diff mbox series

[3/4] selinux: prepare for inlining of hashtab functions

Message ID 20200428125514.2780171-4-omosnace@redhat.com (mailing list archive)
State Changes Requested
Headers show
Series Inline some hashtab functions to improve performance | expand

Commit Message

Ondrej Mosnacek April 28, 2020, 12:55 p.m. UTC 
Refactor searching and inserting into hashtabs to pave way for
converting hashtab_search() and hashtab_insert() to inline functions in
the next patch. This will avoid indirect calls and allow the compiler to
better optimize individual callers, leading to a drastic performance
improvement.

Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 security/selinux/ss/conditional.c |   4 +-
 security/selinux/ss/conditional.h |   2 +-
 security/selinux/ss/hashtab.c     |  44 +++++-----
 security/selinux/ss/hashtab.h     |  22 ++---
 security/selinux/ss/mls.c         |  23 +++---
 security/selinux/ss/policydb.c    | 128 +++++++++++++++++++-----------
 security/selinux/ss/policydb.h    |   9 +++
 security/selinux/ss/services.c    |  38 ++++-----
 security/selinux/ss/symtab.c      |  22 ++++-
 security/selinux/ss/symtab.h      |   3 +
 10 files changed, 178 insertions(+), 117 deletions(-)

Comments

Paul Moore May 1, 2020, 8:32 p.m. UTC | #1 
On Tue, Apr 28, 2020 at 8:55 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
>
> Refactor searching and inserting into hashtabs to pave way for
> converting hashtab_search() and hashtab_insert() to inline functions in
> the next patch. This will avoid indirect calls and allow the compiler to
> better optimize individual callers, leading to a drastic performance
> improvement.

This commit description describes the next patch in the series, and
some of your motivation, but doesn't really tell me much about this
patch other than it is a "refactoring".  I need more info here,
especially considering my comment below.

> Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> ---
>  security/selinux/ss/conditional.c |   4 +-
>  security/selinux/ss/conditional.h |   2 +-
>  security/selinux/ss/hashtab.c     |  44 +++++-----
>  security/selinux/ss/hashtab.h     |  22 ++---
>  security/selinux/ss/mls.c         |  23 +++---
>  security/selinux/ss/policydb.c    | 128 +++++++++++++++++++-----------
>  security/selinux/ss/policydb.h    |   9 +++
>  security/selinux/ss/services.c    |  38 ++++-----
>  security/selinux/ss/symtab.c      |  22 ++++-
>  security/selinux/ss/symtab.h      |   3 +
>  10 files changed, 178 insertions(+), 117 deletions(-)

...

> diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h
> index 31c11511fe10..4885234257d4 100644
> --- a/security/selinux/ss/hashtab.h
> +++ b/security/selinux/ss/hashtab.h
> @@ -13,6 +13,12 @@
>
>  #define HASHTAB_MAX_NODES      0xffffffff
>
> +struct hashtab_key_params {
> +       u32 (*hash)(const void *key);   /* hash function */
> +       int (*cmp)(const void *key1, const void *key2);
> +                                       /* key comparison function */
> +};
> +
>  struct hashtab_node {
>         void *key;
>         void *datum;
> @@ -23,10 +29,6 @@ struct hashtab {
>         struct hashtab_node **htable;   /* hash table */
>         u32 size;                       /* number of slots in hash table */
>         u32 nel;                        /* number of elements in hash table */
> -       u32 (*hash_value)(struct hashtab *h, const void *key);
> -                                       /* hash function */
> -       int (*keycmp)(struct hashtab *h, const void *key1, const void *key2);
> -                                       /* key comparison function */

I don't like how you've split the hashing and comparison functions out
of the hashtab struct and into their own data structure with no
explicit linkage between the two.  This is a bad design decision in my
opinion, and something we should try to avoid.

>  };
>
>  struct hashtab_info {
Ondrej Mosnacek May 2, 2020, 9:11 a.m. UTC | #2 
On Fri, May 1, 2020 at 10:33 PM Paul Moore <paul@paul-moore.com> wrote:
> On Tue, Apr 28, 2020 at 8:55 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> >
> > Refactor searching and inserting into hashtabs to pave way for
> > converting hashtab_search() and hashtab_insert() to inline functions in
> > the next patch. This will avoid indirect calls and allow the compiler to
> > better optimize individual callers, leading to a drastic performance
> > improvement.
>
> This commit description describes the next patch in the series, and
> some of your motivation, but doesn't really tell me much about this
> patch other than it is a "refactoring".  I need more info here,
> especially considering my comment below.

Yes, the commit message needs some more love... See the clarification below.

>
> > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
> > ---
> >  security/selinux/ss/conditional.c |   4 +-
> >  security/selinux/ss/conditional.h |   2 +-
> >  security/selinux/ss/hashtab.c     |  44 +++++-----
> >  security/selinux/ss/hashtab.h     |  22 ++---
> >  security/selinux/ss/mls.c         |  23 +++---
> >  security/selinux/ss/policydb.c    | 128 +++++++++++++++++++-----------
> >  security/selinux/ss/policydb.h    |   9 +++
> >  security/selinux/ss/services.c    |  38 ++++-----
> >  security/selinux/ss/symtab.c      |  22 ++++-
> >  security/selinux/ss/symtab.h      |   3 +
> >  10 files changed, 178 insertions(+), 117 deletions(-)
>
> ...
>
> > diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h
> > index 31c11511fe10..4885234257d4 100644
> > --- a/security/selinux/ss/hashtab.h
> > +++ b/security/selinux/ss/hashtab.h
> > @@ -13,6 +13,12 @@
> >
> >  #define HASHTAB_MAX_NODES      0xffffffff
> >
> > +struct hashtab_key_params {
> > +       u32 (*hash)(const void *key);   /* hash function */
> > +       int (*cmp)(const void *key1, const void *key2);
> > +                                       /* key comparison function */
> > +};
> > +
> >  struct hashtab_node {
> >         void *key;
> >         void *datum;
> > @@ -23,10 +29,6 @@ struct hashtab {
> >         struct hashtab_node **htable;   /* hash table */
> >         u32 size;                       /* number of slots in hash table */
> >         u32 nel;                        /* number of elements in hash table */
> > -       u32 (*hash_value)(struct hashtab *h, const void *key);
> > -                                       /* hash function */
> > -       int (*keycmp)(struct hashtab *h, const void *key1, const void *key2);
> > -                                       /* key comparison function */
>
> I don't like how you've split the hashing and comparison functions out
> of the hashtab struct and into their own data structure with no
> explicit linkage between the two.  This is a bad design decision in my
> opinion, and something we should try to avoid.

