__phys_to_pfn and __pfn_to_phys are symmetric, PHYS_PFN and PFN_PHYS are
semmetric:

 - y = (phys_addr_t)x << PAGE_SHIFT

 - y >> PAGE_SHIFT = (phys_add_t)x

 - (unsigned long)(y >> PAGE_SHIFT) = x

[akpm@linux-foundation.org: use macro arg name `x']
[arnd@arndb.de: include linux/pfn.h for PHYS_PFN definition]
Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The various definitions of __pfn_to_phys() have been consolidated to
use a generic macro in include/asm-generic/memory_model.h. This hit
mainline in the form of 012dcef3f058 "mm: move __phys_to_pfn and
__pfn_to_phys to asm/generic/memory_model.h". When the generic macro
was implemented the type cast to phys_addr_t was dropped which caused
boot regressions on ARM platforms with more than 4GB of memory and
LPAE enabled.

It was suggested to use PFN_PHYS() defined in include/linux/pfn.h
as provides the correct logic and avoids further duplication.

Reported-by: kernelci.org bot <bot@kernelci.org>
Suggested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Three architectures already define these, and we'll need them genericly
soon.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

Fix typo in __page_to_pfn comment: s/encorded/encoded.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

This allows the cast in lowmem_page_address (introduced as a warning
fixup to 33dd4e0ec911 "mm: make some struct page's const") to be
removed.

Propagate const'ness to page_to_section() as well since it is required
by __page_to_pfn.

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

That is "success", "unknown", "through", "performance", "[re|un]mapping"
, "access", "default", "reasonable", "[con]currently", "temperature"
, "channel", "[un]used", "application", "example","hierarchy", "therefore"
, "[over|under]flow", "contiguous", "threshold", "enough" and others.

Signed-off-by: André Goddard Rosa <andre.goddard@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

No architectures use CONFIG_OUT_OF_LINE_PFN_TO_PAGE - it can be removed.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

For CONFIG_SPARSEMEM_VMEMMAP=y on s390 I get warnings like

init/main.c: In function 'start_kernel':
init/main.c:641: warning: format '%08lx' expects type 'long unsigned int', but argument 2 has type 'int'

The warning can be suppressed with a cast to unsigned long in the
CONFIG_SPARSEMEM_VMEMMAP=y version of __page_to_pfn.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

Fix the __pfn_to_page(pfn) macro so that it doesn't evaluate its
argument twice in the CONFIG_DISCONTIGMEM=y case, because 'pfn' may
be a result of a funtion call having side effects.

For example, the hibernation code applies pfn_to_page(pfn) to the
result of a function returning the pfn corresponding to the next set
bit in a bitmap and the current bit position is modified on each
call.  This leads to "interesting" failures for CONFIG_DISCONTIGMEM=y
due to the current behavior of __pfn_to_page(pfn).

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>