From: ira.weiny@intel.com
To: Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Ira Weiny <ira.weiny@intel.com>,
Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Christoph Hellwig <hch@infradead.org>,
Eric Biggers <ebiggers@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
Al Viro <viro@zeniv.linux.org.uk>,
linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [PATCH V3 0/3] Begin converting kmap calls to kmap_local_page()
Date: Thu, 10 Dec 2020 09:18:32 -0800 [thread overview]
Message-ID: <20201210171834.2472353-1-ira.weiny@intel.com> (raw)
From: Ira Weiny <ira.weiny@intel.com>
Changes from V2[1]:
Update this cover letter
Update commit messages
From Matthew Wilcox
Put functions in highmem.h rather than pagemap.h
Investigate 0-day build errors.
AFAICT the patches were applied to the wrong tree and caused
build errors.
There are many places in the kernel where kmap is used for a simple memory
operation like memcpy, memset, or memmove and then the page is unmapped.
This kmap/mem*/kunmap pattern is mixed between kmap and kmap_atomic uses. All
of them could use kmap_atomic() which is faster. However, kmap_atomic() is
being deprecated in favor of kmap_local_page().
Use kmap_local_page() in the existing page operations. Lift
memcpy_[to|from]_page to highmem.h. Remove memzero_page() and use zero_user()
instead. Add memcpy_page(), memmove_page(), and memset_page() to be used in
future patches. Finally, add BUG_ON()s to check for any miss use of the API
and prevent data corruption in the same way zero_user() does.
This is V3 to get into 5.11 so that we can start to convert all the various
subsystems in 5.12.[2]
These are based on tip/core/mm. I'm sending to Andrew and Thomas but I'm
expecting these to go through tip/core/mm via Thomas if that is ok with Andrew.
[1] https://lore.kernel.org/lkml/20201207225703.2033611-1-ira.weiny@intel.com/
[2] https://lore.kernel.org/lkml/20201204160504.GH1563847@iweiny-DESK2.sc.intel.com/
Ira Weiny (2):
mm/highmem: Remove deprecated kmap_atomic
mm/highmem: Lift memcpy_[to|from]_page to core
include/linux/highmem.h | 81 ++++++++++++++++++++++++++++++++++-------
lib/iov_iter.c | 26 ++-----------
2 files changed, 70 insertions(+), 37 deletions(-)
--
2.28.0.rc0.12.gb6a658bd00c9
next reply other threads:[~2020-12-10 17:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-10 17:18 ira.weiny [this message]
2020-12-10 17:18 ` [PATCH V3 1/2] mm/highmem: Remove deprecated kmap_atomic ira.weiny
2020-12-10 17:18 ` [PATCH V3 2/2] mm/highmem: Lift memcpy_[to|from]_page to core ira.weiny
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