From: Andrew Morton <akpm@linux-foundation.org>
To: "Lorenzo Stoakes (ARM)" <ljs@kernel.org>
Cc: Avi Weiss <thnkslprpt@gmail.com>,
David Hildenbrand <david@kernel.org>,
"Liam R. Howlett" <liam@infradead.org>,
Vlastimil Babka <vbabka@kernel.org>,
Mike Rapoport <rppt@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Soheil Hassas Yeganeh <soheil@google.com>,
Arjun Roy <arjunroy@google.com>,
Eric Dumazet <edumazet@google.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: return -ENOMEM for page-table allocation failure in insert_pages()
Date: Thu, 30 Jul 2026 09:15:58 -0700 [thread overview]
Message-ID: <20260730091558.12e3d9029002c87c1f00b4aa@linux-foundation.org> (raw)
In-Reply-To: <amr9zoSncZguF_uu@lucifer>
On Thu, 30 Jul 2026 08:42:49 +0100 "Lorenzo Stoakes (ARM)" <ljs@kernel.org> wrote:
> pages_to_write_in_pmd = min_t(unsigned long,
> remaining_pages_total, PTRS_PER_PTE - pte_index(addr));
>
> /* Allocate the PTE if necessary; takes PMD lock once only. */
> ret = -ENOMEM; <------------------------------ set it again?
> if (pte_alloc(mm, pmd))
> goto out;
>
> The way this function is written is horrible in general, I hate 'preset default
> return value' as a pattern.
It used to be the preferred way because
ret = -ENOMEM;
if (expr)
goto out;
generated slightly better code than
if (expr) {
ret = -ENOMEM;
goto out;
}
Whether that is the case with current compilers I don't know.
next prev parent reply other threads:[~2026-07-30 16:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-30 7:13 [PATCH] mm: return -ENOMEM for page-table allocation failure in insert_pages() Avi Weiss
2026-07-30 7:42 ` Lorenzo Stoakes (ARM)
2026-07-30 7:43 ` Lorenzo Stoakes (ARM)
2026-07-30 8:27 ` David Hildenbrand (Arm)
2026-07-30 8:36 ` Lorenzo Stoakes (ARM)
2026-07-30 16:15 ` Andrew Morton [this message]
2026-07-30 16:27 ` Lorenzo Stoakes (ARM)
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