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Zach Brown 848c4dd515 dio: zero struct dio with kzalloc instead of manually 
This patch uses kzalloc to zero all of struct dio rather than manually
trying to track which fields we rely on being zero.  It passed aio+dio
stress testing and some bug regression testing on ext3.

This patch was introduced by Linus in the conversation that lead up to
Badari's minimal fix to manually zero .map_bh.b_state in commit:

  6a648fa721

It makes the code a bit smaller.  Maybe a couple fewer cachelines to
load, if we're lucky:

   text    data     bss     dec     hex filename
3285925  568506 1304616 5159047  4eb887 vmlinux
3285797  568506 1304616 5158919  4eb807 vmlinux.patched

I was unable to measure a stable difference in the number of cpu cycles
spent in blockdev_direct_IO() when pushing aio+dio 256K reads at
~340MB/s.

So the resulting intent of the patch isn't a performance gain but to
avoid exposing ourselves to the risk of finding another field like
.map_bh.b_state where we rely on zeroing but don't enforce it in the
code.

Signed-off-by: Zach Brown <zach.brown@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-08-20 22:50:25 -07:00
..
9p 9p: fix debug compilation error 2007-07-16 16:03:25 -05:00
adfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
affs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
afs AFS: fix file locking 2007-07-31 15:39:40 -07:00
autofs
autofs4
befs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
bfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
cifs [CIFS] Check return code on failed alloc 2007-08-18 00:15:20 +00:00
coda coda: remove CODA_STORE/CODA_RELEASE upcalls 2007-07-21 17:49:14 -07:00
configfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
cramfs
debugfs debugfs: remove rmdir() non-empty complaint 2007-07-18 15:49:48 -07:00
devpts
dlm [DLM] fix basts for granted PR waiting CW 2007-08-14 10:31:02 +01:00
ecryptfs eCryptfs: fix error handling in ecryptfs_init 2007-08-11 15:47:40 -07:00
efs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
exportfs knfsd: exportfs: split out reconnecting a dentry from find_exported_dentry 2007-07-17 10:23:06 -07:00
ext2 fix inode_table test in ext234_check_descriptors 2007-07-26 11:35:17 -07:00
ext3 fix inode_table test in ext234_check_descriptors 2007-07-26 11:35:17 -07:00
ext4 "ext4_ext_put_in_cache" uses __u32 to receive physical block number 2007-07-31 15:39:37 -07:00
fat mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
freevxfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
fuse mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
gfs2 [GFS2] Revert remounting w/o acl option leaves acls enabled 2007-08-14 10:34:40 +01:00
hfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
hfsplus mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
hostfs
hpfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
hppfs
hugetlbfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
isofs isofs: mounting to regular file may succeed 2007-07-31 15:39:41 -07:00
jbd mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
jbd2 mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
jffs2 JFFS2 locking regression fix. 2007-08-20 22:44:27 -07:00
jfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
lockd lockd and nfsd endianness annotation fixes 2007-07-26 11:11:56 -07:00
minix mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
msdos
ncpfs NCP: delete test of long-deceased CONFIG_NCPFS_DEBUGDENTRY 2007-07-31 15:39:41 -07:00
nfs NFS: Replace flush_scheduled_work with cancel_work_sync() and friends 2007-08-07 16:12:50 -04:00
nfs_common
nfsd knfsd: eliminate unnecessary -ENOENT returns on export downcalls 2007-07-31 15:39:38 -07:00
nls NLS: Remove obsolete Makefile entries 2007-07-16 09:05:52 -07:00
ntfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
ocfs2 ocfs2: set non-default s_time_gran during mount 2007-08-09 17:27:58 -07:00
openpromfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
partitions [PARTITION]: Sun/Solaris VTOC table corrections 2007-07-30 00:27:31 -07:00
