crypto: change transient busy return code to -ENOSPC

The crypto API was using the -EBUSY return value to indicate
both a hard failure to submit a crypto operation into a
transformation provider when the latter was busy and the backlog
mechanism was not enabled as well as a notification that the
operation was queued into the backlog when the backlog mechanism
was enabled.

Having the same return code indicate two very different conditions
depending on a flag is both error prone and requires extra runtime
check like the following to discern between the cases:

	if (err == -EINPROGRESS ||
	    (err == -EBUSY && (ahash_request_flags(req) &
			       CRYPTO_TFM_REQ_MAY_BACKLOG)))

This patch changes the return code used to indicate a crypto op
failed due to the transformation provider being transiently busy
to -ENOSPC.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 4 insertions, 2 deletions

diff --git a/crypto/algapi.c b/crypto/algapi.c
index aa699ff6c876..60d7366ed343 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -897,9 +897,11 @@ int crypto_enqueue_request(struct crypto_queue *queue,
         int err = -EINPROGRESS;
 
         if (unlikely(queue->qlen >= queue->max_qlen)) {
-                err = -EBUSY;
-                if (!(request->flags & CRYPTO_TFM_REQ_MAY_BACKLOG))
+                if (!(request->flags & CRYPTO_TFM_REQ_MAY_BACKLOG)) {
+                        err = -ENOSPC;
                         goto out;
+                }
+                err = -EBUSY;
                 if (queue->backlog == &queue->list)
                         queue->backlog = &request->list;
         }