From: Roman Penyaev <rpenyaev@suse.de>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Andrey Ryabinin <aryabinin@virtuozzo.com>,
Mike Rapoport <rppt@linux.ibm.com>, Roman Gushchin <guro@fb.com>,
Michal Hocko <mhocko@suse.com>,
"Uladzislau Rezki (Sony)" <urezki@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm/vmalloc: Check absolute error return from vmap_[p4d|pud|pmd|pte]_range()
Date: Thu, 13 Jun 2019 11:33:02 +0200 [thread overview]
Message-ID: <7cc6a46c50c2008bfb968c5e48af5a49@suse.de> (raw)
In-Reply-To: <1560413551-17460-1-git-send-email-anshuman.khandual@arm.com>
On 2019-06-13 10:12, Anshuman Khandual wrote:
> vmap_pte_range() returns an -EBUSY when it encounters a non-empty PTE.
> But
> currently vmap_pmd_range() unifies both -EBUSY and -ENOMEM return code
> as
> -ENOMEM and send it up the call chain which is wrong. Interestingly
> enough
> vmap_page_range_noflush() tests for the absolute error return value
> from
> vmap_p4d_range() but it does not help because -EBUSY has been merged
> with
> -ENOMEM. So all it can return is -ENOMEM. Fix this by testing for
> absolute
> error return from vmap_pmd_range() all the way up to vmap_p4d_range().
I could not find any real external caller of vmap API who really cares
about the errno, and frankly why they should? This is allocation path,
allocation failed - game over. When you step on -EBUSY case something
has gone completely wrong in your kernel, you get a big warning in
your dmesg and it is already does not matter what errno you get.
--
Roman
next prev parent reply other threads:[~2019-06-13 9:33 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-13 8:12 [PATCH] mm/vmalloc: Check absolute error return from vmap_[p4d|pud|pmd|pte]_range() Anshuman Khandual
2019-06-13 9:33 ` Roman Penyaev [this message]
2019-06-13 15:21 ` Anshuman Khandual
2019-06-13 15:31 ` Matthew Wilcox
2019-06-14 5:27 ` Anshuman Khandual
2019-06-14 13:42 ` Matthew Wilcox
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