mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 02:39:48 +00:00
![Liam Howlett](/assets/img/avatar_default.png)
The check for mm being null has never been needed since the only caller has always passed in current->mm. Remove the check from count_mm_mlocked_page_nr(). Link: https://lkml.kernel.org/r/20220615174050.738523-1-Liam.Howlett@oracle.com Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com> Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
777 lines
19 KiB
C
777 lines
19 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* linux/mm/mlock.c
|
|
*
|
|
* (C) Copyright 1995 Linus Torvalds
|
|
* (C) Copyright 2002 Christoph Hellwig
|
|
*/
|
|
|
|
#include <linux/capability.h>
|
|
#include <linux/mman.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/sched/user.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/swapops.h>
|
|
#include <linux/pagemap.h>
|
|
#include <linux/pagevec.h>
|
|
#include <linux/pagewalk.h>
|
|
#include <linux/mempolicy.h>
|
|
#include <linux/syscalls.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/export.h>
|
|
#include <linux/rmap.h>
|
|
#include <linux/mmzone.h>
|
|
#include <linux/hugetlb.h>
|
|
#include <linux/memcontrol.h>
|
|
#include <linux/mm_inline.h>
|
|
#include <linux/secretmem.h>
|
|
|
|
#include "internal.h"
|
|
|
|
struct mlock_pvec {
|
|
local_lock_t lock;
|
|
struct pagevec vec;
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct mlock_pvec, mlock_pvec) = {
|
|
.lock = INIT_LOCAL_LOCK(lock),
|
|
};
|
|
|
|
bool can_do_mlock(void)
|
|
{
|
|
if (rlimit(RLIMIT_MEMLOCK) != 0)
|
|
return true;
|
|
if (capable(CAP_IPC_LOCK))
|
|
return true;
|
|
return false;
|
|
}
|
|
EXPORT_SYMBOL(can_do_mlock);
|
|
|
|
/*
|
|
* Mlocked pages are marked with PageMlocked() flag for efficient testing
|
|
* in vmscan and, possibly, the fault path; and to support semi-accurate
|
|
* statistics.
|
|
*
|
|
* An mlocked page [PageMlocked(page)] is unevictable. As such, it will
|
|
* be placed on the LRU "unevictable" list, rather than the [in]active lists.
|
|
* The unevictable list is an LRU sibling list to the [in]active lists.
|
|
* PageUnevictable is set to indicate the unevictable state.
|
|
*/
|
|
|
|
static struct lruvec *__mlock_page(struct page *page, struct lruvec *lruvec)
|
|
{
|
|
/* There is nothing more we can do while it's off LRU */
|
|
if (!TestClearPageLRU(page))
|
|
return lruvec;
|
|
|
|
lruvec = folio_lruvec_relock_irq(page_folio(page), lruvec);
|
|
|
|
if (unlikely(page_evictable(page))) {
|
|
/*
|
|
* This is a little surprising, but quite possible:
|
|
* PageMlocked must have got cleared already by another CPU.
|
|
* Could this page be on the Unevictable LRU? I'm not sure,
|
|
* but move it now if so.
