Currently for_each_mem_range() and for_each_mem_range_rev() iterators are
the most generic way to traverse memblock regions.  As such, they have 8
parameters and they are hardly convenient to users.  Most users choose to
utilize one of their wrappers and the only user that actually needs most
of the parameters is memblock itself.

To avoid yet another naming for memblock iterators, rename the existing
for_each_mem_range[_rev]() to __for_each_mem_range[_rev]() and add a new
for_each_mem_range[_rev]() wrappers with only index, start and end
parameters.

The new wrapper nicely fits into init_unavailable_mem() and will be used
in upcoming changes to simplify memblock traversals.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>	[MIPS]
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-11-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The only user of memblock_dbg() outside memblock was s390 setup code and
it is converted to use pr_debug() instead.  This allows to stop exposing
memblock_debug and memblock_dbg() to the rest of the kernel.

[akpm@linux-foundation.org: make memblock_dbg() safer and neater]

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-10-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

for_each_memblock_type() is not used outside mm/memblock.c, move it there
from include/linux/memblock.h

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-9-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

microblaze does not support neither NUMA not SPARSMEM, so there is no
point to call memblock_set_node() and
sparse_memory_present_with_active_regions() functions during microblaze
memory initialization.

Remove these calls and the surrounding code.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-8-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

RISC-V does not (yet) support NUMA and for UMA architectures node 0 is
used implicitly during early memory initialization.

There is no need to call memblock_set_node(), remove this call and the
surrounding code.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-7-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Instead of traversing memblock.memory regions to find memory_start and
memory_end, simply query memblock_{start,end}_of_DRAM().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Stafford Horne <shorne@gmail.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-6-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

dummy_numa_init() loops over memblock.memory and passes nid=0 to
numa_add_memblk() which essentially wraps memblock_set_node().  However,
memblock_set_node() can cope with entire memory span itself, so the loop
over memblock.memory regions is redundant.

Using a single call to memblock_set_node() rather than a loop also fixes
an issue with a buggy ACPI firmware in which the SRAT table covers some
but not all of the memory in the EFI memory map.

Jonathan Cameron says:

  This issue can be easily triggered by having an SRAT table which fails
  to cover all elements of the EFI memory map.

  This firmware error is detected and a warning printed. e.g.
  "NUMA: Warning: invalid memblk node 64 [mem 0x240000000-0x27fffffff]"
  At that point we fall back to dummy_numa_init().

  However, the failed ACPI init has left us with our memblocks all broken
  up as we split them when trying to assign them to NUMA nodes.

  We then iterate over the memblocks and add them to node 0.

  numa_add_memblk() calls memblock_set_node() which merges regions that
  were previously split up during the earlier attempt to add them to
  different nodes during parsing of SRAT.

  This means elements are moved in the memblock array and we can end up
  in a different memblock after the call to numa_add_memblk().
  Result is:

  Unable to handle kernel paging request at virtual address 0000000000003a40
  Mem abort info:
    ESR = 0x96000004
    EC = 0x25: DABT (current EL), IL = 32 bits
    SET = 0, FnV = 0
    EA = 0, S1PTW = 0
  Data abort info:
    ISV = 0, ISS = 0x00000004
    CM = 0, WnR = 0
  [0000000000003a40] user address but active_mm is swapper
  Internal error: Oops: 96000004 [#1] PREEMPT SMP

  ...

  Call trace:
    sparse_init_nid+0x5c/0x2b0
    sparse_init+0x138/0x170
    bootmem_init+0x80/0xe0
    setup_arch+0x2a0/0x5fc
    start_kernel+0x8c/0x648

Replace the loop with a single call to memblock_set_node() to the entire
memory.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-5-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

free_highpages() in both arm and xtensa essentially open-code
for_each_free_mem_range() loop to detect high memory pages that were not
reserved and that should be initialized and passed to the buddy allocator.

Replace open-coded implementation of for_each_free_mem_range() with usage
of memblock API to simplify the code.

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>	[xtensa]
Reviewed-by: Max Filippov <jcmvbkbc@gmail.com>	[xtensa]
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-4-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The memory size calculation in cma_early_percent_memory() traverses
memblock.memory rather than simply call memblock_phys_mem_size().  The
comment in that function suggests that at some point there should have
been call to memblock_analyze() before memblock_phys_mem_size() could be
used.  As of now, there is no memblock_analyze() at all and
memblock_phys_mem_size() can be used as soon as cold-plug memory is
registered with memblock.