proc Fix leaks on /proc/{*/sched,sched_debug,timer_list,timer_stats} 2007-07-31 15:39:40 -07:00
qnx4 mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
ramfs NOMMU: Fix SYSV IPC SHM 2007-07-31 15:39:36 -07:00
reiserfs more reiserfs endianness annotations 2007-07-26 11:11:58 -07:00
romfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
smbfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
sysfs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
sysv mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
udf UDF: fix UID and GID mount option ignorance 2007-07-31 15:39:43 -07:00
ufs mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
vfat
xfs xfs ioctl __user annotations 2007-07-26 11:11:57 -07:00
aio.c
anon_inodes.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/avi/kvm 2007-07-17 11:50:26 -07:00
attr.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
bad_inode.c
binfmt_aout.c
binfmt_elf_fdpic.c coredump masking: ELF-FDPIC: enable core dump filtering 2007-07-19 10:04:47 -07:00
binfmt_elf.c revert "PIE randomization" 2007-07-21 17:49:14 -07:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c mm: variable length argument support 2007-07-19 10:04:45 -07:00
binfmt_script.c mm: variable length argument support 2007-07-19 10:04:45 -07:00
binfmt_som.c
bio.c [BLOCK] Get rid of request_queue_t typedef 2007-07-24 09:28:11 +02:00
block_dev.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
buffer.c fix some conversion overflows 2007-07-20 08:44:19 -07:00
char_dev.c unregister_chrdev() return void 2007-07-19 10:04:43 -07:00
compat_ioctl.c [PATCH] remove duplicated ioctl entries in compat_ioctl.c 2007-08-06 15:06:03 -04:00
compat.c mm: variable length argument support 2007-07-19 10:04:45 -07:00
dcache.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
dcookies.c Remove fs.h from mm.h 2007-07-29 17:09:29 -07:00
direct-io.c dio: zero struct dio with kzalloc instead of manually 2007-08-20 22:50:25 -07:00
dnotify.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
dquot.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
drop_caches.c invalidate_mapping_pages(): add cond_resched 2007-07-16 09:05:36 -07:00
eventfd.c
eventpoll.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
exec.c Reset current->pdeath_signal on SUID binary execution 2007-08-18 09:29:07 -07:00
fcntl.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
fifo.c
file_table.c
file.c
filesystems.c
fs-writeback.c
generic_acl.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
inode.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
inotify_user.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
inotify.c
internal.h
ioctl.c drop obsolete sys_ioctl export 2007-07-16 09:05:48 -07:00
ioprio.c
Kconfig NFSD/SUNRPC: Fix the automatic selection of RPCSEC_GSS 2007-07-19 15:09:02 -04:00
Kconfig.binfmt
libfs.c
locks.c rename setlease to generic_setlease 2007-07-31 15:39:43 -07:00
Makefile
mbcache.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
mpage.c
namei.c fs: remove path_walk export 2007-07-19 10:04:45 -07:00
namespace.c mm: Remove slab destructors from kmem_cache_create(). 2007-07-20 10:11:58 +09:00
nfsctl.c nfsctl: use vfs_path_lookup 2007-07-19 10:04:45 -07:00
no-block.c
open.c VFS: fix a race in lease-breaking during truncate 2007-07-31 15:39:42 -07:00
pipe.c docbook: add pipes, other fixes 2007-07-27 08:08:51 +02:00
pnode.c
pnode.h
posix_acl.c
quota_v1.c
quota_v2.c
quota.c [IA64] Fix build failure in fs/quota.c 2007-07-27 15:40:13 -07:00
read_write.c
read_write.h
readdir.c
select.c
seq_file.c seq_file: more atomicity in traverse() 2007-07-16 09:05:45 -07:00
signalfd.c tiny signalfd cleanup 2007-07-26 11:33:06 -07:00
splice.c docbook: add pipes, other fixes 2007-07-27 08:08:51 +02:00
stack.c
stat.c
super.c hugetlbfs: handle empty options string 2007-07-16 09:05:46 -07:00
sync.c
timerfd.c make timerfd return a u64 and fix the __put_user 2007-07-26 11:35:17 -07:00
utimes.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00
xattr_acl.c
xattr.c Introduce is_owner_or_cap() to wrap CAP_FOWNER use with fsuid check 2007-07-17 12:00:03 -07:00