In general, I would totally agree with you, but in this case this is
crucial to avoid the indirect calls. Granted, the commit message fails
to explain this and I need to rewrite it (and the callback separation
probably deserves a comment in the code as well).

The thing is, if you store the callbacks in the hashtab struct, then
any function that didn't also initialize that hashtab has to fetch the
callbacks from the struct and call them indirectly (via something like
"call *%rax" in the case of x86_64, although in practice it will be
something more weird due to Spectre mitigations...). In C, there is no
other way to keep the hashtab generic without forcing the indirect
calls.

Note that rhashtable (see <linux/rhashtable.h>) does exactly the same
thing. When I first saw it, I also thought "what a horrible
interface", until I realized it is necessary to avoid the costly
indirect calls.

I tried to encapsulate the callback structs as much as possible -
symtab has them hidden nicely behind the specialized symtab_insert()
and symtab_search() functions and the other hashtab instances are
encapsulated in policydb.c (inserts are done always in that file and
for lookups I added specialized functions). Although now I realize I
could go one step further and extract all the policydb hashtab-related
code (read, write, lookup, destroy for each type of hashtab except
symtab) into a separate compilation unit (or even each type into its
own?)... The policydb.c file is getting quite big and unwieldy, so I
think it would be a good thing even as a separate patch below the
rest.

Does this alleviate your concerns regarding the design (assuming I
expand the commit message and keep the code using the generic hashtab
functions hidden behind a more high-level interface as suggested
above)?
Paul Moore May 3, 2020, 8:34 p.m. UTC | #3 
On Sat, May 2, 2020 at 5:11 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:
> On Fri, May 1, 2020 at 10:33 PM Paul Moore <paul@paul-moore.com> wrote:
> > On Tue, Apr 28, 2020 at 8:55 AM Ondrej Mosnacek <omosnace@redhat.com> wrote:

...

> > > diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h
> > > index 31c11511fe10..4885234257d4 100644
> > > --- a/security/selinux/ss/hashtab.h
> > > +++ b/security/selinux/ss/hashtab.h
> > > @@ -13,6 +13,12 @@
> > >
> > >  #define HASHTAB_MAX_NODES      0xffffffff
> > >
> > > +struct hashtab_key_params {
> > > +       u32 (*hash)(const void *key);   /* hash function */
> > > +       int (*cmp)(const void *key1, const void *key2);
> > > +                                       /* key comparison function */
> > > +};
> > > +
> > >  struct hashtab_node {
> > >         void *key;
> > >         void *datum;
> > > @@ -23,10 +29,6 @@ struct hashtab {
> > >         struct hashtab_node **htable;   /* hash table */
> > >         u32 size;                       /* number of slots in hash table */
> > >         u32 nel;                        /* number of elements in hash table */
> > > -       u32 (*hash_value)(struct hashtab *h, const void *key);
> > > -                                       /* hash function */
> > > -       int (*keycmp)(struct hashtab *h, const void *key1, const void *key2);
> > > -                                       /* key comparison function */
> >
> > I don't like how you've split the hashing and comparison functions out
> > of the hashtab struct and into their own data structure with no
> > explicit linkage between the two.  This is a bad design decision in my
> > opinion, and something we should try to avoid.
>
> In general, I would totally agree with you, but in this case this is
> crucial to avoid the indirect calls. Granted, the commit message fails
> to explain this and I need to rewrite it (and the callback separation
> probably deserves a comment in the code as well) ...

Write a proper commit description for the patches and resubmit them,
I'll take a closer look then.  Generally when I see a poor commit
description and something odd in the code I stop reviewing the patch
and push back asking for a better explanation, which is what I did
here.

As a reminder, I have yet to reject a patch because the commit
description was too long, or too detailed.
diff mbox series

Patch

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
index 939a74fd8fb4..a07cf947376f 100644
--- a/security/selinux/ss/conditional.c
+++ b/security/selinux/ss/conditional.c
@@ -200,7 +200,7 @@  static int bool_isvalid(struct cond_bool_datum *b)
 	return 1;
 }
 
-int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
+int cond_read_bool(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct cond_bool_datum *booldatum;
@@ -235,7 +235,7 @@  int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
 	if (rc)
 		goto err;
 	key[len] = '\0';
-	rc = hashtab_insert(h, key, booldatum);
+	rc = symtab_insert(s, key, booldatum);
 	if (rc)
 		goto err;
 
diff --git a/security/selinux/ss/conditional.h b/security/selinux/ss/conditional.h
index 90c9c964f5f5..79e7e03db859 100644
--- a/security/selinux/ss/conditional.h
+++ b/security/selinux/ss/conditional.h
@@ -69,7 +69,7 @@  int cond_destroy_bool(void *key, void *datum, void *p);
 
 int cond_index_bool(void *key, void *datum, void *datap);
 
