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![Tejun Heo](/assets/img/avatar_default.png)
percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
520 lines
13 KiB
C
520 lines
13 KiB
C
/*
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* mm/mremap.c
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*
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* (C) Copyright 1996 Linus Torvalds
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*
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* Address space accounting code <alan@lxorguk.ukuu.org.uk>
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* (C) Copyright 2002 Red Hat Inc, All Rights Reserved
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*/
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#include <linux/mm.h>
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#include <linux/hugetlb.h>
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#include <linux/shm.h>
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#include <linux/ksm.h>
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#include <linux/mman.h>
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#include <linux/swap.h>
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#include <linux/capability.h>
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#include <linux/fs.h>
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#include <linux/highmem.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/mmu_notifier.h>
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#include <asm/uaccess.h>
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#include <asm/cacheflush.h>
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#include <asm/tlbflush.h>
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#include "internal.h"
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static pmd_t *get_old_pmd(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pgd = pgd_offset(mm, addr);
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if (pgd_none_or_clear_bad(pgd))
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return NULL;
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pud = pud_offset(pgd, addr);
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if (pud_none_or_clear_bad(pud))
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return NULL;
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pmd = pmd_offset(pud, addr);
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if (pmd_none_or_clear_bad(pmd))
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return NULL;
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return pmd;
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}
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static pmd_t *alloc_new_pmd(struct mm_struct *mm, unsigned long addr)
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{
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pgd_t *pgd;
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pud_t *pud;
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pmd_t *pmd;
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pgd = pgd_offset(mm, addr);
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pud = pud_alloc(mm, pgd, addr);
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if (!pud)
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return NULL;
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pmd = pmd_alloc(mm, pud, addr);
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if (!pmd)
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return NULL;
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if (!pmd_present(*pmd) && __pte_alloc(mm, pmd, addr))
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return NULL;
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return pmd;
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}
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static void move_ptes(struct vm_area_struct *vma, pmd_t *old_pmd,
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unsigned long old_addr, unsigned long old_end,
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struct vm_area_struct *new_vma, pmd_t *new_pmd,
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unsigned long new_addr)
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{
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struct address_space *mapping = NULL;
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struct mm_struct *mm = vma->vm_mm;
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pte_t *old_pte, *new_pte, pte;
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spinlock_t *old_ptl, *new_ptl;
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unsigned long old_start;
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old_start = old_addr;
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mmu_notifier_invalidate_range_start(vma->vm_mm,
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old_start, old_end);
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if (vma->vm_file) {
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/*
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* Subtle point from Rajesh Venkatasubramanian: before
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* moving file-based ptes, we must lock truncate_pagecache
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* out, since it might clean the dst vma before the src vma,
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* and we propagate stale pages into the dst afterward.
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*/
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mapping = vma->vm_file->f_mapping;
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spin_lock(&mapping->i_mmap_lock);
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if (new_vma->vm_truncate_count &&
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new_vma->vm_truncate_count != vma->vm_truncate_count)
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new_vma->vm_truncate_count = 0;
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}
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/*
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* We don't have to worry about the ordering of src and dst
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* pte locks because exclusive mmap_sem prevents deadlock.