|
|
*/
|
|
if (PageUnevictable(page)) {
|
|
del_page_from_lru_list(page, lruvec);
|
|
ClearPageUnevictable(page);
|
|
add_page_to_lru_list(page, lruvec);
|
|
__count_vm_events(UNEVICTABLE_PGRESCUED,
|
|
thp_nr_pages(page));
|
|
}
|
|
goto out;
|
|
}
|
|
|
|
if (PageUnevictable(page)) {
|
|
if (PageMlocked(page))
|
|
page->mlock_count++;
|
|
goto out;
|
|
}
|
|
|
|
del_page_from_lru_list(page, lruvec);
|
|
ClearPageActive(page);
|
|
SetPageUnevictable(page);
|
|
page->mlock_count = !!PageMlocked(page);
|
|
add_page_to_lru_list(page, lruvec);
|
|
__count_vm_events(UNEVICTABLE_PGCULLED, thp_nr_pages(page));
|
|
out:
|
|
SetPageLRU(page);
|
|
return lruvec;
|
|
}
|
|
|
|
static struct lruvec *__mlock_new_page(struct page *page, struct lruvec *lruvec)
|
|
{
|
|
VM_BUG_ON_PAGE(PageLRU(page), page);
|
|
|
|
lruvec = folio_lruvec_relock_irq(page_folio(page), lruvec);
|
|
|
|
/* As above, this is a little surprising, but possible */
|
|
if (unlikely(page_evictable(page)))
|
|
goto out;
|
|
|
|
SetPageUnevictable(page);
|
|
page->mlock_count = !!PageMlocked(page);
|
|
__count_vm_events(UNEVICTABLE_PGCULLED, thp_nr_pages(page));
|
|
out:
|
|
add_page_to_lru_list(page, lruvec);
|
|
SetPageLRU(page);
|
|
return lruvec;
|
|
}
|
|
|
|
static struct lruvec *__munlock_page(struct page *page, struct lruvec *lruvec)
|
|
{
|
|
int nr_pages = thp_nr_pages(page);
|
|
bool isolated = false;
|
|
|
|
if (!TestClearPageLRU(page))
|
|
goto munlock;
|
|
|
|
isolated = true;
|
|
lruvec = folio_lruvec_relock_irq(page_folio(page), lruvec);
|
|
|
|
if (PageUnevictable(page)) {
|
|
/* Then mlock_count is maintained, but might undercount */
|
|
if (page->mlock_count)
|
|
page->mlock_count--;
|
|
if (page->mlock_count)
|
|
goto out;
|
|
}
|
|
/* else assume that was the last mlock: reclaim will fix it if not */
|
|
|
|
munlock:
|
|
if (TestClearPageMlocked(page)) {
|
|
__mod_zone_page_state(page_zone(page), NR_MLOCK, -nr_pages);
|
|
if (isolated || !PageUnevictable(page))
|
|
__count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages);
|
|
else
|
|
__count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages);
|
|
}
|
|
|
|
/* page_evictable() has to be checked *after* clearing Mlocked */
|
|
if (isolated && PageUnevictable(page) && page_evictable(page)) {
|
|
del_page_from_lru_list(page, lruvec);
|
|
ClearPageUnevictable(page);
|
|
add_page_to_lru_list(page, lruvec);
|
|
__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
|
|
}
|
|
out:
|
|
if (isolated)
|
|
SetPageLRU(page);
|
|
return lruvec;
|
|
}
|
|
|
|
/*
|
|
* Flags held in the low bits of a struct page pointer on the mlock_pvec.
|
|
*/
|
|
#define LRU_PAGE 0x1
|
|
#define NEW_PAGE 0x2
|
|
static inline struct page *mlock_lru(struct page *page)
|
|
{
|
|
return (struct page *)((unsigned long)page + LRU_PAGE);
|
|
}
|
|
|
|
static inline struct page *mlock_new(struct page *page)
|
|
{
|
|
return (struct page *)((unsigned long)page + NEW_PAGE);
|
|
}
|
|
|
|
/*
|
|
* mlock_pagevec() is derived from pagevec_lru_move_fn():
|
|
* perhaps that can make use of such page pointer flags in future,
|
|
* but for now just keep it for mlock. We could use three separate
|
|
* pagevecs instead, but one feels better (munlocking a full pagevec
|
|
* does not need to drain mlocking pagevecs first).
