When SPHINXDIRS is used, the current logic produces a wrong
list of files, as it will not pick the SPHINXDIRS directory,
picking instead their children.

Add a rule to detect it and create the PDF doc with the right
name.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 Documentation/conf.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/Documentation/conf.py b/Documentation/conf.py
index 2c1be59fd54b..c8401ed75402 100644
--- a/Documentation/conf.py
+++ b/Documentation/conf.py
@@ -91,6 +91,19 @@ def config_init(app, config):
     # LaTeX and PDF output require a list of documents with are dependent
     # of the app.srcdir. Add them here
 
+    # When SPHINXDIRS is used, we just need to get index.rst, if it exists
+    if not os.path.samefile(doctree, app.srcdir):
+        doc = "index"
+        doc_name = os.path.basename(app.srcdir)
+        if os.path.exists(os.path.join(app.srcdir, doc + ".rst")):
+            latex_documents.append((doc, doc_name + ".tex",
+                                    "Linux %s Documentation" % doc_name.capitalize(),
+                                    "The kernel development community",
+                                    "manual"))
+            return
+
+    # When building all docs, or when a main index.rst doesn't exist, seek
+    # for it on subdirectories
     for fn in os.listdir(app.srcdir):
         doc = os.path.join(fn, "index")
         if not os.path.exists(os.path.join(app.srcdir, doc + ".rst")):
-- 
2.50.1