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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


WARNING: multiple messages have this Message-ID
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org, linux-block@vger.kernel.org,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Mike Snitzer <snitzer@redhat.com>,
	Geoff Levand <geoff@infradead.org>,
	linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org,
	Dongsheng Yang <dongsheng.yang@easystack.cn>,
	linux-kernel@vger.kernel.org,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	dm-devel@redhat.com, Ilya Dryomov <idryomov@gmail.com>,
	Ira Weiny <ira.weiny@intel.com>,
	ceph-devel@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


WARNING: multiple messages have this Message-ID
From: Christoph Hellwig <hch@lst.de>
To: Jens Axboe <axboe@kernel.dk>, Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org, linux-block@vger.kernel.org,
	Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
	Mike Snitzer <snitzer@redhat.com>,
	Geoff Levand <geoff@infradead.org>,
	linuxppc-dev@lists.ozlabs.org, linux-mips@vger.kernel.org,
	Dongsheng Yang <dongsheng.yang@easystack.cn>,
	linux-kernel@vger.kernel.org,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	dm-devel@redhat.com, Ilya Dryomov <idryomov@gmail.com>,
	Ira Weiny <ira.weiny@intel.com>,
	ceph-devel@vger.kernel.org
Subject: [dm-devel] [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

--
dm-devel mailing list
dm-devel@redhat.com
https://listman.redhat.com/mailman/listinfo/dm-devel


  reply	other threads:[~2021-06-15 13:26 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-15 13:24 [dm-devel] 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   ` [dm-devel] [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         ` [dm-devel] [PATCH] crypto: scatterwalk - Remove obsolete PageSlab check Herbert Xu
2021-06-15 13:24 ` [dm-devel] [PATCH 02/18] mm: use kunmap_local_dirty in memcpy_to_page Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 03/18] mm: use kmap_local_page in memzero_page Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 04/18] MIPS: don't include <linux/genhd.h> in <asm/mach-rc32434/rb.h> Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 05/18] bvec: fix the include guards for bvec.h Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 06/18] bvec: add a bvec_kmap_local helper Christoph Hellwig
2021-06-16 16:52   ` Bart Van Assche
2021-06-15 13:24 ` [dm-devel] [PATCH 07/18] bvec: add memcpy_{from, to}_bvec and memzero_bvec helper Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 08/18] block: use memzero_page in zero_fill_bio Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 09/18] rbd: use memzero_bvec Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 10/18] dm-writecache: use bvec_kmap_local instead of bvec_kmap_irq Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 11/18] ps3disk: use memcpy_{from,to}_bvec Christoph Hellwig
2021-06-16 16:36   ` Geoff Levand
2021-06-15 13:24 ` [dm-devel] [PATCH 12/18] block: remove bvec_kmap_irq and bvec_kunmap_irq Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [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 ` [dm-devel] [PATCH 14/18] block: use memcpy_to_bvec in copy_to_high_bio_irq Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 15/18] block: use memcpy_from_bvec in bio_copy_kern_endio_read Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 16/18] block: use memcpy_from_bvec in __blk_queue_bounce Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 17/18] block: use bvec_kmap_local in t10_pi_type1_{prepare, complete} Christoph Hellwig
2021-06-15 13:24 ` [dm-devel] [PATCH 18/18] block: use bvec_kmap_local in bio_integrity_process Christoph Hellwig
2021-06-16 16:03 ` [dm-devel] switch the block layer to use kmap_local_page v2 Martin K. Petersen

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