+ mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/zswap: replace zswap_init_{started/failed} with zswap_init_state
has been added to the -mm mm-unstable branch.  Its filename is
     mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Liu Shixin <liushixin2@huawei.com>
Subject: mm/zswap: replace zswap_init_{started/failed} with zswap_init_state
Date: Sat, 27 Aug 2022 18:45:58 +0800

zswap_init_started indicates that the initialization is started.  And
zswap_init_failed indicates that the initialization is failed.  As we will
support to init zswap after system startup, it's necessary to add a state
to indicate the initialization is complete and succeed to avoid
concurrency issues.  Since we don't care about the difference between init
started with init completion.  We only need three states: uninitialized,
initial failed, initial succeed.

Link: https://lkml.kernel.org/r/20220827104600.1813214-4-liushixin2@huawei.com
Signed-off-by: Liu Shixin <liushixin2@huawei.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/zswap.c |   22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

--- a/mm/zswap.c~mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state
+++ a/mm/zswap.c
@@ -214,11 +214,12 @@ static DEFINE_SPINLOCK(zswap_pools_lock)
 /* pool counter to provide unique names to zpool */
 static atomic_t zswap_pools_count = ATOMIC_INIT(0);
 
-/* used by param callback function */
-static bool zswap_init_started;
+#define ZSWAP_UNINIT		0
+#define ZSWAP_INIT_SUCCEED	1
+#define ZSWAP_INIT_FAILED	2
 
-/* fatal error during init */
-static bool zswap_init_failed;
+/* init state */
+static int zswap_init_state;
 
 /* init completed, but couldn't create the initial pool */
 static bool zswap_has_pool;
@@ -772,7 +773,7 @@ static int __zswap_param_set(const char
 	char *s = strstrip((char *)val);
 	int ret;
 
-	if (zswap_init_failed) {
+	if (zswap_init_state == ZSWAP_INIT_FAILED) {
 		pr_err("can't set param, initialization failed\n");
 		return -ENODEV;
 	}
@@ -784,7 +785,7 @@ static int __zswap_param_set(const char
 	/* if this is load-time (pre-init) param setting,
 	 * don't create a pool; that's done during init.
 	 */
-	if (!zswap_init_started)
+	if (zswap_init_state == ZSWAP_UNINIT)
 		return param_set_charp(s, kp);
 
 	if (!type) {
@@ -875,11 +876,11 @@ static int zswap_zpool_param_set(const c
 static int zswap_enabled_param_set(const char *val,
 				   const struct kernel_param *kp)
 {
-	if (zswap_init_failed) {
+	if (zswap_init_state == ZSWAP_INIT_FAILED) {
 		pr_err("can't enable, initialization failed\n");
 		return -ENODEV;
 	}
-	if (!zswap_has_pool && zswap_init_started) {
+	if (!zswap_has_pool && zswap_init_state == ZSWAP_INIT_SUCCEED) {
 		pr_err("can't enable, no pool configured\n");
 		return -ENODEV;
 	}
@@ -1476,8 +1477,6 @@ static int __init init_zswap(void)
 	struct zswap_pool *pool;
 	int ret;
 
-	zswap_init_started = true;
-
 	if (zswap_entry_cache_create()) {
 		pr_err("entry cache creation failed\n");
 		goto cache_fail;
@@ -1517,6 +1516,7 @@ static int __init init_zswap(void)
 		goto destroy_wq;
 	if (zswap_debugfs_init())
 		pr_warn("debugfs initialization failed\n");
+	zswap_init_state = ZSWAP_INIT_SUCCEED;
 	return 0;
 
 destroy_wq:
@@ -1530,7 +1530,7 @@ dstmem_fail:
 	zswap_entry_cache_destroy();
 cache_fail:
 	/* if built-in, we aren't unloaded on failure; don't allow use */
-	zswap_init_failed = true;
+	zswap_init_state = ZSWAP_INIT_FAILED;
 	zswap_enabled = false;
 	return -ENOMEM;
 }
_

Patches currently in -mm which might be from liushixin2@huawei.com are

bootmem-remove-the-vmemmap-pages-from-kmemleak-in-put_page_bootmem.patch
frontswap-skip-frontswap_ops-init-if-zswap-init-failed.patch
frontswap-invoke-ops-init-for-online-swap-device-in-frontswap_register_ops.patch
mm-zswap-replace-zswap_init_started-failed-with-zswap_init_state.patch
mm-zswap-delay-the-initializaton-of-zswap-until-the-first-enablement.patch
mm-zswap-skip-confusing-print-info.patch