From ac145e1cb6a5ea21671c3b8f6546948fda1d7c77 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Fri, 8 Nov 2019 21:28:37 +0000
Subject: [PATCH] ib_srpt: Detect ib_sg_dma_len() presence at compile time

This patch makes it possible to build the ib_srpt driver against a kernel
before v5.1 + latest MOFED.


git-svn-id: http://svn.code.sf.net/p/scst/svn/trunk@8655 d57e44dd-8a1f-0410-8b47-8ef2f437770f
---
 scripts/specialize-patch                    |  4 ++++
 scst/include/backport.h                     |  5 -----
 srpt/Makefile                               |  5 +++++
 srpt/conftest/ib_sg_dma_len/Makefile        |  3 +++
 srpt/conftest/ib_sg_dma_len/ib_sg_dma_len.c | 11 +++++++++++
 srpt/src/ib_srpt.h                          |  5 +++++
 6 files changed, 28 insertions(+), 5 deletions(-)
 create mode 100644 srpt/conftest/ib_sg_dma_len/Makefile
 create mode 100644 srpt/conftest/ib_sg_dma_len/ib_sg_dma_len.c

diff --git a/scripts/specialize-patch b/scripts/specialize-patch
index 26bd3dfc1..e75c60c46 100755
--- a/scripts/specialize-patch
+++ b/scripts/specialize-patch
@@ -148,6 +148,9 @@ function evaluate(stmnt, pattern, arg, op, result) {
   gsub("defined\\(HAVE_IB_DMA_MAP_OPS\\)",
        "(LINUX_VERSION_CODE >= KERNEL_VERSION(0, 0, 0))", stmnt)
 
+  gsub("defined\\(HAVE_IB_SG_DMA_LEN\\)",
+       "(LINUX_VERSION_CODE < KERNEL_VERSION(5, 1, 0))", stmnt)
+
   gsub("defined(ENABLE_NPIV)", 0, stmnt)
 
   gsub("defined(FC_VPORT_CREATE_DEFINED)", 0, stmnt)
@@ -398,6 +401,7 @@ function handle_if(evaluated)
       || $0 ~ "HAVE_IB_DMA_MAP_OPS"					\
       || $0 ~ "HAVE_IB_QUERY_DEVICE"					\
       || $0 ~ "HAVE_IB_SET_CPI_RESP_TIME"				\
+      || $0 ~ "HAVE_IB_SG_DMA_LEN"					\
       || $0 ~ "HAVE_RDMA_DESTROY_AH"					\
       || $0 ~ "HAVE_RDMA_DESTROY_AH_WITH_FLAGS"				\
       || $0 ~ "HAVE_RDMA_QUERY_GID"					\
diff --git a/scst/include/backport.h b/scst/include/backport.h
index 7f8bb03a7..6df7ca081 100644
--- a/scst/include/backport.h
+++ b/scst/include/backport.h
@@ -1588,11 +1588,6 @@ static inline struct ib_pd *ib_alloc_pd_backport(struct ib_device *device)
 	})
 #endif
 
-#if LINUX_VERSION_CODE >= KERNEL_VERSION(5, 1, 0)
-#define ib_sg_dma_len(dev, sg) sg_dma_len(sg)
-#define ib_sg_dma_address(dev, sg) sg_dma_address(sg)
-#endif
-
 /* <scsi/scsi_cmnd.h> */
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 24) || \
diff --git a/srpt/Makefile b/srpt/Makefile
index ced096d17..65d562afd 100644
--- a/srpt/Makefile
+++ b/srpt/Makefile
@@ -212,6 +212,11 @@ conftest/ib_set_cpi_resp_time/result-$(KVER).txt:			\
 	echo "$(call run_conftest,ib_set_cpi_resp_time,			\
 		-DHAVE_IB_SET_CPI_RESP_TIME)" >"$@"
 
+conftest/ib_sg_dma_len/result-$(KVER).txt:				\
+	conftest/ib_sg_dma_len/ib_sg_dma_len.c				\
+	conftest/ib_sg_dma_len/Makefile
+	echo "$(call run_conftest_bool,ib_sg_dma_len,HAVE_IB_SG_DMA_LEN)" >"$@"
+
 conftest/mad_handler_takes_send_buf/result-$(KVER).txt:			\
 	conftest/mad_handler_takes_send_buf/mad_handler_takes_send_buf.c\
 	conftest/mad_handler_takes_send_buf/Makefile
diff --git a/srpt/conftest/ib_sg_dma_len/Makefile b/srpt/conftest/ib_sg_dma_len/Makefile
new file mode 100644
index 000000000..199542f31
--- /dev/null
+++ b/srpt/conftest/ib_sg_dma_len/Makefile
@@ -0,0 +1,3 @@
+LINUXINCLUDE := $(PRE_CFLAGS) $(LINUXINCLUDE)
+
+obj-m += ib_sg_dma_len.o
diff --git a/srpt/conftest/ib_sg_dma_len/ib_sg_dma_len.c b/srpt/conftest/ib_sg_dma_len/ib_sg_dma_len.c
new file mode 100644
index 000000000..4ac94b31c
--- /dev/null
+++ b/srpt/conftest/ib_sg_dma_len/ib_sg_dma_len.c
@@ -0,0 +1,11 @@
+#include <linux/module.h>
+#include <rdma/ib_verbs.h>
+
+#undef ib_sg_dma_len
+
+static int modinit(void)
+{
+	return ib_sg_dma_len != NULL;
+}
+
+module_init(modinit);
diff --git a/srpt/src/ib_srpt.h b/srpt/src/ib_srpt.h
index 2af8422ba..ce680261a 100644
--- a/srpt/src/ib_srpt.h
+++ b/srpt/src/ib_srpt.h
@@ -66,6 +66,11 @@
 
 struct srpt_nexus;
 
+#if !HAVE_IB_SG_DMA_LEN
+#define ib_sg_dma_len(dev, sg) sg_dma_len(sg)
+#define ib_sg_dma_address(dev, sg) sg_dma_address(sg)
+#endif
+
 #if !HAVE_SRP_DATA_DESC_IMM
 enum {
 	SRP_DATA_DESC_IMM	 = 3,