Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Nicholas Piggin <npiggin@gmail.com>
To:     Nick Terrell <terrelln@fb.com>
Cc:     Nicholas Piggin <npiggin@gmail.com>,
        Masahiro Yamada <masahiroy@kernel.org>,
        linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org
Subject: [PATCH] lib: zstd: build common files separately for compress and decompress
Date:   Mon, 19 Sep 2022 22:04:08 +1000
Message-Id: <20220919120408.3956424-1-npiggin@gmail.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

It is possible for compress to be built as a module and decompress to
be built in, and kernel and module C flags can be different. This can
cause module built code to be linked into the kernel or vice versa.

Use symbolic links from the common code to compression and decompression
module directories to avoid this problem.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
I'm not sure if this is the preferred way to fix it. I hadn't
thought about this problem before but now I notice it in zstd
it seems like it could be a pitfall in other parts of the kernel
as well. Is there a better way to solve it? Or some way to
automatically detect the conflict and fail the build rather than
silently succeed?

Thanks,
Nick

 lib/zstd/Makefile                           | 20 ++++++++++----------
 lib/zstd/compress/common/bitstream.h        |  1 +
 lib/zstd/compress/common/compiler.h         |  1 +
 lib/zstd/compress/common/cpu.h              |  1 +
 lib/zstd/compress/common/debug.c            |  1 +
 lib/zstd/compress/common/debug.h            |  1 +
 lib/zstd/compress/common/entropy_common.c   |  1 +
 lib/zstd/compress/common/error_private.c    |  1 +
 lib/zstd/compress/common/error_private.h    |  1 +
 lib/zstd/compress/common/fse.h              |  1 +
 lib/zstd/compress/common/fse_decompress.c   |  1 +
 lib/zstd/compress/common/huf.h              |  1 +
 lib/zstd/compress/common/mem.h              |  1 +
 lib/zstd/compress/common/zstd_common.c      |  1 +
 lib/zstd/compress/common/zstd_deps.h        |  1 +
 lib/zstd/compress/common/zstd_internal.h    |  1 +
 lib/zstd/decompress/common/bitstream.h      |  1 +
 lib/zstd/decompress/common/compiler.h       |  1 +
 lib/zstd/decompress/common/cpu.h            |  1 +
 lib/zstd/decompress/common/debug.c          |  1 +
 lib/zstd/decompress/common/debug.h          |  1 +
 lib/zstd/decompress/common/entropy_common.c |  1 +
 lib/zstd/decompress/common/error_private.c  |  1 +
 lib/zstd/decompress/common/error_private.h  |  1 +
 lib/zstd/decompress/common/fse.h            |  1 +
 lib/zstd/decompress/common/fse_decompress.c |  1 +
 lib/zstd/decompress/common/huf.h            |  1 +
 lib/zstd/decompress/common/mem.h            |  1 +
 lib/zstd/decompress/common/zstd_common.c    |  1 +
 lib/zstd/decompress/common/zstd_deps.h      |  1 +
 lib/zstd/decompress/common/zstd_internal.h  |  1 +
 31 files changed, 40 insertions(+), 10 deletions(-)
 create mode 120000 lib/zstd/compress/common/bitstream.h
 create mode 120000 lib/zstd/compress/common/compiler.h
 create mode 120000 lib/zstd/compress/common/cpu.h
 create mode 120000 lib/zstd/compress/common/debug.c
 create mode 120000 lib/zstd/compress/common/debug.h
 create mode 120000 lib/zstd/compress/common/entropy_common.c
 create mode 120000 lib/zstd/compress/common/error_private.c
 create mode 120000 lib/zstd/compress/common/error_private.h
 create mode 120000 lib/zstd/compress/common/fse.h
 create mode 120000 lib/zstd/compress/common/fse_decompress.c
 create mode 120000 lib/zstd/compress/common/huf.h
 create mode 120000 lib/zstd/compress/common/mem.h
 create mode 120000 lib/zstd/compress/common/zstd_common.c
 create mode 120000 lib/zstd/compress/common/zstd_deps.h
 create mode 120000 lib/zstd/compress/common/zstd_internal.h
 create mode 120000 lib/zstd/decompress/common/bitstream.h
 create mode 120000 lib/zstd/decompress/common/compiler.h
 create mode 120000 lib/zstd/decompress/common/cpu.h
 create mode 120000 lib/zstd/decompress/common/debug.c
 create mode 120000 lib/zstd/decompress/common/debug.h
 create mode 120000 lib/zstd/decompress/common/entropy_common.c
 create mode 120000 lib/zstd/decompress/common/error_private.c
 create mode 120000 lib/zstd/decompress/common/error_private.h
 create mode 120000 lib/zstd/decompress/common/fse.h
 create mode 120000 lib/zstd/decompress/common/fse_decompress.c
 create mode 120000 lib/zstd/decompress/common/huf.h
 create mode 120000 lib/zstd/decompress/common/mem.h
 create mode 120000 lib/zstd/decompress/common/zstd_common.c
 create mode 120000 lib/zstd/decompress/common/zstd_deps.h
 create mode 120000 lib/zstd/decompress/common/zstd_internal.h

