Commit 8aa23bae authored by Stefan Metzmacher's avatar Stefan Metzmacher Committed by Steve French
Browse files

smb: server: make consitent use of spin_lock_irq{save,restore}() in transport_rdma.c 



There is a mix of using spin_lock() and spin_lock_irq(), which
is confusing as IB_POLL_WORKQUEUE is used and no code would
be called from any interrupt. So using spin_lock() or even
mutexes would be ok.

But we'll soon share common code with the client, which uses
IB_POLL_SOFTIRQ.

And Documentation/kernel-hacking/locking.rst section
"Cheat Sheet For Locking" says:

-  Otherwise (== data can be touched in an interrupt), use
   spin_lock_irqsave() and
   spin_unlock_irqrestore().

So in order to keep it simple and safe we use that version
now. It will help merging functions into common code and
have consistent locking in all cases.

Acked-by: default avatarNamjae Jeon <linkinjeon@kernel.org>
Cc: Steve French <smfrench@gmail.com>
Cc: Tom Talpey <tom@talpey.com>
Cc: linux-cifs@vger.kernel.org
Cc: samba-technical@lists.samba.org
Signed-off-by: default avatarStefan Metzmacher <metze@samba.org>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent 0491f26f

fs/smb/server/transport_rdma.c

+24 −15
Original line number Diff line number Diff line
@@ -150,21 +150,24 @@ static struct 
smbdirect_recv_io *get_free_recvmsg(struct smbdirect_socket *sc)

{

	struct smbdirect_recv_io *recvmsg = NULL;

	unsigned long flags;



	spin_lock(&sc->recv_io.free.lock);

	spin_lock_irqsave(&sc->recv_io.free.lock, flags);

	if (!list_empty(&sc->recv_io.free.list)) {

		recvmsg = list_first_entry(&sc->recv_io.free.list,

					   struct smbdirect_recv_io,

					   list);

		list_del(&recvmsg->list);

	}

	spin_unlock(&sc->recv_io.free.lock);

	spin_unlock_irqrestore(&sc->recv_io.free.lock, flags);

	return recvmsg;

}



static void put_recvmsg(struct smbdirect_socket *sc,

			struct smbdirect_recv_io *recvmsg)

{

	unsigned long flags;



	if (likely(recvmsg->sge.length != 0)) {

		ib_dma_unmap_single(sc->ib.dev,

				    recvmsg->sge.addr,
@@ -173,9 +176,9 @@ static void put_recvmsg(struct smbdirect_socket *sc, 
		recvmsg->sge.length = 0;

	}



	spin_lock(&sc->recv_io.free.lock);

	spin_lock_irqsave(&sc->recv_io.free.lock, flags);

	list_add(&recvmsg->list, &sc->recv_io.free.list);

	spin_unlock(&sc->recv_io.free.lock);

	spin_unlock_irqrestore(&sc->recv_io.free.lock, flags);



	queue_work(sc->workqueue, &sc->recv_io.posted.refill_work);

}
@@ -184,7 +187,9 @@ static void enqueue_reassembly(struct smbdirect_socket *sc, 
			       struct smbdirect_recv_io *recvmsg,

			       int data_length)

{

	spin_lock(&sc->recv_io.reassembly.lock);

	unsigned long flags;



	spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);

	list_add_tail(&recvmsg->list, &sc->recv_io.reassembly.list);

	sc->recv_io.reassembly.queue_length++;

	/*
@@ -195,7 +200,7 @@ static void enqueue_reassembly(struct smbdirect_socket *sc, 
	 */

	virt_wmb();

	sc->recv_io.reassembly.data_length += data_length;

	spin_unlock(&sc->recv_io.reassembly.lock);

	spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);

}



static struct smbdirect_recv_io *get_first_reassembly(struct smbdirect_socket *sc)
@@ -468,14 +473,16 @@ static void free_transport(struct smb_direct_transport *t) 


	ksmbd_debug(RDMA, "drain the reassembly queue\n");

	do {

		spin_lock(&sc->recv_io.reassembly.lock);

		unsigned long flags;



		spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);

		recvmsg = get_first_reassembly(sc);

		if (recvmsg) {

			list_del(&recvmsg->list);

			spin_unlock(&sc->recv_io.reassembly.lock);

			spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);

			put_recvmsg(sc, recvmsg);

		} else {

			spin_unlock(&sc->recv_io.reassembly.lock);

			spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);

		}

	} while (recvmsg);

	sc->recv_io.reassembly.data_length = 0;
@@ -768,6 +775,7 @@ static int smb_direct_read(struct ksmbd_transport *t, char *buf, 
	if (sc->recv_io.reassembly.data_length >= size) {

		int queue_length;

		int queue_removed = 0;

		unsigned long flags;



		/*

		 * Need to make sure reassembly_data_length is read before
@@ -823,9 +831,9 @@ static int smb_direct_read(struct ksmbd_transport *t, char *buf, 
				if (queue_length) {

					list_del(&recvmsg->list);

				} else {

					spin_lock_irq(&sc->recv_io.reassembly.lock);

					spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);

					list_del(&recvmsg->list);

					spin_unlock_irq(&sc->recv_io.reassembly.lock);

					spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);

				}

				queue_removed++;

				put_recvmsg(sc, recvmsg);
@@ -838,10 +846,10 @@ static int smb_direct_read(struct ksmbd_transport *t, char *buf, 
			data_read += to_copy;

		}



		spin_lock_irq(&sc->recv_io.reassembly.lock);

		spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);

		sc->recv_io.reassembly.data_length -= data_read;

		sc->recv_io.reassembly.queue_length -= queue_removed;

		spin_unlock_irq(&sc->recv_io.reassembly.lock);

		spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);



		sc->recv_io.reassembly.first_entry_offset = offset;

		ksmbd_debug(RDMA,
@@ -2107,6 +2115,7 @@ static int smb_direct_prepare(struct ksmbd_transport *t) 
	struct smbdirect_socket_parameters *sp = &sc->parameters;

	struct smbdirect_recv_io *recvmsg;

	struct smbdirect_negotiate_req *req;

	unsigned long flags;

	int ret;



	/*
@@ -2153,10 +2162,10 @@ static int smb_direct_prepare(struct ksmbd_transport *t) 


	ret = smb_direct_send_negotiate_response(sc, ret);

out:

	spin_lock_irq(&sc->recv_io.reassembly.lock);

	spin_lock_irqsave(&sc->recv_io.reassembly.lock, flags);

	sc->recv_io.reassembly.queue_length--;

	list_del(&recvmsg->list);

	spin_unlock_irq(&sc->recv_io.reassembly.lock);

	spin_unlock_irqrestore(&sc->recv_io.reassembly.lock, flags);

	put_recvmsg(sc, recvmsg);



	return ret;