From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Matthew Wilcox <willy@infradead.org>
Cc: Roman Penyaev <rpenyaev@suse.de>,
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: Fri, 14 Jun 2019 10:57:42 +0530 [thread overview]
Message-ID: <4b5c0b18-c670-3631-f47f-3f80bae8fe4b@arm.com> (raw)
In-Reply-To: <20190613153141.GJ32656@bombadil.infradead.org>
On 06/13/2019 09:01 PM, Matthew Wilcox wrote:
> On Thu, Jun 13, 2019 at 08:51:17PM +0530, Anshuman Khandual wrote:
>> acceptable ? What we have currently is wrong where vmap_pmd_range() could
>> just wrap EBUSY as ENOMEM and send up the call chain.
>
> It's not wrong. We do it in lots of places. Unless there's a caller
> which really needs to know the difference, it's often better than
> returning the "real error".
I can understand the fact that because there are no active users of this
return code, the current situation has been alright. But then I fail to
understand how can EBUSY be made ENOMEM and let the caller to think that
vmap_page_rage() failed because of lack of memory when it is clearly not
the case. It is really surprising how it can be acceptable inside kernel
(init_mm) page table functions which need to be thorough enough.
next prev parent reply other threads:[~2019-06-14 5:27 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
2019-06-13 15:21 ` Anshuman Khandual
2019-06-13 15:31 ` Matthew Wilcox
2019-06-14 5:27 ` Anshuman Khandual [this message]
2019-06-14 13:42 ` Matthew Wilcox
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