-int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp);
+int cond_read_bool(struct policydb *p, struct symtab *s, void *fp);
 int cond_read_list(struct policydb *p, void *fp);
 int cond_write_bool(void *key, void *datum, void *ptr);
 int cond_write_list(struct policydb *p, void *fp);
diff --git a/security/selinux/ss/hashtab.c b/security/selinux/ss/hashtab.c
index 5ee868116d70..8126b909a757 100644
--- a/security/selinux/ss/hashtab.c
+++ b/security/selinux/ss/hashtab.c
@@ -29,16 +29,10 @@  static u32 hashtab_compute_size(u32 nel)
 	return nel == 0 ? 0 : roundup_pow_of_two(nel);
 }
 
-int hashtab_init(struct hashtab *h,
-		 u32 (*hash_value)(struct hashtab *h, const void *key),
-		 int (*keycmp)(struct hashtab *h, const void *key1,
-			       const void *key2),
-		 u32 nel_hint)
+int hashtab_init(struct hashtab *h, u32 nel_hint)
 {
 	h->size = hashtab_compute_size(nel_hint);
 	h->nel = 0;
-	h->hash_value = hash_value;
-	h->keycmp = keycmp;
 	if (!h->size)
 		return 0;
 
@@ -46,7 +40,8 @@  int hashtab_init(struct hashtab *h,
 	return h->htable ? 0 : -ENOMEM;
 }
 
-int hashtab_insert(struct hashtab *h, void *key, void *datum)
+int hashtab_insert(struct hashtab *h, void *key, void *datum,
+		   struct hashtab_key_params key_params)
 {
 	u32 hvalue;
 	struct hashtab_node *prev, *cur, *newnode;
@@ -56,17 +51,20 @@  int hashtab_insert(struct hashtab *h, void *key, void *datum)
 	if (!h->size || h->nel == HASHTAB_MAX_NODES)
 		return -EINVAL;
 
-	hvalue = h->hash_value(h, key);
+	hvalue = key_params.hash(key) & (h->size - 1);
 	prev = NULL;
 	cur = h->htable[hvalue];
-	while (cur && h->keycmp(h, key, cur->key) > 0) {
+	while (cur) {
+		int cmp = key_params.cmp(key, cur->key);
+
+		if (cmp == 0)
+			return -EEXIST;
+		if (cmp < 0)
+			break;
 		prev = cur;
 		cur = cur->next;
 	}
 
-	if (cur && (h->keycmp(h, key, cur->key) == 0))
-		return -EEXIST;
-
 	newnode = kmem_cache_zalloc(hashtab_node_cachep, GFP_KERNEL);
 	if (!newnode)
 		return -ENOMEM;
@@ -84,7 +82,8 @@  int hashtab_insert(struct hashtab *h, void *key, void *datum)
 	return 0;
 }
 
-void *hashtab_search(struct hashtab *h, const void *key)
+void *hashtab_search(struct hashtab *h, const void *key,
+		     struct hashtab_key_params key_params)
 {
 	u32 hvalue;
 	struct hashtab_node *cur;
@@ -92,15 +91,18 @@  void *hashtab_search(struct hashtab *h, const void *key)
 	if (!h->size)
 		return NULL;
 
-	hvalue = h->hash_value(h, key);
+	hvalue = key_params.hash(key) & (h->size - 1);
 	cur = h->htable[hvalue];
-	while (cur && h->keycmp(h, key, cur->key) > 0)
-		cur = cur->next;
+	while (cur) {
+		int cmp = key_params.cmp(key, cur->key);
 
-	if (!cur || (h->keycmp(h, key, cur->key) != 0))
-		return NULL;
-
-	return cur->datum;
+		if (cmp == 0)
+			return cur->datum;
+		if (cmp < 0)
+			break;
+		cur = cur->next;
+	}
+	return NULL;
 }
 
 void hashtab_destroy(struct hashtab *h)
diff --git a/security/selinux/ss/hashtab.h b/security/selinux/ss/hashtab.h
index 31c11511fe10..4885234257d4 100644
--- a/security/selinux/ss/hashtab.h
+++ b/security/selinux/ss/hashtab.h
@@ -13,6 +13,12 @@ 
 
 #define HASHTAB_MAX_NODES	0xffffffff
 
+struct hashtab_key_params {
+	u32 (*hash)(const void *key);	/* hash function */
+	int (*cmp)(const void *key1, const void *key2);
+					/* key comparison function */
+};
+
 struct hashtab_node {
 	void *key;
 	void *datum;
@@ -23,10 +29,6 @@  struct hashtab {
 	struct hashtab_node **htable;	/* hash table */
 	u32 size;			/* number of slots in hash table */
 	u32 nel;			/* number of elements in hash table */
-	u32 (*hash_value)(struct hashtab *h, const void *key);
-					/* hash function */
-	int (*keycmp)(struct hashtab *h, const void *key1, const void *key2);
-					/* key comparison function */
 };
 
 struct hashtab_info {
@@ -39,11 +41,7 @@  struct hashtab_info {
  *
  * Returns -ENOMEM if insufficient space is available or 0 otherwise.
  */
-int hashtab_init(struct hashtab *h,
-		 u32 (*hash_value)(struct hashtab *h, const void *key),
-		 int (*keycmp)(struct hashtab *h, const void *key1,
-			       const void *key2),
-		 u32 nel_hint);
+int hashtab_init(struct hashtab *h, u32 nel_hint);
 
