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Date: Sun, 18 Jun 2017 10:28:41 +0200
From: Christoph Hellwig <hch@lst.de>
To: Dan Williams <dan.j.williams@intel.com>
Cc: linux-nvdimm@lists.01.org, Jan Kara <jack@suse.cz>,
        dm-devel@redhat.com, Toshi Kani <toshi.kani@hpe.com>,
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        linux-fsdevel@vger.kernel.org, Thomas Gleixner <tglx@linutronix.de>,
        Ross Zwisler <ross.zwisler@linux.intel.com>
Subject: Re: [PATCH v3 01/14] x86, uaccess: introduce
        copy_from_iter_flushcache for pmem / cache-bypass operations
Message-ID: <20170618082841.GA26456@lst.de>
References: <149703982465.20620.14881139332926778446.stgit@dwillia2-desk3.amr.corp.intel.com> <149703983098.20620.14791162611225792317.stgit@dwillia2-desk3.amr.corp.intel.com>
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On Fri, Jun 09, 2017 at 01:23:51PM -0700, Dan Williams wrote:
> Implement a __copy_from_user_inatomic_flushcache, memcpy_page_flushcache, and
> memcpy_flushcache, that guarantee that the destination buffer is not dirty in
> the cpu cache on completion. The new copy_from_iter_flushcache and sub-routines

Wouldn't writethrough be a better name?

> will be used to replace the "pmem api" (include/linux/pmem.h +
> arch/x86/include/asm/pmem.h). The availability of copy_from_iter_flushcache()
> and memcpy_flushcache() are gated by the CONFIG_ARCH_HAS_UACCESS_FLUSHCACHE
> config symbol, and fallback to copy_from_iter_nocache() and plain memcpy()
> otherwise.

What is UACCESS about memcpy_flushcache?