diff --git a/fs/smb/server/smb2pdu.c b/fs/smb/server/smb2pdu.c
index 7460089c186f..797b0f24097b 100644
--- a/fs/smb/server/smb2pdu.c
+++ b/fs/smb/server/smb2pdu.c
@@ -4883,7 +4883,7 @@ static void get_file_alternate_info(struct ksmbd_work *work,
 	spin_unlock(&dentry->d_lock);
 	file_info->FileNameLength = cpu_to_le32(conv_len);
 	rsp->OutputBufferLength =
-		cpu_to_le32(sizeof(struct smb2_file_alt_name_info) + conv_len);
+		cpu_to_le32(struct_size(file_info, FileName, conv_len));
 }
 
 static int get_file_stream_info(struct ksmbd_work *work,
@@ -7562,7 +7562,6 @@ static int fsctl_copychunk(struct ksmbd_work *work,
 	ci_rsp->TotalBytesWritten =
 		cpu_to_le32(ksmbd_server_side_copy_max_total_size());
 
-	chunks = (struct srv_copychunk *)&ci_req->Chunks[0];
 	chunk_count = le32_to_cpu(ci_req->ChunkCount);
 	if (chunk_count == 0)
 		goto out;
@@ -7570,12 +7569,12 @@ static int fsctl_copychunk(struct ksmbd_work *work,
 
 	/* verify the SRV_COPYCHUNK_COPY packet */
 	if (chunk_count > ksmbd_server_side_copy_max_chunk_count() ||
-	    input_count < offsetof(struct copychunk_ioctl_req, Chunks) +
-	     chunk_count * sizeof(struct srv_copychunk)) {
+	    input_count < struct_size(ci_req, Chunks, chunk_count)) {
 		rsp->hdr.Status = STATUS_INVALID_PARAMETER;
 		return -EINVAL;
 	}
 
+	chunks = &ci_req->Chunks[0];
 	for (i = 0; i < chunk_count; i++) {
 		if (le32_to_cpu(chunks[i].Length) == 0 ||
 		    le32_to_cpu(chunks[i].Length) > ksmbd_server_side_copy_max_chunk_size())
diff --git a/fs/smb/server/smb2pdu.h b/fs/smb/server/smb2pdu.h
index 73aff20e22d0..649dacf7e8c4 100644
--- a/fs/smb/server/smb2pdu.h
+++ b/fs/smb/server/smb2pdu.h
@@ -190,13 +190,6 @@ struct resume_key_ioctl_rsp {
 	__u8 Context[4]; /* ignored, Windows sets to 4 bytes of zero */
 } __packed;
 
-struct copychunk_ioctl_req {
-	__le64 ResumeKey[3];
-	__le32 ChunkCount;
-	__le32 Reserved;
-	__u8 Chunks[]; /* array of srv_copychunk */
-} __packed;
-
 struct srv_copychunk {
 	__le64 SourceOffset;
 	__le64 TargetOffset;
@@ -204,6 +197,13 @@ struct srv_copychunk {
 	__le32 Reserved;
 } __packed;
 
+struct copychunk_ioctl_req {
+	__le64 ResumeKey[3];
+	__le32 ChunkCount;
+	__le32 Reserved;
+	struct srv_copychunk Chunks[] __counted_by_le(ChunkCount);
+} __packed;
+
 struct copychunk_ioctl_rsp {
 	__le32 ChunksWritten;
 	__le32 ChunkBytesWritten;
diff --git a/fs/smb/server/transport_rdma.c b/fs/smb/server/transport_rdma.c
index 44c87e300c16..17c76713c6d0 100644
--- a/fs/smb/server/transport_rdma.c
+++ b/fs/smb/server/transport_rdma.c
@@ -1405,8 +1405,8 @@ static int smb_direct_rdma_xmit(struct smb_direct_transport *t,
 	/* build rdma_rw_ctx for each descriptor */
 	desc_buf = buf;
 	for (i = 0; i < desc_num; i++) {
-		msg = kzalloc(offsetof(struct smb_direct_rdma_rw_msg, sg_list) +
-			      sizeof(struct scatterlist) * SG_CHUNK_SIZE, GFP_KERNEL);
+		msg = kzalloc(struct_size(msg, sg_list, SG_CHUNK_SIZE),
+			      GFP_KERNEL);
 		if (!msg) {
 			ret = -ENOMEM;
 			goto out;