From mboxrd@z Thu Jan  1 00:00:00 1970
From: Claude Code Review Bot <claude-review@example.com>
To: dri-devel-reviews@example.com
Subject: Claude review: drm/amdgpu: use bitmap_clear() in amdgpu_amdkfd_device_init()
Date: Tue, 28 Apr 2026 13:43:04 +1000
Message-ID: <review-patch1-20260428023536.449877-1-ynorov@nvidia.com>
In-Reply-To: <20260428023536.449877-1-ynorov@nvidia.com>
References: <20260428023536.449877-1-ynorov@nvidia.com> <20260428023536.449877-1-ynorov@nvidia.com>
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Patch Review

**Correctness:**

The transformation from:
```c
for (i =3D last_valid_bit; i < AMDGPU_MAX_QUEUES; ++i)
    clear_bit(i, gpu_resources.cp_queue_bitmap);
```
to:
```c
bitmap_clear(gpu_resources.cp_queue_bitmap, last_valid_bit,
             AMDGPU_MAX_QUEUES - last_valid_bit);
```
is semantically correct. Both clear the same range of bits `[last_valid_bit=
, AMDGPU_MAX_QUEUES)`.

**Atomicity change is safe:** The old code used `clear_bit()` (atomic), whi=
le `bitmap_clear()` uses `__bitmap_clear()` (non-atomic) for the runtime-nb=
its path. This is fine because `gpu_resources` is a local variable on the s=
tack =E2=80=94 it was just initialized a few lines above and no other threa=
d can observe it. There is no need for atomic operations on stack-local dat=
a.

**Removal of misleading comment:** Correct to remove. The comment:
```c
/* According to linux/bitmap.h we shouldn't use bitmap_clear if
 * nbits is not compile time constant
 */
```
was wrong. `bitmap_clear()` at `include/linux/bitmap.h:547` handles non-con=
stant `nbits` via `__bitmap_clear()`.

**Removal of `int i`:** Clean =E2=80=94 the loop variable is no longer need=
ed, and `last_valid_bit` is the only remaining local.

**Alignment nit (cosmetic only):** The continuation line aligns `AMDGPU_MAX=
_QUEUES - last_valid_bit` with a tab+spaces to match the opening paren, whi=
ch results in slightly unusual indentation but is consistent with the surro=
unding code style (e.g., the `bitmap_complement` call just above uses the s=
ame pattern).

**No functional concerns.** This is a clean, correct simplification.

**Reviewed-by recommendation: Yes.**

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