From: Christoph Hellwig <hch@lst.de>
To: Kanchan Joshi <joshi.k@samsung.com>
Cc: kbusch@kernel.org, hch@lst.de, axboe@kernel.dk,
linux-block@vger.kernel.org, martin.petersen@oracle.com,
anuj20.g@samsung.com
Subject: Re: [PATCH] block: streamline meta bounce buffer handling
Date: Mon, 6 May 2024 08:05:09 +0200 [thread overview]
Message-ID: <20240506060509.GA5362@lst.de> (raw)
In-Reply-To: <20240506051047.4291-1-joshi.k@samsung.com>
Can we take a step back first?
Current the blk-map user buffer handling decided to either pin
the memory and use that directly or use the normal user copy helpers
through copy_page_to_iter/copy_page_from_iter.
Why do we even pin the memory here to then do an in-kernel copy instead
of doing the copy_from/to_user which is going to be a lot more efficient?
Sort of related to that is that this does driver the copy to user and
unpin from bio_integrity_free, which is a low-level routine. It really
should be driven from the highlevel blk-map code that is the I/O
submitter, just like the data side. Shoe-horning uaccess into the
low-level block layer plumbing is just going to get us into trouble.
next prev parent reply other threads:[~2024-05-06 6:05 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20240506051751epcas5p1ed84e21495e12c7bf41e94827aa85e33@epcas5p1.samsung.com>
2024-05-06 5:10 ` [PATCH] block: streamline meta bounce buffer handling Kanchan Joshi
2024-05-06 6:05 ` Christoph Hellwig [this message]
2024-05-06 12:46 ` Kanchan Joshi
2024-05-06 14:56 ` Christoph Hellwig
2024-05-06 20:36 ` Keith Busch
2024-05-07 5:45 ` Christoph Hellwig
2024-05-24 10:28 ` Kanchan Joshi
2024-05-28 7:59 ` Christoph Hellwig
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