+ documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch added to -mm tree

+ documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch added to -mm tree

[Andrew Morton]

The patch titled
     Subject: Documentation/vm: remove "Using kmap-atomic" from highmem.rst.
has been added to the -mm tree.  Its filename is
     documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch

This patch should soon appear at
    https://ozlabs.org/~akpm/mmots/broken-out/documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch
and later at
    https://ozlabs.org/~akpm/mmotm/broken-out/documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch

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------------------------------------------------------
From: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Subject: Documentation/vm: remove "Using kmap-atomic" from highmem.rst.

The use of kmap_atomic() is deprecated in favor of kmap_local_page().  For
this reason the "Using kmap_atomic" section in highmem.rst is obsolete and
unnecessary.

Therefore, just remove it.

Link: https://lkml.kernel.org/r/20220421180200.16901-4-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 Documentation/vm/highmem.rst |   35 ---------------------------------
 1 file changed, 35 deletions(-)

--- a/Documentation/vm/highmem.rst~documentation-vm-remove-using-kmap-atomic-from-highmemrst
+++ a/Documentation/vm/highmem.rst
@@ -72,41 +72,6 @@ The kernel contains several ways of crea
   It may be assumed that k[un]map_atomic() won't fail.
 
 
-Using kmap_atomic
-=================
-
-When and where to use kmap_atomic() is straightforward.  It is used when code
-wants to access the contents of a page that might be allocated from high memory
-(see __GFP_HIGHMEM), for example a page in the pagecache.  The API has two
-functions, and they can be used in a manner similar to the following::
-
-	/* Find the page of interest. */
-	struct page *page = find_get_page(mapping, offset);
-
-	/* Gain access to the contents of that page. */
-	void *vaddr = kmap_atomic(page);
-
-	/* Do something to the contents of that page. */
-	memset(vaddr, 0, PAGE_SIZE);
-
-	/* Unmap that page. */
-	kunmap_atomic(vaddr);
-
-Note that the kunmap_atomic() call takes the result of the kmap_atomic() call
-not the argument.
-
-If you need to map two pages because you want to copy from one page to
-another you need to keep the kmap_atomic calls strictly nested, like::
-
-	vaddr1 = kmap_atomic(page1);
-	vaddr2 = kmap_atomic(page2);
-
-	memcpy(vaddr1, vaddr2, PAGE_SIZE);
-
-	kunmap_atomic(vaddr2);
-	kunmap_atomic(vaddr1);
-
-
 Cost of Temporary Mappings
 ==========================
 
_

Patches currently in -mm which might be from fmdefrancesco@gmail.com are

mm-highmem-fix-kernel-doc-warnings-in-highmemh.patch
documentation-vm-include-kdocs-from-highmemh-into-highmemrst.patch
documentation-vm-remove-using-kmap-atomic-from-highmemrst.patch
documentation-vm-rework-temporary-virtual-mappings.patch