diff --git a/lib/zstd/Makefile b/lib/zstd/Makefile
index fc45339fc3a3..6d785268f8c3 100644
--- a/lib/zstd/Makefile
+++ b/lib/zstd/Makefile
@@ -13,11 +13,11 @@ obj-$(CONFIG_ZSTD_DECOMPRESS) += zstd_decompress.o
 
 zstd_compress-y := \
 		zstd_compress_module.o \
-		common/debug.o \
-		common/entropy_common.o \
-		common/error_private.o \
-		common/fse_decompress.o \
-		common/zstd_common.o \
+		compress/common/debug.o \
+		compress/common/entropy_common.o \
+		compress/common/error_private.o \
+		compress/common/fse_decompress.o \
+		compress/common/zstd_common.o \
 		compress/fse_compress.o \
 		compress/hist.o \
 		compress/huf_compress.o \
@@ -33,11 +33,11 @@ zstd_compress-y := \
 
 zstd_decompress-y := \
 		zstd_decompress_module.o \
-		common/debug.o \
-		common/entropy_common.o \
-		common/error_private.o \
-		common/fse_decompress.o \
-		common/zstd_common.o \
+		decompress/common/debug.o \
+		decompress/common/entropy_common.o \
+		decompress/common/error_private.o \
+		decompress/common/fse_decompress.o \
+		decompress/common/zstd_common.o \
 		decompress/huf_decompress.o \
 		decompress/zstd_ddict.o \
 		decompress/zstd_decompress.o \
diff --git a/lib/zstd/compress/common/bitstream.h b/lib/zstd/compress/common/bitstream.h
new file mode 120000
index 000000000000..de97b72f47ce
--- /dev/null
+++ b/lib/zstd/compress/common/bitstream.h
@@ -0,0 +1 @@
+../../common/bitstream.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/compiler.h b/lib/zstd/compress/common/compiler.h
new file mode 120000
index 000000000000..a316286adf05
--- /dev/null
+++ b/lib/zstd/compress/common/compiler.h
@@ -0,0 +1 @@
+../../common/compiler.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/cpu.h b/lib/zstd/compress/common/cpu.h
new file mode 120000
index 000000000000..35282be494a2
--- /dev/null
+++ b/lib/zstd/compress/common/cpu.h
@@ -0,0 +1 @@
+../../common/cpu.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/debug.c b/lib/zstd/compress/common/debug.c
new file mode 120000
index 000000000000..5d7b272026d6
--- /dev/null
+++ b/lib/zstd/compress/common/debug.c
@@ -0,0 +1 @@
+../../common/debug.c
\ No newline at end of file
diff --git a/lib/zstd/compress/common/debug.h b/lib/zstd/compress/common/debug.h
new file mode 120000
index 000000000000..15c1e1cd5c95
--- /dev/null
+++ b/lib/zstd/compress/common/debug.h
@@ -0,0 +1 @@
+../../common/debug.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/entropy_common.c b/lib/zstd/compress/common/entropy_common.c
new file mode 120000
index 000000000000..221119c32817
--- /dev/null
+++ b/lib/zstd/compress/common/entropy_common.c
@@ -0,0 +1 @@
+../../common/entropy_common.c
\ No newline at end of file
diff --git a/lib/zstd/compress/common/error_private.c b/lib/zstd/compress/common/error_private.c
new file mode 120000
index 000000000000..f87d3cf6851f
--- /dev/null
+++ b/lib/zstd/compress/common/error_private.c
@@ -0,0 +1 @@
+../../common/error_private.c
\ No newline at end of file
diff --git a/lib/zstd/compress/common/error_private.h b/lib/zstd/compress/common/error_private.h
new file mode 120000
index 000000000000..30d469222942
--- /dev/null
+++ b/lib/zstd/compress/common/error_private.h
@@ -0,0 +1 @@
+../../common/error_private.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/fse.h b/lib/zstd/compress/common/fse.h
new file mode 120000
index 000000000000..29c44ebdd2da
--- /dev/null
+++ b/lib/zstd/compress/common/fse.h
@@ -0,0 +1 @@
+../../common/fse.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/fse_decompress.c b/lib/zstd/compress/common/fse_decompress.c
new file mode 120000
index 000000000000..658e375541f1
--- /dev/null
+++ b/lib/zstd/compress/common/fse_decompress.c
@@ -0,0 +1 @@
+../../common/fse_decompress.c
\ No newline at end of file
diff --git a/lib/zstd/compress/common/huf.h b/lib/zstd/compress/common/huf.h
new file mode 120000
index 000000000000..7c9142232da6
--- /dev/null
+++ b/lib/zstd/compress/common/huf.h
@@ -0,0 +1 @@
+../../common/huf.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/mem.h b/lib/zstd/compress/common/mem.h
new file mode 120000
index 000000000000..0d9921eb1ca4
--- /dev/null
+++ b/lib/zstd/compress/common/mem.h
@@ -0,0 +1 @@
+../../common/mem.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/zstd_common.c b/lib/zstd/compress/common/zstd_common.c
new file mode 120000
index 000000000000..5a7475cd3b87
--- /dev/null
+++ b/lib/zstd/compress/common/zstd_common.c
@@ -0,0 +1 @@
+../../common/zstd_common.c
