crypto: chcr - Select device in Round Robin fashion

When multiple devices are present in system select device
in round-robin fashion for crypto operations

Signed-off-by: Atul Gupta <atul.gupta@chelsio.com>
Reviewed-by: Ganesh Goudar <ganeshgr@chelsio.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

3 files changed, 42 insertions, 21 deletions

diff --git a/drivers/crypto/chelsio/chcr_algo.c b/drivers/crypto/chelsio/chcr_algo.c
index 9a84ffa2adf3..aa4e5b88483d 100644
--- a/drivers/crypto/chelsio/chcr_algo.c
+++ b/drivers/crypto/chelsio/chcr_algo.c
@@ -1216,7 +1216,7 @@ static int chcr_aes_decrypt(struct ablkcipher_request *req)
 
 static int chcr_device_init(struct chcr_context *ctx)
 {
-	struct uld_ctx *u_ctx;
+	struct uld_ctx *u_ctx = NULL;
 	struct adapter *adap;
 	unsigned int id;
 	int txq_perchan, txq_idx, ntxq;
@@ -1224,12 +1224,12 @@ static int chcr_device_init(struct chcr_context *ctx)
 
 	id = smp_processor_id();
 	if (!ctx->dev) {
-		err = assign_chcr_device(&ctx->dev);
-		if (err) {
+		u_ctx = assign_chcr_device();
+		if (!u_ctx) {
 			pr_err("chcr device assignment fails\n");
 			goto out;
 		}
-		u_ctx = ULD_CTX(ctx);
+		ctx->dev = u_ctx->dev;
 		adap = padap(ctx->dev);
 		ntxq = min_not_zero((unsigned int)u_ctx->lldi.nrxq,
 				    adap->vres.ncrypto_fc);
diff --git a/drivers/crypto/chelsio/chcr_core.c b/drivers/crypto/chelsio/chcr_core.c
index 5ae659af6a90..b6dd9cbe815f 100644
--- a/drivers/crypto/chelsio/chcr_core.c
+++ b/drivers/crypto/chelsio/chcr_core.c
@@ -29,6 +29,7 @@
 static LIST_HEAD(uld_ctx_list);
 static DEFINE_MUTEX(dev_mutex);
 static atomic_t dev_count;
+static struct uld_ctx *ctx_rr;
 
 typedef int (*chcr_handler_func)(struct chcr_dev *dev, unsigned char *input);
 static int cpl_fw6_pld_handler(struct chcr_dev *dev, unsigned char *input);
@@ -49,25 +50,28 @@ static struct cxgb4_uld_info chcr_uld_info = {
 	.rx_handler = chcr_uld_rx_handler,
 };
 
-int assign_chcr_device(struct chcr_dev **dev)
+struct uld_ctx *assign_chcr_device(void)
 {
-	struct uld_ctx *u_ctx;
-	int ret = -ENXIO;
+	struct uld_ctx *u_ctx = NULL;
 
 	/*
-	 * Which device to use if multiple devices are available TODO
-	 * May be select the device based on round robin. One session
-	 * must go to the same device to maintain the ordering.
+	 * When multiple devices are present in system select
+	 * device in round-robin fashion for crypto operations
+	 * Although One session must use the same device to
+	 * maintain request-response ordering.
 	 */
-	mutex_lock(&dev_mutex); /* TODO ? */
-	list_for_each_entry(u_ctx, &uld_ctx_list, entry)
-		if (u_ctx->dev) {
-			*dev = u_ctx->dev;
-			ret = 0;
-			break;
+	mutex_lock(&dev_mutex);
+	if (!list_empty(&uld_ctx_list)) {
+		u_ctx = ctx_rr;
+		if (list_is_last(&ctx_rr->entry, &uld_ctx_list))
+			ctx_rr = list_first_entry(&uld_ctx_list,
+						  struct uld_ctx,
+						  entry);
+		else
+			ctx_rr = list_next_entry(ctx_rr, entry);
 	}
 	mutex_unlock(&dev_mutex);
-	return ret;
+	return u_ctx;
 }
 
 static int chcr_dev_add(struct uld_ctx *u_ctx)
@@ -82,11 +86,27 @@ static int chcr_dev_add(struct uld_ctx *u_ctx)
 	u_ctx->dev = dev;
 	dev->u_ctx = u_ctx;
 	atomic_inc(&dev_count);
+	mutex_lock(&dev_mutex);
+	list_add_tail(&u_ctx->entry, &uld_ctx_list);
+	if (!ctx_rr)
+		ctx_rr = u_ctx;
+	mutex_unlock(&dev_mutex);
 	return 0;
 }
 
 static int chcr_dev_remove(struct uld_ctx *u_ctx)
 {
+	if (ctx_rr == u_ctx) {
+		if (list_is_last(&ctx_rr->entry, &uld_ctx_list))
+			ctx_rr = list_first_entry(&uld_ctx_list,
+						  struct uld_ctx,
+						  entry);
+		else
+			ctx_rr = list_next_entry(ctx_rr, entry);
+	}
+	list_del(&u_ctx->entry);
+	if (list_empty(&uld_ctx_list))
+		ctx_rr = NULL;
 	kfree(u_ctx->dev);
 	u_ctx->dev = NULL;
 	atomic_dec(&dev_count);
@@ -139,10 +159,11 @@ static void *chcr_uld_add(const struct cxgb4_lld_info *lld)
 		u_ctx = ERR_PTR(-ENOMEM);
 		goto out;
 	}
+	if (!(lld->ulp_crypto & ULP_CRYPTO_LOOKASIDE)) {
+		u_ctx = ERR_PTR(-ENOMEM);
+		goto out;
+	}
 	u_ctx->lldi = *lld;
-	mutex_lock(&dev_mutex);
-	list_add_tail(&u_ctx->entry, &uld_ctx_list);
-	mutex_unlock(&dev_mutex);
 out:
 	return u_ctx;
 }
diff --git a/drivers/crypto/chelsio/chcr_core.h b/drivers/crypto/chelsio/chcr_core.h
index ddfb2c934551..c9a19b2a1e9f 100644
--- a/drivers/crypto/chelsio/chcr_core.h
+++ b/drivers/crypto/chelsio/chcr_core.h
@@ -89,7 +89,7 @@ struct uld_ctx {
 	struct chcr_dev *dev;
 };
 
-int assign_chcr_device(struct chcr_dev **dev);
+struct uld_ctx * assign_chcr_device(void);
 int chcr_send_wr(struct sk_buff *skb);
 int start_crypto(void);
 int stop_crypto(void);