|
|
*/
|
|
static void mlock_pagevec(struct pagevec *pvec)
|
|
{
|
|
struct lruvec *lruvec = NULL;
|
|
unsigned long mlock;
|
|
struct page *page;
|
|
int i;
|
|
|
|
for (i = 0; i < pagevec_count(pvec); i++) {
|
|
page = pvec->pages[i];
|
|
mlock = (unsigned long)page & (LRU_PAGE | NEW_PAGE);
|
|
page = (struct page *)((unsigned long)page - mlock);
|
|
pvec->pages[i] = page;
|
|
|
|
if (mlock & LRU_PAGE)
|
|
lruvec = __mlock_page(page, lruvec);
|
|
else if (mlock & NEW_PAGE)
|
|
lruvec = __mlock_new_page(page, lruvec);
|
|
else
|
|
lruvec = __munlock_page(page, lruvec);
|
|
}
|
|
|
|
if (lruvec)
|
|
unlock_page_lruvec_irq(lruvec);
|
|
release_pages(pvec->pages, pvec->nr);
|
|
pagevec_reinit(pvec);
|
|
}
|
|
|
|
void mlock_page_drain_local(void)
|
|
{
|
|
struct pagevec *pvec;
|
|
|
|
local_lock(&mlock_pvec.lock);
|
|
pvec = this_cpu_ptr(&mlock_pvec.vec);
|
|
if (pagevec_count(pvec))
|
|
mlock_pagevec(pvec);
|
|
local_unlock(&mlock_pvec.lock);
|
|
}
|
|
|
|
void mlock_page_drain_remote(int cpu)
|
|
{
|
|
struct pagevec *pvec;
|
|
|
|
WARN_ON_ONCE(cpu_online(cpu));
|
|
pvec = &per_cpu(mlock_pvec.vec, cpu);
|
|
if (pagevec_count(pvec))
|
|
mlock_pagevec(pvec);
|
|
}
|
|
|
|
bool need_mlock_page_drain(int cpu)
|
|
{
|
|
return pagevec_count(&per_cpu(mlock_pvec.vec, cpu));
|
|
}
|
|
|
|
/**
|
|
* mlock_folio - mlock a folio already on (or temporarily off) LRU
|
|
* @folio: folio to be mlocked.
|
|
*/
|
|
void mlock_folio(struct folio *folio)
|
|
{
|
|
struct pagevec *pvec;
|
|
|
|
local_lock(&mlock_pvec.lock);
|
|
pvec = this_cpu_ptr(&mlock_pvec.vec);
|
|
|
|
if (!folio_test_set_mlocked(folio)) {
|
|
int nr_pages = folio_nr_pages(folio);
|
|
|
|
zone_stat_mod_folio(folio, NR_MLOCK, nr_pages);
|
|
__count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
|
|
}
|
|
|
|
folio_get(folio);
|
|
if (!pagevec_add(pvec, mlock_lru(&folio->page)) ||
|
|
folio_test_large(folio) || lru_cache_disabled())
|
|
mlock_pagevec(pvec);
|
|
local_unlock(&mlock_pvec.lock);
|
|
}
|
|
|
|
/**
|
|
* mlock_new_page - mlock a newly allocated page not yet on LRU
|
|
* @page: page to be mlocked, either a normal page or a THP head.
|
|
*/
|
|
void mlock_new_page(struct page *page)
|
|
{
|
|
struct pagevec *pvec;
|
|
int nr_pages = thp_nr_pages(page);
|
|
|
|
local_lock(&mlock_pvec.lock);
|
|
pvec = this_cpu_ptr(&mlock_pvec.vec);
|
|
SetPageMlocked(page);
|
|
mod_zone_page_state(page_zone(page), NR_MLOCK, nr_pages);
|
|
__count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
|
|
|
|
get_page(page);
|
|
if (!pagevec_add(pvec, mlock_new(page)) ||
|
|
PageHead(page) || lru_cache_disabled())
|
|
mlock_pagevec(pvec);
|
|
local_unlock(&mlock_pvec.lock);
|
|
}
|
|
|
|
/**
|
|
* munlock_page - munlock a page
|
|
* @page: page to be munlocked, either a normal page or a THP head.
|
|
*/
|
|
void munlock_page(struct page *page)
|
|
{
|
|
struct pagevec *pvec;
|
|
|
|
local_lock(&mlock_pvec.lock);
|
|
pvec = this_cpu_ptr(&mlock_pvec.vec);
|
|
/*
|
|
* TestClearPageMlocked(page) must be left to __munlock_page(),
|
|
* which will check whether the page is multiply mlocked.
