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Commit 01997bbc authored by Heiko Carstens's avatar Heiko Carstens Committed by Martin Schwidefsky
Browse files

s390/gup: reduce code duplication between [__]get_user_pages_fast functions 



Just call __get_user_pages_fast() from get_user_pages_fast() like powerpc.
This saves a lot of duplicated code.

Reviewed-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 127c1fef

arch/s390/mm/gup.c

+23 −58
Original line number Diff line number Diff line
@@ -182,7 +182,13 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, 
	end = start + len;

	if ((end < start) || (end > TASK_SIZE))

		return 0;



	/*

	 * local_irq_save() doesn't prevent pagetable teardown, but does

	 * prevent the pagetables from being freed on s390.

	 *

	 * So long as we atomically load page table pointers versus teardown,

	 * we can follow the address down to the the page and take a ref on it.

	 */

	local_irq_save(flags);

	pgdp = pgd_offset(mm, addr);

	do {
@@ -219,63 +225,22 @@ int get_user_pages_fast(unsigned long start, int nr_pages, int write, 
			struct page **pages)

{

	struct mm_struct *mm = current->mm;

	unsigned long addr, len, end;

	unsigned long next;

	pgd_t *pgdp, pgd;

	int nr = 0;

	int nr, ret;



	start &= PAGE_MASK;

	addr = start;

	len = (unsigned long) nr_pages << PAGE_SHIFT;

	end = start + len;

	if ((end < start) || (end > TASK_SIZE))

		goto slow_irqon;



	/*

	 * local_irq_disable() doesn't prevent pagetable teardown, but does

	 * prevent the pagetables from being freed on s390.

	 *

	 * So long as we atomically load page table pointers versus teardown,

	 * we can follow the address down to the the page and take a ref on it.

	 */

	local_irq_disable();

	pgdp = pgd_offset(mm, addr);

	do {

		pgd = *pgdp;

		barrier();

		next = pgd_addr_end(addr, end);

		if (pgd_none(pgd))

			goto slow;

		if (!gup_pud_range(pgdp, pgd, addr, next, write, pages, &nr))

			goto slow;

	} while (pgdp++, addr = next, addr != end);

	local_irq_enable();



	VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT);

	nr = __get_user_pages_fast(start, nr_pages, write, pages);

	if (nr == nr_pages)

		return nr;



	{

		int ret;

slow:

		local_irq_enable();

slow_irqon:

	/* Try to get the remaining pages with get_user_pages */

	start += nr << PAGE_SHIFT;

	pages += nr;



	down_read(&mm->mmap_sem);

	ret = get_user_pages(current, mm, start,

			(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);

			     nr_pages - nr, write, 0, pages, NULL);

	up_read(&mm->mmap_sem);



	/* Have to be a bit careful with return values */

		if (nr > 0) {

			if (ret < 0)

				ret = nr;

			else

				ret += nr;

		}



	if (nr > 0)

		ret = (ret < 0) ? nr : ret + nr;

	return ret;

}
 
}