Commit 8b7457ef authored by Lorenzo Stoakes's avatar Lorenzo Stoakes Committed by Linus Torvalds
Browse files

mm: unexport __get_user_pages_unlocked() 

Unexport the low-level __get_user_pages_unlocked() function and replaces
invocations with calls to more appropriate higher-level functions.

In hva_to_pfn_slow() we are able to replace __get_user_pages_unlocked()
with get_user_pages_unlocked() since we can now pass gup_flags.

In async_pf_execute() and process_vm_rw_single_vec() we need to pass
different tsk, mm arguments so get_user_pages_remote() is the sane
replacement in these cases (having added manual acquisition and release
of mmap_sem.)

Additionally get_user_pages_remote() reintroduces use of the FOLL_TOUCH
flag.  However, this flag was originally silently dropped by commit
1e987790 ("mm/gup: Introduce get_user_pages_remote()"), so this
appears to have been unintentional and reintroducing it is therefore not
an issue.

[akpm@linux-foundation.org: coding-style fixes]
Link: http://lkml.kernel.org/r/20161027095141.2569-3-lstoakes@gmail.com


Signed-off-by: default avatarLorenzo Stoakes <lstoakes@gmail.com>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 5b56d49f

include/linux/mm.h

+0 −3
Original line number Diff line number Diff line
@@ -1280,9 +1280,6 @@ long get_user_pages(unsigned long start, unsigned long nr_pages, 
			    struct vm_area_struct **vmas);

long get_user_pages_locked(unsigned long start, unsigned long nr_pages,

		    unsigned int gup_flags, struct page **pages, int *locked);

long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,

			       unsigned long start, unsigned long nr_pages,

			       struct page **pages, unsigned int gup_flags);

long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,

		    struct page **pages, unsigned int gup_flags);

int get_user_pages_fast(unsigned long start, int nr_pages, int write,

mm/gup.c

+4 −4
Original line number Diff line number Diff line
@@ -865,9 +865,10 @@ EXPORT_SYMBOL(get_user_pages_locked); 
 * caller if required (just like with __get_user_pages). "FOLL_GET"

 * is set implicitly if "pages" is non-NULL.

 */

__always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,

					       unsigned long start, unsigned long nr_pages,

					       struct page **pages, unsigned int gup_flags)

static __always_inline long __get_user_pages_unlocked(struct task_struct *tsk,

		struct mm_struct *mm, unsigned long start,

		unsigned long nr_pages, struct page **pages,

		unsigned int gup_flags)

{

	long ret;

	int locked = 1;
@@ -879,7 +880,6 @@ __always_inline long __get_user_pages_unlocked(struct task_struct *tsk, struct m 
		up_read(&mm->mmap_sem);

	return ret;

}

EXPORT_SYMBOL(__get_user_pages_unlocked);



/*

 * get_user_pages_unlocked() is suitable to replace the form:

mm/nommu.c

+4 −4
Original line number Diff line number Diff line
@@ -176,9 +176,10 @@ long get_user_pages_locked(unsigned long start, unsigned long nr_pages, 
}

EXPORT_SYMBOL(get_user_pages_locked);



long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm,

			       unsigned long start, unsigned long nr_pages,

			       struct page **pages, unsigned int gup_flags)

static long __get_user_pages_unlocked(struct task_struct *tsk,

			struct mm_struct *mm, unsigned long start,

			unsigned long nr_pages, struct page **pages,

			unsigned int gup_flags)

{

	long ret;

	down_read(&mm->mmap_sem);
@@ -187,7 +188,6 @@ long __get_user_pages_unlocked(struct task_struct *tsk, struct mm_struct *mm, 
	up_read(&mm->mmap_sem);

	return ret;

}

EXPORT_SYMBOL(__get_user_pages_unlocked);



long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages,

			     struct page **pages, unsigned int gup_flags)

mm/process_vm_access.c

+8 −4
Original line number Diff line number Diff line
@@ -88,7 +88,7 @@ static int process_vm_rw_single_vec(unsigned long addr, 
	ssize_t rc = 0;

	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES

		/ sizeof(struct pages *);

	unsigned int flags = FOLL_REMOTE;

	unsigned int flags = 0;



	/* Work out address and page range required */

	if (len == 0)
@@ -100,15 +100,19 @@ static int process_vm_rw_single_vec(unsigned long addr, 


	while (!rc && nr_pages && iov_iter_count(iter)) {

		int pages = min(nr_pages, max_pages_per_loop);

		int locked = 1;

		size_t bytes;



		/*

		 * Get the pages we're interested in.  We must

		 * add FOLL_REMOTE because task/mm might not

		 * access remotely because task/mm might not

		 * current/current->mm

		 */

		pages = __get_user_pages_unlocked(task, mm, pa, pages,

						  process_pages, flags);

		down_read(&mm->mmap_sem);

		pages = get_user_pages_remote(task, mm, pa, pages, flags,

					      process_pages, NULL, &locked);

		if (locked)

			up_read(&mm->mmap_sem);

		if (pages <= 0)

			return -EFAULT;

virt/kvm/async_pf.c

+7 −3
Original line number Diff line number Diff line
@@ -76,16 +76,20 @@ static void async_pf_execute(struct work_struct *work) 
	struct kvm_vcpu *vcpu = apf->vcpu;

	unsigned long addr = apf->addr;

	gva_t gva = apf->gva;

	int locked = 1;



	might_sleep();



	/*

	 * This work is run asynchromously to the task which owns

	 * mm and might be done in another context, so we must

	 * use FOLL_REMOTE.

	 * access remotely.

	 */

	__get_user_pages_unlocked(NULL, mm, addr, 1, NULL,

			FOLL_WRITE | FOLL_REMOTE);

	down_read(&mm->mmap_sem);

	get_user_pages_remote(NULL, mm, addr, 1, FOLL_WRITE, NULL, NULL,

			&locked);

	if (locked)

		up_read(&mm->mmap_sem);



	kvm_async_page_present_sync(vcpu, apf);

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