Contributors: 60
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Hugh Dickins |
685 |
20.49% |
12 |
7.59% |
| Linus Torvalds (pre-git) |
533 |
15.94% |
32 |
20.25% |
| Lorenzo Stoakes |
257 |
7.69% |
3 |
1.90% |
| Vlastimil Babka |
226 |
6.76% |
9 |
5.70% |
| Yin Fengwei |
183 |
5.47% |
1 |
0.63% |
| Nicholas Piggin |
142 |
4.25% |
4 |
2.53% |
| Simon Guo |
136 |
4.07% |
2 |
1.27% |
| Rik Van Riel |
125 |
3.74% |
2 |
1.27% |
| Sebastian Andrzej Siewior |
102 |
3.05% |
1 |
0.63% |
| Eric B Munson |
102 |
3.05% |
3 |
1.90% |
| Matthew Wilcox |
84 |
2.51% |
5 |
3.16% |
| Liam R. Howlett |
80 |
2.39% |
2 |
1.27% |
| Chris Wright |
69 |
2.06% |
4 |
2.53% |
| Alexey Gladkov |
63 |
1.88% |
1 |
0.63% |
| Kirill A. Shutemov |
56 |
1.68% |
5 |
3.16% |
| Heiko Carstens |
49 |
1.47% |
2 |
1.27% |
| Michel Lespinasse |
47 |
1.41% |
7 |
4.43% |
| Lee Schermerhorn |
39 |
1.17% |
1 |
0.63% |
| Andrew Morton |
37 |
1.11% |
8 |
5.06% |
| Michal Hocko |
33 |
0.99% |
1 |
0.63% |
| Lance Yang |
30 |
0.90% |
1 |
0.63% |
| Alex Shi |
27 |
0.81% |
3 |
1.90% |
| Suren Baghdasaryan |
25 |
0.75% |
6 |
3.80% |
| Davidlohr Bueso A |
20 |
0.60% |
1 |
0.63% |
| Andrey Konovalov |
14 |
0.42% |
1 |
0.63% |
| Ingo Molnar |
13 |
0.39% |
2 |
1.27% |
| Ryan Roberts |
12 |
0.36% |
1 |
0.63% |
| Jiri Slaby |
11 |
0.33% |
1 |
0.63% |
| Michael Kerrisk |
11 |
0.33% |
1 |
0.63% |
| Chris Metcalf |
9 |
0.27% |
1 |
0.63% |
| Alexander Kuleshov |
9 |
0.27% |
1 |
0.63% |
| Mike Rapoport |
8 |
0.24% |
1 |
0.63% |
| MinChan Kim |
7 |
0.21% |
2 |
1.27% |
| Alexey Klimov |
7 |
0.21% |
1 |
0.63% |
| Gerald Schaefer |
6 |
0.18% |
1 |
0.63% |
| Jason A. Donenfeld |
6 |
0.18% |
1 |
0.63% |
| Linus Torvalds |
6 |
0.18% |
1 |
0.63% |
| Jeff Vander Stoep |
6 |
0.18% |
1 |
0.63% |
| Dave Jiang |
5 |
0.15% |
1 |
0.63% |
| David Rientjes |
5 |
0.15% |
1 |
0.63% |
| Miaohe Lin |
5 |
0.15% |
2 |
1.27% |
| Mel Gorman |
5 |
0.15% |
2 |
1.27% |
| Herbert van den Bergh |
5 |
0.15% |
1 |
0.63% |
| Shakeel Butt |
4 |
0.12% |
2 |
1.27% |
| Stefan Potyra |
4 |
0.12% |
1 |
0.63% |
| Weikang Shi |
4 |
0.12% |
1 |
0.63% |
| Thomas Gleixner |
4 |
0.12% |
1 |
0.63% |
| Alexey Dobriyan |
4 |
0.12% |
1 |
0.63% |
| Wang Xiaoqiang |
4 |
0.12% |
1 |
0.63% |
| Paul E. McKenney |
3 |
0.09% |
2 |
1.27% |
| Motohiro Kosaki |
3 |
0.09% |
1 |
0.63% |
| Alex Sierra |
3 |
0.09% |
1 |
0.63% |
| Adrian Bunk |
2 |
0.06% |
1 |
0.63% |
| Stephen Wilson |
2 |
0.06% |
1 |
0.63% |
| Andi Kleen |
1 |
0.03% |
1 |
0.63% |
| Andrey Ryabinin |
1 |
0.03% |
1 |
0.63% |
| Paul Gortmaker |
1 |
0.03% |
1 |
0.63% |
| Qi Zheng |
1 |
0.03% |
1 |
0.63% |
| Greg Kroah-Hartman |
1 |
0.03% |
1 |
0.63% |
| JoonSoo Kim |
1 |
0.03% |
1 |
0.63% |
| Total |
3343 |
|
158 |
|
// 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_fbatch {
local_lock_t lock;
struct folio_batch fbatch;
};
static DEFINE_PER_CPU(struct mlock_fbatch, mlock_fbatch) = {
.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 folios are marked with the PG_mlocked flag for efficient testing
* in vmscan and, possibly, the fault path; and to support semi-accurate
* statistics.
