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crypto: pcrypt - Make tfm_count an atomic_t

Message ID 20150522123422.GA6000@gondor.apana.org.au (mailing list archive)
State Accepted
Delegated to: Herbert Xu
Headers show

Commit Message

Herbert Xu May 22, 2015, 12:34 p.m. UTC 
The variable tfm_count is accessed by multiple threads without
locking.  This patch converts it to an atomic_t.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Patch

diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c
index 3942a9f..ff174b6 100644
--- a/crypto/pcrypt.c
+++ b/crypto/pcrypt.c
@@ -20,6 +20,7 @@ 
 
 #include <crypto/algapi.h>
 #include <crypto/internal/aead.h>
+#include <linux/atomic.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/module.h>
@@ -61,7 +62,7 @@  static struct kset           *pcrypt_kset;
 
 struct pcrypt_instance_ctx {
 	struct crypto_aead_spawn spawn;
-	unsigned int tfm_count;
+	atomic_t tfm_count;
 };
 
 struct pcrypt_aead_ctx {
@@ -278,9 +279,8 @@  static int pcrypt_aead_init_tfm(struct crypto_tfm *tfm)
 	struct pcrypt_aead_ctx *ctx = crypto_tfm_ctx(tfm);
 	struct crypto_aead *cipher;
 
-	ictx->tfm_count++;
-
-	cpu_index = ictx->tfm_count % cpumask_weight(cpu_online_mask);
+	cpu_index = (unsigned int)atomic_inc_return(&ictx->tfm_count) %
+		    cpumask_weight(cpu_online_mask);
 
 	ctx->cb_cpu = cpumask_first(cpu_online_mask);
 	for (cpu = 0; cpu < cpu_index; cpu++)