linux-kernel - Re: [PATCH 0/2] vmalloc: Introduce vmap

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Message-ID: <Z5x3TwhAWadIV8oJ@infradead.org>
Date: Thu, 30 Jan 2025 23:10:07 -0800
From: Christoph Hellwig <hch@...radead.org>
To: "Vishal Moola (Oracle)" <vishal.moola@...il.com>
Cc: akpm@...ux-foundation.org, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, hch@...radead.org, urezki@...il.com,
	intel-gfx@...ts.freedesktop.org
Subject: Re: [PATCH 0/2] vmalloc: Introduce vmap_file()

On Thu, Jan 30, 2025 at 04:18:04PM -0800, Vishal Moola (Oracle) wrote:
> Currently, users have to call vmap() or vmap_pfn() to map pages to
> kernel virtual space. vmap() requires the page references, and
> vmap_pfn() requires page pfns. If we have a file but no page references,
> we have to do extra work to map them.
> 
> Create a function, vmap_file(), to map a specified range of a given
> file to kernel virtual space. Also convert a user that benefits from
> vmap_file().

As far as I can tell there is exatly one user that maps file pages
into vmalloc space.  It's a pretty odd thing to do, so figuring out
a way to get rid of that might be a better use of time.