fallback_fail:
+-	if (pool)
+-		zswap_pool_destroy(pool);
+ hp_fail:
+ 	cpuhp_remove_state(CPUHP_MM_ZSWP_MEM_PREPARE);
+ dstmem_fail: