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Commit 58f2a4c7 authored by Mikulas Patocka's avatar Mikulas Patocka Committed by Greg Kroah-Hartman
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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: default avatarMikulas Patocka <mpatocka@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 4f72c0ca

fs/sysfs/dir.c

+7 −12
Original line number Diff line number Diff line
@@ -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);

fs/sysfs/sysfs.h

+5 −0
Original line number Diff line number Diff line
@@ -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;