Claude review: drm/panthor: Implement evicted status for GEM objects

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

Patch Review

This is the meat of the series. It adds `atomic_t reclaimed_count` to `panthor_gem_object`, increments it during eviction, and uses it to report status via both fdinfo and debugfs.

**Correctness of the eviction path ordering is good:**
```c
atomic_add_unless(&bo->reclaimed_count, 1, INT_MAX);

panthor_gem_dev_map_cleanup_locked(bo);
panthor_gem_backing_cleanup_locked(bo);
```
The counter is incremented *before* pages are cleared, which avoids a window where a concurrent lockless reader in `panthor_gem_status()` could see the object as neither resident nor evicted. This is the right order.

**The status callback logic is correct:**
```c
if (drm_gem_is_imported(&bo->base) || bo->backing.pages)
    res |= DRM_GEM_OBJECT_RESIDENT;
else if (atomic_read(&bo->reclaimed_count))
    res |= DRM_GEM_OBJECT_EVICTED;
```
The `else if` correctly makes RESIDENT and EVICTED mutually exclusive, and the `reclaimed_count` check distinguishes evicted objects from objects that were never backed. The `atomic_read()` is appropriate here since `panthor_gem_status()` can be called under a spinlock without holding the BO's own lock.

**Debugfs evicted state flag logic:**
```c
if (drm_gem_is_imported(&bo->base))
    gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_IMPORTED;
else if (!resident_size && reclaimed_count)
    gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_EVICTED;

if (bo->base.dma_buf)
    gem_state_flags |= PANTHOR_DEBUGFS_GEM_STATE_FLAG_EXPORTED;
```
Note that `EVICTED` and `IMPORTED` are mutually exclusive via `else if`, but `EVICTED` and `EXPORTED` are not (an exported BO that gets evicted would show both flags). Is that the desired behavior? An exported BO could conceivably be evicted, so allowing both flags seems reasonable. But the fdinfo path in `panthor_gem_status()` similarly makes EVICTED exclusive with imported — worth confirming this is intentional for imported buffers (which typically have backing managed by the exporter, so they shouldn't get evicted anyway).

**Minor: `int reclaimed_count` local variable.** The `atomic_read()` returns `int`, so the local is correctly typed. However, the debugfs format uses `%-11d` which handles 10-digit signed ints. Since the value saturates at INT_MAX (~2.1 billion, 10 digits), `%-11d` (10 digits + 1 space) is exactly right.

**No initialization needed** — `panthor_gem_object` is allocated via `kzalloc` (through `drm_gem_shmem_create`), so `reclaimed_count` starts at 0 implicitly. Good.

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Generated by Claude Code Patch Reviewer