AMI driver fails to build on RHEL 9.5+: eventfd_signal() has wrong number of arguments

[amd-vserbu]

Summary

The AMI kernel module (sw/AMI/driver/ami_program.c) fails to compile on RHEL 9.5+ and its rebuilds (Rocky Linux 9.5, AlmaLinux 9.5, …), because the preprocessor gate around eventfd_signal() only checks LINUX_VERSION_CODE and not RHEL_RELEASE_CODE.

Affected file

sw/AMI/driver/ami_program.c, two sites:

• around line 94 (inside do_image_download() per-chunk loop)
• around line 153 (the boot-tag rewrite path)

Both look like this today:

#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 8, 0)
    eventfd_signal(efd_ctx);
#else
    eventfd_signal(efd_ctx, bytes_to_write);
#endif

Reproduction

1. Install a RHEL 9.5+ or a derivative (e.g. Rocky Linux 9.5) with matching kernel-devel (any kernel-5.14.0-503.*.el9_5 or newer).

2. From AVED main, build the AMI driver:

   cd sw/AMI
   python3 scripts/gen_package.py -o /tmp/ami-build

3. Build fails:

   INFO: [BUILD_CHECK_DRIVER] Executing: $ cd driver && make clean && make
   ERROR: [BUILD_CHECK_DRIVER] Step driver compilation confidence check failed: Unexpected non-zero return code (2) for command: cd driver && make clean && make
   

Root cause

Upstream Linux v6.8 dropped the unused n argument of eventfd_signal():

commit 3652117f854819a148ff0fbe4492587d3520b5e5
Author: Christian Brauner brauner@kernel.org
Date: Tue Oct 17 17:09:25 2023 +0200

eventfd: simplify eventfd_signal()

Red Hat then backported that change into the 5.14-based RHEL 9.5 kernel; it ships in the GA kernel-5.14.0-503.*.el9_5 and all later 9.5/9.6 errata kernels. On those kernels:

• LINUX_VERSION_CODE == KERNEL_VERSION(5, 14, 0), so the current >= KERNEL_VERSION(6, 8, 0) gate evaluates false and the compiler picks the two-arg branch, …
• …but <linux/eventfd.h> only declares the new one-arg form, so the build fails with too many arguments to function 'eventfd_signal'.

The gate is still correct on stock RHEL 9.4 and earlier (two-arg form), and on stock 6.8+ kernels (one-arg form). Only the RHEL 9.5+ backport case is misdetected.

Proposed fix

Extend the gate to also accept RHEL 9.5+ via RHEL_RELEASE_CODE:

#if LINUX_VERSION_CODE >= KERNEL_VERSION(6, 8, 0) || \
    (defined(RHEL_RELEASE_CODE) && RHEL_RELEASE_CODE >= RHEL_RELEASE_VERSION(9, 5))
    eventfd_signal(efd_ctx);
#else
    eventfd_signal(efd_ctx, bytes_to_write);
#endif

This matches the pattern already used in this same driver in sw/AMI/driver/ami_cdev.c (around the class_create() and devnode() signature changes).

I'll open a PR with the fix.