tools/docs: sphinx-build-wrapper: only generate rust docs when requested

When the user explicitly specifies SPHINXDIRS to build a specific
subdirectory it is unexpected that the rust docs are also generated.
Especially as their generation may dominate the execution time.

Only generate the rust docs when they are part of the SPHINXDIRS
requested by the user. 'rust/rustdocs' is not considered, as it is
not a valid SPHINXDIRS anyways.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Tested-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260118-docs-spurious-rust-v1-4-998e14b9ed9e@weissschuh.net>

diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
index 04eb300dab4a7574df7878f67c61a5607ea7abd7..78ff7ac202effb9970a30dd3759b42cc69759283 100755 (executable)
--- a/tools/docs/sphinx-build-wrapper
+++ b/tools/docs/sphinx-build-wrapper
@@ -119,12 +119,15 @@ class SphinxBuilder:
 
         return path
 
-    def check_rust(self):
+    def check_rust(self, sphinxdirs):
         """
         Checks if Rust is enabled
         """
         config = os.path.join(self.srctree, ".config")
 
+        if not {'.', 'rust'}.intersection(sphinxdirs):
+            return False
+
         if not os.path.isfile(config):
             return False
 
@@ -691,7 +694,7 @@ class SphinxBuilder:
 
             args.extend(["-D", f"latex_elements.papersize={paper}paper"])
 
-        rustdoc = self.check_rust()
+        rustdoc = self.check_rust(sphinxdirs_list)
         if rustdoc:
             args.extend(["-t", "rustdoc"])