From 102a0743326a03cd1a1202ceda21e175b7d3575c Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Tue, 20 Feb 2024 01:20:52 +0000
Subject: [PATCH] add new system file
---
kernel/lib/crc-t10dif.c | 99 ++++++++++++++++++++++++++++++++++++++++---------
1 files changed, 80 insertions(+), 19 deletions(-)
diff --git a/kernel/lib/crc-t10dif.c b/kernel/lib/crc-t10dif.c
index 1ad33e5..1ed2ed4 100644
--- a/kernel/lib/crc-t10dif.c
+++ b/kernel/lib/crc-t10dif.c
@@ -1,11 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0-only
/*
* T10 Data Integrity Field CRC16 calculation
*
* Copyright (c) 2007 Oracle Corporation. All rights reserved.
* Written by Martin K. Petersen <martin.petersen@oracle.com>
- *
- * This source code is licensed under the GNU General Public License,
- * Version 2. See the file COPYING for more details.
*/
#include <linux/types.h>
@@ -14,30 +12,74 @@
#include <linux/err.h>
#include <linux/init.h>
#include <crypto/hash.h>
+#include <crypto/algapi.h>
#include <linux/static_key.h>
+#include <linux/notifier.h>
-static struct crypto_shash *crct10dif_tfm;
-static struct static_key crct10dif_fallback __read_mostly;
+static struct crypto_shash __rcu *crct10dif_tfm;
+static DEFINE_STATIC_KEY_TRUE(crct10dif_fallback);
+static DEFINE_MUTEX(crc_t10dif_mutex);
+static struct work_struct crct10dif_rehash_work;
+
+static int crc_t10dif_notify(struct notifier_block *self, unsigned long val, void *data)
+{
+ struct crypto_alg *alg = data;
+
+ if (val != CRYPTO_MSG_ALG_LOADED ||
+ strcmp(alg->cra_name, CRC_T10DIF_STRING))
+ return NOTIFY_DONE;
+
+ schedule_work(&crct10dif_rehash_work);
+ return NOTIFY_OK;
+}
+
+static void crc_t10dif_rehash(struct work_struct *work)
+{
+ struct crypto_shash *new, *old;
+
+ mutex_lock(&crc_t10dif_mutex);
+ old = rcu_dereference_protected(crct10dif_tfm,
+ lockdep_is_held(&crc_t10dif_mutex));
+ new = crypto_alloc_shash(CRC_T10DIF_STRING, 0, 0);
+ if (IS_ERR(new)) {
+ mutex_unlock(&crc_t10dif_mutex);
+ return;
+ }
+ rcu_assign_pointer(crct10dif_tfm, new);
+ mutex_unlock(&crc_t10dif_mutex);
+
+ if (old) {
+ synchronize_rcu();
+ crypto_free_shash(old);
+ } else {
+ static_branch_disable(&crct10dif_fallback);
+ }
+}
+
+static struct notifier_block crc_t10dif_nb = {
+ .notifier_call = crc_t10dif_notify,
+};
__u16 crc_t10dif_update(__u16 crc, const unsigned char *buffer, size_t len)
{
struct {
struct shash_desc shash;
- char ctx[2];
+ __u16 crc;
} desc;
int err;
- if (static_key_false(&crct10dif_fallback))
+ if (static_branch_unlikely(&crct10dif_fallback))
return crc_t10dif_generic(crc, buffer, len);
- desc.shash.tfm = crct10dif_tfm;
- desc.shash.flags = 0;
- *(__u16 *)desc.ctx = crc;
-
+ rcu_read_lock();
+ desc.shash.tfm = rcu_dereference(crct10dif_tfm);
+ desc.crc = crc;
err = crypto_shash_update(&desc.shash, buffer, len);
+ rcu_read_unlock();
+
BUG_ON(err);
- return *(__u16 *)desc.ctx;
+ return desc.crc;
}
EXPORT_SYMBOL(crc_t10dif_update);
@@ -49,22 +91,41 @@
static int __init crc_t10dif_mod_init(void)
{
- crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0);
- if (IS_ERR(crct10dif_tfm)) {
- static_key_slow_inc(&crct10dif_fallback);
- crct10dif_tfm = NULL;
- }
+ INIT_WORK(&crct10dif_rehash_work, crc_t10dif_rehash);
+ crypto_register_notifier(&crc_t10dif_nb);
+ crc_t10dif_rehash(&crct10dif_rehash_work);
return 0;
}
static void __exit crc_t10dif_mod_fini(void)
{
- crypto_free_shash(crct10dif_tfm);
+ crypto_unregister_notifier(&crc_t10dif_nb);
+ cancel_work_sync(&crct10dif_rehash_work);
+ crypto_free_shash(rcu_dereference_protected(crct10dif_tfm, 1));
}
module_init(crc_t10dif_mod_init);
module_exit(crc_t10dif_mod_fini);
-MODULE_DESCRIPTION("T10 DIF CRC calculation");
+static int crc_t10dif_transform_show(char *buffer, const struct kernel_param *kp)
+{
+ struct crypto_shash *tfm;
+ int len;
+
+ if (static_branch_unlikely(&crct10dif_fallback))
+ return sprintf(buffer, "fallback\n");
+
+ rcu_read_lock();
+ tfm = rcu_dereference(crct10dif_tfm);
+ len = snprintf(buffer, PAGE_SIZE, "%s\n",
+ crypto_shash_driver_name(tfm));
+ rcu_read_unlock();
+
+ return len;
+}
+
+module_param_call(transform, NULL, crc_t10dif_transform_show, NULL, 0444);
+
+MODULE_DESCRIPTION("T10 DIF CRC calculation (library API)");
MODULE_LICENSE("GPL");
MODULE_SOFTDEP("pre: crct10dif");
--
Gitblit v1.6.2