From 90794bf19dc19691a16b71bcd75c04094d9e392d Mon Sep 17 00:00:00 2001
From: Andrea Arcangeli <aarcange@redhat.com>
Date: Wed, 22 Feb 2017 15:42:37 -0800
Subject: [PATCH] userfaultfd: non-cooperative: optimize
mremap_userfaultfd_complete()
Optimize the mremap_userfaultfd_complete() interface to pass only the
vm_userfaultfd_ctx pointer through the stack as a microoptimization.
Link: http://lkml.kernel.org/r/20161216144821.5183-13-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Michael Rapoport <RAPOPORT@il.ibm.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
fs/userfaultfd.c | 4 ++--
include/linux/userfaultfd_k.h | 4 ++--
mm/mremap.c | 2 +-
3 files changed, 5 insertions(+), 5 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 68f978beefac1..5d37c37854b09 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -608,11 +608,11 @@ void mremap_userfaultfd_prep(struct vm_area_struct *vma,
}
}
-void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx vm_ctx,
+void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
unsigned long from, unsigned long to,
unsigned long len)
{
- struct userfaultfd_ctx *ctx = vm_ctx.ctx;
+ struct userfaultfd_ctx *ctx = vm_ctx->ctx;
struct userfaultfd_wait_queue ewq;
if (!ctx)
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 7f318a46044b0..78ec197e8b47e 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -57,7 +57,7 @@ extern void dup_userfaultfd_complete(struct list_head *);
extern void mremap_userfaultfd_prep(struct vm_area_struct *,
struct vm_userfaultfd_ctx *);
-extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx,
+extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
unsigned long from, unsigned long to,
unsigned long len);
@@ -100,7 +100,7 @@ static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
{
}
-static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx ctx,
+static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
unsigned long from,
unsigned long to,
unsigned long len)
diff --git a/mm/mremap.c b/mm/mremap.c
index 504b560c013cb..8779928d6a702 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -608,6 +608,6 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
up_write(¤t->mm->mmap_sem);
if (locked && new_len > old_len)
mm_populate(new_addr + old_len, new_len - old_len);
- mremap_userfaultfd_complete(uf, addr, new_addr, old_len);
+ mremap_userfaultfd_complete(&uf, addr, new_addr, old_len);
return ret;
}
--
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