Re: [PATCH v1] erofs-utils: Fix cross compile with autoconf

[Gao Xiang]

Hi Sandeep!

On 2023/10/6 06:40, Sandeep Dhavale wrote:

AC_RUN_IFELSE expects the action if cross compiling. If not provided
cross compilation fails with error "configure: error: cannot run test
program while cross compiling".
Use 4096 as the buest guess PAGESIZE if cross compiling as it is still
the most common page size.

Thanks for your report!

Reported-in: 
https://lore.kernel.org/all/0101018aec71b531-0a354b1a-0b70-47a1-8efc-fea8c439304c-000...@us-west-2.amazonses.com/
Fixes: 8ee2e591dfd6 ("erofs-utils: support detecting maximum block size")
Signed-off-by: Sandeep Dhavale <dhav...@google.com>
---
  configure.ac | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/configure.ac b/configure.ac
index 13ee616..a546310 100644
--- a/configure.ac
+++ b/configure.ac
@@ -284,8 +284,8 @@ AS_IF([test "x$MAX_BLOCK_SIZE" = "x"], [
      return 0;
  ]])],
                               [erofs_cv_max_block_size=`cat conftest.out`],
-                             [],
-                             []))
+                             [erofs_cv_max_block_size=4096],
+                             [erofs_cv_max_block_size=4096]))
  ], [erofs_cv_max_block_size=$MAX_BLOCK_SIZE])

Actually the following check will reset erofs_cv_max_block_size to 4096
if needed. But it seems that it has syntax errors.

I wonder if the following diff could fix the issue too?

Thanks,
Gao Xiang

diff --git a/configure.ac b/configure.ac
index 13ee616..94eec01 100644
--- a/configure.ac
+++ b/configure.ac
@@ -288,6 +288,9 @@ AS_IF([test "x$MAX_BLOCK_SIZE" = "x"], [
                              []))
 ], [erofs_cv_max_block_size=$MAX_BLOCK_SIZE])

+AS_IF([test "x$erofs_cv_max_block_size" = "x"],
+      [erofs_cv_max_block_size=4096], [])
+
 # Configure debug mode
 AS_IF([test "x$enable_debug" != "xno"], [], [
   dnl Turn off all assert checking.
@@ -501,9 +504,6 @@ if test "x$have_libdeflate" = "xyes"; then
 fi

 # Dump maximum block size
-AS_IF([test "x$erofs_cv_max_block_size" = "x"],
-      [$erofs_cv_max_block_size = 4096], [])
-
 AC_DEFINE_UNQUOTED([EROFS_MAX_BLOCK_SIZE], [$erofs_cv_max_block_size],
                   [The maximum block size which erofs-utils supports])