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authorChristoph Hellwig <hch@infradead.org>2013-09-04 15:04:39 +0200
committerAl Viro <viro@zeniv.linux.org.uk>2013-09-04 09:23:46 -0400
commit7b7a8665edd8db733980389b098530f9e4f630b2 (patch)
tree968d570a9f0c4d861226aefed2f5f97a131c8d53 /include
parent4b6ccca701ef5977d0ffbc2c932430dea88b38b6 (diff)
downloadlinux-linaro-stable-7b7a8665edd8db733980389b098530f9e4f630b2.tar.gz
direct-io: Implement generic deferred AIO completions
Add support to the core direct-io code to defer AIO completions to user context using a workqueue. This replaces opencoded and less efficient code in XFS and ext4 (we save a memory allocation for each direct IO) and will be needed to properly support O_(D)SYNC for AIO. The communication between the filesystem and the direct I/O code requires a new buffer head flag, which is a bit ugly but not avoidable until the direct I/O code stops abusing the buffer_head structure for communicating with the filesystems. Currently this creates a per-superblock unbound workqueue for these completions, which is taken from an earlier patch by Jan Kara. I'm not really convinced about this use and would prefer a "normal" global workqueue with a high concurrency limit, but this needs further discussion. JK: Fixed ext4 part, dynamic allocation of the workqueue. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'include')
-rw-r--r--include/linux/buffer_head.h2
-rw-r--r--include/linux/fs.h7
2 files changed, 7 insertions, 2 deletions
diff --git a/include/linux/buffer_head.h b/include/linux/buffer_head.h
index 91fa9a94ae92..d77797a52b7b 100644
--- a/include/linux/buffer_head.h
+++ b/include/linux/buffer_head.h
@@ -36,6 +36,7 @@ enum bh_state_bits {
BH_Quiet, /* Buffer Error Prinks to be quiet */
BH_Meta, /* Buffer contains metadata */
BH_Prio, /* Buffer should be submitted with REQ_PRIO */
+ BH_Defer_Completion, /* Defer AIO completion to workqueue */
BH_PrivateStart,/* not a state bit, but the first bit available
* for private allocation by other entities
@@ -128,6 +129,7 @@ BUFFER_FNS(Write_EIO, write_io_error)
BUFFER_FNS(Unwritten, unwritten)
BUFFER_FNS(Meta, meta)
BUFFER_FNS(Prio, prio)
+BUFFER_FNS(Defer_Completion, defer_completion)
#define bh_offset(bh) ((unsigned long)(bh)->b_data & ~PAGE_MASK)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 65c9929cd340..c9013876eb29 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -46,6 +46,7 @@ struct vfsmount;
struct cred;
struct swap_info_struct;
struct seq_file;
+struct workqueue_struct;
extern void __init inode_init(void);
extern void __init inode_init_early(void);
@@ -63,8 +64,7 @@ struct buffer_head;
typedef int (get_block_t)(struct inode *inode, sector_t iblock,
struct buffer_head *bh_result, int create);
typedef void (dio_iodone_t)(struct kiocb *iocb, loff_t offset,
- ssize_t bytes, void *private, int ret,
- bool is_async);
+ ssize_t bytes, void *private);
#define MAY_EXEC 0x00000001
#define MAY_WRITE 0x00000002
@@ -1328,6 +1328,9 @@ struct super_block {
/* Being remounted read-only */
int s_readonly_remount;
+
+ /* AIO completions deferred from interrupt context */
+ struct workqueue_struct *s_dio_done_wq;
};
/* superblock cache pruning functions */