Replace loop over memblock.memory with a call to memblock_phys_mem_size().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Baoquan He <bhe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: https://lkml.kernel.org/r/20200818151634.14343-3-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "memblock: seasonal cleaning^w cleanup", v3.

These patches simplify several uses of memblock iterators and hide some of
the memblock implementation details from the rest of the system.

This patch (of 17):

The memory size calculation in kvm_cma_reserve() traverses memblock.memory
rather than simply call memblock_phys_mem_size().  The comment in that
function suggests that at some point there should have been call to
memblock_analyze() before memblock_phys_mem_size() could be used.  As of
now, there is no memblock_analyze() at all and memblock_phys_mem_size()
can be used as soon as cold-plug memory is registered with memblock.

Replace loop over memblock.memory with a call to memblock_phys_mem_size().

Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Daniel Axtens <dja@axtens.net>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Emil Renner Berthing <kernel@esmil.dk>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Hari Bathini <hbathini@linux.ibm.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Miguel Ojeda <miguel.ojeda.sandonis@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Link: https://lkml.kernel.org/r/20200818151634.14343-1-rppt@kernel.org
Link: https://lkml.kernel.org/r/20200818151634.14343-2-rppt@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Add else to split mutually exclusive case and avoid some unnecessary check.
It doesn't seem to change code generation (compiler is smart), but I think
it helps readability.

[akpm@linux-foundation.org: fix comment location]

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200924111641.28922-1-linmiaohe@huawei.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

No one use this macro anymore.

Also fix code style of policy_node().

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200921021401.84508-1-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

It is not necessary to hold the lock of current when setting nodemask of
a new policy.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200921040416.86185-1-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

This patch reduces the running time for compaction_test from about 27 sec,
to 3.3 sec, which is about an 8x speedup.

These numbers are for an Intel x86_64 system with 32 GB of DRAM.

The compaction_test.c program was spending most of its time doing mmap(),
1 MB at a time, on about 25 GB of memory.

Instead, do the mmaps 100 MB at a time.  (Going past 100 MB doesn't make
things go much faster, because other parts of the program are using the
remaining time.)

Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Sri Jayaramappa <sjayaram@akamai.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Link: https://lkml.kernel.org/r/20201002080621.551044-2-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The enum value 'COMPACT_INACTIVE' is never used so can be removed.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200917110750.12015-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The same code can work both for 'zone->compact_considered > defer_limit'
and 'zone->compact_considered >= defer_limit'.  In the latter there is one
branch less which is more effective considering performance.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@suse.de>
Cc: David Rientjes <rientjes@google.com>
Link: https://lkml.kernel.org/r/20200913190448.28649-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

zhdr is already initialized in the front of the function, so remove
redundant initialization here.

Signed-off-by: Xiang Chen <chenxiang66@hisilicon.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Link: https://lkml.kernel.org/r/1600419885-191907-1-git-send-email-chenxiang66@hisilicon.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

alloc_slots() allocates memory for slots using kmem_cache_alloc(), then
memsets it.  We can just use kmem_cache_zalloc().

Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200926100834.GA184671@rlk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fix comments for isolate_lru_page():
s/fundamentnal/fundamental

Signed-off-by: Hui Su <sh_def@163.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200927173923.GA8058@rlk
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We have observed that drop_caches can take a considerable amount of
time (<put data here>).  Especially when there are many memcgs involved
because they are adding an additional overhead.

It is quite unfortunate that the operation cannot be interrupted by a
signal currently.  Add a check for fatal signals into the main loop so
that userspace can control early bailout.

There are two reasons:

1. We have too many memcgs, even though one object freed in one memcg,
   the sum of object is bigger than 10.

2. We spend a lot of time in traverse memcg once.  So, the memcg who
   traversed at the first have been freed many objects.  Traverse memcg
   next time, the freed count bigger than 10 again.

