Commit 83e57e47 authored by Eric Biggers's avatar Eric Biggers
Browse files

fscrypt: optimize fscrypt_initialize() 

fscrypt_initialize() is a "one-time init" function that is called
whenever the key is set up for any inode on any filesystem.  Make it
implement "one-time init" more efficiently by not taking a global mutex
in the "already initialized case" and doing fewer pointer dereferences.

Link: https://lore.kernel.org/r/20230406181245.36091-1-ebiggers@kernel.org


Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
parent 41b2ad80

fs/crypto/crypto.c

+12 −7
Original line number Diff line number Diff line
@@ -308,19 +308,24 @@ EXPORT_SYMBOL(fscrypt_decrypt_block_inplace); 


/**

 * fscrypt_initialize() - allocate major buffers for fs encryption.

 * @cop_flags:  fscrypt operations flags

 * @sb: the filesystem superblock

 *

 * We only call this when we start accessing encrypted files, since it

 * results in memory getting allocated that wouldn't otherwise be used.

 *

 * Return: 0 on success; -errno on failure

 */

int fscrypt_initialize(unsigned int cop_flags)

int fscrypt_initialize(struct super_block *sb)

{

	int err = 0;

	mempool_t *pool;



	/* pairs with smp_store_release() below */

	if (likely(smp_load_acquire(&fscrypt_bounce_page_pool)))

		return 0;



	/* No need to allocate a bounce page pool if this FS won't use it. */

	if (cop_flags & FS_CFLG_OWN_PAGES)

	if (sb->s_cop->flags & FS_CFLG_OWN_PAGES)

		return 0;



	mutex_lock(&fscrypt_init_mutex);
@@ -328,11 +333,11 @@ int fscrypt_initialize(unsigned int cop_flags) 
		goto out_unlock;



	err = -ENOMEM;

	fscrypt_bounce_page_pool =

		mempool_create_page_pool(num_prealloc_crypto_pages, 0);

	if (!fscrypt_bounce_page_pool)

	pool = mempool_create_page_pool(num_prealloc_crypto_pages, 0);

	if (!pool)

		goto out_unlock;



	/* pairs with smp_load_acquire() above */

	smp_store_release(&fscrypt_bounce_page_pool, pool);

	err = 0;

out_unlock:

	mutex_unlock(&fscrypt_init_mutex);

fs/crypto/fscrypt_private.h

+1 −1
Original line number Diff line number Diff line
@@ -264,7 +264,7 @@ typedef enum { 


/* crypto.c */

extern struct kmem_cache *fscrypt_info_cachep;

int fscrypt_initialize(unsigned int cop_flags);

int fscrypt_initialize(struct super_block *sb);

int fscrypt_crypt_block(const struct inode *inode, fscrypt_direction_t rw,

			u64 lblk_num, struct page *src_page,

			struct page *dest_page, unsigned int len,

fs/crypto/keysetup.c

+1 −1
Original line number Diff line number Diff line
@@ -560,7 +560,7 @@ fscrypt_setup_encryption_info(struct inode *inode, 
	struct fscrypt_master_key *mk = NULL;

	int res;



	res = fscrypt_initialize(inode->i_sb->s_cop->flags);

	res = fscrypt_initialize(inode->i_sb);

	if (res)

		return res;