*
* An mlocked folio [folio_test_mlocked(folio)] is unevictable. As such, it
* will be ostensibly placed on the LRU "unevictable" list (actually no such
* list exists), rather than the [in]active lists. PG_unevictable is set to
* indicate the unevictable state.
*/
static struct lruvec *__mlock_folio(struct folio *folio, struct lruvec *lruvec)
{
/* There is nothing more we can do while it's off LRU */
if (!folio_test_clear_lru(folio))
return lruvec;
lruvec = folio_lruvec_relock_irq(folio, lruvec);
if (unlikely(folio_evictable(folio))) {
/*
* This is a little surprising, but quite possible: PG_mlocked
* must have got cleared already by another CPU. Could this
* folio be unevictable? I'm not sure, but move it now if so.
*/
if (folio_test_unevictable(folio)) {
lruvec_del_folio(lruvec, folio);
folio_clear_unevictable(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(UNEVICTABLE_PGRESCUED,
folio_nr_pages(folio));
}
goto out;
}
if (folio_test_unevictable(folio)) {
if (folio_test_mlocked(folio))
folio->mlock_count++;
goto out;
}
lruvec_del_folio(lruvec, folio);
folio_clear_active(folio);
folio_set_unevictable(folio);
folio->mlock_count = !!folio_test_mlocked(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(UNEVICTABLE_PGCULLED, folio_nr_pages(folio));
out:
folio_set_lru(folio);
return lruvec;
}
static struct lruvec *__mlock_new_folio(struct folio *folio, struct lruvec *lruvec)
{
VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);
lruvec = folio_lruvec_relock_irq(folio, lruvec);
/* As above, this is a little surprising, but possible */
if (unlikely(folio_evictable(folio)))
goto out;
folio_set_unevictable(folio);
folio->mlock_count = !!folio_test_mlocked(folio);
__count_vm_events(UNEVICTABLE_PGCULLED, folio_nr_pages(folio));
out:
lruvec_add_folio(lruvec, folio);
folio_set_lru(folio);
return lruvec;
}
static struct lruvec *__munlock_folio(struct folio *folio, struct lruvec *lruvec)
{
int nr_pages = folio_nr_pages(folio);
bool isolated = false;
if (!folio_test_clear_lru(folio))
goto munlock;
isolated = true;
lruvec = folio_lruvec_relock_irq(folio, lruvec);
if (folio_test_unevictable(folio)) {
/* Then mlock_count is maintained, but might undercount */
if (folio->mlock_count)
folio->mlock_count--;
if (folio->mlock_count)
goto out;
}
/* else assume that was the last mlock: reclaim will fix it if not */
munlock:
if (folio_test_clear_mlocked(folio)) {
__zone_stat_mod_folio(folio, NR_MLOCK, -nr_pages);
if (isolated || !folio_test_unevictable(folio))
__count_vm_events(UNEVICTABLE_PGMUNLOCKED, nr_pages);
else
__count_vm_events(UNEVICTABLE_PGSTRANDED, nr_pages);
}
/* folio_evictable() has to be checked *after* clearing Mlocked */
if (isolated && folio_test_unevictable(folio) && folio_evictable(folio)) {
lruvec_del_folio(lruvec, folio);
folio_clear_unevictable(folio);
lruvec_add_folio(lruvec, folio);
__count_vm_events(UNEVICTABLE_PGRESCUED, nr_pages);
}
out:
if (isolated)
folio_set_lru(folio);
return lruvec;
}
/*
* Flags held in the low bits of a struct folio pointer on the mlock_fbatch.
