[PATCH 3/6] DIO: Rearrange fields in dio/dio_submit to avoid holes.

From: Andi Kleen
Date: Wed Jun 22 2011 - 15:21:47 EST


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Fix most problems reported by pahole.

There is still a weird 104 byte hole after map_bh. I'm not sure what
causes this.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
fs/direct-io.c | 13 ++++++-------
1 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/fs/direct-io.c b/fs/direct-io.c
index 823d2fe..03deca3 100644
--- a/fs/direct-io.c
+++ b/fs/direct-io.c
@@ -73,10 +73,10 @@ struct dio_submit {
sector_t block_in_file; /* Current offset into the underlying
file in dio_block units. */
unsigned blocks_available; /* At block_in_file. changes */
+ int reap_counter; /* rate limit reaping */
sector_t final_block_in_request;/* doesn't change */
unsigned first_block_in_page; /* doesn't change, Used only once */
int boundary; /* prev block is at a boundary */
- int reap_counter; /* rate limit reaping */
get_block_t *get_block; /* block mapping function */
dio_submit_t *submit_io; /* IO submition function */

@@ -114,27 +114,26 @@ struct dio_submit {
/* dio_state communicated between submission path and end_io */
struct dio {
int flags; /* doesn't change */
- struct inode *inode;
int rw;
+ struct inode *inode;
loff_t i_size; /* i_size when submitted */
dio_iodone_t *end_io; /* IO completion function */
- struct buffer_head map_bh; /* last get_block() result */


/* BIO completion state */
spinlock_t bio_lock; /* protects BIO fields below */
+ int page_errors; /* errno from get_user_pages() */
+ int is_async; /* is IO async ? */
+ int io_error; /* IO error in completion path */
unsigned long refcount; /* direct_io_worker() and bios */
struct bio *bio_list; /* singly linked via bi_private */
struct task_struct *waiter; /* waiting task (NULL if none) */

/* AIO related stuff */
struct kiocb *iocb; /* kiocb */
- int is_async; /* is IO async ? */
- int io_error; /* IO error in completion path */
ssize_t result; /* IO result */

- int page_errors; /* errno from get_user_pages() */
-
+ struct buffer_head map_bh; /* last get_block() result */
/*
* pages[] (and any fields placed after it) are not zeroed out at
* allocation time. Don't add new fields after pages[] unless you
--
1.7.4.4

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