| blob | a3bd560334ba6d154f77de5d242421d636f8cf5a |
1 ext4 crypto: shrink size of the ext4_crypto_ctx structure
3 Some fields are only used when the crypto_ctx is being used on the
4 read path, some are only used on the write path, and some are only
5 used when the structure is on free list. Optimize memory use by using
6 a union.
8 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
9 ---
10 fs/ext4/crypto.c | 31 ++++++++++---------------------
11 fs/ext4/ext4_crypto.h | 21 ++++++++++++++-------
12 fs/ext4/page-io.c | 2 +-
13 fs/ext4/readpage.c | 10 +++++-----
14 4 files changed, 30 insertions(+), 34 deletions(-)
16 diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
17 index 9969d05..28a0e4bd 100644
18 --- a/fs/ext4/crypto.c
19 +++ b/fs/ext4/crypto.c
20 @@ -71,14 +71,14 @@ void ext4_release_crypto_ctx(struct ext4_crypto_ctx *ctx)
21 {
22 unsigned long flags;
24 - if (ctx->bounce_page) {
25 + if (ctx->flags & EXT4_WRITE_PATH_FL && ctx->w.bounce_page) {
26 if (ctx->flags & EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL)
27 - __free_page(ctx->bounce_page);
28 + __free_page(ctx->w.bounce_page);
29 else
30 - mempool_free(ctx->bounce_page, ext4_bounce_page_pool);
31 - ctx->bounce_page = NULL;
32 + mempool_free(ctx->w.bounce_page, ext4_bounce_page_pool);
33 }
34 - ctx->control_page = NULL;
35 + ctx->w.bounce_page = NULL;
36 + ctx->w.control_page = NULL;
37 if (ctx->flags & EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL) {
38 if (ctx->tfm)
39 crypto_free_tfm(ctx->tfm);
40 @@ -134,6 +134,7 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
41 } else {
42 ctx->flags &= ~EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL;
43 }
44 + ctx->flags &= ~EXT4_WRITE_PATH_FL;
46 /* Allocate a new Crypto API context if we don't already have
47 * one or if it isn't the right mode. */
48 @@ -165,10 +166,6 @@ struct ext4_crypto_ctx *ext4_get_crypto_ctx(struct inode *inode)
49 }
50 BUG_ON(ci->ci_size != ext4_encryption_key_size(ci->ci_data_mode));
52 - /* There shouldn't be a bounce page attached to the crypto
53 - * context at this point. */
54 - BUG_ON(ctx->bounce_page);
55 -
56 out:
57 if (res) {
58 if (!IS_ERR_OR_NULL(ctx))
59 @@ -189,15 +186,6 @@ void ext4_exit_crypto(void)
60 struct ext4_crypto_ctx *pos, *n;
62 list_for_each_entry_safe(pos, n, &ext4_free_crypto_ctxs, free_list) {
63 - if (pos->bounce_page) {
64 - if (pos->flags &
65 - EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL) {
66 - __free_page(pos->bounce_page);
67 - } else {
68 - mempool_free(pos->bounce_page,
69 - ext4_bounce_page_pool);
70 - }
71 - }
72 if (pos->tfm)
73 crypto_free_tfm(pos->tfm);
74 kmem_cache_free(ext4_crypto_ctx_cachep, pos);
75 @@ -425,8 +413,9 @@ struct page *ext4_encrypt(struct inode *inode,
76 } else {
77 ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
78 }
79 - ctx->bounce_page = ciphertext_page;
80 - ctx->control_page = plaintext_page;
81 + ctx->flags |= EXT4_WRITE_PATH_FL;
82 + ctx->w.bounce_page = ciphertext_page;
83 + ctx->w.control_page = plaintext_page;
84 err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,
85 plaintext_page, ciphertext_page);
86 if (err) {
87 @@ -505,7 +494,7 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
88 } else {
89 ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
90 }
91 - ctx->bounce_page = ciphertext_page;
92 + ctx->w.bounce_page = ciphertext_page;
94 while (len--) {
95 err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,
96 diff --git a/fs/ext4/ext4_crypto.h b/fs/ext4/ext4_crypto.h
97 index 69faf0e..c5258f2 100644
98 --- a/fs/ext4/ext4_crypto.h
99 +++ b/fs/ext4/ext4_crypto.h
100 @@ -86,16 +86,23 @@ struct ext4_crypt_info {
102 #define EXT4_CTX_REQUIRES_FREE_ENCRYPT_FL 0x00000001
103 #define EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL 0x00000002
104 +#define EXT4_WRITE_PATH_FL 0x00000004
106 struct ext4_crypto_ctx {
107 struct crypto_tfm *tfm; /* Crypto API context */
108 - struct page *bounce_page; /* Ciphertext page on write path */
109 - struct page *control_page; /* Original page on write path */
110 - struct bio *bio; /* The bio for this context */
111 - struct work_struct work; /* Work queue for read complete path */
112 - struct list_head free_list; /* Free list */
113 - int flags; /* Flags */
114 - int mode; /* Encryption mode for tfm */
115 + union {
116 + struct {
117 + struct page *bounce_page; /* Ciphertext page */
118 + struct page *control_page; /* Original page */
119 + } w;
120 + struct {
121 + struct bio *bio;
122 + struct work_struct work;
123 + } r;
124 + struct list_head free_list; /* Free list */
125 + };
126 + char flags; /* Flags */
127 + char mode; /* Encryption mode for tfm */
128 };
130 struct ext4_completion_result {
131 diff --git a/fs/ext4/page-io.c b/fs/ext4/page-io.c
132 index 5765f88..79636e2 100644
133 --- a/fs/ext4/page-io.c
134 +++ b/fs/ext4/page-io.c
135 @@ -84,7 +84,7 @@ static void ext4_finish_bio(struct bio *bio)
136 /* The bounce data pages are unmapped. */
137 data_page = page;
138 ctx = (struct ext4_crypto_ctx *)page_private(data_page);
139 - page = ctx->control_page;
140 + page = ctx->w.control_page;
141 }
142 #endif
144 diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
145 index 171b9ac..ec3ef93 100644
146 --- a/fs/ext4/readpage.c
147 +++ b/fs/ext4/readpage.c
148 @@ -54,8 +54,8 @@ static void completion_pages(struct work_struct *work)
149 {
150 #ifdef CONFIG_EXT4_FS_ENCRYPTION
151 struct ext4_crypto_ctx *ctx =
152 - container_of(work, struct ext4_crypto_ctx, work);
153 - struct bio *bio = ctx->bio;
154 + container_of(work, struct ext4_crypto_ctx, r.work);
155 + struct bio *bio = ctx->r.bio;
156 struct bio_vec *bv;
157 int i;
159 @@ -109,9 +109,9 @@ static void mpage_end_io(struct bio *bio, int err)
160 if (err) {
161 ext4_release_crypto_ctx(ctx);
162 } else {
163 - INIT_WORK(&ctx->work, completion_pages);
164 - ctx->bio = bio;
165 - queue_work(ext4_read_workqueue, &ctx->work);
166 + INIT_WORK(&ctx->r.work, completion_pages);
167 + ctx->r.bio = bio;
168 + queue_work(ext4_read_workqueue, &ctx->r.work);
169 return;
170 }
171 }