*/
#define LRU_FOLIO 0x1
#define NEW_FOLIO 0x2
static inline struct folio *mlock_lru(struct folio *folio)
{
return (struct folio *)((unsigned long)folio + LRU_FOLIO);
}
static inline struct folio *mlock_new(struct folio *folio)
{
return (struct folio *)((unsigned long)folio + NEW_FOLIO);
}
/*
* mlock_folio_batch() is derived from folio_batch_move_lru(): perhaps that can
* make use of such folio pointer flags in future, but for now just keep it for
* mlock. We could use three separate folio batches instead, but one feels
* better (munlocking a full folio batch does not need to drain mlocking folio
* batches first).
*/
static void mlock_folio_batch(struct folio_batch *fbatch)
{
struct lruvec *lruvec = NULL;
unsigned long mlock;
struct folio *folio;
int i;
for (i = 0; i < folio_batch_count(fbatch); i++) {
folio = fbatch->folios[i];
mlock = (unsigned long)folio & (LRU_FOLIO | NEW_FOLIO);
folio = (struct folio *)((unsigned long)folio - mlock);
fbatch->folios[i] = folio;
if (mlock & LRU_FOLIO)
lruvec = __mlock_folio(folio, lruvec);
else if (mlock & NEW_FOLIO)
lruvec = __mlock_new_folio(folio, lruvec);
else
lruvec = __munlock_folio(folio, lruvec);
}
if (lruvec)
unlock_page_lruvec_irq(lruvec);
folios_put(fbatch);
}
void mlock_drain_local(void)
{
struct folio_batch *fbatch;
local_lock(&mlock_fbatch.lock);
fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
if (folio_batch_count(fbatch))
mlock_folio_batch(fbatch);
local_unlock(&mlock_fbatch.lock);
}
void mlock_drain_remote(int cpu)
{
struct folio_batch *fbatch;
WARN_ON_ONCE(cpu_online(cpu));
fbatch = &per_cpu(mlock_fbatch.fbatch, cpu);
if (folio_batch_count(fbatch))
mlock_folio_batch(fbatch);
}
bool need_mlock_drain(int cpu)
{
return folio_batch_count(&per_cpu(mlock_fbatch.fbatch, cpu));
}
/**
* mlock_folio - mlock a folio already on (or temporarily off) LRU
* @folio: folio to be mlocked.
*/
void mlock_folio(struct folio *folio)
{
struct folio_batch *fbatch;
local_lock(&mlock_fbatch.lock);
fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
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 (!folio_batch_add(fbatch, mlock_lru(folio)) ||
folio_test_large(folio) || lru_cache_disabled())
mlock_folio_batch(fbatch);
local_unlock(&mlock_fbatch.lock);
}
/**
* mlock_new_folio - mlock a newly allocated folio not yet on LRU
* @folio: folio to be mlocked, either normal or a THP head.
*/
void mlock_new_folio(struct folio *folio)
{
struct folio_batch *fbatch;
int nr_pages = folio_nr_pages(folio);
local_lock(&mlock_fbatch.lock);
fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
folio_set_mlocked(folio);
zone_stat_mod_folio(folio, NR_MLOCK, nr_pages);
__count_vm_events(UNEVICTABLE_PGMLOCKED, nr_pages);
folio_get(folio);
if (!folio_batch_add(fbatch, mlock_new(folio)) ||
folio_test_large(folio) || lru_cache_disabled())
mlock_folio_batch(fbatch);
local_unlock(&mlock_fbatch.lock);
}
/**
* munlock_folio - munlock a folio
* @folio: folio to be munlocked, either normal or a THP head.
*/
void munlock_folio(struct folio *folio)
{
struct folio_batch *fbatch;
local_lock(&mlock_fbatch.lock);
fbatch = this_cpu_ptr(&mlock_fbatch.fbatch);
/*
* folio_test_clear_mlocked(folio) must be left to __munlock_folio(),
* which will check whether the folio is multiply mlocked.
