crypto: axis - fix for recursive locking from bottom half

Clients may submit a new requests from the completion callback
context. The driver was not prepared to receive a request in this
state because it already held the request queue lock and a recursive
lock error is triggered.

Now all completions are queued up until we are ready to drop the queue
lock and then delivered.

The fault was triggered by TCP over an IPsec connection in the LTP
test suite:
  LTP: starting tcp4_ipsec02 (tcp_ipsec.sh -p ah -m transport -s "100 1000 65535")
  BUG: spinlock recursion on CPU#1, genload/943
   lock: 0xbf3c3094, .magic: dead4ead, .owner: genload/943, .owner_cpu: 1
  CPU: 1 PID: 943 Comm: genload Tainted: G           O    4.9.62-axis5-devel #6
  Hardware name: Axis ARTPEC-6 Platform
   (unwind_backtrace) from [<8010d134>] (show_stack+0x18/0x1c)
   (show_stack) from [<803a289c>] (dump_stack+0x84/0x98)
   (dump_stack) from [<8016e164>] (do_raw_spin_lock+0x124/0x128)
   (do_raw_spin_lock) from [<804de1a4>] (artpec6_crypto_submit+0x2c/0xa0)
   (artpec6_crypto_submit) from [<804def38>] (artpec6_crypto_prepare_submit_hash+0xd0/0x54c)
   (artpec6_crypto_prepare_submit_hash) from [<7f3165f0>] (ah_output+0x2a4/0x3dc [ah4])
   (ah_output [ah4]) from [<805df9bc>] (xfrm_output_resume+0x178/0x4a4)
   (xfrm_output_resume) from [<805d283c>] (xfrm4_output+0xac/0xbc)
   (xfrm4_output) from [<80587928>] (ip_queue_xmit+0x140/0x3b4)
   (ip_queue_xmit) from [<805a13b4>] (tcp_transmit_skb+0x4c4/0x95c)
   (tcp_transmit_skb) from [<8059f218>] (tcp_rcv_state_process+0xdf4/0xdfc)
   (tcp_rcv_state_process) from [<805a7530>] (tcp_v4_do_rcv+0x64/0x1ac)
   (tcp_v4_do_rcv) from [<805a9724>] (tcp_v4_rcv+0xa34/0xb74)
   (tcp_v4_rcv) from [<80581d34>] (ip_local_deliver_finish+0x78/0x2b0)
   (ip_local_deliver_finish) from [<8058259c>] (ip_local_deliver+0xe4/0x104)
   (ip_local_deliver) from [<805d23ec>] (xfrm4_transport_finish+0xf4/0x144)
   (xfrm4_transport_finish) from [<805df564>] (xfrm_input+0x4f4/0x74c)
   (xfrm_input) from [<804de420>] (artpec6_crypto_task+0x208/0x38c)
   (artpec6_crypto_task) from [<801271b0>] (tasklet_action+0x60/0xec)
   (tasklet_action) from [<801266d4>] (__do_softirq+0xcc/0x3a4)
   (__do_softirq) from [<80126d20>] (irq_exit+0xf4/0x15c)
   (irq_exit) from [<801741e8>] (__handle_domain_irq+0x68/0xbc)
   (__handle_domain_irq) from [<801014f0>] (gic_handle_irq+0x50/0x94)
   (gic_handle_irq) from [<80657370>] (__irq_usr+0x50/0x80)
Signed-off-by: Lars Persson <larper@axis.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/axis/artpec6_crypto.c

@@ -278,6 +278,7 @@ enum artpec6_crypto_hash_flags {
 
 struct artpec6_crypto_req_common {
 	struct list_head list;
+	struct list_head complete_in_progress;
 	struct artpec6_crypto_dma_descriptors *dma;
 	struct crypto_async_request *req;
 	void (*complete)(struct crypto_async_request *req);
@@ -2028,7 +2029,8 @@ static int artpec6_crypto_prepare_aead(struct aead_request *areq)
 	return artpec6_crypto_dma_map_descs(common);
 }
 
-static void artpec6_crypto_process_queue(struct artpec6_crypto *ac)
+static void artpec6_crypto_process_queue(struct artpec6_crypto *ac,
+	    struct list_head *completions)
 {
 	struct artpec6_crypto_req_common *req;
 
@@ -2039,7 +2041,7 @@ static void artpec6_crypto_process_queue(struct artpec6_crypto *ac)
 		list_move_tail(&req->list, &ac->pending);
 		artpec6_crypto_start_dma(req);
 
-		req->req->complete(req->req, -EINPROGRESS);
+		list_add_tail(&req->complete_in_progress, completions);
 	}
 
 	/*
@@ -2069,6 +2071,11 @@ static void artpec6_crypto_task(unsigned long data)
 	struct artpec6_crypto *ac = (struct artpec6_crypto *)data;
 	struct artpec6_crypto_req_common *req;
 	struct artpec6_crypto_req_common *n;
+	struct list_head complete_done;
+	struct list_head complete_in_progress;
+
+	INIT_LIST_HEAD(&complete_done);
+	INIT_LIST_HEAD(&complete_in_progress);
 
 	if (list_empty(&ac->pending)) {
 		pr_debug("Spurious IRQ\n");
@@ -2102,19 +2109,30 @@ static void artpec6_crypto_task(unsigned long data)
 
 		pr_debug("Completing request %p\n", req);
 
-		list_del(&req->list);
+		list_move_tail(&req->list, &complete_done);
 
 		artpec6_crypto_dma_unmap_all(req);
 		artpec6_crypto_copy_bounce_buffers(req);
 
 		ac->pending_count--;
 		artpec6_crypto_common_destroy(req);
-		req->complete(req->req);
 	}
 
-	artpec6_crypto_process_queue(ac);
+	artpec6_crypto_process_queue(ac, &complete_in_progress);
 
 	spin_unlock_bh(&ac->queue_lock);
+
+	/* Perform the completion callbacks without holding the queue lock
+	 * to allow new request submissions from the callbacks.
+	 */
+	list_for_each_entry_safe(req, n, &complete_done, list) {
+		req->complete(req->req);
+	}
+
+	list_for_each_entry_safe(req, n, &complete_in_progress,
+				 complete_in_progress) {
+		req->req->complete(req->req, -EINPROGRESS);
+	}
 }
 
 static void artpec6_crypto_complete_crypto(struct crypto_async_request *req)