From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
Geoff Levand <geoff@infradead.org>,
Ilya Dryomov <idryomov@gmail.com>,
Dongsheng Yang <dongsheng.yang@easystack.cn>,
Mike Snitzer <snitzer@redhat.com>,
"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
Ira Weiny <ira.weiny@intel.com>,
dm-devel@redhat.com, linux-mips@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linuxppc-dev@lists.ozlabs.org, ceph-devel@vger.kernel.org,
linux-arch@vger.kernel.org
Subject: [PATCH 01/18] mm: add a kunmap_local_dirty helper
Date: Tue, 15 Jun 2021 15:24:39 +0200 [thread overview]
Message-ID: <20210615132456.753241-2-hch@lst.de> (raw)
In-Reply-To: <20210615132456.753241-1-hch@lst.de>
Add a helper that calls flush_kernel_dcache_page before unmapping the
local mapping. flush_kernel_dcache_page is required for all pages
potentially mapped into userspace that were written to using kmap*,
so having a helper that does the right thing can be very convenient.
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
include/linux/highmem-internal.h | 7 +++++++
include/linux/highmem.h | 4 ++++
2 files changed, 11 insertions(+)
diff --git a/include/linux/highmem-internal.h b/include/linux/highmem-internal.h
index 7902c7d8b55f..bd37706db147 100644
--- a/include/linux/highmem-internal.h
+++ b/include/linux/highmem-internal.h
@@ -224,4 +224,11 @@ do { \
__kunmap_local(__addr); \
} while (0)
+#define kunmap_local_dirty(__page, __addr) \
+do { \
+ if (!PageSlab(__page)) \
+ flush_kernel_dcache_page(__page); \
+ kunmap_local(__addr); \
+} while (0)
+
#endif
diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 832b49b50c7b..65f548db4f2d 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -93,6 +93,10 @@ static inline void kmap_flush_unused(void);
* On HIGHMEM enabled systems mapping a highmem page has the side effect of
* disabling migration in order to keep the virtual address stable across
* preemption. No caller of kmap_local_page() can rely on this side effect.
+ *
+ * If data is written to the returned kernel mapping, the callers needs to
+ * unmap the mapping using kunmap_local_dirty(), else kunmap_local() should
+ * be used.
*/
static inline void *kmap_local_page(struct page *page);
--
2.30.2
next prev parent reply other threads:[~2021-06-15 13:26 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-15 13:24 switch the block layer to use kmap_local_page v2 Christoph Hellwig
2021-06-15 13:24 ` Christoph Hellwig [this message]
2021-06-18 3:01 ` [PATCH 01/18] mm: add a kunmap_local_dirty helper Ira Weiny
2021-06-18 3:37 ` Herbert Xu
2021-06-18 18:12 ` Ira Weiny
2021-06-24 6:32 ` [PATCH] crypto: scatterwalk - Remove obsolete PageSlab check Herbert Xu
2021-06-15 13:24 ` [PATCH 02/18] mm: use kunmap_local_dirty in memcpy_to_page Christoph Hellwig
2021-06-15 13:24 ` [PATCH 03/18] mm: use kmap_local_page in memzero_page Christoph Hellwig
2021-06-15 13:24 ` [PATCH 04/18] MIPS: don't include <linux/genhd.h> in <asm/mach-rc32434/rb.h> Christoph Hellwig
2021-06-15 13:24 ` [PATCH 05/18] bvec: fix the include guards for bvec.h Christoph Hellwig
2021-06-15 13:24 ` [PATCH 06/18] bvec: add a bvec_kmap_local helper Christoph Hellwig
2021-06-16 16:52 ` [dm-devel] " Bart Van Assche
2021-06-15 13:24 ` [PATCH 07/18] bvec: add memcpy_{from,to}_bvec and memzero_bvec helper Christoph Hellwig
2021-06-15 13:24 ` [PATCH 08/18] block: use memzero_page in zero_fill_bio Christoph Hellwig
2021-06-15 13:24 ` [PATCH 09/18] rbd: use memzero_bvec Christoph Hellwig
2021-06-15 13:24 ` [PATCH 10/18] dm-writecache: use bvec_kmap_local instead of bvec_kmap_irq Christoph Hellwig
2021-06-15 13:24 ` [PATCH 11/18] ps3disk: use memcpy_{from,to}_bvec Christoph Hellwig
2021-06-16 16:36 ` Geoff Levand
2021-06-15 13:24 ` [PATCH 12/18] block: remove bvec_kmap_irq and bvec_kunmap_irq Christoph Hellwig
2021-06-15 13:24 ` [PATCH 13/18] block: rewrite bio_copy_data_iter to use bvec_kmap_local and memcpy_to_bvec Christoph Hellwig
2021-06-15 13:24 ` [PATCH 14/18] block: use memcpy_to_bvec in copy_to_high_bio_irq Christoph Hellwig
2021-06-15 13:24 ` [PATCH 15/18] block: use memcpy_from_bvec in bio_copy_kern_endio_read Christoph Hellwig
2021-06-15 13:24 ` [PATCH 16/18] block: use memcpy_from_bvec in __blk_queue_bounce Christoph Hellwig
2021-06-15 13:24 ` [PATCH 17/18] block: use bvec_kmap_local in t10_pi_type1_{prepare,complete} Christoph Hellwig
2021-06-15 13:24 ` [PATCH 18/18] block: use bvec_kmap_local in bio_integrity_process Christoph Hellwig
2021-06-16 16:03 ` switch the block layer to use kmap_local_page v2 Martin K. Petersen
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