Commit edf3d1ae authored by Eric Paris's avatar Eric Paris Committed by James Morris
Browse files

SELinux: code readability with avc_cache 



The code making use of struct avc_cache was not easy to read thanks to liberal
use of &avc_cache.{slots_lock,slots}[hvalue] throughout.  This patch simply
creates local pointers and uses those instead of the long global names.

Signed-off-by: default avatarEric Paris <eparis@redhat.com>
Signed-off-by: default avatarJames Morris <jmorris@namei.org>
parent f1c6381a

security/selinux/avc.c

+44 −19
Original line number Diff line number Diff line
@@ -92,12 +92,12 @@ struct avc_entry { 


struct avc_node {

	struct avc_entry	ae;

	struct list_head	list;

	struct list_head	list; /* anchored in avc_cache->slots[i] */

	struct rcu_head		rhead;

};



struct avc_cache {

	struct list_head	slots[AVC_CACHE_SLOTS];

	struct list_head	slots[AVC_CACHE_SLOTS]; /* head for avc_node->list */

	spinlock_t		slots_lock[AVC_CACHE_SLOTS]; /* lock for writes */

	atomic_t		lru_hint;	/* LRU hint for reclaim scan */

	atomic_t		active_nodes;
@@ -249,16 +249,18 @@ int avc_get_hash_stats(char *page) 
{

	int i, chain_len, max_chain_len, slots_used;

	struct avc_node *node;

	struct list_head *head;



	rcu_read_lock();



	slots_used = 0;

	max_chain_len = 0;

	for (i = 0; i < AVC_CACHE_SLOTS; i++) {

		if (!list_empty(&avc_cache.slots[i])) {

		head = &avc_cache.slots[i];

		if (!list_empty(head)) {

			slots_used++;

			chain_len = 0;

			list_for_each_entry_rcu(node, &avc_cache.slots[i], list)

			list_for_each_entry_rcu(node, head, list)

				chain_len++;

			if (chain_len > max_chain_len)

				max_chain_len = chain_len;
@@ -306,26 +308,30 @@ static inline int avc_reclaim_node(void) 
	struct avc_node *node;

	int hvalue, try, ecx;

	unsigned long flags;

	struct list_head *head;

	spinlock_t *lock;



	for (try = 0, ecx = 0; try < AVC_CACHE_SLOTS; try++) {

		hvalue = atomic_inc_return(&avc_cache.lru_hint) & (AVC_CACHE_SLOTS - 1);

		head = &avc_cache.slots[hvalue];

		lock = &avc_cache.slots_lock[hvalue];



		if (!spin_trylock_irqsave(&avc_cache.slots_lock[hvalue], flags))

		if (!spin_trylock_irqsave(lock, flags))

			continue;



		rcu_read_lock();

		list_for_each_entry(node, &avc_cache.slots[hvalue], list) {

		list_for_each_entry(node, head, list) {

			avc_node_delete(node);

			avc_cache_stats_incr(reclaims);

			ecx++;

			if (ecx >= AVC_CACHE_RECLAIM) {

				rcu_read_unlock();

				spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);

				spin_unlock_irqrestore(lock, flags);

				goto out;

			}

		}

		rcu_read_unlock();

		spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flags);

		spin_unlock_irqrestore(lock, flags);

	}

out:

	return ecx;
@@ -362,9 +368,11 @@ static inline struct avc_node *avc_search_node(u32 ssid, u32 tsid, u16 tclass) 
{

	struct avc_node *node, *ret = NULL;

	int hvalue;

	struct list_head *head;



	hvalue = avc_hash(ssid, tsid, tclass);

	list_for_each_entry_rcu(node, &avc_cache.slots[hvalue], list) {

	head = &avc_cache.slots[hvalue];

	list_for_each_entry_rcu(node, head, list) {

		if (ssid == node->ae.ssid &&

		    tclass == node->ae.tclass &&

		    tsid == node->ae.tsid) {
@@ -453,11 +461,17 @@ static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_dec 


	node = avc_alloc_node();

	if (node) {

		struct list_head *head;

		spinlock_t *lock;



		hvalue = avc_hash(ssid, tsid, tclass);

		avc_node_populate(node, ssid, tsid, tclass, avd);



		spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);

		list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {

		head = &avc_cache.slots[hvalue];

		lock = &avc_cache.slots_lock[hvalue];



		spin_lock_irqsave(lock, flag);

		list_for_each_entry(pos, head, list) {

			if (pos->ae.ssid == ssid &&

			    pos->ae.tsid == tsid &&

			    pos->ae.tclass == tclass) {
@@ -465,9 +479,9 @@ static struct avc_node *avc_insert(u32 ssid, u32 tsid, u16 tclass, struct av_dec 
				goto found;

			}

		}

		list_add_rcu(&node->list, &avc_cache.slots[hvalue]);

		list_add_rcu(&node->list, head);

found:

		spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);

		spin_unlock_irqrestore(lock, flag);

	}

out:

	return node;
@@ -736,6 +750,8 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, 
	int hvalue, rc = 0;

	unsigned long flag;

	struct avc_node *pos, *node, *orig = NULL;

	struct list_head *head;

	spinlock_t *lock;



	node = avc_alloc_node();

	if (!node) {
@@ -745,9 +761,13 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, 


	/* Lock the target slot */

	hvalue = avc_hash(ssid, tsid, tclass);

	spin_lock_irqsave(&avc_cache.slots_lock[hvalue], flag);



	list_for_each_entry(pos, &avc_cache.slots[hvalue], list) {

	head = &avc_cache.slots[hvalue];

	lock = &avc_cache.slots_lock[hvalue];



	spin_lock_irqsave(lock, flag);



	list_for_each_entry(pos, head, list) {

		if (ssid == pos->ae.ssid &&

		    tsid == pos->ae.tsid &&

		    tclass == pos->ae.tclass &&
@@ -792,7 +812,7 @@ static int avc_update_node(u32 event, u32 perms, u32 ssid, u32 tsid, u16 tclass, 
	}

	avc_node_replace(node, orig);

out_unlock:

	spin_unlock_irqrestore(&avc_cache.slots_lock[hvalue], flag);

	spin_unlock_irqrestore(lock, flag);

out:

	return rc;

}
@@ -807,18 +827,23 @@ int avc_ss_reset(u32 seqno) 
	int i, rc = 0, tmprc;

	unsigned long flag;

	struct avc_node *node;

	struct list_head *head;

	spinlock_t *lock;



	for (i = 0; i < AVC_CACHE_SLOTS; i++) {

		spin_lock_irqsave(&avc_cache.slots_lock[i], flag);

		head = &avc_cache.slots[i];

		lock = &avc_cache.slots_lock[i];



		spin_lock_irqsave(lock, flag);

		/*

		 * With preemptable RCU, the outer spinlock does not

		 * prevent RCU grace periods from ending.

		 */

		rcu_read_lock();

		list_for_each_entry(node, &avc_cache.slots[i], list)

		list_for_each_entry(node, head, list)

			avc_node_delete(node);

		rcu_read_unlock();

		spin_unlock_irqrestore(&avc_cache.slots_lock[i], flag);

		spin_unlock_irqrestore(lock, flag);

	}



	for (c = avc_callbacks; c; c = c->next) {

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