[PATCH v2 019/127] smb: smbdirect: introduce smbdirect_connection_{alloc, free}_send_io()

[Stefan Metzmacher]

These are more or less copies of smb_direct_{alloc,free}_sendmsg()
in the server.

The only difference is that we use ib_dma_unmap_page() for all sges,
this simplifies the logic and doesn't matter as
ib_dma_unmap_single() and ib_dma_unmap_page() both operate
on dma_addr_t and dma_unmap_single_attrs() is just an
alias for dma_unmap_page_attrs().
We already have in inconsistency like that in the client
code where we use ib_dma_unmap_single(), while we mapped
using ib_dma_map_page().

The new functions will replace the existing once in the next commits and
will also be used in the client.

Cc: Steve French <smfrench at gmail.com>
Cc: Tom Talpey <tom at talpey.com>
Cc: Long Li <longli at microsoft.com>
Cc: Namjae Jeon <linkinjeon at kernel.org>
Cc: linux-cifs at vger.kernel.org
Cc: samba-technical at lists.samba.org
Signed-off-by: Stefan Metzmacher <metze at samba.org>
Signed-off-by: Steve French <stfrench at microsoft.com>
---
 .../common/smbdirect/smbdirect_connection.c   | 47 +++++++++++++++++++
 1 file changed, 47 insertions(+)

diff --git a/fs/smb/common/smbdirect/smbdirect_connection.c b/fs/smb/common/smbdirect/smbdirect_connection.c
index e90aa3b72b44..e5e8432f88e6 100644
--- a/fs/smb/common/smbdirect/smbdirect_connection.c
+++ b/fs/smb/common/smbdirect/smbdirect_connection.c
@@ -88,6 +88,53 @@ static void smbdirect_connection_wake_up_all(struct smbdirect_socket *sc)
 	wake_up_all(&sc->mr_io.cleanup.wait_queue);
 }
 
+__maybe_unused /* this is temporary while this file is included in orders */
+static struct smbdirect_send_io *smbdirect_connection_alloc_send_io(struct smbdirect_socket *sc)
+{
+	struct smbdirect_send_io *msg;
+
+	msg = mempool_alloc(sc->send_io.mem.pool, sc->send_io.mem.gfp_mask);
+	if (!msg)
+		return ERR_PTR(-ENOMEM);
+	msg->socket = sc;
+	INIT_LIST_HEAD(&msg->sibling_list);
+	msg->num_sge = 0;
+
+	return msg;
+}
+
+__maybe_unused /* this is temporary while this file is included in orders */
+static void smbdirect_connection_free_send_io(struct smbdirect_send_io *msg)
+{
+	struct smbdirect_socket *sc = msg->socket;
+	size_t i;
+
+	/*
+	 * The list needs to be empty!
+	 * The caller should take care of it.
+	 */
+	WARN_ON_ONCE(!list_empty(&msg->sibling_list));
+
+	/*
+	 * Note we call ib_dma_unmap_page(), even if some sges are mapped using
+	 * ib_dma_map_single().
+	 *
+	 * The difference between _single() and _page() only matters for the
+	 * ib_dma_map_*() case.
+	 *
+	 * For the ib_dma_unmap_*() case it does not matter as both take the
+	 * dma_addr_t and dma_unmap_single_attrs() is just an alias to
+	 * dma_unmap_page_attrs().
+	 */
+	for (i = 0; i < msg->num_sge; i++)
+		ib_dma_unmap_page(sc->ib.dev,
+				  msg->sge[i].addr,
+				  msg->sge[i].length,
+				  DMA_TO_DEVICE);
+
+	mempool_free(msg, sc->send_io.mem.pool);
+}
+
 __maybe_unused /* this is temporary while this file is included in orders */
 static struct smbdirect_recv_io *smbdirect_connection_get_recv_io(struct smbdirect_socket *sc)
 {
-- 
2.43.0