Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 9b11c791 authored by Martin Schwidefsky's avatar Martin Schwidefsky
Browse files

s390/mm: simplify arch_get_unmapped_area[_topdown] 



With TASK_SIZE now reflecting the maximum size of the address space for
a process the code for arch_get_unmapped_area[_topdown] can be simplified.
Just let the logic pick a suitable address and deal with the page table
upgrade after the address has been selected.

Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent ee71d16d

arch/s390/mm/mmap.c

+32 −57
Original line number Diff line number Diff line
@@ -89,32 +89,43 @@ arch_get_unmapped_area(struct file *filp, unsigned long addr, 
	struct mm_struct *mm = current->mm;

	struct vm_area_struct *vma;

	struct vm_unmapped_area_info info;

	int rc;



	if (len > mm->context.asce_limit - mmap_min_addr)

	if (len > TASK_SIZE - mmap_min_addr)

		return -ENOMEM;



	if (flags & MAP_FIXED)

		return addr;

		goto check_asce_limit;



	if (addr) {

		addr = PAGE_ALIGN(addr);

		vma = find_vma(mm, addr);

		if (mm->context.asce_limit - len >= addr &&

		    addr >= mmap_min_addr &&

		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&

		    (!vma || addr + len <= vma->vm_start))

			return addr;

			goto check_asce_limit;

	}



	info.flags = 0;

	info.length = len;

	info.low_limit = mm->mmap_base;

	info.high_limit = mm->context.asce_limit;

	info.high_limit = TASK_SIZE;

	if (filp || (flags & MAP_SHARED))

		info.align_mask = MMAP_ALIGN_MASK << PAGE_SHIFT;

	else

		info.align_mask = 0;

	info.align_offset = pgoff << PAGE_SHIFT;

	return vm_unmapped_area(&info);

	addr = vm_unmapped_area(&info);

	if (addr & ~PAGE_MASK)

		return addr;



check_asce_limit:

	if (addr + len > current->mm->context.asce_limit) {

		rc = crst_table_upgrade(mm);

		if (rc)

			return (unsigned long) rc;

	}



	return addr;

}



unsigned long
@@ -126,22 +137,22 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
	struct mm_struct *mm = current->mm;

	unsigned long addr = addr0;

	struct vm_unmapped_area_info info;

	int rc;



	/* requested length too big for entire address space */

	if (len > mm->context.asce_limit - mmap_min_addr)

	if (len > TASK_SIZE - mmap_min_addr)

		return -ENOMEM;



	if (flags & MAP_FIXED)

		return addr;

		goto check_asce_limit;



	/* requesting a specific address */

	if (addr) {

		addr = PAGE_ALIGN(addr);

		vma = find_vma(mm, addr);

		if (mm->context.asce_limit - len >= addr &&

		    addr >= mmap_min_addr &&

		if (TASK_SIZE - len >= addr && addr >= mmap_min_addr &&

				(!vma || addr + len <= vma->vm_start))

			return addr;

			goto check_asce_limit;

	}



	info.flags = VM_UNMAPPED_AREA_TOPDOWN;
@@ -165,58 +176,22 @@ arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0, 
		VM_BUG_ON(addr != -ENOMEM);

		info.flags = 0;

		info.low_limit = TASK_UNMAPPED_BASE;

		info.high_limit = mm->context.asce_limit;

		info.high_limit = TASK_SIZE;

		addr = vm_unmapped_area(&info);

	}



		if (addr & ~PAGE_MASK)

			return addr;

	}



static unsigned long

s390_get_unmapped_area(struct file *filp, unsigned long addr,

		unsigned long len, unsigned long pgoff, unsigned long flags)

{

	struct mm_struct *mm = current->mm;

	unsigned long area;

	int rc;



	area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);

	if (!(area & ~PAGE_MASK))

		return area;

	if (area == -ENOMEM && !is_compat_task() &&

	    current->mm->context.asce_limit < TASK_SIZE_MAX) {

		/* Upgrade the page table to 4 levels and retry. */

check_asce_limit:

	if (addr + len > current->mm->context.asce_limit) {

		rc = crst_table_upgrade(mm);

		if (rc)

			return (unsigned long) rc;

		area = arch_get_unmapped_area(filp, addr, len, pgoff, flags);

	}

	return area;

	}



static unsigned long

s390_get_unmapped_area_topdown(struct file *filp, const unsigned long addr,

			  const unsigned long len, const unsigned long pgoff,

			  const unsigned long flags)

{

	struct mm_struct *mm = current->mm;

	unsigned long area;

	int rc;



	area = arch_get_unmapped_area_topdown(filp, addr, len, pgoff, flags);

	if (!(area & ~PAGE_MASK))

		return area;

	if (area == -ENOMEM && !is_compat_task() &&

	    current->mm->context.asce_limit < TASK_SIZE_MAX) {

		/* Upgrade the page table to 4 levels and retry. */

		rc = crst_table_upgrade(mm);

		if (rc)

			return (unsigned long) rc;

		area = arch_get_unmapped_area_topdown(filp, addr, len,

						      pgoff, flags);

	}

	return area;

	return addr;

}



/*

 * This function, called very early during the creation of a new

 * process VM image, sets up which VM layout function to use:
@@ -234,9 +209,9 @@ void arch_pick_mmap_layout(struct mm_struct *mm) 
	 */

	if (mmap_is_legacy()) {

		mm->mmap_base = mmap_base_legacy(random_factor);

		mm->get_unmapped_area = s390_get_unmapped_area;

		mm->get_unmapped_area = arch_get_unmapped_area;

	} else {

		mm->mmap_base = mmap_base(random_factor);

		mm->get_unmapped_area = s390_get_unmapped_area_topdown;

		mm->get_unmapped_area = arch_get_unmapped_area_topdown;

	}

}