[PATCH] eCryptfs: Reduce stack usage in ecryptfs_generate_key_packet_set()
eCryptfs is gobbling a lot of stack in ecryptfs_generate_key_packet_set() because it allocates a temporary memory-hungry ecryptfs_key_record struct. This patch introduces a new kmem_cache for that struct and converts ecryptfs_generate_key_packet_set() to use it. Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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29dbb3fc80
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@ -467,6 +467,7 @@ extern struct kmem_cache *ecryptfs_header_cache_1;
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extern struct kmem_cache *ecryptfs_header_cache_2;
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extern struct kmem_cache *ecryptfs_xattr_cache;
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extern struct kmem_cache *ecryptfs_lower_page_cache;
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extern struct kmem_cache *ecryptfs_key_record_cache;
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int ecryptfs_interpose(struct dentry *hidden_dentry,
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struct dentry *this_dentry, struct super_block *sb,
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@ -1638,6 +1638,8 @@ out:
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return rc;
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}
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struct kmem_cache *ecryptfs_key_record_cache;
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/**
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* ecryptfs_generate_key_packet_set
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* @dest: Virtual address from which to write the key record set
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@ -1664,50 +1666,55 @@ ecryptfs_generate_key_packet_set(char *dest_base,
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&ecryptfs_superblock_to_private(
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ecryptfs_dentry->d_sb)->mount_crypt_stat;
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size_t written;
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struct ecryptfs_key_record key_rec;
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struct ecryptfs_key_record *key_rec;
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int rc = 0;
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(*len) = 0;
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key_rec = kmem_cache_alloc(ecryptfs_key_record_cache, GFP_KERNEL);
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if (!key_rec) {
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rc = -ENOMEM;
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goto out;
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}
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if (mount_crypt_stat->global_auth_tok) {
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auth_tok = mount_crypt_stat->global_auth_tok;
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if (auth_tok->token_type == ECRYPTFS_PASSWORD) {
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rc = write_tag_3_packet((dest_base + (*len)),
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max, auth_tok,
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crypt_stat, &key_rec,
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crypt_stat, key_rec,
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&written);
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if (rc) {
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ecryptfs_printk(KERN_WARNING, "Error "
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"writing tag 3 packet\n");
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goto out;
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goto out_free;
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}
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(*len) += written;
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/* Write auth tok signature packet */
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rc = write_tag_11_packet(
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(dest_base + (*len)),
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(max - (*len)),
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key_rec.sig, ECRYPTFS_SIG_SIZE, &written);
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key_rec->sig, ECRYPTFS_SIG_SIZE, &written);
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if (rc) {
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ecryptfs_printk(KERN_ERR, "Error writing "
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"auth tok signature packet\n");
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goto out;
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goto out_free;
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}
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(*len) += written;
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} else if (auth_tok->token_type == ECRYPTFS_PRIVATE_KEY) {
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rc = write_tag_1_packet(dest_base + (*len),
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max, auth_tok,
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crypt_stat,mount_crypt_stat,
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&key_rec, &written);
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key_rec, &written);
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if (rc) {
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ecryptfs_printk(KERN_WARNING, "Error "
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"writing tag 1 packet\n");
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goto out;
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goto out_free;
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}
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(*len) += written;
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} else {
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ecryptfs_printk(KERN_WARNING, "Unsupported "
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"authentication token type\n");
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rc = -EINVAL;
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goto out;
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goto out_free;
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}
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} else
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BUG();
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@ -1717,6 +1724,9 @@ ecryptfs_generate_key_packet_set(char *dest_base,
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ecryptfs_printk(KERN_ERR, "Error writing boundary byte\n");
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rc = -EIO;
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}
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out_free:
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kmem_cache_free(ecryptfs_key_record_cache, key_rec);
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out:
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if (rc)
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(*len) = 0;
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@ -651,6 +651,11 @@ static struct ecryptfs_cache_info {
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.name = "ecryptfs_lower_page_cache",
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.size = PAGE_CACHE_SIZE,
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},
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{
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.cache = &ecryptfs_key_record_cache,
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.name = "ecryptfs_key_record_cache",
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.size = sizeof(struct ecryptfs_key_record),
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},
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};
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static void ecryptfs_free_kmem_caches(void)
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