From 9b11c7912d00d0e5fe0d7f8973b77dac4f69d3df Mon Sep 17 00:00:00 2001 From: Martin Schwidefsky Date: Mon, 24 Apr 2017 18:14:48 +0200 Subject: [PATCH] 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: Martin Schwidefsky --- arch/s390/mm/mmap.c | 95 +++++++++++++++++---------------------------- 1 file changed, 35 insertions(+), 60 deletions(-) diff --git a/arch/s390/mm/mmap.c b/arch/s390/mm/mmap.c index eed233ce59dd..b017daed6887 100644 --- a/arch/s390/mm/mmap.c +++ b/arch/s390/mm/mmap.c @@ -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; } }