|
|
*/
|
|
|
|
get_page(page);
|
|
if (!pagevec_add(pvec, page) ||
|
|
PageHead(page) || lru_cache_disabled())
|
|
mlock_pagevec(pvec);
|
|
local_unlock(&mlock_pvec.lock);
|
|
}
|
|
|
|
static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
|
|
unsigned long end, struct mm_walk *walk)
|
|
|
|
{
|
|
struct vm_area_struct *vma = walk->vma;
|
|
spinlock_t *ptl;
|
|
pte_t *start_pte, *pte;
|
|
struct page *page;
|
|
|
|
ptl = pmd_trans_huge_lock(pmd, vma);
|
|
if (ptl) {
|
|
if (!pmd_present(*pmd))
|
|
goto out;
|
|
if (is_huge_zero_pmd(*pmd))
|
|
goto out;
|
|
page = pmd_page(*pmd);
|
|
if (vma->vm_flags & VM_LOCKED)
|
|
mlock_folio(page_folio(page));
|
|
else
|
|
munlock_page(page);
|
|
goto out;
|
|
}
|
|
|
|
start_pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
|
|
for (pte = start_pte; addr != end; pte++, addr += PAGE_SIZE) {
|
|
if (!pte_present(*pte))
|
|
continue;
|
|
page = vm_normal_page(vma, addr, *pte);
|
|
if (!page || is_zone_device_page(page))
|
|
continue;
|
|
if (PageTransCompound(page))
|
|
continue;
|
|
if (vma->vm_flags & VM_LOCKED)
|
|
mlock_folio(page_folio(page));
|
|
else
|
|
munlock_page(page);
|
|
}
|
|
pte_unmap(start_pte);
|
|
out:
|
|
spin_unlock(ptl);
|
|
cond_resched();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* mlock_vma_pages_range() - mlock any pages already in the range,
|
|
* or munlock all pages in the range.
|
|
* @vma - vma containing range to be mlock()ed or munlock()ed
|
|
* @start - start address in @vma of the range
|
|
* @end - end of range in @vma
|
|
* @newflags - the new set of flags for @vma.
|
|
*
|
|
* Called for mlock(), mlock2() and mlockall(), to set @vma VM_LOCKED;
|
|
* called for munlock() and munlockall(), to clear VM_LOCKED from @vma.
|
|
*/
|
|
static void mlock_vma_pages_range(struct vm_area_struct *vma,
|
|
unsigned long start, unsigned long end, vm_flags_t newflags)
|
|
{
|
|
static const struct mm_walk_ops mlock_walk_ops = {
|
|
.pmd_entry = mlock_pte_range,
|
|
};
|
|
|
|
/*
|
|
* There is a slight chance that concurrent page migration,
|
|
* or page reclaim finding a page of this now-VM_LOCKED vma,
|
|
* will call mlock_vma_page() and raise page's mlock_count:
|
|
* double counting, leaving the page unevictable indefinitely.
|
|
* Communicate this danger to mlock_vma_page() with VM_IO,
|
|
* which is a VM_SPECIAL flag not allowed on VM_LOCKED vmas.
|
|
* mmap_lock is held in write mode here, so this weird
|
|
* combination should not be visible to other mmap_lock users;
|
|
* but WRITE_ONCE so rmap walkers must see VM_IO if VM_LOCKED.
|
|
*/
|
|
if (newflags & VM_LOCKED)
|
|
newflags |= VM_IO;
|
|
WRITE_ONCE(vma->vm_flags, newflags);
|
|
|
|
lru_add_drain();
|
|
walk_page_range(vma->vm_mm, start, end, &mlock_walk_ops, NULL);
|
|
lru_add_drain();
|
|
|
|
if (newflags & VM_IO) {
|
|
newflags &= ~VM_IO;
|
|
WRITE_ONCE(vma->vm_flags, newflags);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* mlock_fixup - handle mlock[all]/munlock[all] requests.
|
|
*
|
|
* Filters out "special" vmas -- VM_LOCKED never gets set for these, and
|
|
* munlock is a no-op. However, for some special vmas, we go ahead and
|
|
* populate the ptes.
|
|
*
|
|
* For vmas that pass the filters, merge/split as appropriate.
