ext4 crypto: shrink size of the ext4_crypto_ctx structure
Some fields are only used when the crypto_ctx is being used on the
read path, some are only used on the write path, and some are only
used when the structure is on free list. Optimize memory use by using
a union.
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index 9969d05..28a0e4bd 100644
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -71,14 +71,14 @@
{
unsigned long flags;
- if (ctx->bounce_page) {
+ if (ctx->flags & EXT4_WRITE_PATH_FL && ctx->w.bounce_page) {
if (ctx->flags & EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL)
- __free_page(ctx->bounce_page);
+ __free_page(ctx->w.bounce_page);
else
- mempool_free(ctx->bounce_page, ext4_bounce_page_pool);
- ctx->bounce_page = NULL;
+ mempool_free(ctx->w.bounce_page, ext4_bounce_page_pool);
}
- ctx->control_page = NULL;
+ ctx->w.bounce_page = NULL;
+ ctx->w.control_page = NULL;
if (ctx->flags & EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL) {
if (ctx->tfm)
crypto_free_tfm(ctx->tfm);
@@ -134,6 +134,7 @@
} else {
ctx->flags &= ~EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
}
+ ctx->flags &= ~EXT4_WRITE_PATH_FL;
/* Allocate a new Crypto API context if we don't already have
* one or if it isn't the right mode. */
@@ -165,10 +166,6 @@
}
BUG_ON(ci->ci_size != ext4_encryption_key_size(ci->ci_data_mode));
- /* There shouldn't be a bounce page attached to the crypto
- * context at this point. */
- BUG_ON(ctx->bounce_page);
-
out:
if (res) {
if (!IS_ERR_OR_NULL(ctx))
@@ -189,15 +186,6 @@
struct ext4_crypto_ctx *pos, *n;
list_for_each_entry_safe(pos, n, &ext4_free_crypto_ctxs, free_list) {
- if (pos->bounce_page) {
- if (pos->flags &
- EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) {
- __free_page(pos->bounce_page);
- } else {
- mempool_free(pos->bounce_page,
- ext4_bounce_page_pool);
- }
- }
if (pos->tfm)
crypto_free_tfm(pos->tfm);
kmem_cache_free(ext4_crypto_ctx_cachep, pos);
@@ -425,8 +413,9 @@
} else {
ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
}
- ctx->bounce_page = ciphertext_page;
- ctx->control_page = plaintext_page;
+ ctx->flags |= EXT4_WRITE_PATH_FL;
+ ctx->w.bounce_page = ciphertext_page;
+ ctx->w.control_page = plaintext_page;
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,
plaintext_page, ciphertext_page);
if (err) {
@@ -505,7 +494,7 @@
} else {
ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
}
- ctx->bounce_page = ciphertext_page;
+ ctx->w.bounce_page = ciphertext_page;
while (len--) {
err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,