\ No newline at end of file
diff --git a/lib/zstd/compress/common/zstd_deps.h b/lib/zstd/compress/common/zstd_deps.h
new file mode 120000
index 000000000000..21b3a7e967da
--- /dev/null
+++ b/lib/zstd/compress/common/zstd_deps.h
@@ -0,0 +1 @@
+../../common/zstd_deps.h
\ No newline at end of file
diff --git a/lib/zstd/compress/common/zstd_internal.h b/lib/zstd/compress/common/zstd_internal.h
new file mode 120000
index 000000000000..3bf2b94e718f
--- /dev/null
+++ b/lib/zstd/compress/common/zstd_internal.h
@@ -0,0 +1 @@
+../../common/zstd_internal.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/bitstream.h b/lib/zstd/decompress/common/bitstream.h
new file mode 120000
index 000000000000..de97b72f47ce
--- /dev/null
+++ b/lib/zstd/decompress/common/bitstream.h
@@ -0,0 +1 @@
+../../common/bitstream.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/compiler.h b/lib/zstd/decompress/common/compiler.h
new file mode 120000
index 000000000000..a316286adf05
--- /dev/null
+++ b/lib/zstd/decompress/common/compiler.h
@@ -0,0 +1 @@
+../../common/compiler.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/cpu.h b/lib/zstd/decompress/common/cpu.h
new file mode 120000
index 000000000000..35282be494a2
--- /dev/null
+++ b/lib/zstd/decompress/common/cpu.h
@@ -0,0 +1 @@
+../../common/cpu.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/debug.c b/lib/zstd/decompress/common/debug.c
new file mode 120000
index 000000000000..5d7b272026d6
--- /dev/null
+++ b/lib/zstd/decompress/common/debug.c
@@ -0,0 +1 @@
+../../common/debug.c
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/debug.h b/lib/zstd/decompress/common/debug.h
new file mode 120000
index 000000000000..15c1e1cd5c95
--- /dev/null
+++ b/lib/zstd/decompress/common/debug.h
@@ -0,0 +1 @@
+../../common/debug.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/entropy_common.c b/lib/zstd/decompress/common/entropy_common.c
new file mode 120000
index 000000000000..221119c32817
--- /dev/null
+++ b/lib/zstd/decompress/common/entropy_common.c
@@ -0,0 +1 @@
+../../common/entropy_common.c
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/error_private.c b/lib/zstd/decompress/common/error_private.c
new file mode 120000
index 000000000000..f87d3cf6851f
--- /dev/null
+++ b/lib/zstd/decompress/common/error_private.c
@@ -0,0 +1 @@
+../../common/error_private.c
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/error_private.h b/lib/zstd/decompress/common/error_private.h
new file mode 120000
index 000000000000..30d469222942
--- /dev/null
+++ b/lib/zstd/decompress/common/error_private.h
@@ -0,0 +1 @@
+../../common/error_private.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/fse.h b/lib/zstd/decompress/common/fse.h
new file mode 120000
index 000000000000..29c44ebdd2da
--- /dev/null
+++ b/lib/zstd/decompress/common/fse.h
@@ -0,0 +1 @@
+../../common/fse.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/fse_decompress.c b/lib/zstd/decompress/common/fse_decompress.c
new file mode 120000
index 000000000000..658e375541f1
--- /dev/null
+++ b/lib/zstd/decompress/common/fse_decompress.c
@@ -0,0 +1 @@
+../../common/fse_decompress.c
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/huf.h b/lib/zstd/decompress/common/huf.h
new file mode 120000
index 000000000000..7c9142232da6
--- /dev/null
+++ b/lib/zstd/decompress/common/huf.h
@@ -0,0 +1 @@
+../../common/huf.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/mem.h b/lib/zstd/decompress/common/mem.h
new file mode 120000
index 000000000000..0d9921eb1ca4
--- /dev/null
+++ b/lib/zstd/decompress/common/mem.h
@@ -0,0 +1 @@
+../../common/mem.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/zstd_common.c b/lib/zstd/decompress/common/zstd_common.c
new file mode 120000
index 000000000000..5a7475cd3b87
--- /dev/null
+++ b/lib/zstd/decompress/common/zstd_common.c
@@ -0,0 +1 @@
+../../common/zstd_common.c
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/zstd_deps.h b/lib/zstd/decompress/common/zstd_deps.h
new file mode 120000
index 000000000000..21b3a7e967da
--- /dev/null
+++ b/lib/zstd/decompress/common/zstd_deps.h
@@ -0,0 +1 @@
+../../common/zstd_deps.h
\ No newline at end of file
diff --git a/lib/zstd/decompress/common/zstd_internal.h b/lib/zstd/decompress/common/zstd_internal.h
new file mode 120000
index 000000000000..3bf2b94e718f
--- /dev/null
+++ b/lib/zstd/decompress/common/zstd_internal.h
@@ -0,0 +1 @@
+../../common/zstd_internal.h
\ No newline at end of file
-- 
2.37.2