smb3: only offload decryption of read responses if multiple requests

No point in offloading read decryption if no other requests on the
wire

Signed-off-by: Steve French <stfrench@microsoft.com>
Signed-off-by: Ronnie Sahlberg <lsahlber@redhat.com>

2 files changed, 7 insertions, 4 deletions

diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index ebf85a5d95e4..c1b685072063 100644
--- a/fs/cifs/cifsfs.c
+++ b/fs/cifs/cifsfs.c
@@ -1503,11 +1503,14 @@ init_cifs(void)
         }
 
         /*
-         * BB Consider setting limit!=0 maybe to min(num_of_cores - 1, 3) so we
-         * don't launch too many worker threads
+         * Consider in future setting limit!=0 maybe to min(num_of_cores - 1, 3)
+         * so that we don't launch too many worker threads but
+         * Documentation/workqueue.txt recommends setting it to 0
          */
+
+        /* WQ_UNBOUND allows decrypt tasks to run on any CPU */
         decrypt_wq = alloc_workqueue("smb3decryptd",
-                                     WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
+                                     WQ_UNBOUND|WQ_FREEZABLE|WQ_MEM_RECLAIM, 0);
         if (!decrypt_wq) {
                 rc = -ENOMEM;
                 goto out_destroy_cifsiod_wq;
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index 1cfb8d518132..72b3e39d7f4f 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -4121,7 +4121,7 @@ receive_encrypted_read(struct TCP_Server_Info *server, struct mid_q_entry **mid,
          * use more cores decrypting which can be expensive
          */
 
-        if ((server->min_offload) &&
+        if ((server->min_offload) && (server->in_flight > 1) &&
             (server->pdu_size >= server->min_offload)) {
                 dw = kmalloc(sizeof(struct smb2_decrypt_work), GFP_KERNEL);
                 if (dw == NULL)