4 files changed, 30 insertions, 7 deletions
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index 29b5a9bd3128..678e638c1e69 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -230,8 +230,14 @@ struct smb_version_operations {
 	__u64 (*get_next_mid)(struct TCP_Server_Info *);
 	/* data offset from read response message */
 	unsigned int (*read_data_offset)(char *);
-	/* data length from read response message */
-	unsigned int (*read_data_length)(char *);
+	/*
+	 * Data length from read response message
+	 * When in_remaining is true, the returned data length is in
+	 * message field DataRemaining for out-of-band data read (e.g through
+	 * Memory Registration RDMA write in SMBD).
+	 * Otherwise, the returned data length is in message field DataLength.
+	 */
+	unsigned int (*read_data_length)(char *, bool in_remaining);
 	/* map smb to linux error */
 	int (*map_error)(char *, bool);
 	/* find mid corresponding to the response message */
@@ -1152,6 +1158,9 @@ struct cifs_readdata {
 				struct cifs_readdata *rdata,
 				struct iov_iter *iter);
 	struct kvec			iov[2];
+#ifdef CONFIG_CIFS_SMB_DIRECT
+	struct smbd_mr			*mr;
+#endif
 	unsigned int			pagesz;
 	unsigned int			tailsz;
 	unsigned int			credits;
diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
index 66d1ebfe75dd..49cf999f3d46 100644
--- a/fs/cifs/cifssmb.c
+++ b/fs/cifs/cifssmb.c
@@ -1455,6 +1455,7 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 	struct cifs_readdata *rdata = mid->callback_data;
 	char *buf = server->smallbuf;
 	unsigned int buflen = get_rfc1002_length(buf) + 4;
+	bool use_rdma_mr = false;
 
 	cifs_dbg(FYI, "%s: mid=%llu offset=%llu bytes=%u\n",
 		 __func__, mid->mid, rdata->offset, rdata->bytes);
@@ -1543,8 +1544,11 @@ cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
 		 rdata->iov[0].iov_base, server->total_read);
 
 	/* how much data is in the response? */
-	data_len = server->ops->read_data_length(buf);
-	if (data_offset + data_len > buflen) {
+#ifdef CONFIG_CIFS_SMB_DIRECT
+	use_rdma_mr = rdata->mr;
+#endif
+	data_len = server->ops->read_data_length(buf, use_rdma_mr);
+	if (!use_rdma_mr && (data_offset + data_len > buflen)) {
 		/* data_len is corrupt -- discard frame */
 		rdata->result = -EIO;
 		return cifs_readv_discard(server, mid);
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index a723df3e0197..3d495e440c87 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -87,9 +87,11 @@ cifs_read_data_offset(char *buf)
 }
 
 static unsigned int
-cifs_read_data_length(char *buf)
+cifs_read_data_length(char *buf, bool in_remaining)
 {
 	READ_RSP *rsp = (READ_RSP *)buf;
+	/* It's a bug reading remaining data for SMB1 packets */
+	WARN_ON(in_remaining);
 	return (le16_to_cpu(rsp->DataLengthHigh) << 16) +
 	       le16_to_cpu(rsp->DataLength);
 }
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index c8fa4c4ccc50..e3393ff5d458 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -957,9 +957,13 @@ smb2_read_data_offset(char *buf)
 }
 
 static unsigned int
-smb2_read_data_length(char *buf)
+smb2_read_data_length(char *buf, bool in_remaining)
 {
 	struct smb2_read_rsp *rsp = (struct smb2_read_rsp *)buf;
+
+	if (in_remaining)
+		return le32_to_cpu(rsp->DataRemaining);
+
 	return le32_to_cpu(rsp->DataLength);
 }
 
@@ -2421,6 +2425,7 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 	struct iov_iter iter;
 	struct kvec iov;
 	int length;
+	bool use_rdma_mr = false;
 
 	if (shdr->Command != SMB2_READ) {
 		cifs_dbg(VFS, "only big read responses are supported\n");
@@ -2447,7 +2452,10 @@ handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid,
 	}
 
 	data_offset = server->ops->read_data_offset(buf) + 4;
-	data_len = server->ops->read_data_length(buf);
+#ifdef CONFIG_CIFS_SMB_DIRECT
+	use_rdma_mr = rdata->mr;
+#endif
+	data_len = server->ops->read_data_length(buf, use_rdma_mr);
 
 	if (data_offset < server->vals->read_rsp_size) {
 		/*