kbuild: use $(src) instead of $(srctree)/$(src) for source directory

Kbuild conventionally uses $(obj)/ for generated files, and $(src)/ for
checked-in source files. It is merely a convention without any functional
difference. In fact, $(obj) and $(src) are exactly the same, as defined
in scripts/Makefile.build:

    src := $(obj)

When the kernel is built in a separate output directory, $(src) does
not accurately reflect the source directory location. While Kbuild
resolves this discrepancy by specifying VPATH=$(srctree) to search for
source files, it does not cover all cases. For example, when adding a
header search path for local headers, -I$(srctree)/$(src) is typically
passed to the compiler.

This introduces inconsistency between upstream and downstream Makefiles
because $(src) is used instead of $(srctree)/$(src) for the latter.

To address this inconsistency, this commit changes the semantics of
$(src) so that it always points to the directory in the source tree.

Going forward, the variables used in Makefiles will have the following
meanings:

  $(obj)     - directory in the object tree
  $(src)     - directory in the source tree  (changed by this commit)
  $(objtree) - the top of the kernel object tree
  $(srctree) - the top of the kernel source tree

Consequently, $(srctree)/$(src) in upstream Makefiles need to be replaced
with $(src).

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>

drivers/crypto/intel/qat/qat_420xx/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_420XX) += qat_420xx.o
 qat_420xx-objs := adf_drv.o adf_420xx_hw_data.o

drivers/crypto/intel/qat/qat_4xxx/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: (BSD-3-Clause OR GPL-2.0-only)
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_4XXX) += qat_4xxx.o
 qat_4xxx-objs := adf_drv.o adf_4xxx_hw_data.o

drivers/crypto/intel/qat/qat_c3xxx/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_C3XXX) += qat_c3xxx.o
 qat_c3xxx-objs := adf_drv.o adf_c3xxx_hw_data.o

drivers/crypto/intel/qat/qat_c3xxxvf/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_C3XXXVF) += qat_c3xxxvf.o
 qat_c3xxxvf-objs := adf_drv.o adf_c3xxxvf_hw_data.o

drivers/crypto/intel/qat/qat_c62x/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_C62X) += qat_c62x.o
 qat_c62x-objs := adf_drv.o adf_c62x_hw_data.o

drivers/crypto/intel/qat/qat_c62xvf/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_C62XVF) += qat_c62xvf.o
 qat_c62xvf-objs := adf_drv.o adf_c62xvf_hw_data.o

drivers/crypto/intel/qat/qat_dh895xcc/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_DH895xCC) += qat_dh895xcc.o
 qat_dh895xcc-objs := adf_drv.o adf_dh895xcc_hw_data.o

drivers/crypto/intel/qat/qat_dh895xccvf/Makefile

@@ -1,4 +1,4 @@
 # SPDX-License-Identifier: GPL-2.0-only
-ccflags-y := -I $(srctree)/$(src)/../qat_common
+ccflags-y := -I $(src)/../qat_common
 obj-$(CONFIG_CRYPTO_DEV_QAT_DH895xCCVF) += qat_dh895xccvf.o
 qat_dh895xccvf-objs := adf_drv.o adf_dh895xccvf_hw_data.o