Claude review: accel/amdxdna: Remove mmap and export support for ubuf

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

Patch Review

**Dead code: `amdxdna_ubuf_vm_ops` and `amdxdna_ubuf_vm_fault` are now orphaned.**

The patch removes `amdxdna_ubuf_mmap` which was the sole user of `amdxdna_ubuf_vm_ops`, which in turn was the sole user of `amdxdna_ubuf_vm_fault`. After this patch, both `amdxdna_ubuf_vm_fault` (line 72) and `amdxdna_ubuf_vm_ops` (line 86) in `amdxdna_ubuf.c` are dead code. They should be removed in this patch to avoid a compiler warning (`-Wunused-function` for the static `amdxdna_ubuf_vm_fault`). This will actually cause a build failure with `-Werror`, which the kernel uses.

**Flag naming: `pri` is cryptic and misleading.**

The new field:
```c
/* True, if BO is not exportable */
bool				pri;
```
The name `pri` doesn't convey "not exportable." It could be misread as "priority" or "primary" or "private." A name like `no_export` or `unexportable` would be immediately clear. Even `private` (spelled out) would be better. The comment helps, but a self-documenting name costs nothing.

**The export-blocking logic is correct but could be more robust.**

The check in `amdxdna_gem_prime_export`:
```c
if (abo->pri)
    return ERR_PTR(-EOPNOTSUPP);
```
This correctly prevents re-export. The ubuf object is created through `amdxdna_gem_prime_import` and then marked with `abo->pri = true`, which will prevent it from being re-exported through the shmem funcs' `.export = amdxdna_gem_prime_export` path.

**No mmap blocking on the GEM object side.**

The patch removes `amdxdna_ubuf_mmap` from the dma-buf ops, which prevents mmap through the dma-buf fd. However, ubuf objects are imported via `drm_gem_shmem_prime_import_sg_table`, and the resulting GEM shmem object has `.mmap = amdxdna_gem_obj_mmap` set via `amdxdna_gem_shmem_funcs`. The commit message says "ubuf pages should not be mmaped" — should `amdxdna_gem_obj_mmap` also check `abo->pri` and reject the mmap? If the intent is only to block the dma-buf mmap path (since user already has the pages mapped), this should be clarified in the commit message. If GEM mmap should also be blocked, it's missing.

**Summary:**
- **Must fix:** Remove the now-dead `amdxdna_ubuf_vm_fault` and `amdxdna_ubuf_vm_ops` — this will cause a build warning/error.
- **Should fix:** Rename `pri` to something self-documenting (`no_export`, `unexportable`, etc.).
- **Should clarify:** Whether GEM-object-level mmap should also be blocked for ubuf objects, or only dma-buf mmap. If only dma-buf mmap, update the commit message to be precise.

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Generated by Claude Code Patch Reviewer