From: Lorenzo Stoakes <lstoakes@gmail.com> To: linux-mm@kvack.org Cc: "Linus Torvalds" <torvalds@linux-foundation.org>, "Michal Hocko" <mhocko@kernel.org>, "Jan Kara" <jack@suse.cz>, "Hugh Dickins" <hughd@google.com>, "Dave Hansen" <dave.hansen@linux.intel.com>, "Rik van Riel" <riel@redhat.com>, "Mel Gorman" <mgorman@techsingularity.net>, "Andrew Morton" <akpm@linux-foundation.org>, "Paolo Bonzini" <pbonzini@redhat.com>, "Radim Krčmář" <rkrcmar@redhat.com>, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "Lorenzo Stoakes" <lstoakes@gmail.com> Subject: [PATCH] mm: unexport __get_user_pages() Date: Mon, 24 Oct 2016 10:57:25 +0100 [thread overview] Message-ID: <20161024095725.17229-1-lstoakes@gmail.com> (raw) This patch unexports the low-level __get_user_pages() function. Recent refactoring of the get_user_pages* functions allow flags to be passed through get_user_pages() which eliminates the need for access to this function from its one user, kvm. We can see that the 2 calls to get_user_pages() which replace __get_user_pages() in kvm_main.c are equivalent by examining their call stacks: get_user_page_nowait(): get_user_pages(start, 1, flags, page, NULL) __get_user_pages_locked(current, current->mm, start, 1, page, NULL, NULL, false, flags | FOLL_TOUCH) __get_user_pages(current, current->mm, start, 1, flags | FOLL_TOUCH | FOLL_GET, page, NULL, NULL) check_user_page_hwpoison(): get_user_pages(addr, 1, flags, NULL, NULL) __get_user_pages_locked(current, current->mm, addr, 1, NULL, NULL, NULL, false, flags | FOLL_TOUCH) __get_user_pages(current, current->mm, addr, 1, flags | FOLL_TOUCH, NULL, NULL, NULL) Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> --- include/linux/mm.h | 4 ---- mm/gup.c | 3 +-- mm/nommu.c | 2 +- virt/kvm/kvm_main.c | 10 ++++------ 4 files changed, 6 insertions(+), 13 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 3a19185..a92c8d7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1271,10 +1271,6 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void * extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags); -long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, - unsigned int foll_flags, struct page **pages, - struct vm_area_struct **vmas, int *nonblocking); long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, diff --git a/mm/gup.c b/mm/gup.c index 7aa113c..ec4f827 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -526,7 +526,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) * instead of __get_user_pages. __get_user_pages should be used only if * you need some special @gup_flags. */ -long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, +static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas, int *nonblocking) @@ -631,7 +631,6 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } while (nr_pages); return i; } -EXPORT_SYMBOL(__get_user_pages); bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) { diff --git a/mm/nommu.c b/mm/nommu.c index db5fd17..8b8faaf 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -109,7 +109,7 @@ unsigned int kobjsize(const void *objp) return PAGE_SIZE << compound_order(page); } -long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, +static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int foll_flags, struct page **pages, struct vm_area_struct **vmas, int *nonblocking) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 28510e7..2907b7b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1346,21 +1346,19 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w static int get_user_page_nowait(unsigned long start, int write, struct page **page) { - int flags = FOLL_TOUCH | FOLL_NOWAIT | FOLL_HWPOISON | FOLL_GET; + int flags = FOLL_NOWAIT | FOLL_HWPOISON; if (write) flags |= FOLL_WRITE; - return __get_user_pages(current, current->mm, start, 1, flags, page, - NULL, NULL); + return get_user_pages(start, 1, flags, page, NULL); } static inline int check_user_page_hwpoison(unsigned long addr) { - int rc, flags = FOLL_TOUCH | FOLL_HWPOISON | FOLL_WRITE; + int rc, flags = FOLL_HWPOISON | FOLL_WRITE; - rc = __get_user_pages(current, current->mm, addr, 1, - flags, NULL, NULL, NULL); + rc = get_user_pages(addr, 1, flags, NULL, NULL); return rc == -EHWPOISON; } -- 2.10.1
WARNING: multiple messages have this Message-ID (diff)