|
|
*/
|
|
static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
|
|
unsigned long start, unsigned long end, vm_flags_t newflags)
|
|
{
|
|
struct mm_struct *mm = vma->vm_mm;
|
|
pgoff_t pgoff;
|
|
int nr_pages;
|
|
int ret = 0;
|
|
vm_flags_t oldflags = vma->vm_flags;
|
|
|
|
if (newflags == oldflags || (oldflags & VM_SPECIAL) ||
|
|
is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm) ||
|
|
vma_is_dax(vma) || vma_is_secretmem(vma))
|
|
/* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */
|
|
goto out;
|
|
|
|
pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
|
|
*prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
|
|
vma->vm_file, pgoff, vma_policy(vma),
|
|
vma->vm_userfaultfd_ctx, anon_vma_name(vma));
|
|
if (*prev) {
|
|
vma = *prev;
|
|
goto success;
|
|
}
|
|
|
|
if (start != vma->vm_start) {
|
|
ret = split_vma(mm, vma, start, 1);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
if (end != vma->vm_end) {
|
|
ret = split_vma(mm, vma, end, 0);
|
|
if (ret)
|
|
goto out;
|
|
}
|
|
|
|
success:
|
|
/*
|
|
* Keep track of amount of locked VM.
|
|
*/
|
|
nr_pages = (end - start) >> PAGE_SHIFT;
|
|
if (!(newflags & VM_LOCKED))
|
|
nr_pages = -nr_pages;
|
|
else if (oldflags & VM_LOCKED)
|
|
nr_pages = 0;
|
|
mm->locked_vm += nr_pages;
|
|
|
|
/*
|
|
* vm_flags is protected by the mmap_lock held in write mode.
|
|
* It's okay if try_to_unmap_one unmaps a page just after we
|
|
* set VM_LOCKED, populate_vma_page_range will bring it back.
|
|
*/
|
|
|
|
if ((newflags & VM_LOCKED) && (oldflags & VM_LOCKED)) {
|
|
/* No work to do, and mlocking twice would be wrong */
|
|
vma->vm_flags = newflags;
|
|
} else {
|
|
mlock_vma_pages_range(vma, start, end, newflags);
|
|
}
|
|
out:
|
|
*prev = vma;
|
|
return ret;
|
|
}
|
|
|
|
static int apply_vma_lock_flags(unsigned long start, size_t len,
|
|
vm_flags_t flags)
|
|
{
|
|
unsigned long nstart, end, tmp;
|
|
struct vm_area_struct *vma, *prev;
|
|
int error;
|
|
MA_STATE(mas, ¤t->mm->mm_mt, start, start);
|
|
|
|
VM_BUG_ON(offset_in_page(start));
|
|
VM_BUG_ON(len != PAGE_ALIGN(len));
|
|
end = start + len;
|
|
if (end < start)
|
|
return -EINVAL;
|
|
if (end == start)
|
|
return 0;
|
|
vma = mas_walk(&mas);
|
|
if (!vma)
|
|
return -ENOMEM;
|
|
|
|
if (start > vma->vm_start)
|
|
prev = vma;
|
|
else
|
|
prev = mas_prev(&mas, 0);
|
|
|
|
for (nstart = start ; ; ) {
|
|
vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
|
|
|
|
newflags |= flags;
|
|
|
|
/* Here we know that vma->vm_start <= nstart < vma->vm_end. */
|
|
tmp = vma->vm_end;
|
|
if (tmp > end)
|
|
tmp = end;
|
|
error = mlock_fixup(vma, &prev, nstart, tmp, newflags);
|
|
if (error)
|
|
break;
|
|
nstart = tmp;
|
|
if (nstart < prev->vm_end)
|
|
nstart = prev->vm_end;
|
|
if (nstart >= end)
|
|
break;
|
|
|
|
vma = find_vma(prev->vm_mm, prev->vm_end);
|
|
if (!vma || vma->vm_start != nstart) {
|
|
error = -ENOMEM;
|
|
break;
|
|
}
|
|
}
|
|
return error;
|
|
}
|
|
|
|
/*
|
|
* Go through vma areas and sum size of mlocked
|
|
* vma pages, as return value.
|
|
* Note deferred memory locking case(mlock2(,,MLOCK_ONFAULT)
|
|
* is also counted.