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*/
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old_pte = pte_offset_map_lock(mm, old_pmd, old_addr, &old_ptl);
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new_pte = pte_offset_map_nested(new_pmd, new_addr);
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new_ptl = pte_lockptr(mm, new_pmd);
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if (new_ptl != old_ptl)
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spin_lock_nested(new_ptl, SINGLE_DEPTH_NESTING);
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arch_enter_lazy_mmu_mode();
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for (; old_addr < old_end; old_pte++, old_addr += PAGE_SIZE,
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new_pte++, new_addr += PAGE_SIZE) {
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if (pte_none(*old_pte))
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continue;
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pte = ptep_clear_flush(vma, old_addr, old_pte);
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pte = move_pte(pte, new_vma->vm_page_prot, old_addr, new_addr);
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set_pte_at(mm, new_addr, new_pte, pte);
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}
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arch_leave_lazy_mmu_mode();
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if (new_ptl != old_ptl)
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spin_unlock(new_ptl);
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pte_unmap_nested(new_pte - 1);
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pte_unmap_unlock(old_pte - 1, old_ptl);
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if (mapping)
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spin_unlock(&mapping->i_mmap_lock);
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mmu_notifier_invalidate_range_end(vma->vm_mm, old_start, old_end);
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}
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#define LATENCY_LIMIT (64 * PAGE_SIZE)
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unsigned long move_page_tables(struct vm_area_struct *vma,
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unsigned long old_addr, struct vm_area_struct *new_vma,
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unsigned long new_addr, unsigned long len)
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{
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unsigned long extent, next, old_end;
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pmd_t *old_pmd, *new_pmd;
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old_end = old_addr + len;
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flush_cache_range(vma, old_addr, old_end);
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for (; old_addr < old_end; old_addr += extent, new_addr += extent) {
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cond_resched();
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next = (old_addr + PMD_SIZE) & PMD_MASK;
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if (next - 1 > old_end)
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next = old_end;
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extent = next - old_addr;
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old_pmd = get_old_pmd(vma->vm_mm, old_addr);
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if (!old_pmd)
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continue;
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new_pmd = alloc_new_pmd(vma->vm_mm, new_addr);
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if (!new_pmd)
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break;
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next = (new_addr + PMD_SIZE) & PMD_MASK;
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if (extent > next - new_addr)
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extent = next - new_addr;
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if (extent > LATENCY_LIMIT)
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extent = LATENCY_LIMIT;
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move_ptes(vma, old_pmd, old_addr, old_addr + extent,
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new_vma, new_pmd, new_addr);
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}
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return len + old_addr - old_end; /* how much done */
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}
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static unsigned long move_vma(struct vm_area_struct *vma,
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unsigned long old_addr, unsigned long old_len,
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unsigned long new_len, unsigned long new_addr)
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{
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struct mm_struct *mm = vma->vm_mm;
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struct vm_area_struct *new_vma;
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unsigned long vm_flags = vma->vm_flags;
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unsigned long new_pgoff;
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unsigned long moved_len;
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unsigned long excess = 0;
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unsigned long hiwater_vm;
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int split = 0;
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int err;
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/*
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* We'd prefer to avoid failure later on in do_munmap:
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* which may split one vma into three before unmapping.
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*/
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if (mm->map_count >= sysctl_max_map_count - 3)
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return -ENOMEM;
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/*
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* Advise KSM to break any KSM pages in the area to be moved:
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* it would be confusing if they were to turn up at the new
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* location, where they happen to coincide with different KSM
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* pages recently unmapped. But leave vma->vm_flags as it was,
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* so KSM can come around to merge on vma and new_vma afterwards.
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*/
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err = ksm_madvise(vma, old_addr, old_addr + old_len,
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MADV_UNMERGEABLE, &vm_flags);
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if (err)
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return err;
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new_pgoff = vma->vm_pgoff + ((old_addr - vma->vm_start) >> PAGE_SHIFT);
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new_vma = copy_vma(&vma, new_addr, new_len, new_pgoff);
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if (!new_vma)
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return -ENOMEM;
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moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len);
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if (moved_len < old_len) {
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/*
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* On error, move entries back from new area to old,
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* which will succeed since page tables still there,
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* and then proceed to unmap new area instead of old.
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*/
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move_page_tables(new_vma, new_addr, vma, old_addr, moved_len);
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vma = new_vma;
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old_len = new_len;
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old_addr = new_addr;
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new_addr = -ENOMEM;
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}
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/* Conceal VM_ACCOUNT so old reservation is not undone */
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if (vm_flags & VM_ACCOUNT) {
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vma->vm_flags &= ~VM_ACCOUNT;
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excess = vma->vm_end - vma->vm_start - old_len;
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if (old_addr > vma->vm_start &&
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old_addr + old_len < vma->vm_end)
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split = 1;
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}
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/*
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* If we failed to move page tables we still do total_vm increment
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* since do_munmap() will decrement it by old_len == new_len.
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*
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* Since total_vm is about to be raised artificially high for a
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* moment, we need to restore high watermark afterwards: if stats
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* are taken meanwhile, total_vm and hiwater_vm appear too high.
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* If this were a serious issue, we'd add a flag to do_munmap().
