f2fs crypto: shrink size of the f2fs_crypto_ctx structure

This patch integrates the below patch into f2fs.

"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>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 18 insertions, 22 deletions

diff --git a/fs/f2fs/crypto.c b/fs/f2fs/crypto.c
index e4058b92c774..6d38da11918d 100644
--- a/fs/f2fs/crypto.c
+++ b/fs/f2fs/crypto.c
@@ -82,14 +82,14 @@ void f2fs_release_crypto_ctx(struct f2fs_crypto_ctx *ctx)
 {
 	unsigned long flags;
 
-	if (ctx->bounce_page) {
+	if (ctx->flags & F2FS_WRITE_PATH_FL && ctx->w.bounce_page) {
 		if (ctx->flags & F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL)
-			__free_page(ctx->bounce_page);
+			__free_page(ctx->w.bounce_page);
 		else
-			mempool_free(ctx->bounce_page, f2fs_bounce_page_pool);
-		ctx->bounce_page = NULL;
+			mempool_free(ctx->w.bounce_page, f2fs_bounce_page_pool);
+		ctx->w.bounce_page = NULL;
 	}
-	ctx->control_page = NULL;
+	ctx->w.control_page = NULL;
 	if (ctx->flags & F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL) {
 		if (ctx->tfm)
 			crypto_free_tfm(ctx->tfm);
@@ -146,6 +146,7 @@ struct f2fs_crypto_ctx *f2fs_get_crypto_ctx(struct inode *inode)
 	} else {
 		ctx->flags &= ~F2FS_CTX_REQUIRES_FREE_ENCRYPT_FL;
 	}
+	ctx->flags &= ~F2FS_WRITE_PATH_FL;
 
 	/*
 	 * Allocate a new Crypto API context if we don't already have
@@ -181,12 +182,6 @@ struct f2fs_crypto_ctx *f2fs_get_crypto_ctx(struct inode *inode)
 	}
 	BUG_ON(ci->ci_size != f2fs_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))
@@ -203,8 +198,8 @@ out:
 static void completion_pages(struct work_struct *work)
 {
 	struct f2fs_crypto_ctx *ctx =
-		container_of(work, struct f2fs_crypto_ctx, work);
-	struct bio *bio	= ctx->bio;
+		container_of(work, struct f2fs_crypto_ctx, r.work);
+	struct bio *bio = ctx->r.bio;
 	struct bio_vec *bv;
 	int i;
 
@@ -225,9 +220,9 @@ static void completion_pages(struct work_struct *work)
 
 void f2fs_end_io_crypto_work(struct f2fs_crypto_ctx *ctx, struct bio *bio)
 {
-	INIT_WORK(&ctx->work, completion_pages);
-	ctx->bio = bio;
-	queue_work(f2fs_read_workqueue, &ctx->work);
+	INIT_WORK(&ctx->r.work, completion_pages);
+	ctx->r.bio = bio;
+	queue_work(f2fs_read_workqueue, &ctx->r.work);
 }
 
 /**
@@ -238,12 +233,12 @@ void f2fs_exit_crypto(void)
 	struct f2fs_crypto_ctx *pos, *n;
 
 	list_for_each_entry_safe(pos, n, &f2fs_free_crypto_ctxs, free_list) {
-		if (pos->bounce_page) {
+		if (pos->w.bounce_page) {
 			if (pos->flags &
 				F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL)
-				__free_page(pos->bounce_page);
+				__free_page(pos->w.bounce_page);
 			else
-				mempool_free(pos->bounce_page,
+				mempool_free(pos->w.bounce_page,
 						f2fs_bounce_page_pool);
 		}
 		if (pos->tfm)
@@ -335,7 +330,7 @@ void f2fs_restore_and_release_control_page(struct page **page)
 	ctx = (struct f2fs_crypto_ctx *)page_private(bounce_page);
 
 	/* restore control page */
-	*page = ctx->control_page;
+	*page = ctx->w.control_page;
 
 	f2fs_restore_control_page(bounce_page);
 }
@@ -492,8 +487,9 @@ struct page *f2fs_encrypt(struct inode *inode,
 	} else {
 		ctx->flags |= F2FS_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
 	}
-	ctx->bounce_page = ciphertext_page;
-	ctx->control_page = plaintext_page;
+	ctx->flags |= F2FS_WRITE_PATH_FL;
+	ctx->w.bounce_page = ciphertext_page;
+	ctx->w.control_page = plaintext_page;
 	err = f2fs_page_crypto(ctx, inode, F2FS_ENCRYPT, plaintext_page->index,
 					plaintext_page, ciphertext_page);
 	if (err) {