We can get the following info through 'ps':

  root:~# ps -aux | grep drop
  root  357956 ... R    Aug25 21119854:55 echo 3 > /proc/sys/vm/drop_caches
  root 1771385 ... R    Aug16 21146421:17 echo 3 > /proc/sys/vm/drop_caches
  root 1986319 ... R    18:56 117:27 echo 3 > /proc/sys/vm/drop_caches
  root 2002148 ... R    Aug24 5720:39 echo 3 > /proc/sys/vm/drop_caches
  root 2564666 ... R    18:59 113:58 echo 3 > /proc/sys/vm/drop_caches
  root 2639347 ... R    Sep03 2383:39 echo 3 > /proc/sys/vm/drop_caches
  root 3904747 ... R    03:35 993:31 echo 3 > /proc/sys/vm/drop_caches
  root 4016780 ... R    Aug21 7882:18 echo 3 > /proc/sys/vm/drop_caches

Use bpftrace follow 'freed' value in drop_slab_node:

  root:~# bpftrace -e 'kprobe:drop_slab_node+70 {@ret=hist(reg("bp")); }'
  Attaching 1 probe...
  ^B^C

  @ret:
  [64, 128)        1 |                                                    |
  [128, 256)      28 |                                                    |
  [256, 512)     107 |@                                                   |
  [512, 1K)      298 |@@@                                                 |
  [1K, 2K)       613 |@@@@@@@                                             |
  [2K, 4K)      4435 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
  [4K, 8K)       442 |@@@@@                                               |
  [8K, 16K)      299 |@@@                                                 |
  [16K, 32K)     100 |@                                                   |
  [32K, 64K)     139 |@                                                   |
  [64K, 128K)     56 |                                                    |
  [128K, 256K)    26 |                                                    |
  [256K, 512K)     2 |                                                    |

In the while loop, we can check whether the TASK_KILLABLE signal is set,
if so, we should break the loop.

Signed-off-by: Chunxin Zang <zangchunxin@bytedance.com>
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Chris Down <chris@chrisdown.name>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Link: https://lkml.kernel.org/r/20200909152047.27905-1-zangchunxin@bytedance.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As a debugging aid, huge_pmd_share should make sure i_mmap_rwsem is held
if necessary.  To clarify the 'if necessary', expand the comment block at
the beginning of huge_pmd_share.

No functional change.  The added i_mmap_assert_locked() call is only
enabled if CONFIG_LOCKDEP.

Ideally, this should have been included with commit 34ae204f


("hugetlbfs: remove call to huge_pte_alloc without i_mmap_rwsem").

Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: https://lkml.kernel.org/r/20200911201248.88537-1-mike.kravetz@oracle.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Function dequeue_huge_page_node_exact() iterates the free list and return
the first valid free hpage.

Instead of break and check the loop variant, we could return in the loop
directly.  This could reduce some redundant check.

[mike.kravetz@oracle.com: points out a logic error]
[richard.weiyang@linux.alibaba.com: v4]
  Link: https://lkml.kernel.org/r/20200901014636.29737-8-richard.weiyang@linux.alibaba.com

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-8-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

set_hugetlb_cgroup_[rsvd] just manipulate page local data, which is not
necessary to be protected by hugetlb_lock.

Let's take this out.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-7-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The page allocated from buddy is not on any list, so just use list_add()
is enough.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-6-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There are only two cases of function add_reservation_in_range()

    * count file_region and return the number in regions_needed
    * do the real list operation without counting

This means it is not necessary to have two parameters to classify these
two cases.

Just use regions_needed to separate them.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-5-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Instead of add allocated file_region one by one to region_cache, we could
use list_splice to merge two list at once.

Also we know the number of entries in the list, increase the number
directly.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-4-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

We are sure to get a valid file_region, otherwise the
VM_BUG_ON(resv->region_cache_count <= 0) at the very beginning would be
triggered.

Let's remove the redundant one.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200831022351.20916-3-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm/hugetlb: code refine and simplification", v4.

Following are some cleanups for hugetlb.  Simple testing with
tools/testing/selftests/vm/map_hugetlb passes.

This patch (of 7):

Per my understanding, we keep the regions ordered and would always
coalesce regions properly.  So the task to keep this property is just to
coalesce its neighbour.

Let's simplify this.

Signed-off-by: Wei Yang <richard.weiyang@linux.alibaba.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: https://lkml.kernel.org/r/20200901014636.29737-1-richard.weiyang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20200831022351.20916-1-richard.weiyang@linux.alibaba.com
Link: https://lkml.kernel.org/r/20200831022351.20916-2-richard.weiyang@linux.alibaba.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Change 'pecify' to 'Specify'.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200723032248.24772-4-bhe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

If a swap entry tests positive for either is_[migration|hwpoison]_entry(),
then its swap_type() is among SWP_MIGRATION_READ, SWP_MIGRATION_WRITE and
SWP_HWPOISON.  All these types >= MAX_SWAPFILES, exactly what is asserted
with non_swap_entry().

So the checking non_swap_entry() in is_hugetlb_entry_migration() and
is_hugetlb_entry_hwpoisoned() is redundant.