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*/
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hiwater_vm = mm->hiwater_vm;
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mm->total_vm += new_len >> PAGE_SHIFT;
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vm_stat_account(mm, vma->vm_flags, vma->vm_file, new_len>>PAGE_SHIFT);
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if (do_munmap(mm, old_addr, old_len) < 0) {
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/* OOM: unable to split vma, just get accounts right */
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vm_unacct_memory(excess >> PAGE_SHIFT);
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excess = 0;
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}
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mm->hiwater_vm = hiwater_vm;
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/* Restore VM_ACCOUNT if one or two pieces of vma left */
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if (excess) {
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vma->vm_flags |= VM_ACCOUNT;
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if (split)
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vma->vm_next->vm_flags |= VM_ACCOUNT;
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}
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if (vm_flags & VM_LOCKED) {
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mm->locked_vm += new_len >> PAGE_SHIFT;
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if (new_len > old_len)
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mlock_vma_pages_range(new_vma, new_addr + old_len,
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new_addr + new_len);
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}
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return new_addr;
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}
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static struct vm_area_struct *vma_to_resize(unsigned long addr,
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unsigned long old_len, unsigned long new_len, unsigned long *p)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma = find_vma(mm, addr);
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if (!vma || vma->vm_start > addr)
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goto Efault;
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if (is_vm_hugetlb_page(vma))
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goto Einval;
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/* We can't remap across vm area boundaries */
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if (old_len > vma->vm_end - addr)
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goto Efault;
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if (vma->vm_flags & (VM_DONTEXPAND | VM_PFNMAP)) {
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if (new_len > old_len)
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goto Efault;
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}
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if (vma->vm_flags & VM_LOCKED) {
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unsigned long locked, lock_limit;
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locked = mm->locked_vm << PAGE_SHIFT;
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lock_limit = rlimit(RLIMIT_MEMLOCK);
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locked += new_len - old_len;
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if (locked > lock_limit && !capable(CAP_IPC_LOCK))
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goto Eagain;
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}
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if (!may_expand_vm(mm, (new_len - old_len) >> PAGE_SHIFT))
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goto Enomem;
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if (vma->vm_flags & VM_ACCOUNT) {
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unsigned long charged = (new_len - old_len) >> PAGE_SHIFT;
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if (security_vm_enough_memory(charged))
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goto Efault;
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*p = charged;
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}
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return vma;
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Efault: /* very odd choice for most of the cases, but... */
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return ERR_PTR(-EFAULT);
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Einval:
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return ERR_PTR(-EINVAL);
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Enomem:
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return ERR_PTR(-ENOMEM);
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Eagain:
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return ERR_PTR(-EAGAIN);
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}
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static unsigned long mremap_to(unsigned long addr,
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unsigned long old_len, unsigned long new_addr,
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unsigned long new_len)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long ret = -EINVAL;
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unsigned long charged = 0;
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unsigned long map_flags;
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if (new_addr & ~PAGE_MASK)
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goto out;
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if (new_len > TASK_SIZE || new_addr > TASK_SIZE - new_len)
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goto out;
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/* Check if the location we're moving into overlaps the
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* old location at all, and fail if it does.
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*/
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if ((new_addr <= addr) && (new_addr+new_len) > addr)
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goto out;
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if ((addr <= new_addr) && (addr+old_len) > new_addr)
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goto out;
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ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
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if (ret)
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goto out;
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ret = do_munmap(mm, new_addr, new_len);
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if (ret)
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goto out;
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if (old_len >= new_len) {
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ret = do_munmap(mm, addr+new_len, old_len - new_len);
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if (ret && old_len != new_len)
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goto out;
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old_len = new_len;
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}
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vma = vma_to_resize(addr, old_len, new_len, &charged);
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if (IS_ERR(vma)) {
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ret = PTR_ERR(vma);
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goto out;
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}
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map_flags = MAP_FIXED;
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if (vma->vm_flags & VM_MAYSHARE)
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map_flags |= MAP_SHARED;
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ret = get_unmapped_area(vma->vm_file, new_addr, new_len, vma->vm_pgoff +
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((addr - vma->vm_start) >> PAGE_SHIFT),
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map_flags);
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if (ret & ~PAGE_MASK)
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goto out1;
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ret = move_vma(vma, addr, old_len, new_len, new_addr);
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if (!(ret & ~PAGE_MASK))
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goto out;
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out1:
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vm_unacct_memory(charged);
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out:
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return ret;
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}
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static int vma_expandable(struct vm_area_struct *vma, unsigned long delta)
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{
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unsigned long end = vma->vm_end + delta;
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if (end < vma->vm_end) /* overflow */
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return 0;
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if (vma->vm_next && vma->vm_next->vm_start < end) /* intersection */
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return 0;
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if (get_unmapped_area(NULL, vma->vm_start, end - vma->vm_start,
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0, MAP_FIXED) & ~PAGE_MASK)
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return 0;
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return 1;
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}
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/*
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* Expand (or shrink) an existing mapping, potentially moving it at the
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* same time (controlled by the MREMAP_MAYMOVE flag and available VM space)
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*
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* MREMAP_FIXED option added 5-Dec-1999 by Benjamin LaHaise
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* This option implies MREMAP_MAYMOVE.
