ext4 crypto: use slab caches
Theodore Ts'o [Tue, 12 May 2015 15:22:05 +0000 (11:22 -0400)]
Use slab caches the ext4_crypto_ctx and ext4_crypt_info structures for
slighly better memory efficiency and debuggability.

Change-Id: If47986e2e29fa181d113864dcd9d1cae79c72639
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: "Theodore Ts'o" <tytso@google.com>

fs/ext4/crypto.c
fs/ext4/crypto_key.c
fs/ext4/ext4.h

index c879a7b..b879441 100644 (file)
@@ -55,6 +55,9 @@ static mempool_t *ext4_bounce_page_pool;
 static LIST_HEAD(ext4_free_crypto_ctxs);
 static DEFINE_SPINLOCK(ext4_crypto_ctx_lock);
 
+static struct kmem_cache *ext4_crypto_ctx_cachep;
+struct kmem_cache *ext4_crypt_info_cachep;
+
 /**
  * ext4_release_crypto_ctx() - Releases an encryption context
  * @ctx: The encryption context to release.
@@ -79,7 +82,7 @@ void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx)
        if (ctx->flags & EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL) {
                if (ctx->tfm)
                        crypto_free_tfm(ctx->tfm);
-               kfree(ctx);
+               kmem_cache_free(ext4_crypto_ctx_cachep, ctx);
        } else {
                spin_lock_irqsave(&ext4_crypto_ctx_lock, flags);
                list_add(&ctx->free_list, &ext4_free_crypto_ctxs);
@@ -88,23 +91,6 @@ void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx)
 }
 
 /**
- * ext4_alloc_and_init_crypto_ctx() - Allocates and inits an encryption context
- * @mask: The allocation mask.
- *
- * Return: An allocated and initialized encryption context on success. An error
- * value or NULL otherwise.
- */
-static struct ext4_crypto_ctx *ext4_alloc_and_init_crypto_ctx(gfp_t mask)
-{
-       struct ext4_crypto_ctx *ctx = kzalloc(sizeof(struct ext4_crypto_ctx),
-                                             mask);
-
-       if (!ctx)
-               return ERR_PTR(-ENOMEM);
-       return ctx;
-}
-
-/**
  * ext4_get_crypto_ctx() - Gets an encryption context
  * @inode:       The inode for which we are doing the crypto
  *
@@ -121,8 +107,6 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
        struct ext4_crypt_info *ci = EXT4_I(inode)->i_crypt_info;
 
        BUG_ON(ci == NULL);
-       if (!ext4_read_workqueue)
-               ext4_init_crypto();
 
        /*
         * We first try getting the ctx from a free list because in
@@ -141,9 +125,9 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
                list_del(&ctx->free_list);
        spin_unlock_irqrestore(&ext4_crypto_ctx_lock, flags);
        if (!ctx) {
-               ctx = ext4_alloc_and_init_crypto_ctx(GFP_NOFS);
-               if (IS_ERR(ctx)) {
-                       res = PTR_ERR(ctx);
+               ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS);
+               if (!ctx) {
+                       res = -ENOMEM;
                        goto out;
                }
                ctx->flags |= EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
@@ -217,7 +201,7 @@ void ext4_exit_crypto(void)
                }
                if (pos->tfm)
                        crypto_free_tfm(pos->tfm);
-               kfree(pos);
+               kmem_cache_free(ext4_crypto_ctx_cachep, pos);
        }
        INIT_LIST_HEAD(&ext4_free_crypto_ctxs);
        if (ext4_bounce_page_pool)
@@ -226,6 +210,12 @@ void ext4_exit_crypto(void)
        if (ext4_read_workqueue)
                destroy_workqueue(ext4_read_workqueue);
        ext4_read_workqueue = NULL;
+       if (ext4_crypto_ctx_cachep)
+               kmem_cache_destroy(ext4_crypto_ctx_cachep);
+       ext4_crypto_ctx_cachep = NULL;
+       if (ext4_crypt_info_cachep)
+               kmem_cache_destroy(ext4_crypt_info_cachep);
+       ext4_crypt_info_cachep = NULL;
 }
 
