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90794bf19d
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>
111 lines
2.8 KiB
C
111 lines
2.8 KiB
C
/*
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* include/linux/userfaultfd_k.h
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*
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* Copyright (C) 2015 Red Hat, Inc.
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*
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*/
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#ifndef _LINUX_USERFAULTFD_K_H
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#define _LINUX_USERFAULTFD_K_H
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#ifdef CONFIG_USERFAULTFD
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#include <linux/userfaultfd.h> /* linux/include/uapi/linux/userfaultfd.h */
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#include <linux/fcntl.h>
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/*
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* CAREFUL: Check include/uapi/asm-generic/fcntl.h when defining
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* new flags, since they might collide with O_* ones. We want
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* to re-use O_* flags that couldn't possibly have a meaning
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* from userfaultfd, in order to leave a free define-space for
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* shared O_* flags.
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*/
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#define UFFD_CLOEXEC O_CLOEXEC
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#define UFFD_NONBLOCK O_NONBLOCK
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#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
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#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
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extern int handle_userfault(struct vm_fault *vmf, unsigned long reason);
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extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
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unsigned long src_start, unsigned long len);
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extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
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unsigned long dst_start,
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unsigned long len);
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/* mm helpers */
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static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
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struct vm_userfaultfd_ctx vm_ctx)
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{
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return vma->vm_userfaultfd_ctx.ctx == vm_ctx.ctx;
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}
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static inline bool userfaultfd_missing(struct vm_area_struct *vma)
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{
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return vma->vm_flags & VM_UFFD_MISSING;
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}
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static inline bool userfaultfd_armed(struct vm_area_struct *vma)
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{
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return vma->vm_flags & (VM_UFFD_MISSING | VM_UFFD_WP);
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}
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extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
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extern void dup_userfaultfd_complete(struct list_head *);
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extern void mremap_userfaultfd_prep(struct vm_area_struct *,
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struct vm_userfaultfd_ctx *);
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extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,
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unsigned long from, unsigned long to,
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unsigned long len);
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#else /* CONFIG_USERFAULTFD */
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/* mm helpers */
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static inline int handle_userfault(struct vm_fault *vmf, unsigned long reason)
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{
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return VM_FAULT_SIGBUS;
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}
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static inline bool is_mergeable_vm_userfaultfd_ctx(struct vm_area_struct *vma,
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struct vm_userfaultfd_ctx vm_ctx)
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{
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return true;
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}
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static inline bool userfaultfd_missing(struct vm_area_struct *vma)
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{
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return false;
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}
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static inline bool userfaultfd_armed(struct vm_area_struct *vma)
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{
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return false;
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}
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static inline int dup_userfaultfd(struct vm_area_struct *vma,
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struct list_head *l)
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{
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return 0;
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}
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static inline void dup_userfaultfd_complete(struct list_head *l)
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{
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}
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static inline void mremap_userfaultfd_prep(struct vm_area_struct *vma,
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struct vm_userfaultfd_ctx *ctx)
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{
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}
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static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,
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unsigned long from,
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unsigned long to,
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unsigned long len)
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{
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}
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#endif /* CONFIG_USERFAULTFD */
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#endif /* _LINUX_USERFAULTFD_K_H */
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