From: Andrew Morton <akpm@linux-foundation.org>
To: liuqiangneo@163.com
Cc: jgg@ziepe.ca, leon@kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, Qiang Liu <liuqiang@kylinos.cn>
Subject: Re: [PATCH v2] lib/test_hmm: fix garbage pfn and wrong direction in devmem fault debug
Date: Wed, 12 Aug 2026 15:58:29 -0700 [thread overview]
Message-ID: <20260812155829.43ebf2838420b8dcab83f55d@linux-foundation.org> (raw)
In-Reply-To: <20260812092856.55296-1-liuqiangneo@163.com>
On Wed, 12 Aug 2026 17:28:56 +0800 liuqiangneo@163.com wrote:
> From: Qiang Liu <liuqiang@kylinos.cn>
>
> Move pr_debug() inside the `if (dpage)` block to avoid
> printing garbage pfn for NULL dpage, and correct the
> direction label from "sys to dev" to "dev to sys".
>
> ...
>
> --- a/lib/test_hmm.c
> +++ b/lib/test_hmm.c
> @@ -1151,10 +1151,9 @@ static vm_fault_t dmirror_devmem_fault_alloc_and_copy(struct migrate_vma *args,
> if (!dpage && !order)
> return VM_FAULT_OOM;
>
> - pr_debug("migrating from sys to dev pfn src: 0x%lx pfn dst: 0x%lx\n",
> - page_to_pfn(spage), page_to_pfn(dpage));
> -
> if (dpage) {
> + pr_debug("migrating from dev to sys pfn src: 0x%lx pfn dst: 0x%lx\n",
> + page_to_pfn(spage), page_to_pfn(dpage));
> lock_page(dpage);
> *dst |= migrate_pfn(page_to_pfn(dpage));
Looks OK to me, thanks.
We could just remove the pr_debug. I suspect it was a development-time
thing and nobody uses it any more.
Your patch prompted Sashiko to find three possible pre-existing issues
in this code:
https://sashiko.dev/#/patchset/20260812092856.55296-1-liuqiangneo@163.com
prev parent reply other threads:[~2026-08-12 22:58 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-12 9:28 liuqiangneo
2026-08-12 22:58 ` Andrew Morton [this message]
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