 /*
  * Inserts the specified (key, datum) pair into the specified hash table.
@@ -53,7 +51,8 @@  int hashtab_init(struct hashtab *h,
  * -EINVAL for general errors or
   0 otherwise.
  */
-int hashtab_insert(struct hashtab *h, void *k, void *d);
+int hashtab_insert(struct hashtab *h, void *k, void *d,
+		   struct hashtab_key_params key_params);
 
 /*
  * Searches for the entry with the specified key in the hash table.
@@ -61,7 +60,8 @@  int hashtab_insert(struct hashtab *h, void *k, void *d);
  * Returns NULL if no entry has the specified key or
  * the datum of the entry otherwise.
  */
-void *hashtab_search(struct hashtab *h, const void *k);
+void *hashtab_search(struct hashtab *h, const void *k,
+		     struct hashtab_key_params key_params);
 
 /*
  * Destroys the specified hash table.
diff --git a/security/selinux/ss/mls.c b/security/selinux/ss/mls.c
index cd8734f25b39..408d306895f8 100644
--- a/security/selinux/ss/mls.c
+++ b/security/selinux/ss/mls.c
@@ -165,8 +165,8 @@  int mls_level_isvalid(struct policydb *p, struct mls_level *l)
 
 	if (!l->sens || l->sens > p->p_levels.nprim)
 		return 0;
-	levdatum = hashtab_search(&p->p_levels.table,
-				  sym_name(p, SYM_LEVELS, l->sens - 1));
+	levdatum = symtab_search(&p->p_levels,
+				 sym_name(p, SYM_LEVELS, l->sens - 1));
 	if (!levdatum)
 		return 0;
 
@@ -293,7 +293,7 @@  int mls_context_to_sid(struct policydb *pol,
 			*(next_cat++) = '\0';
 
 		/* Parse sensitivity. */
-		levdatum = hashtab_search(&pol->p_levels.table, sensitivity);
+		levdatum = symtab_search(&pol->p_levels, sensitivity);
 		if (!levdatum)
 			return -EINVAL;
 		context->range.level[l].sens = levdatum->level->sens;
@@ -312,7 +312,7 @@  int mls_context_to_sid(struct policydb *pol,
 				*rngptr++ = '\0';
 			}
 
-			catdatum = hashtab_search(&pol->p_cats.table, cur_cat);
+			catdatum = symtab_search(&pol->p_cats, cur_cat);
 			if (!catdatum)
 				return -EINVAL;
 
@@ -325,7 +325,7 @@  int mls_context_to_sid(struct policydb *pol,
 			if (rngptr == NULL)
 				continue;
 
-			rngdatum = hashtab_search(&pol->p_cats.table, rngptr);
+			rngdatum = symtab_search(&pol->p_cats, rngptr);
 			if (!rngdatum)
 				return -EINVAL;
 
@@ -458,9 +458,10 @@  int mls_convert_context(struct policydb *oldp,
 		return 0;
 
 	for (l = 0; l < 2; l++) {
-		levdatum = hashtab_search(&newp->p_levels.table,
-					  sym_name(oldp, SYM_LEVELS,
-						   oldc->range.level[l].sens - 1));
+		char *name = sym_name(oldp, SYM_LEVELS,
+				      oldc->range.level[l].sens - 1);
+
+		levdatum = symtab_search(&newp->p_levels, name);
 
 		if (!levdatum)
 			return -EINVAL;
@@ -470,8 +471,8 @@  int mls_convert_context(struct policydb *oldp,
 					      node, i) {
 			int rc;
 
-			catdatum = hashtab_search(&newp->p_cats.table,
-						  sym_name(oldp, SYM_CATS, i));
+			catdatum = symtab_search(&newp->p_cats,
+						 sym_name(oldp, SYM_CATS, i));
 			if (!catdatum)
 				return -EINVAL;
 			rc = ebitmap_set_bit(&newc->range.level[l].cat,
@@ -506,7 +507,7 @@  int mls_compute_sid(struct policydb *p,
 		rtr.source_type = scontext->type;
 		rtr.target_type = tcontext->type;
 		rtr.target_class = tclass;
-		r = hashtab_search(&p->range_tr, &rtr);
+		r = policydb_rangetr_search(p, &rtr);
 		if (r)
 			return mls_range_set(newcontext, r);
 
diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index 3c346d5d6faa..7aadfaf6513e 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -400,7 +400,7 @@  static int roles_init(struct policydb *p)
 	if (!key)
 		goto out;
 
-	rc = hashtab_insert(&p->p_roles.table, key, role);
+	rc = symtab_insert(&p->p_roles, key, role);
 	if (rc)
 		goto out;
 
@@ -411,7 +411,7 @@  out:
 	return rc;
 }
 
-static u32 filenametr_hash(struct hashtab *h, const void *k)
+static u32 filenametr_hash(const void *k)
 {
 	const struct filename_trans_key *ft = k;
 	unsigned long hash;
@@ -423,10 +423,10 @@  static u32 filenametr_hash(struct hashtab *h, const void *k)
 	byte_num = 0;
 	while ((focus = ft->name[byte_num++]))
 		hash = partial_name_hash(focus, hash);
-	return hash & (h->size - 1);
+	return hash;
 }
 
-static int filenametr_cmp(struct hashtab *h, const void *k1, const void *k2)
+static int filenametr_cmp(const void *k1, const void *k2)
 {
 	const struct filename_trans_key *ft1 = k1;
 	const struct filename_trans_key *ft2 = k2;
@@ -444,15 +444,26 @@  static int filenametr_cmp(struct hashtab *h, const void *k1, const void *k2)
 
