Claude review: accel/amdxdna: Fix dead lock for suspend and resume

[Claude Code Review Bot <claude-review@example.com>]

Overall Series Review

Subject: accel/amdxdna: Fix dead lock for suspend and resume
Author: Lizhi Hou <lizhi.hou@amd.com>
Patches: 1
Reviewed: 2026-02-11T16:16:32.498103

---

This single-patch series addresses a **critical deadlock** in the amdxdna accelerator driver that occurs during power management operations. The deadlock scenario is:

1. IOCTL path: holds `dev_lock` → calls `pm_runtime_resume_and_get()` → waits for suspend to complete
2. Suspend path: tries to acquire `dev_lock` → blocks waiting for IOCTL to release it

**Deadlock: ABBA lock ordering problem** (dev_lock vs PM subsystem internal locks)

The fix introduces `amdxdna_pm_resume_get_locked()` helper that temporarily drops `dev_lock` before calling into PM runtime, then reacquires it. The suspend/resume callbacks now also explicitly take `dev_lock`.

**Concerns:**
- **Race conditions**: Dropping and reacquiring locks creates windows where device state could change
- **Inconsistent locking**: Not all PM callsites converted (only some use `_locked` variant)
- **Unprotected hardware access**: Code between unlock/lock may execute with device in inconsistent state
- **Missing validation**: After reacquiring lock, no checks if device state changed
- **SRCU removal**: Unrelated cleanup removing SRCU protection without justification

**Severity: HIGH** - This fixes a deadlock but introduces potential race conditions that could cause use-after-free or hardware corruption.

---

---
Generated by Claude Code Patch Reviewer