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*/
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unsigned long do_mremap(unsigned long addr,
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unsigned long old_len, unsigned long new_len,
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unsigned long flags, unsigned long new_addr)
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{
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struct mm_struct *mm = current->mm;
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struct vm_area_struct *vma;
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unsigned long ret = -EINVAL;
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unsigned long charged = 0;
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if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
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goto out;
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if (addr & ~PAGE_MASK)
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goto out;
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old_len = PAGE_ALIGN(old_len);
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new_len = PAGE_ALIGN(new_len);
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/*
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* We allow a zero old-len as a special case
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* for DOS-emu "duplicate shm area" thing. But
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* a zero new-len is nonsensical.
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*/
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if (!new_len)
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goto out;
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if (flags & MREMAP_FIXED) {
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if (flags & MREMAP_MAYMOVE)
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ret = mremap_to(addr, old_len, new_addr, new_len);
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goto out;
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}
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/*
|
|
* Always allow a shrinking remap: that just unmaps
|
|
* the unnecessary pages..
|
|
* do_munmap does all the needed commit accounting
|
|
*/
|
|
if (old_len >= new_len) {
|
|
ret = do_munmap(mm, addr+new_len, old_len - new_len);
|
|
if (ret && old_len != new_len)
|
|
goto out;
|
|
ret = addr;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Ok, we need to grow..
|
|
*/
|
|
vma = vma_to_resize(addr, old_len, new_len, &charged);
|
|
if (IS_ERR(vma)) {
|
|
ret = PTR_ERR(vma);
|
|
goto out;
|
|
}
|
|
|
|
/* old_len exactly to the end of the area..
|
|
*/
|
|
if (old_len == vma->vm_end - addr) {
|
|
/* can we just expand the current mapping? */
|
|
if (vma_expandable(vma, new_len - old_len)) {
|
|
int pages = (new_len - old_len) >> PAGE_SHIFT;
|
|
|
|
if (vma_adjust(vma, vma->vm_start, addr + new_len,
|
|
vma->vm_pgoff, NULL)) {
|
|
ret = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
mm->total_vm += pages;
|
|
vm_stat_account(mm, vma->vm_flags, vma->vm_file, pages);
|
|
if (vma->vm_flags & VM_LOCKED) {
|
|
mm->locked_vm += pages;
|
|
mlock_vma_pages_range(vma, addr + old_len,
|
|
addr + new_len);
|
|
}
|
|
ret = addr;
|
|
goto out;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* We weren't able to just expand or shrink the area,
|
|
* we need to create a new one and move it..
|
|
*/
|
|
ret = -ENOMEM;
|
|
if (flags & MREMAP_MAYMOVE) {
|
|
unsigned long map_flags = 0;
|
|
if (vma->vm_flags & VM_MAYSHARE)
|
|
map_flags |= MAP_SHARED;
|
|
|
|
new_addr = get_unmapped_area(vma->vm_file, 0, new_len,
|
|
vma->vm_pgoff +
|
|
((addr - vma->vm_start) >> PAGE_SHIFT),
|
|
map_flags);
|
|
if (new_addr & ~PAGE_MASK) {
|
|
ret = new_addr;
|
|
goto out;
|
|
}
|
|
|
|
ret = security_file_mmap(NULL, 0, 0, 0, new_addr, 1);
|
|
if (ret)
|
|
goto out;
|
|
ret = move_vma(vma, addr, old_len, new_len, new_addr);
|
|
}
|
|
out:
|
|
if (ret & ~PAGE_MASK)
|
|
vm_unacct_memory(charged);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
|
|
unsigned long, new_len, unsigned long, flags,
|
|
unsigned long, new_addr)
|
|
{
|
|
unsigned long ret;
|
|
|
|
down_write(¤t->mm->mmap_sem);
|
|
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
|
|
up_write(¤t->mm->mmap_sem);
|
|
return ret;
|
|
}
|