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sysfs: remove s_sibling hacks 

sysfs: remove s_sibling hacks

s_sibling was used for three different purposes:
1) as a linked list of entries in the directory
2) as a linked list of entries to be deleted
3) as a pointer to "struct completion"

This patch removes the hack and introduces new union u which
holds pointers for cases 2) and 3).

This change is needed for the following patch that removes s_sibling at all
and replaces it with a rb tree.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Mikulas Patocka 2011-07-21 20:01:12 -04:00 committed by Greg Kroah-Hartman
parent 4f72c0cab4
commit 58f2a4c793
2 changed files with 12 additions and 12 deletions
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19
fs/sysfs/dir.c
View File

@ -154,7 +154,6 @@ struct sysfs_dirent *sysfs_get_active(struct sysfs_dirent *sd)
*/
void sysfs_put_active(struct sysfs_dirent *sd)
{
struct completion *cmpl;
int v;
if (unlikely(!sd))
@ -166,10 +165,9 @@ void sysfs_put_active(struct sysfs_dirent *sd)
return;
/* atomic_dec_return() is a mb(), we'll always see the updated
* sd->s_sibling.
* sd->u.completion.
*/
cmpl = (void *)sd->s_sibling;
complete(cmpl);
complete(sd->u.completion);
}
/**
@ -183,16 +181,16 @@ static void sysfs_deactivate(struct sysfs_dirent *sd)
DECLARE_COMPLETION_ONSTACK(wait);
int v;
BUG_ON(sd->s_sibling || !(sd->s_flags & SYSFS_FLAG_REMOVED));
BUG_ON(!(sd->s_flags & SYSFS_FLAG_REMOVED));
if (!(sysfs_type(sd) & SYSFS_ACTIVE_REF))
return;
sd->s_sibling = (void *)&wait;
sd->u.completion = (void *)&wait;
rwsem_acquire(&sd->dep_map, 0, 0, _RET_IP_);
/* atomic_add_return() is a mb(), put_active() will always see
* the updated sd->s_sibling.
* the updated sd->u.completion.
*/
v = atomic_add_return(SD_DEACTIVATED_BIAS, &sd->s_active);
@ -201,8 +199,6 @@ static void sysfs_deactivate(struct sysfs_dirent *sd)
wait_for_completion(&wait);
}
sd->s_sibling = NULL;
lock_acquired(&sd->dep_map, _RET_IP_);
rwsem_release(&sd->dep_map, 1, _RET_IP_);
}
@ -518,7 +514,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
}
sd->s_flags |= SYSFS_FLAG_REMOVED;
sd->s_sibling = acxt->removed;
sd->u.removed_list = acxt->removed;
acxt->removed = sd;
}
@ -542,8 +538,7 @@ void sysfs_addrm_finish(struct sysfs_addrm_cxt *acxt)
while (acxt->removed) {
struct sysfs_dirent *sd = acxt->removed;
acxt->removed = sd->s_sibling;
sd->s_sibling = NULL;
acxt->removed = sd->u.removed_list;
sysfs_deactivate(sd);
unmap_bin_file(sd);

5
fs/sysfs/sysfs.h
View File

@ -66,6 +66,11 @@ struct sysfs_dirent {
struct rb_node name_node;
union {
struct completion *completion;
struct sysfs_dirent *removed_list;
} u;
const void *s_ns; /* namespace tag */
union {
struct sysfs_elem_dir s_dir;