From: "Arnd Bergmann" <arnd@arndb.de>
To: "Alexander Gordeev" <agordeev@linux.ibm.com>
Cc: "Christophe Leroy" <christophe.leroy@csgroup.eu>,
"Baoquan He" <bhe@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Linux-Arch <linux-arch@vger.kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Christoph Hellwig" <hch@infradead.org>,
wangkefeng.wang@huawei.com, schnelle@linux.ibm.com,
"David Laight" <David.Laight@aculab.com>,
"Stafford Horne" <shorne@gmail.com>,
"Benjamin Herrenschmidt" <benh@kernel.crashing.org>
Subject: Re: [RFC PATCH 7/8] mm/ioremap: Consider IOREMAP space in generic ioremap
Date: Sun, 16 Oct 2022 13:51:57 +0200 [thread overview]
Message-ID: <af8ba7b8-5198-42a1-84c7-9b7d7892ceb3@app.fastmail.com> (raw)
In-Reply-To: <Y0u4tN+mIgNSWwdi@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com>
On Sun, Oct 16, 2022, at 9:54 AM, Alexander Gordeev wrote:
> On Wed, Oct 12, 2022 at 12:39:11PM +0200, Arnd Bergmann wrote:
>> "Some" means exactly powerpc64, right? It looks like microblaze
>> and powerpc32 still share some of this code, but effectively
>> just use the vmalloc area once the slab allocator is up.
>>
>> Is the special case still useful for powerpc64 or could this be
>> changed to do it the same as everything else?
>
> Or make it the other way around and set IOREMAP_START/IOREMAP_END
> to VMALLOC_START/VMALLOC_END by default?
Sure, if there is a reason for actually making them different.
From the git history, it appears that before commit 3d5134ee8341
("[POWERPC] Rewrite IO allocation & mapping on powerpc64"), the
ioremap() and vmalloc() handling was largely duplicated. Ben
cleaned it up by making most of the implementation shared but left
the separate address spaces.
My guess is that there was no technical reason for this, other
than having no reason to change the behavior at the time.
Arnd
next prev parent reply other threads:[~2022-10-16 11:52 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-12 10:09 [RFC PATCH 0/8] mm: ioremap: Convert architectures to take GENERIC_IOREMAP way (Alternative) Christophe Leroy
2022-10-12 10:09 ` [RFC PATCH 1/8] hexagon: mm: Convert to GENERIC_IOREMAP Christophe Leroy
2022-10-12 10:09 ` [RFC PATCH 2/8] openrisc: mm: remove unneeded early ioremap code Christophe Leroy
2022-10-12 16:47 ` Stafford Horne
2022-10-12 10:09 ` [RFC PATCH 3/8] mm/ioremap: Define generic_ioremap_prot() and generic_iounmap() Christophe Leroy
2022-10-16 8:14 ` Alexander Gordeev
2022-10-16 16:54 ` Christophe Leroy
2022-10-12 10:09 ` [RFC PATCH 4/8] mm: ioremap: allow ARCH to have its own ioremap definition Christophe Leroy
2022-10-12 10:09 ` [RFC PATCH 5/8] arc: mm: Convert to GENERIC_IOREMAP Christophe Leroy
2022-10-12 10:09 ` [RFC PATCH 6/8] ia64: " Christophe Leroy
2022-10-12 10:09 ` [RFC PATCH 7/8] mm/ioremap: Consider IOREMAP space in generic ioremap Christophe Leroy
2022-10-12 10:39 ` Arnd Bergmann
2022-10-16 7:54 ` Alexander Gordeev
2022-10-16 11:51 ` Arnd Bergmann [this message]
2022-10-16 16:56 ` Christophe Leroy
2022-10-17 12:50 ` Michael Ellerman
2022-10-17 20:52 ` Arnd Bergmann
2022-10-12 10:09 ` [RFC PATCH 8/8] powerpc: mm: Convert to GENERIC_IOREMAP Christophe Leroy
2022-10-17 0:37 ` [RFC PATCH 0/8] mm: ioremap: Convert architectures to take GENERIC_IOREMAP way (Alternative) Baoquan He
2022-10-17 17:06 ` Christophe Leroy
2022-10-19 0:25 ` Baoquan He
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