|WARNING| [v4] eal/x86: fix memcpy alignment mask definition

[dpdklab at iol.unh.edu]

Test-Label: ai-code-review
Test-Status: WARNING
https://dpdk.org/patch/169097

_AI Code Review_

=== Patch Review: series.patch (via Claude) ===
Review date: 2026-09-04

# DPDK Patch Review

## Patch Summary
This patch fixes a namespace pollution issue in `rte_memcpy.h` by renaming `ALIGNMENT_MASK` to `RTE_MEMCPY_ALIGNMENT_MASK`, moves function documentation, and updates a comparison to follow DPDK coding style.

---

## Findings

### Errors

None found.

### Warnings

None found.

### Info

**1. Documentation formatting improvement opportunity**

The Doxygen comment for `rte_memcpy()` could use the `@note` tag to highlight the non-overlapping requirement, making it more prominent in generated documentation:

```c
/**
 * Copy bytes from one location to another.
 *
 * @note The locations must not overlap.
 *
 * @param dst
 *   Pointer to the destination of the data.
 * @param src
 *   Pointer to the source data.
 * @param n
 *   Number of bytes to copy.
 * @return
 *   Pointer to the destination data.
 */
```

This is a minor style preference for API documentation clarity.

---

## Summary

The patch correctly addresses the namespace pollution issue and follows DPDK coding style. The changes are appropriate:

1. **Namespace fix**: Adding `RTE_MEMCPY_` prefix to the internal macro is the correct solution and follows DPDK conventions for internal definitions in installed headers.

2. **Style compliance**: The change from `!(addrs & MASK)` to `(addrs & MASK) == 0` correctly follows DPDK's explicit comparison requirement.

3. **Documentation reorganization**: Moving the function documentation from the forward declaration to the actual definition improves code organization and makes the documentation easier to find in source code browsers.

All three changes are appropriate for this header file context and improve code quality without affecting functionality.