修改内核路径

hc

2024-05-14 bedbef8ad3e75a304af6361af235302bcc61d06b

 kernel/drivers/block/zram/zcomp.c
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@@ -1,10 +1,6 @@
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+// SPDX-License-Identifier: GPL-2.0-or-later
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 /*
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  * Copyright (C) 2014 Sergey Senozhatsky.
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- *
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- * This program is free software; you can redistribute it and/or
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- * modify it under the terms of the GNU General Public License
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- * as published by the Free Software Foundation; either version
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- * 2 of the License, or (at your option) any later version.
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  */
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 #include <linux/kernel.h>
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@@ -20,6 +16,7 @@
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 static const char * const backends[] = {
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 	"lzo",
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+	"lzo-rle",
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 #if IS_ENABLED(CONFIG_CRYPTO_LZ4)
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 	"lz4",
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 #endif
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@@ -32,7 +29,6 @@
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 #if IS_ENABLED(CONFIG_CRYPTO_ZSTD)
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 	"zstd",
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 #endif
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-	NULL
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 };
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 static void zcomp_strm_free(struct zcomp_strm *zstrm)
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@@ -40,19 +36,16 @@
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 	if (!IS_ERR_OR_NULL(zstrm->tfm))
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 		crypto_free_comp(zstrm->tfm);
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 	free_pages((unsigned long)zstrm->buffer, 1);
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-	kfree(zstrm);
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+	zstrm->tfm = NULL;
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+	zstrm->buffer = NULL;
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 }
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 /*
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- * allocate new zcomp_strm structure with ->tfm initialized by
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- * backend, return NULL on error
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+ * Initialize zcomp_strm structure with ->tfm initialized by backend, and
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+ * ->buffer. Return a negative value on error.
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  */
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-static struct zcomp_strm *zcomp_strm_alloc(struct zcomp *comp)
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+static int zcomp_strm_init(struct zcomp_strm *zstrm, struct zcomp *comp)
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 {
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-	struct zcomp_strm *zstrm = kmalloc(sizeof(*zstrm), GFP_KERNEL);
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-	if (!zstrm)
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-		return NULL;
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-
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 	zstrm->tfm = crypto_alloc_comp(comp->name, 0, 0);
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 	/*
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 	 * allocate 2 pages. 1 for compressed data, plus 1 extra for the
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@@ -61,19 +54,13 @@
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 	zstrm->buffer = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO, 1);
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 	if (IS_ERR_OR_NULL(zstrm->tfm) || !zstrm->buffer) {
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 		zcomp_strm_free(zstrm);
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-		zstrm = NULL;
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+		return -ENOMEM;
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 	}
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-	return zstrm;
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+	return 0;
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 }
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 bool zcomp_available_algorithm(const char *comp)
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 {
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-	int i;
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-
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-	i = __sysfs_match_string(backends, -1, comp);
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-	if (i >= 0)
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-		return true;
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-
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 	/*
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 	 * Crypto does not ignore a trailing new line symbol,
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 	 * so make sure you don't supply a string containing
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@@ -89,9 +76,9 @@
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 {
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 	bool known_algorithm = false;
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 	ssize_t sz = 0;
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-	int i = 0;
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+	int i;
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-	for (; backends[i]; i++) {
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+	for (i = 0; i < ARRAY_SIZE(backends); i++) {
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 		if (!strcmp(comp, backends[i])) {
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 			known_algorithm = true;
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 			sz += scnprintf(buf + sz, PAGE_SIZE - sz - 2,
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@@ -116,12 +103,13 @@
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 struct zcomp_strm *zcomp_stream_get(struct zcomp *comp)
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 {
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-	return *get_cpu_ptr(comp->stream);
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+	local_lock(&comp->stream->lock);
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+	return this_cpu_ptr(comp->stream);
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 }
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 void zcomp_stream_put(struct zcomp *comp)
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 {
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-	put_cpu_ptr(comp->stream);
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+	local_unlock(&comp->stream->lock);
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 }
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 int zcomp_compress(struct zcomp_strm *zstrm,
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@@ -162,17 +150,15 @@
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 {
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 	struct zcomp *comp = hlist_entry(node, struct zcomp, node);
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 	struct zcomp_strm *zstrm;
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+	int ret;
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-	if (WARN_ON(*per_cpu_ptr(comp->stream, cpu)))
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-		return 0;
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+	zstrm = per_cpu_ptr(comp->stream, cpu);
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+	local_lock_init(&zstrm->lock);
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-	zstrm = zcomp_strm_alloc(comp);
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-	if (IS_ERR_OR_NULL(zstrm)) {
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+	ret = zcomp_strm_init(zstrm, comp);
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+	if (ret)
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 		pr_err("Can't allocate a compression stream\n");
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-		return -ENOMEM;
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-	}
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-	*per_cpu_ptr(comp->stream, cpu) = zstrm;
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-	return 0;
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+	return ret;
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 }
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 int zcomp_cpu_dead(unsigned int cpu, struct hlist_node *node)
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@@ -180,10 +166,8 @@
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 	struct zcomp *comp = hlist_entry(node, struct zcomp, node);
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 	struct zcomp_strm *zstrm;
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-	zstrm = *per_cpu_ptr(comp->stream, cpu);
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-	if (!IS_ERR_OR_NULL(zstrm))
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-		zcomp_strm_free(zstrm);
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-	*per_cpu_ptr(comp->stream, cpu) = NULL;
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+	zstrm = per_cpu_ptr(comp->stream, cpu);
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+	zcomp_strm_free(zstrm);
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 	return 0;
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 }
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@@ -191,7 +175,7 @@
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 {
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 	int ret;
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-	comp->stream = alloc_percpu(struct zcomp_strm *);
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+	comp->stream = alloc_percpu(struct zcomp_strm);
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 	if (!comp->stream)
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 		return -ENOMEM;
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@@ -225,6 +209,11 @@
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 	struct zcomp *comp;
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 	int error;
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+	/*
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+	 * Crypto API will execute /sbin/modprobe if the compression module
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+	 * is not loaded yet. We must do it here, otherwise we are about to
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+	 * call /sbin/modprobe under CPU hot-plug lock.
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+	 */
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 	if (!zcomp_available_algorithm(compress))
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 		return ERR_PTR(-EINVAL);
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