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From: Matthew Wilcox <willy@infradead.org>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
	linux-s390@vger.kernel.org, kvm@vger.kernel.org,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>,
	Janosch Frank <frankja@linux.ibm.com>,
	Claudio Imbrenda <imbrenda@linux.ibm.com>,
	Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
	Thomas Huth <thuth@redhat.com>
Subject: Re: [PATCH v1 2/5] s390/uv: convert gmap_make_secure() to work on folios
Date: Fri, 5 Apr 2024 04:29:56 +0100	[thread overview]
Message-ID: <Zg9wNKTu4JxGXrHs@casper.infradead.org> (raw)
In-Reply-To: <20240404163642.1125529-3-david@redhat.com>

On Thu, Apr 04, 2024 at 06:36:39PM +0200, David Hildenbrand wrote:
> +		/* We might get PTE-mapped large folios; split them first. */
> +		if (folio_test_large(folio)) {
> +			rc = -E2BIG;

We agree to this point.  I just turned this into -EINVAL.

>  
> +	if (rc == -E2BIG) {
> +		/*
> +		 * Splitting might fail with -EBUSY due to unexpected folio
> +		 * references, just like make_folio_secure(). So handle it
> +		 * ahead of time without the PTL being held.
> +		 */
> +		folio_lock(folio);
> +		rc = split_folio(folio);
> +		folio_unlock(folio);
> +		folio_put(folio);
> +	}

Ummm ... if split_folio() succeeds, aren't we going to return 0 from
this function, which will be interpreted as make_folio_secure() having
succeeded?



  reply	other threads:[~2024-04-05  3:30 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-04 16:36 [PATCH v1 0/5] s390: page_mapcount(), page_has_private() and PG_arch_1 David Hildenbrand
2024-04-04 16:36 ` [PATCH v1 1/5] s390/uv: don't call wait_on_page_writeback() without a reference David Hildenbrand
2024-04-10 17:21   ` Claudio Imbrenda
2024-04-11  8:24     ` David Hildenbrand
2024-04-11 13:13       ` Alexander Gordeev
2024-04-04 16:36 ` [PATCH v1 2/5] s390/uv: convert gmap_make_secure() to work on folios David Hildenbrand
2024-04-05  3:29   ` Matthew Wilcox [this message]
     [not found]     ` <67557c5b-afd8-4578-a00d-6750accc1026@redhat.com>
2024-04-10 17:32       ` Claudio Imbrenda
2024-04-10 17:31   ` Claudio Imbrenda
2024-04-11  9:09     ` David Hildenbrand
2024-04-04 16:36 ` [PATCH v1 3/5] s390/uv: convert PG_arch_1 users to only work on small folios David Hildenbrand
2024-04-05  3:36   ` Matthew Wilcox
2024-04-10 17:42   ` Claudio Imbrenda
2024-04-04 16:36 ` [PATCH v1 4/5] s390/uv: update PG_arch_1 comment David Hildenbrand
2024-04-10 17:19   ` Claudio Imbrenda
2024-04-04 16:36 ` [PATCH v1 5/5] s390/hugetlb: convert PG_arch_1 code to work on folio->flags David Hildenbrand
2024-04-05  3:42 ` [PATCH v1 0/5] s390: page_mapcount(), page_has_private() and PG_arch_1 Matthew Wilcox

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