Commit c45c06d4 authored by Peter Newman's avatar Peter Newman Committed by Borislav Petkov (AMD)
Browse files

x86/resctrl: Factor rdtgroup lock for multi-file ops 



rdtgroup_kn_lock_live() can only release a kernfs reference for a single
file before waiting on the rdtgroup_mutex, limiting its usefulness for
operations on multiple files, such as rename.

Factor the work needed to respectively break and unbreak active
protection on an individual file into rdtgroup_kn_{get,put}().

No functional change.

Signed-off-by: default avatarPeter Newman <peternewman@google.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarReinette Chatre <reinette.chatre@intel.com>
Tested-by: default avatarBabu Moger <babu.moger@amd.com>
Link: https://lore.kernel.org/r/20230419125015.693566-2-peternewman@google.com
parent 2997d94b

arch/x86/kernel/cpu/resctrl/rdtgroup.c

+22 −13
Original line number Diff line number Diff line
@@ -2305,6 +2305,26 @@ static struct rdtgroup *kernfs_to_rdtgroup(struct kernfs_node *kn) 
	}

}



static void rdtgroup_kn_get(struct rdtgroup *rdtgrp, struct kernfs_node *kn)

{

	atomic_inc(&rdtgrp->waitcount);

	kernfs_break_active_protection(kn);

}



static void rdtgroup_kn_put(struct rdtgroup *rdtgrp, struct kernfs_node *kn)

{

	if (atomic_dec_and_test(&rdtgrp->waitcount) &&

	    (rdtgrp->flags & RDT_DELETED)) {

		if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||

		    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)

			rdtgroup_pseudo_lock_remove(rdtgrp);

		kernfs_unbreak_active_protection(kn);

		rdtgroup_remove(rdtgrp);

	} else {

		kernfs_unbreak_active_protection(kn);

	}

}



struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn)

{

	struct rdtgroup *rdtgrp = kernfs_to_rdtgroup(kn);
@@ -2312,8 +2332,7 @@ struct rdtgroup *rdtgroup_kn_lock_live(struct kernfs_node *kn) 
	if (!rdtgrp)

		return NULL;



	atomic_inc(&rdtgrp->waitcount);

	kernfs_break_active_protection(kn);

	rdtgroup_kn_get(rdtgrp, kn);



	mutex_lock(&rdtgroup_mutex);
@@ -2332,17 +2351,7 @@ void rdtgroup_kn_unlock(struct kernfs_node *kn) 
		return;



	mutex_unlock(&rdtgroup_mutex);



	if (atomic_dec_and_test(&rdtgrp->waitcount) &&

	    (rdtgrp->flags & RDT_DELETED)) {

		if (rdtgrp->mode == RDT_MODE_PSEUDO_LOCKSETUP ||

		    rdtgrp->mode == RDT_MODE_PSEUDO_LOCKED)

			rdtgroup_pseudo_lock_remove(rdtgrp);

		kernfs_unbreak_active_protection(kn);

		rdtgroup_remove(rdtgrp);

	} else {

		kernfs_unbreak_active_protection(kn);

	}

	rdtgroup_kn_put(rdtgrp, kn);

}



static int mkdir_mondata_all(struct kernfs_node *parent_kn,