 }
 
-static u32 rangetr_hash(struct hashtab *h, const void *k)
+static const struct hashtab_key_params filenametr_key_params = {
+	.hash = filenametr_hash,
+	.cmp = filenametr_cmp,
+};
+
+struct filename_trans_datum *policydb_filenametr_search(
+	struct policydb *p, struct filename_trans_key *key)
+{
+	return hashtab_search(&p->filename_trans, key, filenametr_key_params);
+}
+
+static u32 rangetr_hash(const void *k)
 {
 	const struct range_trans *key = k;
 
-	return (key->source_type + (key->target_type << 3) +
-		(key->target_class << 5)) & (h->size - 1);
+	return key->source_type + (key->target_type << 3) +
+		(key->target_class << 5);
 }
 
-static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
+static int rangetr_cmp(const void *k1, const void *k2)
 {
 	const struct range_trans *key1 = k1, *key2 = k2;
 	int v;
@@ -470,15 +481,25 @@  static int rangetr_cmp(struct hashtab *h, const void *k1, const void *k2)
 	return v;
 }
 
-static u32 role_trans_hash(struct hashtab *h, const void *k)
+static const struct hashtab_key_params rangetr_key_params = {
+	.hash = rangetr_hash,
+	.cmp = rangetr_cmp,
+};
+
+struct mls_range *policydb_rangetr_search(struct policydb *p,
+					  struct range_trans *key)
+{
+	return hashtab_search(&p->range_tr, key, rangetr_key_params);
+}
+
+static u32 role_trans_hash(const void *k)
 {
 	const struct role_trans_key *key = k;
 
-	return (key->role + (key->type << 3) + (key->tclass << 5)) &
-		(h->size - 1);
+	return key->role + (key->type << 3) + (key->tclass << 5);
 }
 
-static int role_trans_cmp(struct hashtab *h, const void *k1, const void *k2)
+static int role_trans_cmp(const void *k1, const void *k2)
 {
 	const struct role_trans_key *key1 = k1, *key2 = k2;
 	int v;
@@ -494,6 +515,17 @@  static int role_trans_cmp(struct hashtab *h, const void *k1, const void *k2)
 	return key1->tclass - key2->tclass;
 }
 
+static const struct hashtab_key_params roletr_key_params = {
+	.hash = role_trans_hash,
+	.cmp = role_trans_cmp,
+};
+
+struct role_trans_datum *policydb_roletr_search(struct policydb *p,
+						struct role_trans_key *key)
+{
+	return hashtab_search(&p->role_tr, key, roletr_key_params);
+}
+
 /*
  * Initialize a policy database structure.
  */
@@ -1065,7 +1097,7 @@  static int str_read(char **strp, gfp_t flags, void *fp, u32 len)
 	return 0;
 }
 
-static int perm_read(struct policydb *p, struct hashtab *h, void *fp)
+static int perm_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct perm_datum *perdatum;
@@ -1088,7 +1120,7 @@  static int perm_read(struct policydb *p, struct hashtab *h, void *fp)
 	if (rc)
 		goto bad;
 
-	rc = hashtab_insert(h, key, perdatum);
+	rc = symtab_insert(s, key, perdatum);
 	if (rc)
 		goto bad;
 
@@ -1098,7 +1130,7 @@  bad:
 	return rc;
 }
 
-static int common_read(struct policydb *p, struct hashtab *h, void *fp)
+static int common_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct common_datum *comdatum;
@@ -1128,12 +1160,12 @@  static int common_read(struct policydb *p, struct hashtab *h, void *fp)
 		goto bad;
 
 	for (i = 0; i < nel; i++) {
-		rc = perm_read(p, &comdatum->permissions.table, fp);
+		rc = perm_read(p, &comdatum->permissions, fp);
 		if (rc)
 			goto bad;
 	}
 
-	rc = hashtab_insert(h, key, comdatum);
+	rc = symtab_insert(s, key, comdatum);
 	if (rc)
 		goto bad;
 	return 0;
@@ -1262,7 +1294,7 @@  static int read_cons_helper(struct policydb *p,
 	return 0;
 }
 
-static int class_read(struct policydb *p, struct hashtab *h, void *fp)
+static int class_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct class_datum *cladatum;
@@ -1300,8 +1332,8 @@  static int class_read(struct policydb *p, struct hashtab *h, void *fp)
 			goto bad;
 
 		rc = -EINVAL;
-		cladatum->comdatum = hashtab_search(&p->p_commons.table,
-						    cladatum->comkey);
+		cladatum->comdatum = symtab_search(&p->p_commons,
+						   cladatum->comkey);
 		if (!cladatum->comdatum) {
 			pr_err("SELinux:  unknown common %s\n",
 			       cladatum->comkey);
@@ -1309,7 +1341,7 @@  static int class_read(struct policydb *p, struct hashtab *h, void *fp)
 		}
 	}
 	for (i = 0; i < nel; i++) {
-		rc = perm_read(p, &cladatum->permissions.table, fp);
+		rc = perm_read(p, &cladatum->permissions, fp);
 		if (rc)
 			goto bad;
 	}
@@ -1347,7 +1379,7 @@  static int class_read(struct policydb *p, struct hashtab *h, void *fp)
 		cladatum->default_type = le32_to_cpu(buf[0]);
 	}
 
-	rc = hashtab_insert(h, key, cladatum);
+	rc = symtab_insert(s, key, cladatum);
 	if (rc)
 		goto bad;
 
@@ -1357,7 +1389,7 @@  bad:
 	return rc;
 }
 
-static int role_read(struct policydb *p, struct hashtab *h, void *fp)
+static int role_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct role_datum *role;
@@ -1404,7 +1436,7 @@  static int role_read(struct policydb *p, struct hashtab *h, void *fp)
 		goto bad;
 	}
 
-	rc = hashtab_insert(h, key, role);
+	rc = symtab_insert(s, key, role);
 	if (rc)
 		goto bad;
 	return 0;
@@ -1413,7 +1445,7 @@  bad:
 	return rc;
 }
 
