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b=k1tnMc2XXtH9vo2gbMgXHk0eQhPJH9hzgaQdexs32uWCR3oU//rRWFsCABuTSYLgY Xka0nBQ9Z91S+NUovmSfzm0LJA5pHWSlhg/jadgQNutqZ6H1m1GZ50h+YW2pLH4v3O M4seZeYHnlT3bl4NxTa0YyPwYPlb7NCrah5531f0= Date: Thu, 30 Jan 2025 16:48:36 -0800 From: Andrew Morton To: "Vishal Moola (Oracle)" Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, hch@infradead.org, urezki@gmail.com, intel-gfx@lists.freedesktop.org Subject: Re: [PATCH 0/2] vmalloc: Introduce vmap_file() Message-Id: <20250130164836.1163f66bede77ec4bcc9d4b9@linux-foundation.org> In-Reply-To: <20250131001806.92349-1-vishal.moola@gmail.com> References: <20250131001806.92349-1-vishal.moola@gmail.com> X-Mailer: Sylpheed 3.8.0beta1 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: r5i7w1uog5gqdep7qkr6q8ajj6fznenx X-Rspamd-Queue-Id: 4330518000F X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1738284518-292039 X-HE-Meta: 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 m/RELV6j XrsTFDew+s3kQK5Lt0qW5mdEb3mI7FqpbUYgHC++j/qpEBW9AQUbot20nZr9r5YXAa5Dgma/P/IpH775ctJnJto2exkBaC9RvBEQbcps0QJP4eBz/y771GwtR8P4gyMW3/iDL8fdlY7do2/Q0zowRFyEeoqb60ujvgMZDdEhewyGYmMsi8+RSFYDSzS6E113C0RR5u8a09HFbohA6CR/t2rs/q8JVtqJJVUfkSAyuZfptvP+l6o6hasrnYMaqKreo6wGqRn0iw+luzt61Z/NzGscyFDK9zJKKK6xfKd6KrMUlC2IG2DSIeZdbX1WlUldweGMWRIRZuoUt86urAT3sFP2+UGUAwqNr3GKwszMLHQcX5KBZpRkhnDrh1DVtyIl1jYDX X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, 30 Jan 2025 16:18:04 -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(). > Seems like a pretty specialized thing. Have you identified any other potential users of vmap_file()? I couldn't see any. If drm is likely to remain the only user of this, perhaps we should leave the code down in drivers/gpu/drm for now? Also, the amount of copy-n-pasting from vmap() into vmap_file() is undesirable - code size, maintenance overhead, etc.