Let's remove it to optimize code.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200723032248.24772-3-bhe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Patch series "mm/hugetlb: Small cleanup and improvement", v2.

This patch (of 3):

Just like its neighbour is_hugetlb_entry_migration() has done.

Signed-off-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Link: https://lkml.kernel.org/r/20200723032248.24772-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20200723032248.24772-2-bhe@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

There is a general understanding that GFP_ATOMIC/GFP_NOWAIT are to be used
from atomic contexts.  E.g.  from within a spin lock or from the IRQ
context.  This is correct but there are some atomic contexts where the
above doesn't hold.  One of them would be an NMI context.  Page allocator
has never supported that and the general fear of this context didn't let
anybody to actually even try to use the allocator there.  Good, but let's
be more specific about that.

Another such a context, and that is where people seem to be more daring,
is raw_spin_lock.  Mostly because it simply resembles regular spin lock
which is supported by the allocator and there is not any implementation
difference with !RT kernels in the first place.  Be explicit that such a
context is not supported by the allocator.  The underlying reason is that
zone->lock would have to become raw_spin_lock as well and that has turned
out to be a problem for RT
(http://lkml.kernel.org/r/87mu305c1w.fsf@nanos.tec.linutronix.de).

Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Uladzislau Rezki <urezki@gmail.com>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Link: https://lkml.kernel.org/r/20200929123010.5137-1-mhocko@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Here is a very rare race which leaks memory:

Page P0 is allocated to the page cache.  Page P1 is free.

Thread A                Thread B                Thread C
find_get_entry():
xas_load() returns P0
						Removes P0 from page cache
						P0 finds its buddy P1
			alloc_pages(GFP_KERNEL, 1) returns P0
			P0 has refcount 1
page_cache_get_speculative(P0)
P0 has refcount 2
			__free_pages(P0)
			P0 has refcount 1
put_page(P0)
P1 is not freed

Fix this by freeing all the pages in __free_pages() that won't be freed
by the call to put_page().  It's usually not a good idea to split a page,
but this is a very unlikely scenario.

Fixes: e286781d

 ("mm: speculative page references")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200926213919.26642-1-willy@infradead.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The function is_huge_zero_page() doesn't call compound_head() to make sure
the page pointer is a head page. The call to is_huge_zero_page() in
release_pages() is made before compound_head() is called so the test would
fail if release_pages() was called with a tail page of the huge_zero_page
and put_page_testzero() would be called releasing the page.
This is unlikely to be happening in normal use or we would be seeing all
sorts of process data corruption when accessing a THP zero page.

Looking at other places where is_huge_zero_page() is called, all seem to
only pass a head page so I think the right solution is to move the call
to compound_head() in release_pages() to a point before calling
is_huge_zero_page().

Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Christoph Hellwig <hch@lst.de>
Link: https://lkml.kernel.org/r/20200917173938.16420-1-rcampbell@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Previously 'for_next_zone_zonelist_nodemask' macro parameter 'zlist' was
unused so this patch removes it.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200917211906.30059-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

__perform_reclaim()'s single caller expects it to return 'unsigned long',
hence change its return value and a local variable to 'unsigned long'.

Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Yanfei Xu <yanfei.xu@windriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200916022138.16740-1-yanfei.xu@windriver.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

finalise_ac() is just 'epilogue' for 'prepare_alloc_pages'.  Therefore
there is no need to keep them both so 'finalise_ac' content can be merged
into prepare_alloc_pages() code.  It would make __alloc_pages_nodemask()
cleaner when it comes to readability.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Mike Rapoport <rppt@kernel.org>
Link: https://lkml.kernel.org/r/20200916110118.6537-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Previously in '__init early_init_on_alloc' and '__init early_init_on_free'
the return values from 'kstrtobool' were not handled properly.  That
caused potential garbage value read from variable 'bool_result'.
Introduced patch fixes error handling.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200916214125.28271-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Previously flags check was separated into two separated checks with two
separated branches. In case of presence of any of two mentioned flags,
the same effect on flow occurs. Therefore checks can be merged and one
branch can be avoided.

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200911092310.31136-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Previously variable 'tmp' was initialized, but was not read later before
reassigning.  So the initialization can be removed.

[akpm@linux-foundation.org: remove `tmp' altogether]

Signed-off-by: Mateusz Nosek <mateusznosek0@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Link: https://lkml.kernel.org/r/20200904132422.17387-1-mateusznosek0@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>