-static int type_read(struct policydb *p, struct hashtab *h, void *fp)
+static int type_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct type_datum *typdatum;
@@ -1451,7 +1483,7 @@  static int type_read(struct policydb *p, struct hashtab *h, void *fp)
 	if (rc)
 		goto bad;
 
-	rc = hashtab_insert(h, key, typdatum);
+	rc = symtab_insert(s, key, typdatum);
 	if (rc)
 		goto bad;
 	return 0;
@@ -1487,7 +1519,7 @@  static int mls_read_level(struct mls_level *lp, void *fp)
 	return 0;
 }
 
-static int user_read(struct policydb *p, struct hashtab *h, void *fp)
+static int user_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct user_datum *usrdatum;
@@ -1528,7 +1560,7 @@  static int user_read(struct policydb *p, struct hashtab *h, void *fp)
 			goto bad;
 	}
 
-	rc = hashtab_insert(h, key, usrdatum);
+	rc = symtab_insert(s, key, usrdatum);
 	if (rc)
 		goto bad;
 	return 0;
@@ -1537,7 +1569,7 @@  bad:
 	return rc;
 }
 
-static int sens_read(struct policydb *p, struct hashtab *h, void *fp)
+static int sens_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct level_datum *levdatum;
@@ -1569,7 +1601,7 @@  static int sens_read(struct policydb *p, struct hashtab *h, void *fp)
 	if (rc)
 		goto bad;
 
-	rc = hashtab_insert(h, key, levdatum);
+	rc = symtab_insert(s, key, levdatum);
 	if (rc)
 		goto bad;
 	return 0;
@@ -1578,7 +1610,7 @@  bad:
 	return rc;
 }
 
-static int cat_read(struct policydb *p, struct hashtab *h, void *fp)
+static int cat_read(struct policydb *p, struct symtab *s, void *fp)
 {
 	char *key = NULL;
 	struct cat_datum *catdatum;
@@ -1602,7 +1634,7 @@  static int cat_read(struct policydb *p, struct hashtab *h, void *fp)
 	if (rc)
 		goto bad;
 
-	rc = hashtab_insert(h, key, catdatum);
+	rc = symtab_insert(s, key, catdatum);
 	if (rc)
 		goto bad;
 	return 0;
@@ -1611,7 +1643,7 @@  bad:
 	return rc;
 }
 
-static int (*read_f[SYM_NUM]) (struct policydb *p, struct hashtab *h, void *fp) =
+static int (*read_f[SYM_NUM]) (struct policydb *p, struct symtab *s, void *fp) =
 {
 	common_read,
 	class_read,
@@ -1751,7 +1783,7 @@  u16 string_to_security_class(struct policydb *p, const char *name)
 {
 	struct class_datum *cladatum;
 
-	cladatum = hashtab_search(&p->p_classes.table, name);
+	cladatum = symtab_search(&p->p_classes, name);
 	if (!cladatum)
 		return 0;
 
@@ -1770,9 +1802,9 @@  u32 string_to_av_perm(struct policydb *p, u16 tclass, const char *name)
 	cladatum = p->class_val_to_struct[tclass-1];
 	comdatum = cladatum->comdatum;
 	if (comdatum)
-		perdatum = hashtab_search(&comdatum->permissions.table, name);
+		perdatum = symtab_search(&comdatum->permissions, name);
 	if (!perdatum)
-		perdatum = hashtab_search(&cladatum->permissions.table, name);
+		perdatum = symtab_search(&cladatum->permissions, name);
 	if (!perdatum)
 		return 0;
 
@@ -1796,7 +1828,7 @@  static int range_read(struct policydb *p, void *fp)
 
 	nel = le32_to_cpu(buf[0]);
 
-	rc = hashtab_init(&p->range_tr, rangetr_hash, rangetr_cmp, nel);
+	rc = hashtab_init(&p->range_tr, nel);
 	if (rc)
 		return rc;
 
@@ -1841,7 +1873,7 @@  static int range_read(struct policydb *p, void *fp)
 			goto out;
 		}
 
-		rc = hashtab_insert(&p->range_tr, rt, r);
+		rc = hashtab_insert(&p->range_tr, rt, r, rangetr_key_params);
 		if (rc)
 			goto out;
 
@@ -1888,7 +1920,7 @@  static int filename_trans_read_helper_compat(struct policydb *p, void *fp)
 	otype = le32_to_cpu(buf[3]);
 
 	last = NULL;
-	datum = hashtab_search(&p->filename_trans, &key);
+	datum = hashtab_search(&p->filename_trans, &key, filenametr_key_params);
 	while (datum) {
 		if (unlikely(ebitmap_get_bit(&datum->stypes, stype - 1))) {
 			/* conflicting/duplicate rules are ignored */
@@ -1918,7 +1950,8 @@  static int filename_trans_read_helper_compat(struct policydb *p, void *fp)
 			if (!ft)
 				goto out;
 
-			rc = hashtab_insert(&p->filename_trans, ft, datum);
+			rc = hashtab_insert(&p->filename_trans, ft, datum,
+					    filenametr_key_params);
 			if (rc)
 				goto out;
 			name = NULL;
@@ -2006,7 +2039,8 @@  static int filename_trans_read_helper(struct policydb *p, void *fp)
 	ft->tclass = tclass;
 	ft->name = name;
 