 /**
@@ -238,23 +228,31 @@ void ext4_exit_crypto(void)
  */
 int ext4_init_crypto(void)
 {
-       int i, res;
+       int i, res = -ENOMEM;
 
        mutex_lock(&crypto_init);
        if (ext4_read_workqueue)
                goto already_initialized;
        ext4_read_workqueue = alloc_workqueue("ext4_crypto", WQ_HIGHPRI, 0);
-       if (!ext4_read_workqueue) {
-               res = -ENOMEM;
+       if (!ext4_read_workqueue)
+               goto fail;
+
+       ext4_crypto_ctx_cachep = KMEM_CACHE(ext4_crypto_ctx,
+                                           SLAB_RECLAIM_ACCOUNT);
+       if (!ext4_crypto_ctx_cachep)
+               goto fail;
+
+       ext4_crypt_info_cachep = KMEM_CACHE(ext4_crypt_info,
+                                           SLAB_RECLAIM_ACCOUNT);
+       if (!ext4_crypt_info_cachep)
                goto fail;
-       }
 
        for (i = 0; i < num_prealloc_crypto_ctxs; i++) {
                struct ext4_crypto_ctx *ctx;
 
-               ctx = ext4_alloc_and_init_crypto_ctx(GFP_KERNEL);
-               if (IS_ERR(ctx)) {
-                       res = PTR_ERR(ctx);
+               ctx = kmem_cache_zalloc(ext4_crypto_ctx_cachep, GFP_NOFS);
+               if (!ctx) {
+                       res = -ENOMEM;
                        goto fail;
                }
                list_add(&ctx->free_list, &ext4_free_crypto_ctxs);
index ac46956..8b2dd43 100644 (file)
@@ -96,7 +96,7 @@ void ext4_free_encryption_info(struct inode *inode)
                key_put(ci->ci_keyring_key);
        crypto_free_ablkcipher(ci->ci_ctfm);
        memset(&ci->ci_raw, 0, sizeof(ci->ci_raw));
-       kfree(ci);
+       kmem_cache_free(ext4_crypt_info_cachep, ci);
        ei->i_crypt_info = NULL;
 }
 
@@ -113,6 +113,12 @@ int _ext4_get_encryption_info(struct inode *inode)
        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
        int res;
 
+       if (!ext4_read_workqueue) {
+               res = ext4_init_crypto();
+               if (res)
+                       return res;
+       }
+
        if (ei->i_crypt_info) {
                if (!ei->i_crypt_info->ci_keyring_key ||
                    key_validate(ei->i_crypt_info->ci_keyring_key) == 0)
@@ -134,7 +140,7 @@ int _ext4_get_encryption_info(struct inode *inode)
                return -EINVAL;
        res = 0;
 
-       crypt_info = kmalloc(sizeof(struct ext4_crypt_info), GFP_KERNEL);
+       crypt_info = kmem_cache_alloc(ext4_crypt_info_cachep, GFP_KERNEL);
        if (!crypt_info)
                return -ENOMEM;
 
@@ -188,7 +194,7 @@ out:
        if (res < 0) {
                if (res == -ENOKEY)
                        res = 0;
-               kfree(crypt_info);
+               kmem_cache_free(ext4_crypt_info_cachep, crypt_info);
        } else {
                ei->i_crypt_info = crypt_info;
                crypt_info->ci_keyring_key = keyring_key;
index c816a9b..2cb40d5 100644 (file)
@@ -2057,6 +2057,7 @@ int ext4_get_policy(struct inode *inode,
                    struct ext4_encryption_policy *policy);
 
 /* crypto.c */
+extern struct kmem_cache *ext4_crypt_info_cachep;
 bool ext4_valid_contents_enc_mode(uint32_t mode);
 uint32_t ext4_validate_encryption_key_size(uint32_t mode, uint32_t size);
 extern struct workqueue_struct *ext4_read_workqueue;