|
|
* Return value: previously mlocked page counts
|
|
*/
|
|
static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
|
|
unsigned long start, size_t len)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
unsigned long count = 0;
|
|
unsigned long end;
|
|
VMA_ITERATOR(vmi, mm, start);
|
|
|
|
/* Don't overflow past ULONG_MAX */
|
|
if (unlikely(ULONG_MAX - len < start))
|
|
end = ULONG_MAX;
|
|
else
|
|
end = start + len;
|
|
|
|
for_each_vma_range(vmi, vma, end) {
|
|
if (vma->vm_flags & VM_LOCKED) {
|
|
if (start > vma->vm_start)
|
|
count -= (start - vma->vm_start);
|
|
if (end < vma->vm_end) {
|
|
count += end - vma->vm_start;
|
|
break;
|
|
}
|
|
count += vma->vm_end - vma->vm_start;
|
|
}
|
|
}
|
|
|
|
return count >> PAGE_SHIFT;
|
|
}
|
|
|
|
/*
|
|
* convert get_user_pages() return value to posix mlock() error
|
|
*/
|
|
static int __mlock_posix_error_return(long retval)
|
|
{
|
|
if (retval == -EFAULT)
|
|
retval = -ENOMEM;
|
|
else if (retval == -ENOMEM)
|
|
retval = -EAGAIN;
|
|
return retval;
|
|
}
|
|
|
|
static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags)
|
|
{
|
|
unsigned long locked;
|
|
unsigned long lock_limit;
|
|
int error = -ENOMEM;
|
|
|
|
start = untagged_addr(start);
|
|
|
|
if (!can_do_mlock())
|
|
return -EPERM;
|
|
|
|
len = PAGE_ALIGN(len + (offset_in_page(start)));
|
|
start &= PAGE_MASK;
|
|
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK);
|
|
lock_limit >>= PAGE_SHIFT;
|
|
locked = len >> PAGE_SHIFT;
|
|
|
|
if (mmap_write_lock_killable(current->mm))
|
|
return -EINTR;
|
|
|
|
locked += current->mm->locked_vm;
|
|
if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) {
|
|
/*
|
|
* It is possible that the regions requested intersect with
|
|
* previously mlocked areas, that part area in "mm->locked_vm"
|
|
* should not be counted to new mlock increment count. So check
|
|
* and adjust locked count if necessary.
|
|
*/
|
|
locked -= count_mm_mlocked_page_nr(current->mm,
|
|
start, len);
|
|
}
|
|
|
|
/* check against resource limits */
|
|
if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
|
|
error = apply_vma_lock_flags(start, len, flags);
|
|
|
|
mmap_write_unlock(current->mm);
|
|
if (error)
|
|
return error;
|
|
|
|
error = __mm_populate(start, len, 0);
|
|
if (error)
|
|
return __mlock_posix_error_return(error);
|
|
return 0;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)
|
|
{
|
|
return do_mlock(start, len, VM_LOCKED);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(mlock2, unsigned long, start, size_t, len, int, flags)
|
|
{
|
|
vm_flags_t vm_flags = VM_LOCKED;
|
|
|
|
if (flags & ~MLOCK_ONFAULT)
|
|
return -EINVAL;
|
|
|
|
if (flags & MLOCK_ONFAULT)
|
|
vm_flags |= VM_LOCKONFAULT;
|
|
|
|
return do_mlock(start, len, vm_flags);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
|
|
{
|
|
int ret;
|
|
|
|
start = untagged_addr(start);
|
|
|
|
len = PAGE_ALIGN(len + (offset_in_page(start)));
|
|
start &= PAGE_MASK;
|
|
|
|
if (mmap_write_lock_killable(current->mm))
|
|
return -EINTR;
|
|
ret = apply_vma_lock_flags(start, len, 0);
|
|
mmap_write_unlock(current->mm);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Take the MCL_* flags passed into mlockall (or 0 if called from munlockall)
|
|
* and translate into the appropriate modifications to mm->def_flags and/or the
|
|
* flags for all current VMAs.
|
|
*
|
|
* There are a couple of subtleties with this. If mlockall() is called multiple
|
|
* times with different flags, the values do not necessarily stack. If mlockall
|
|
* is called once including the MCL_FUTURE flag and then a second time without
|
|
* it, VM_LOCKED and VM_LOCKONFAULT will be cleared from mm->def_flags.