From: Lorenzo Stoakes <lstoakes@gmail.com> To: linux-mm@kvack.org Cc: "Linus Torvalds" <torvalds@linux-foundation.org>, "Michal Hocko" <mhocko@kernel.org>, "Jan Kara" <jack@suse.cz>, "Hugh Dickins" <hughd@google.com>, "Dave Hansen" <dave.hansen@linux.intel.com>, "Rik van Riel" <riel@redhat.com>, "Mel Gorman" <mgorman@techsingularity.net>, "Andrew Morton" <akpm@linux-foundation.org>, "Paolo Bonzini" <pbonzini@redhat.com>, "Radim Krčmář" <rkrcmar@redhat.com>, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, "Lorenzo Stoakes" <lstoakes@gmail.com> Subject: [PATCH] mm: unexport __get_user_pages() Date: Mon, 24 Oct 2016 10:57:25 +0100 [thread overview] Message-ID: <20161024095725.17229-1-lstoakes@gmail.com> (raw) This patch unexports the low-level __get_user_pages() function. Recent refactoring of the get_user_pages* functions allow flags to be passed through get_user_pages() which eliminates the need for access to this function from its one user, kvm. We can see that the 2 calls to get_user_pages() which replace __get_user_pages() in kvm_main.c are equivalent by examining their call stacks: get_user_page_nowait(): get_user_pages(start, 1, flags, page, NULL) __get_user_pages_locked(current, current->mm, start, 1, page, NULL, NULL, false, flags | FOLL_TOUCH) __get_user_pages(current, current->mm, start, 1, flags | FOLL_TOUCH | FOLL_GET, page, NULL, NULL) check_user_page_hwpoison(): get_user_pages(addr, 1, flags, NULL, NULL) __get_user_pages_locked(current, current->mm, addr, 1, NULL, NULL, NULL, false, flags | FOLL_TOUCH) __get_user_pages(current, current->mm, addr, 1, flags | FOLL_TOUCH, NULL, NULL, NULL) Signed-off-by: Lorenzo Stoakes <lstoakes@gmail.com> --- include/linux/mm.h | 4 ---- mm/gup.c | 3 +-- mm/nommu.c | 2 +- virt/kvm/kvm_main.c | 10 ++++------ 4 files changed, 6 insertions(+), 13 deletions(-) diff --git a/include/linux/mm.h b/include/linux/mm.h index 3a19185..a92c8d7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1271,10 +1271,6 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void * extern int access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf, int len, unsigned int gup_flags); -long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, - unsigned long start, unsigned long nr_pages, - unsigned int foll_flags, struct page **pages, - struct vm_area_struct **vmas, int *nonblocking); long get_user_pages_remote(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, diff --git a/mm/gup.c b/mm/gup.c index 7aa113c..ec4f827 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -526,7 +526,7 @@ static int check_vma_flags(struct vm_area_struct *vma, unsigned long gup_flags) * instead of __get_user_pages. __get_user_pages should be used only if * you need some special @gup_flags. */ -long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, +static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int gup_flags, struct page **pages, struct vm_area_struct **vmas, int *nonblocking) @@ -631,7 +631,6 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, } while (nr_pages); return i; } -EXPORT_SYMBOL(__get_user_pages); bool vma_permits_fault(struct vm_area_struct *vma, unsigned int fault_flags) { diff --git a/mm/nommu.c b/mm/nommu.c index db5fd17..8b8faaf 100644 --- a/mm/nommu.c +++ b/mm/nommu.c @@ -109,7 +109,7 @@ unsigned int kobjsize(const void *objp) return PAGE_SIZE << compound_order(page); } -long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, +static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm, unsigned long start, unsigned long nr_pages, unsigned int foll_flags, struct page **pages, struct vm_area_struct **vmas, int *nonblocking) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 28510e7..2907b7b 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -1346,21 +1346,19 @@ unsigned long kvm_vcpu_gfn_to_hva_prot(struct kvm_vcpu *vcpu, gfn_t gfn, bool *w static int get_user_page_nowait(unsigned long start, int write, struct page **page) { - int flags = FOLL_TOUCH | FOLL_NOWAIT | FOLL_HWPOISON | FOLL_GET; + int flags = FOLL_NOWAIT | FOLL_HWPOISON; if (write) flags |= FOLL_WRITE; - return __get_user_pages(current, current->mm, start, 1, flags, page, - NULL, NULL); + return get_user_pages(start, 1, flags, page, NULL); } static inline int check_user_page_hwpoison(unsigned long addr) { - int rc, flags = FOLL_TOUCH | FOLL_HWPOISON | FOLL_WRITE; + int rc, flags = FOLL_HWPOISON | FOLL_WRITE; - rc = __get_user_pages(current, current->mm, addr, 1, - flags, NULL, NULL, NULL); + rc = get_user_pages(addr, 1, flags, NULL, NULL); return rc == -EHWPOISON; } -- 2.10.1 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next reply other threads:[~2016-10-24 9:57 UTC|newest] Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-10-24 9:57 Lorenzo Stoakes [this message] 2016-10-24 9:57 ` [PATCH] mm: unexport __get_user_pages() Lorenzo Stoakes 2016-10-24 11:15 ` Paolo Bonzini 2016-10-24 11:15 ` Paolo Bonzini 2016-10-24 13:01 ` Michal Hocko 2016-10-24 13:01 ` Michal Hocko
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