SUNRPC: simplify auth_unix.

1/ discard 'struct unx_cred'.  We don't need any data that
   is not already in 'struct rpc_cred'.
2/ Don't keep these creds in a hash table.  When a credential
   is needed, simply allocate it.  When not needed, discard it.
   This can easily be faster than performing a lookup on
   a shared hash table.
   As the lookup can happen during write-out, use a mempool
   to ensure forward progress.
   This means that we cannot compare two credentials for
   equality by comparing the pointers, but we never do that anyway.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/auth.c b/net/sunrpc/auth.c
index 867ea98..a07a7c5 100644 (file)
--- a/net/sunrpc/auth.c
+++ b/net/sunrpc/auth.c
@@ -651,6 +651,7 @@ rpcauth_init_cred(struct rpc_cred *cred, const struct auth_cred *acred,
        INIT_LIST_HEAD(&cred->cr_lru);
        refcount_set(&cred->cr_count, 1);
        cred->cr_auth = auth;
+       cred->cr_flags = 0;
        cred->cr_ops = ops;
        cred->cr_expire = jiffies;
        cred->cr_cred = get_cred(acred->cred);

diff --git a/net/sunrpc/auth_unix.c b/net/sunrpc/auth_unix.c
index bff113a..387f6b3 100644 (file)
--- a/net/sunrpc/auth_unix.c
+++ b/net/sunrpc/auth_unix.c
@@ -11,16 +11,11 @@
 #include <linux/types.h>
 #include <linux/sched.h>
 #include <linux/module.h>
+#include <linux/mempool.h>
 #include <linux/sunrpc/clnt.h>
 #include <linux/sunrpc/auth.h>
 #include <linux/user_namespace.h>
 
-struct unx_cred {
-       struct rpc_cred         uc_base;
-       kgid_t                  uc_gid;
-       kgid_t                  uc_gids[UNX_NGROUPS];
-};
-#define uc_uid                 uc_base.cr_uid
 
 #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
 # define RPCDBG_FACILITY       RPCDBG_AUTH
@@ -28,6 +23,7 @@ struct unx_cred {
 
 static struct rpc_auth         unix_auth;
 static const struct rpc_credops        unix_credops;
+static mempool_t               *unix_pool;
 
 static struct rpc_auth *
 unx_create(const struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
@@ -42,15 +38,6 @@ static void
 unx_destroy(struct rpc_auth *auth)
 {
        dprintk("RPC:       destroying UNIX authenticator %p\n", auth);
-       rpcauth_clear_credcache(auth->au_credcache);
-}
-
-static int
-unx_hash_cred(struct auth_cred *acred, unsigned int hashbits)
-{
-       return hash_64(from_kgid(&init_user_ns, acred->cred->fsgid) |
-               ((u64)from_kuid(&init_user_ns, acred->cred->fsuid) <<
-                       (sizeof(gid_t) * 8)), hashbits);
 }
 
 /*
@@ -59,53 +46,24 @@ unx_hash_cred(struct auth_cred *acred, unsigned int hashbits)
 static struct rpc_cred *
 unx_lookup_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags)
 {
-       return rpcauth_lookup_credcache(auth, acred, flags, GFP_NOFS);
-}
-
-static struct rpc_cred *
-unx_create_cred(struct rpc_auth *auth, struct auth_cred *acred, int flags, gfp_t gfp)
-{
-       struct unx_cred *cred;
-       unsigned int groups = 0;
-       unsigned int i;
+       struct rpc_cred *ret = mempool_alloc(unix_pool, GFP_NOFS);
 
        dprintk("RPC:       allocating UNIX cred for uid %d gid %d\n",
                        from_kuid(&init_user_ns, acred->cred->fsuid),
                        from_kgid(&init_user_ns, acred->cred->fsgid));
 
-       if (!(cred = kmalloc(sizeof(*cred), gfp)))
-               return ERR_PTR(-ENOMEM);
-
-       rpcauth_init_cred(&cred->uc_base, acred, auth, &unix_credops);
-       cred->uc_base.cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
-
-       if (acred->cred && acred->cred->group_info != NULL)
-               groups = acred->cred->group_info->ngroups;
-       if (groups > UNX_NGROUPS)
-               groups = UNX_NGROUPS;
-
-       cred->uc_gid = acred->cred->fsgid;
-       for (i = 0; i < groups; i++)
-               cred->uc_gids[i] = acred->cred->group_info->gid[i];
-       if (i < UNX_NGROUPS)
-               cred->uc_gids[i] = INVALID_GID;
-
-       return &cred->uc_base;
-}
-
-static void
-unx_free_cred(struct unx_cred *unx_cred)
-{
-       dprintk("RPC:       unx_free_cred %p\n", unx_cred);
-       put_cred(unx_cred->uc_base.cr_cred);
-       kfree(unx_cred);
+       rpcauth_init_cred(ret, acred, auth, &unix_credops);
+       ret->cr_flags = 1UL << RPCAUTH_CRED_UPTODATE;
+       return ret;
 }
 
 static void
 unx_free_cred_callback(struct rcu_head *head)
 {
-       struct unx_cred *unx_cred = container_of(head, struct unx_cred, uc_base.cr_rcu);
-       unx_free_cred(unx_cred);
+       struct rpc_cred *rpc_cred = container_of(head, struct rpc_cred, cr_rcu);
+       dprintk("RPC:       unx_free_cred %p\n", rpc_cred);
+       put_cred(rpc_cred->cr_cred);
+       mempool_free(rpc_cred, unix_pool);
 }
 
 static void
@@ -115,30 +73,32 @@ unx_destroy_cred(struct rpc_cred *cred)
 }
 
 /*
- * Match credentials against current process creds.
- * The root_override argument takes care of cases where the caller may
- * request root creds (e.g. for NFS swapping).
+ * Match credentials against current the auth_cred.
  */
 static int
-unx_match(struct auth_cred *acred, struct rpc_cred *rcred, int flags)
+unx_match(struct auth_cred *acred, struct rpc_cred *cred, int flags)
 {
-       struct unx_cred *cred = container_of(rcred, struct unx_cred, uc_base);
        unsigned int groups = 0;
        unsigned int i;
 
+       if (cred->cr_cred == acred->cred)
+               return 1;
 
-       if (!uid_eq(cred->uc_uid, acred->cred->fsuid) || !gid_eq(cred->uc_gid, acred->cred->fsgid))
+       if (!uid_eq(cred->cr_cred->fsuid, acred->cred->fsuid) || !gid_eq(cred->cr_cred->fsgid, acred->cred->fsgid))
                return 0;
 
        if (acred->cred && acred->cred->group_info != NULL)
                groups = acred->cred->group_info->ngroups;
        if (groups > UNX_NGROUPS)
                groups = UNX_NGROUPS;
+       if (cred->cr_cred->group_info == NULL)
+               return groups == 0;
+       if (groups != cred->cr_cred->group_info->ngroups)
+               return 0;
+
        for (i = 0; i < groups ; i++)
-               if (!gid_eq(cred->uc_gids[i], acred->cred->group_info->gid[i]))
+               if (!gid_eq(cred->cr_cred->group_info->gid[i], acred->cred->group_info->gid[i]))
                        return 0;
-       if (groups < UNX_NGROUPS && gid_valid(cred->uc_gids[groups]))
-               return 0;
        return 1;
 }
 
@@ -150,9 +110,10 @@ static __be32 *
 unx_marshal(struct rpc_task *task, __be32 *p)
 {
        struct rpc_clnt *clnt = task->tk_client;
-       struct unx_cred *cred = container_of(task->tk_rqstp->rq_cred, struct unx_cred, uc_base);
+       struct rpc_cred *cred = task->tk_rqstp->rq_cred;
        __be32          *base, *hold;
        int             i;
+       struct group_info *gi = cred->cr_cred->group_info;
 
        *p++ = htonl(RPC_AUTH_UNIX);
        base = p++;
@@ -163,11 +124,12 @@ unx_marshal(struct rpc_task *task, __be32 *p)
         */
        p = xdr_encode_array(p, clnt->cl_nodename, clnt->cl_nodelen);
 
-       *p++ = htonl((u32) from_kuid(&init_user_ns, cred->uc_uid));
-       *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gid));
+       *p++ = htonl((u32) from_kuid(&init_user_ns, cred->cr_cred->fsuid));
+       *p++ = htonl((u32) from_kgid(&init_user_ns, cred->cr_cred->fsgid));
        hold = p++;
-       for (i = 0; i < UNX_NGROUPS && gid_valid(cred->uc_gids[i]); i++)
-               *p++ = htonl((u32) from_kgid(&init_user_ns, cred->uc_gids[i]));
+       if (gi)
+               for (i = 0; i < UNX_NGROUPS && i < gi->ngroups; i++)
+                       *p++ = htonl((u32) from_kgid(&init_user_ns, gi->gid[i]));
        *hold = htonl(p - hold - 1);            /* gid array length */
        *base = htonl((p - base - 1) << 2);     /* cred length */
 
@@ -214,12 +176,13 @@ unx_validate(struct rpc_task *task, __be32 *p)
 
 int __init rpc_init_authunix(void)
 {
-       return rpcauth_init_credcache(&unix_auth);
+       unix_pool = mempool_create_kmalloc_pool(16, sizeof(struct rpc_cred));
+       return unix_pool ? 0 : -ENOMEM;
 }
 
 void rpc_destroy_authunix(void)
 {
-       rpcauth_destroy_credcache(&unix_auth);
+       mempool_destroy(unix_pool);
 }
 
 const struct rpc_authops authunix_ops = {
@@ -228,9 +191,7 @@ const struct rpc_authops authunix_ops = {
        .au_name        = "UNIX",
        .create         = unx_create,
        .destroy        = unx_destroy,
-       .hash_cred      = unx_hash_cred,
        .lookup_cred    = unx_lookup_cred,
-       .crcreate       = unx_create_cred,
 };
 
 static