[CRYPTO] api: Added spawns

Spawns lock a specific crypto algorithm in place.  They can then be used
with crypto_spawn_tfm to allocate a tfm for that algorithm.  When the base
algorithm of a spawn is deregistered, all its spawns will be automatically
removed.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 65 insertions, 30 deletions

diff --git a/crypto/api.c b/crypto/api.c
index ddf6a767acdd..7e5522cf856e 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -15,11 +15,13 @@
  *
  */
 
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/module.h>
 #include <linux/param.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 #include <linux/string.h>
 #include "internal.h"
@@ -38,12 +40,6 @@ static inline struct crypto_alg *crypto_alg_get(struct crypto_alg *alg)
         return alg;
 }
 
-static inline void crypto_alg_put(struct crypto_alg *alg)
-{
-        if (atomic_dec_and_test(&alg->cra_refcnt) && alg->cra_destroy)
-                alg->cra_destroy(alg);
-}
-
 struct crypto_alg *crypto_mod_get(struct crypto_alg *alg)
 {
         return try_module_get(alg->cra_module) ? crypto_alg_get(alg) : NULL;
@@ -65,6 +61,9 @@ struct crypto_alg *__crypto_alg_lookup(const char *name, u32 type, u32 mask)
         list_for_each_entry(q, &crypto_alg_list, cra_list) {
                 int exact, fuzzy;
 
+                if (crypto_is_moribund(q))
+                        continue;
+
                 if ((q->cra_flags ^ type) & mask)
                         continue;
 
@@ -111,7 +110,7 @@ static struct crypto_alg *crypto_larval_alloc(const char *name, u32 type,
 
         larval = kzalloc(sizeof(*larval), GFP_KERNEL);
         if (!larval)
-                return NULL;
+                return ERR_PTR(-ENOMEM);
 
         larval->mask = mask;
         larval->alg.cra_flags = CRYPTO_ALG_LARVAL | type;
@@ -153,8 +152,11 @@ static struct crypto_alg *crypto_larval_wait(struct crypto_alg *alg)
 
         wait_for_completion_interruptible_timeout(&larval->completion, 60 * HZ);
         alg = larval->adult;
-        if (alg && !crypto_mod_get(alg))
-                alg = NULL;
+        if (alg) {
+                if (!crypto_mod_get(alg))
+                        alg = ERR_PTR(-EAGAIN);
+        } else
+                alg = ERR_PTR(-ENOENT);
         crypto_mod_put(&larval->alg);
 
         return alg;
@@ -165,9 +167,6 @@ static struct crypto_alg *crypto_alg_lookup(const char *name, u32 type,
 {
         struct crypto_alg *alg;
 
-        if (!name)
-                return NULL;
-
         down_read(&crypto_alg_sem);
         alg = __crypto_alg_lookup(name, type, mask);
         up_read(&crypto_alg_sem);
@@ -181,7 +180,10 @@ struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
         struct crypto_alg *larval;
         int ok;
 
-        mask &= ~CRYPTO_ALG_LARVAL;
+        if (!name)
+                return ERR_PTR(-ENOENT);
+
+        mask &= ~(CRYPTO_ALG_LARVAL | CRYPTO_ALG_DEAD);
         type &= mask;
 
         alg = try_then_request_module(crypto_alg_lookup(name, type, mask),
@@ -190,7 +192,7 @@ struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
                 return crypto_is_larval(alg) ? crypto_larval_wait(alg) : alg;
 
         larval = crypto_larval_alloc(name, type, mask);
-        if (!larval || !crypto_is_larval(larval))
+        if (IS_ERR(larval) || !crypto_is_larval(larval))
                 return larval;
 
         ok = crypto_notify(CRYPTO_MSG_ALG_REQUEST, larval);
@@ -203,7 +205,7 @@ struct crypto_alg *crypto_alg_mod_lookup(const char *name, u32 type, u32 mask)
                 alg = crypto_larval_wait(larval);
         else {
                 crypto_mod_put(larval);
-                alg = NULL;
+                alg = ERR_PTR(-ENOENT);
         }
         crypto_larval_kill(larval);
         return alg;
@@ -298,31 +300,40 @@ static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
         return len + (alg->cra_alignmask & ~(crypto_tfm_ctx_alignment() - 1));
 }
 
-struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
+void crypto_shoot_alg(struct crypto_alg *alg)
+{
+        down_write(&crypto_alg_sem);
+        alg->cra_flags |= CRYPTO_ALG_DYING;
+        up_write(&crypto_alg_sem);
+}
+EXPORT_SYMBOL_GPL(crypto_shoot_alg);
+
+struct crypto_tfm *__crypto_alloc_tfm(struct crypto_alg *alg, u32 flags)
 {
         struct crypto_tfm *tfm = NULL;
-        struct crypto_alg *alg;
         unsigned int tfm_size;
-
-        alg = crypto_alg_mod_lookup(name, 0, 0);
-        if (alg == NULL)
-                goto out;
+        int err = -ENOMEM;
 
         tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
         tfm = kzalloc(tfm_size, GFP_KERNEL);
         if (tfm == NULL)
-                goto out_put;
+                goto out;
 
         tfm->__crt_alg = alg;
-        
-        if (crypto_init_flags(tfm, flags))
+
+        err = crypto_init_flags(tfm, flags);
+        if (err)
                 goto out_free_tfm;
                 
-        if (crypto_init_ops(tfm))
+        err = crypto_init_ops(tfm);
+        if (err)
                 goto out_free_tfm;
 
-        if (alg->cra_init && alg->cra_init(tfm))
+        if (alg->cra_init && (err = alg->cra_init(tfm))) {
+                if (err == -EAGAIN)
+                        crypto_shoot_alg(alg);
                 goto cra_init_failed;
+        }
 
         goto out;
 
@@ -330,12 +341,36 @@ cra_init_failed:
         crypto_exit_ops(tfm);
 out_free_tfm:
         kfree(tfm);
-        tfm = NULL;
-out_put:
-        crypto_mod_put(alg);
+        tfm = ERR_PTR(err);
 out:
         return tfm;
 }
+EXPORT_SYMBOL_GPL(__crypto_alloc_tfm);
+
+struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
+{
+        struct crypto_tfm *tfm = NULL;
+        int err;
+
+        do {
+                struct crypto_alg *alg;
+
+                alg = crypto_alg_mod_lookup(name, 0, 0);
+                err = PTR_ERR(alg);
+                if (IS_ERR(alg))
+                        continue;
+
+                tfm = __crypto_alloc_tfm(alg, flags);
+                err = 0;
+                if (IS_ERR(tfm)) {
+                        crypto_mod_put(alg);
+                        err = PTR_ERR(tfm);
+                        tfm = NULL;
+                }
+        } while (err == -EAGAIN && !signal_pending(current));
+
+        return tfm;
+}
 
 void crypto_free_tfm(struct crypto_tfm *tfm)
 {
@@ -361,7 +396,7 @@ int crypto_alg_available(const char *name, u32 flags)
         int ret = 0;
         struct crypto_alg *alg = crypto_alg_mod_lookup(name, 0, 0);
         
-        if (alg) {
+        if (!IS_ERR(alg)) {
                 crypto_mod_put(alg);
                 ret = 1;
         }