|
|
*/
|
|
static int apply_mlockall_flags(int flags)
|
|
{
|
|
MA_STATE(mas, ¤t->mm->mm_mt, 0, 0);
|
|
struct vm_area_struct *vma, *prev = NULL;
|
|
vm_flags_t to_add = 0;
|
|
|
|
current->mm->def_flags &= VM_LOCKED_CLEAR_MASK;
|
|
if (flags & MCL_FUTURE) {
|
|
current->mm->def_flags |= VM_LOCKED;
|
|
|
|
if (flags & MCL_ONFAULT)
|
|
current->mm->def_flags |= VM_LOCKONFAULT;
|
|
|
|
if (!(flags & MCL_CURRENT))
|
|
goto out;
|
|
}
|
|
|
|
if (flags & MCL_CURRENT) {
|
|
to_add |= VM_LOCKED;
|
|
if (flags & MCL_ONFAULT)
|
|
to_add |= VM_LOCKONFAULT;
|
|
}
|
|
|
|
mas_for_each(&mas, vma, ULONG_MAX) {
|
|
vm_flags_t newflags;
|
|
|
|
newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
|
|
newflags |= to_add;
|
|
|
|
/* Ignore errors */
|
|
mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
|
|
mas_pause(&mas);
|
|
cond_resched();
|
|
}
|
|
out:
|
|
return 0;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(mlockall, int, flags)
|
|
{
|
|
unsigned long lock_limit;
|
|
int ret;
|
|
|
|
if (!flags || (flags & ~(MCL_CURRENT | MCL_FUTURE | MCL_ONFAULT)) ||
|
|
flags == MCL_ONFAULT)
|
|
return -EINVAL;
|
|
|
|
if (!can_do_mlock())
|
|
return -EPERM;
|
|
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK);
|
|
lock_limit >>= PAGE_SHIFT;
|
|
|
|
if (mmap_write_lock_killable(current->mm))
|
|
return -EINTR;
|
|
|
|
ret = -ENOMEM;
|
|
if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
|
|
capable(CAP_IPC_LOCK))
|
|
ret = apply_mlockall_flags(flags);
|
|
mmap_write_unlock(current->mm);
|
|
if (!ret && (flags & MCL_CURRENT))
|
|
mm_populate(0, TASK_SIZE);
|
|
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE0(munlockall)
|
|
{
|
|
int ret;
|
|
|
|
if (mmap_write_lock_killable(current->mm))
|
|
return -EINTR;
|
|
ret = apply_mlockall_flags(0);
|
|
mmap_write_unlock(current->mm);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Objects with different lifetime than processes (SHM_LOCK and SHM_HUGETLB
|
|
* shm segments) get accounted against the user_struct instead.
|
|
*/
|
|
static DEFINE_SPINLOCK(shmlock_user_lock);
|
|
|
|
int user_shm_lock(size_t size, struct ucounts *ucounts)
|
|
{
|
|
unsigned long lock_limit, locked;
|
|
long memlock;
|
|
int allowed = 0;
|
|
|
|
locked = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
lock_limit = rlimit(RLIMIT_MEMLOCK);
|
|
if (lock_limit != RLIM_INFINITY)
|
|
lock_limit >>= PAGE_SHIFT;
|
|
spin_lock(&shmlock_user_lock);
|
|
memlock = inc_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
|
|
|
|
if ((memlock == LONG_MAX || memlock > lock_limit) && !capable(CAP_IPC_LOCK)) {
|
|
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
|
|
goto out;
|
|
}
|
|
if (!get_ucounts(ucounts)) {
|
|
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, locked);
|
|
allowed = 0;
|
|
goto out;
|
|
}
|
|
allowed = 1;
|
|
out:
|
|
spin_unlock(&shmlock_user_lock);
|
|
return allowed;
|
|
}
|
|
|
|
void user_shm_unlock(size_t size, struct ucounts *ucounts)
|
|
{
|
|
spin_lock(&shmlock_user_lock);
|
|
dec_rlimit_ucounts(ucounts, UCOUNT_RLIMIT_MEMLOCK, (size + PAGE_SIZE - 1) >> PAGE_SHIFT);
|
|
spin_unlock(&shmlock_user_lock);
|
|
put_ucounts(ucounts);
|
|
}
|