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@xxxxxxxxxx> --- fs/sysfs/dir.c | 19 +++++++------------ fs/sysfs/sysfs.h | 5 +++++ 2 files changed, 12 insertions(+), 12 deletions(-) Index: linux-3.0-rc7-fast/fs/sysfs/dir.c =================================================================== --- linux-3.0-rc7-fast.orig/fs/sysfs/dir.c 2011-07-20 20:42:25.000000000 +0200 +++ linux-3.0-rc7-fast/fs/sysfs/dir.c 2011-07-20 20:55:15.000000000 +0200 @@ -157,7 +157,6 @@ struct sysfs_dirent *sysfs_get_active(st */ void sysfs_put_active(struct sysfs_dirent *sd) { - struct completion *cmpl; int v; if (unlikely(!sd)) @@ -169,10 +168,9 @@ void sysfs_put_active(struct sysfs_diren 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); } /** @@ -186,16 +184,16 @@ static void sysfs_deactivate(struct sysf 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); @@ -204,8 +202,6 @@ static void sysfs_deactivate(struct sysf wait_for_completion(&wait); } - sd->s_sibling = NULL; - lock_acquired(&sd->dep_map, _RET_IP_); rwsem_release(&sd->dep_map, 1, _RET_IP_); } @@ -521,7 +517,7 @@ void sysfs_remove_one(struct sysfs_addrm } sd->s_flags |= SYSFS_FLAG_REMOVED; - sd->s_sibling = acxt->removed; + sd->u.removed_list = acxt->removed; acxt->removed = sd; } @@ -545,8 +541,7 @@ void sysfs_addrm_finish(struct sysfs_add 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); Index: linux-3.0-rc7-fast/fs/sysfs/sysfs.h =================================================================== --- linux-3.0-rc7-fast.orig/fs/sysfs/sysfs.h 2011-07-20 20:42:12.000000000 +0200 +++ linux-3.0-rc7-fast/fs/sysfs/sysfs.h 2011-07-20 20:46:50.000000000 +0200 @@ -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; -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel