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>

1 files changed, 5 insertions, 5 deletions

diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index 171b9ac4b45e..ec3ef93a52db 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -54,8 +54,8 @@ static void completion_pages(struct work_struct *work)
 {
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
         struct ext4_crypto_ctx *ctx =
-                container_of(work, struct ext4_crypto_ctx, work);
-        struct bio      *bio    = ctx->bio;
+                container_of(work, struct ext4_crypto_ctx, r.work);
+        struct bio      *bio    = ctx->r.bio;
         struct bio_vec  *bv;
         int             i;
 
@@ -109,9 +109,9 @@ static void mpage_end_io(struct bio *bio, int err)
                 if (err) {
                         ext4_release_crypto_ctx(ctx);
                 } else {
-                        INIT_WORK(&ctx->work, completion_pages);
-                        ctx->bio = bio;
-                        queue_work(ext4_read_workqueue, &ctx->work);
+                        INIT_WORK(&ctx->r.work, completion_pages);
+                        ctx->r.bio = bio;
+                        queue_work(ext4_read_workqueue, &ctx->r.work);
                         return;
                 }
         }