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s390/mm: simplify arch_get_unmapped_area[_topdown]

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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: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Martin Schwidefsky 2017-04-24 18:14:48 +02:00
parent ee71d16d22
commit 9b11c7912d
1 changed files with 35 additions and 60 deletions
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95
arch/s390/mm/mmap.c
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@ -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;
}
check_asce_limit:
if (addr + len > current->mm->context.asce_limit) {
rc = crst_table_upgrade(mm);
if (rc)
return (unsigned long) rc;
}
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. */
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;
}
/*
* 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;
}
}