-	rc = hashtab_insert(&p->filename_trans, ft, first);
+	rc = hashtab_insert(&p->filename_trans, ft, first,
+			    filenametr_key_params);
 	if (rc == -EEXIST)
 		pr_err("SELinux:  Duplicate filename transition key\n");
 	if (rc)
@@ -2044,8 +2078,7 @@  static int filename_trans_read(struct policydb *p, void *fp)
 	if (p->policyvers < POLICYDB_VERSION_COMP_FTRANS) {
 		p->compat_filename_trans_count = nel;
 
-		rc = hashtab_init(&p->filename_trans, filenametr_hash,
-				  filenametr_cmp, (1 << 11));
+		rc = hashtab_init(&p->filename_trans, (1 << 11));
 		if (rc)
 			return rc;
 
@@ -2055,8 +2088,7 @@  static int filename_trans_read(struct policydb *p, void *fp)
 				return rc;
 		}
 	} else {
-		rc = hashtab_init(&p->filename_trans, filenametr_hash,
-				  filenametr_cmp, nel);
+		rc = hashtab_init(&p->filename_trans, nel);
 		if (rc)
 			return rc;
 
@@ -2509,7 +2541,7 @@  int policydb_read(struct policydb *p, void *fp)
 		}
 
 		for (j = 0; j < nel; j++) {
-			rc = read_f[i](p, &p->symtab[i].table, fp);
+			rc = read_f[i](p, &p->symtab[i], fp);
 			if (rc)
 				goto bad;
 		}
@@ -2537,7 +2569,7 @@  int policydb_read(struct policydb *p, void *fp)
 		goto bad;
 	nel = le32_to_cpu(buf[0]);
 
-	rc = hashtab_init(&p->role_tr, role_trans_hash, role_trans_cmp, nel);
+	rc = hashtab_init(&p->role_tr, nel);
 	if (rc)
 		goto bad;
 	for (i = 0; i < nel; i++) {
@@ -2574,7 +2606,7 @@  int policydb_read(struct policydb *p, void *fp)
 		    !policydb_role_isvalid(p, rtd->new_role))
 			goto bad;
 
-		rc = hashtab_insert(&p->role_tr, rtk, rtd);
+		rc = hashtab_insert(&p->role_tr, rtk, rtd, roletr_key_params);
 		if (rc)
 			goto bad;
 
diff --git a/security/selinux/ss/policydb.h b/security/selinux/ss/policydb.h
index 9591c9587cb6..c24d4e1063ea 100644
--- a/security/selinux/ss/policydb.h
+++ b/security/selinux/ss/policydb.h
@@ -324,6 +324,15 @@  extern int policydb_role_isvalid(struct policydb *p, unsigned int role);
 extern int policydb_read(struct policydb *p, void *fp);
 extern int policydb_write(struct policydb *p, void *fp);
 
+extern struct filename_trans_datum *policydb_filenametr_search(
+	struct policydb *p, struct filename_trans_key *key);
+
+extern struct mls_range *policydb_rangetr_search(
+	struct policydb *p, struct range_trans *key);
+
+extern struct role_trans_datum *policydb_roletr_search(
+	struct policydb *p, struct role_trans_key *key);
+
 #define POLICYDB_CONFIG_MLS    1
 
 /* the config flags related to unknown classes/perms are bits 2 and 3 */
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 313919bd42f8..9e76a80db6e1 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -1441,7 +1441,7 @@  static int string_to_context_struct(struct policydb *pol,
 
 	*p++ = 0;
 
-	usrdatum = hashtab_search(&pol->p_users.table, scontextp);
+	usrdatum = symtab_search(&pol->p_users, scontextp);
 	if (!usrdatum)
 		goto out;
 
@@ -1457,7 +1457,7 @@  static int string_to_context_struct(struct policydb *pol,
 
 	*p++ = 0;
 
-	role = hashtab_search(&pol->p_roles.table, scontextp);
+	role = symtab_search(&pol->p_roles, scontextp);
 	if (!role)
 		goto out;
 	ctx->role = role->value;
@@ -1469,7 +1469,7 @@  static int string_to_context_struct(struct policydb *pol,
 	oldc = *p;
 	*p++ = 0;
 
-	typdatum = hashtab_search(&pol->p_types.table, scontextp);
+	typdatum = symtab_search(&pol->p_types, scontextp);
 	if (!typdatum || typdatum->attribute)
 		goto out;
 
@@ -1671,7 +1671,7 @@  static void filename_compute_type(struct policydb *policydb,
 	ft.tclass = tclass;
 	ft.name = objname;
 
-	datum = hashtab_search(&policydb->filename_trans, &ft);
+	datum = policydb_filenametr_search(policydb, &ft);
 	while (datum) {
 		if (ebitmap_get_bit(&datum->stypes, stype - 1)) {
 			newcontext->type = datum->otype;
@@ -1834,7 +1834,7 @@  static int security_compute_sid(struct selinux_state *state,
 			.tclass = tclass,
 		};
 
-		rtd = hashtab_search(&policydb->role_tr, &rtk);
+		rtd = policydb_roletr_search(policydb, &rtk);
 		if (rtd)
 			newcontext.role = rtd->new_role;
 	}
@@ -2024,26 +2024,26 @@  static int convert_context(struct context *oldc, struct context *newc, void *p)
 
 	/* Convert the user. */
 	rc = -EINVAL;
-	usrdatum = hashtab_search(&args->newp->p_users.table,
-				  sym_name(args->oldp,
-					   SYM_USERS, oldc->user - 1));
+	usrdatum = symtab_search(&args->newp->p_users,
+				 sym_name(args->oldp,
+					  SYM_USERS, oldc->user - 1));
 	if (!usrdatum)
 		goto bad;
 	newc->user = usrdatum->value;
 
