The patch titled
Subject: powerpc/mmu: drop mmap_sem now that locked_vm is atomic
has been added to the -mm tree. Its filename is
powerpc-mmu-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/powerpc-mmu-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/powerpc-mmu-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
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From: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Subject: powerpc/mmu: drop mmap_sem now that locked_vm is atomic
With locked_vm now an atomic, there is no need to take mmap_sem as writer.
Delete and refactor accordingly.
Link: http://lkml.kernel.org/r/20190402204158.27582-6-daniel.m.jordan@xxxxxxxxxx
Signed-off-by: Daniel Jordan <daniel.m.jordan@xxxxxxxxxx>
Cc: Alexey Kardashevskiy <aik@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Davidlohr Bueso <dave@xxxxxxxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Alan Tull <atull@xxxxxxxxxx>
Cc: Alex Williamson <alex.williamson@xxxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Cc: Moritz Fischer <mdf@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxxx>
Cc: Wu Hao <hao.wu@xxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/powerpc/mm/mmu_context_iommu.c | 27 ++++++++++----------------
1 file changed, 11 insertions(+), 16 deletions(-)
--- a/arch/powerpc/mm/mmu_context_iommu.c~powerpc-mmu-drop-mmap_sem-now-that-locked_vm-is-atomic
+++ a/arch/powerpc/mm/mmu_context_iommu.c
@@ -54,34 +54,29 @@ struct mm_iommu_table_group_mem_t {
static long mm_iommu_adjust_locked_vm(struct mm_struct *mm,
unsigned long npages, bool incr)
{
- long ret = 0, locked, lock_limit;
+ long ret = 0;
+ unsigned long lock_limit;
s64 locked_vm;
if (!npages)
return 0;
- down_write(&mm->mmap_sem);
- locked_vm = atomic64_read(&mm->locked_vm);
if (incr) {
- locked = locked_vm + npages;
lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
- if (locked > lock_limit && !capable(CAP_IPC_LOCK))
+ locked_vm = atomic64_add_return(npages, &mm->locked_vm);
+ if (locked_vm > lock_limit && !capable(CAP_IPC_LOCK)) {
ret = -ENOMEM;
- else
- atomic64_add(npages, &mm->locked_vm);
+ atomic64_sub(npages, &mm->locked_vm);
+ }
} else {
- if (WARN_ON_ONCE(npages > locked_vm))
- npages = locked_vm;
- atomic64_sub(npages, &mm->locked_vm);
+ locked_vm = atomic64_sub_return(npages, &mm->locked_vm);
+ WARN_ON_ONCE(locked_vm < 0);
}
- pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%ld %ld/%ld\n",
- current ? current->pid : 0,
- incr ? '+' : '-',
- npages << PAGE_SHIFT,
- atomic64_read(&mm->locked_vm) << PAGE_SHIFT,
+ pr_debug("[%d] RLIMIT_MEMLOCK HASH64 %c%lu %lld/%lu\n",
+ current ? current->pid : 0, incr ? '+' : '-',
+ npages << PAGE_SHIFT, locked_vm << PAGE_SHIFT,
rlimit(RLIMIT_MEMLOCK));
- up_write(&mm->mmap_sem);
return ret;
}
_
Patches currently in -mm which might be from daniel.m.jordan@xxxxxxxxxx are
mm-change-locked_vms-type-from-unsigned-long-to-atomic64_t.patch
vfio-type1-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
vfio-spapr_tce-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
fpga-dlf-afu-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
powerpc-mmu-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
kvm-book3s-drop-mmap_sem-now-that-locked_vm-is-atomic.patch