*/
folio_get(folio);
if (!folio_batch_add(fbatch, folio) ||
folio_test_large(folio) || lru_cache_disabled())
mlock_folio_batch(fbatch);
local_unlock(&mlock_fbatch.lock);
}
static inline unsigned int folio_mlock_step(struct folio *folio,
pte_t *pte, unsigned long addr, unsigned long end)
{
const fpb_t fpb_flags = FPB_IGNORE_DIRTY | FPB_IGNORE_SOFT_DIRTY;
unsigned int count = (end - addr) >> PAGE_SHIFT;
pte_t ptent = ptep_get(pte);
if (!folio_test_large(folio))
return 1;
return folio_pte_batch(folio, addr, pte, ptent, count, fpb_flags, NULL,
NULL, NULL);
}
static inline bool allow_mlock_munlock(struct folio *folio,
struct vm_area_struct *vma, unsigned long start,
unsigned long end, unsigned int step)
{
/*
* For unlock, allow munlock large folio which is partially
* mapped to VMA. As it's possible that large folio is
* mlocked and VMA is split later.
*
* During memory pressure, such kind of large folio can
* be split. And the pages are not in VM_LOCKed VMA
* can be reclaimed.
*/
if (!(vma->vm_flags & VM_LOCKED))
return true;
/* folio_within_range() cannot take KSM, but any small folio is OK */
if (!folio_test_large(folio))
return true;
/* folio not in range [start, end), skip mlock */
if (!folio_within_range(folio, vma, start, end))
return false;
/* folio is not fully mapped, skip mlock */
if (step != folio_nr_pages(folio))
return false;
return true;
}
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;
pte_t ptent;
struct folio *folio;
unsigned int step = 1;
unsigned long start = addr;
ptl = pmd_trans_huge_lock(pmd, vma);
if (ptl) {
if (!pmd_present(*pmd))
goto out;
if (is_huge_zero_pmd(*pmd))
goto out;
folio = pmd_folio(*pmd);
if (vma->vm_flags & VM_LOCKED)
mlock_folio(folio);
else
munlock_folio(folio);
goto out;
}
start_pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (!start_pte) {
walk->action = ACTION_AGAIN;
return 0;
}
for (pte = start_pte; addr != end; pte++, addr += PAGE_SIZE) {
ptent = ptep_get(pte);
if (!pte_present(ptent))
continue;
folio = vm_normal_folio(vma, addr, ptent);
if (!folio || folio_is_zone_device(folio))
continue;
step = folio_mlock_step(folio, pte, addr, end);
if (!allow_mlock_munlock(folio, vma, start, end, step))
goto next_entry;
if (vma->vm_flags & VM_LOCKED)
mlock_folio(folio);
else
munlock_folio(folio);
next_entry:
pte += step - 1;
addr += (step - 1) << PAGE_SHIFT;
}
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,
.walk_lock = PGWALK_WRLOCK_VERIFY,
};
/*
* 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_folio() and raise page's mlock_count:
* double counting, leaving the page unevictable indefinitely.
* Communicate this danger to mlock_vma_folio() 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;
vma_start_write(vma);
vm_flags_reset_once(vma, 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;
vm_flags_reset_once(vma, 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 vma_iterator *vmi, 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;
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) || (oldflags & VM_DROPPABLE))
/* don't set VM_LOCKED or VM_LOCKONFAULT and don't count */
goto out;
vma = vma_modify_flags(vmi, *prev, vma, start, end, newflags);
if (IS_ERR(vma)) {
ret = PTR_ERR(vma);
goto out;
}
/*
* 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_start_write(vma);
vm_flags_reset(vma, 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;
VMA_ITERATOR(vmi, current->mm, 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 = vma_iter_load(&vmi);
if (!vma)
return -ENOMEM;
prev = vma_prev(&vmi);
if (start > vma->vm_start)
prev = vma;
nstart = start;
tmp = vma->vm_start;
for_each_vma_range(vmi, vma, end) {
int error;
vm_flags_t newflags;
if (vma->vm_start != tmp)
return -ENOMEM;
newflags = vma->vm_flags & ~VM_LOCKED_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(&vmi, vma, &prev, nstart, tmp, newflags);
if (error)
return error;
tmp = vma_iter_end(&vmi);
nstart = tmp;
}
if (tmp < end)
return -ENOMEM;
return 0;
}
/*
* 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)
{
VMA_ITERATOR(vmi, current->mm, 0);
struct vm_area_struct *vma, *prev = NULL;
vm_flags_t to_add = 0;
current->mm->def_flags &= ~VM_LOCKED_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;
}
for_each_vma(vmi, vma) {
vm_flags_t newflags;
newflags = vma->vm_flags & ~VM_LOCKED_MASK;
newflags |= to_add;
/* Ignore errors */
mlock_fixup(&vmi, vma, &prev, vma->vm_start, vma->vm_end,
newflags);
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);
}