[PATCH v6 1/2] docs: Move rustdoc output, cross-reference it

[Carlos Bilbao <carlos.bilbao@amd.com>]

Generate rustdoc documentation with the rest of subsystem's documentation
in Documentation/output. Add a cross reference to the generated rustdoc in
Documentation/rust/index.rst if Sphinx target rustdoc is set.

Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
---
 Documentation/rust/index.rst |  8 ++++++++
 rust/Makefile                | 15 +++++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/Documentation/rust/index.rst b/Documentation/rust/index.rst
index 4ae8c66b94fa..e599be2cec9b 100644
--- a/Documentation/rust/index.rst
+++ b/Documentation/rust/index.rst
@@ -6,6 +6,14 @@ Rust
 Documentation related to Rust within the kernel. To start using Rust
 in the kernel, please read the quick-start.rst guide.
 
+.. only:: rustdoc and html
+
+	You can also browse `rustdoc documentation <rustdoc/kernel/index.html>`_.
+
+.. only:: not rustdoc and html
+
+	This documentation does not include rustdoc generated information.
+
 .. toctree::
     :maxdepth: 1
 
diff --git a/rust/Makefile b/rust/Makefile
index ff70c4c916f8..04f4ee3a193e 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -1,5 +1,8 @@
 # SPDX-License-Identifier: GPL-2.0
 
+# Where to place rustdoc generated documentation
+RUSTDOC_OUTPUT = $(objtree)/Documentation/output/rust/rustdoc
+
 always-$(CONFIG_RUST) += target.json
 no-clean-files += target.json
 
@@ -64,7 +67,7 @@ quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
 	OBJTREE=$(abspath $(objtree)) \
 	$(RUSTDOC) $(if $(rustdoc_host),$(rust_common_flags),$(rust_flags)) \
 		$(rustc_target_flags) -L$(objtree)/$(obj) \
-		--output $(objtree)/$(obj)/doc \
+		--output $(RUSTDOC_OUTPUT) \
 		--crate-name $(subst rustdoc-,,$@) \
 		@$(objtree)/include/generated/rustc_cfg $<
 
@@ -81,15 +84,15 @@ quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
 # and then retouch the generated files.
 rustdoc: rustdoc-core rustdoc-macros rustdoc-compiler_builtins \
     rustdoc-alloc rustdoc-kernel
-	$(Q)cp $(srctree)/Documentation/images/logo.svg $(objtree)/$(obj)/doc
-	$(Q)cp $(srctree)/Documentation/images/COPYING-logo $(objtree)/$(obj)/doc
-	$(Q)find $(objtree)/$(obj)/doc -name '*.html' -type f -print0 | xargs -0 sed -Ei \
+	$(Q)cp $(srctree)/Documentation/images/logo.svg $(RUSTDOC_OUTPUT)
+	$(Q)cp $(srctree)/Documentation/images/COPYING-logo $(RUSTDOC_OUTPUT)
+	$(Q)find $(RUSTDOC_OUTPUT) -name '*.html' -type f -print0 | xargs -0 sed -Ei \
 		-e 's:rust-logo\.svg:logo.svg:g' \
 		-e 's:rust-logo\.png:logo.svg:g' \
 		-e 's:favicon\.svg:logo.svg:g' \
 		-e 's:<link rel="alternate icon" type="image/png" href="[./]*favicon-(16x16|32x32)\.png">::g'
 	$(Q)echo '.logo-container > img { object-fit: contain; }' \
-		>> $(objtree)/$(obj)/doc/rustdoc.css
+		>> $(RUSTDOC_OUTPUT)/rustdoc.css
 
 rustdoc-macros: private rustdoc_host = yes
 rustdoc-macros: private rustc_target_flags = --crate-type proc-macro \
@@ -150,7 +153,7 @@ quiet_cmd_rustdoc_test = RUSTDOC T $<
 		@$(objtree)/include/generated/rustc_cfg \
 		$(rustc_target_flags) $(rustdoc_test_target_flags) \
 		--sysroot $(objtree)/$(obj)/test/sysroot $(rustdoc_test_quiet) \
-		-L$(objtree)/$(obj)/test --output $(objtree)/$(obj)/doc \
+		-L$(objtree)/$(obj)/test --output $(RUSTDOC_OUTPUT) \
 		--crate-name $(subst rusttest-,,$@) $<
 
 # We cannot use `-Zpanic-abort-tests` because some tests are dynamic,
-- 
2.34.1