 	/* Convert the role. */
 	rc = -EINVAL;
-	role = hashtab_search(&args->newp->p_roles.table,
-			      sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
+	role = symtab_search(&args->newp->p_roles,
+			     sym_name(args->oldp, SYM_ROLES, oldc->role - 1));
 	if (!role)
 		goto bad;
 	newc->role = role->value;
 
 	/* Convert the type. */
 	rc = -EINVAL;
-	typdatum = hashtab_search(&args->newp->p_types.table,
-				  sym_name(args->oldp,
-					   SYM_TYPES, oldc->type - 1));
+	typdatum = symtab_search(&args->newp->p_types,
+				 sym_name(args->oldp,
+					  SYM_TYPES, oldc->type - 1));
 	if (!typdatum)
 		goto bad;
 	newc->type = typdatum->value;
@@ -2623,7 +2623,7 @@  int security_get_user_sids(struct selinux_state *state,
 		goto out_unlock;
 
 	rc = -EINVAL;
-	user = hashtab_search(&policydb->p_users.table, username);
+	user = symtab_search(&policydb->p_users, username);
 	if (!user)
 		goto out_unlock;
 
@@ -2975,7 +2975,7 @@  static int security_preserve_bools(struct selinux_state *state,
 	if (rc)
 		goto out;
 	for (i = 0; i < nbools; i++) {
-		booldatum = hashtab_search(&policydb->p_bools.table, bnames[i]);
+		booldatum = symtab_search(&policydb->p_bools, bnames[i]);
 		if (booldatum)
 			booldatum->state = bvalues[i];
 	}
@@ -3226,7 +3226,7 @@  int security_get_permissions(struct selinux_state *state,
 	read_lock(&state->ss->policy_rwlock);
 
 	rc = -EINVAL;
-	match = hashtab_search(&policydb->p_classes.table, class);
+	match = symtab_search(&policydb->p_classes, class);
 	if (!match) {
 		pr_err("SELinux: %s:  unrecognized class %s\n",
 			__func__, class);
@@ -3365,7 +3365,7 @@  int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
 	case AUDIT_SUBJ_USER:
 	case AUDIT_OBJ_USER:
 		rc = -EINVAL;
-		userdatum = hashtab_search(&policydb->p_users.table, rulestr);
+		userdatum = symtab_search(&policydb->p_users, rulestr);
 		if (!userdatum)
 			goto out;
 		tmprule->au_ctxt.user = userdatum->value;
@@ -3373,7 +3373,7 @@  int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
 	case AUDIT_SUBJ_ROLE:
 	case AUDIT_OBJ_ROLE:
 		rc = -EINVAL;
-		roledatum = hashtab_search(&policydb->p_roles.table, rulestr);
+		roledatum = symtab_search(&policydb->p_roles, rulestr);
 		if (!roledatum)
 			goto out;
 		tmprule->au_ctxt.role = roledatum->value;
@@ -3381,7 +3381,7 @@  int selinux_audit_rule_init(u32 field, u32 op, char *rulestr, void **vrule)
 	case AUDIT_SUBJ_TYPE:
 	case AUDIT_OBJ_TYPE:
 		rc = -EINVAL;
-		typedatum = hashtab_search(&policydb->p_types.table, rulestr);
+		typedatum = symtab_search(&policydb->p_types, rulestr);
 		if (!typedatum)
 			goto out;
 		tmprule->au_ctxt.type = typedatum->value;
diff --git a/security/selinux/ss/symtab.c b/security/selinux/ss/symtab.c
index 92d7a948070e..baf22f3b4985 100644
--- a/security/selinux/ss/symtab.c
+++ b/security/selinux/ss/symtab.c
@@ -9,7 +9,7 @@ 
 #include <linux/errno.h>
 #include "symtab.h"
 
-static unsigned int symhash(struct hashtab *h, const void *key)
+static unsigned int symhash(const void *key)
 {
 	const char *p, *keyp;
 	unsigned int size;
@@ -20,10 +20,10 @@  static unsigned int symhash(struct hashtab *h, const void *key)
 	size = strlen(keyp);
 	for (p = keyp; (p - keyp) < size; p++)
 		val = (val << 4 | (val >> (8*sizeof(unsigned int)-4))) ^ (*p);
-	return val & (h->size - 1);
+	return val;
 }
 
-static int symcmp(struct hashtab *h, const void *key1, const void *key2)
+static int symcmp(const void *key1, const void *key2)
 {
 	const char *keyp1, *keyp2;
 
@@ -32,10 +32,24 @@  static int symcmp(struct hashtab *h, const void *key1, const void *key2)
 	return strcmp(keyp1, keyp2);
 }
 
+static const struct hashtab_key_params symtab_key_params = {
+	.hash = symhash,
+	.cmp = symcmp,
+};
 
 int symtab_init(struct symtab *s, unsigned int size)
 {
 	s->nprim = 0;
-	return hashtab_init(&s->table, symhash, symcmp, size);
+	return hashtab_init(&s->table, size);
+}
+
+int symtab_insert(struct symtab *s, void *k, void *d)
+{
+	return hashtab_insert(&s->table, k, d, symtab_key_params);
+}
+
+void *symtab_search(struct symtab *s, const char *name)
+{
+	return hashtab_search(&s->table, name, symtab_key_params);
 }
 
diff --git a/security/selinux/ss/symtab.h b/security/selinux/ss/symtab.h
index f145301b9d9f..b0e9132c7f05 100644
--- a/security/selinux/ss/symtab.h
+++ b/security/selinux/ss/symtab.h
@@ -19,6 +19,9 @@  struct symtab {
 
 int symtab_init(struct symtab *s, unsigned int size);
 
+int symtab_insert(struct symtab *s, void *k, void *d);
+void *symtab_search(struct symtab *s, const char *name);
+
 #endif	/* _SS_SYMTAB_H_ */