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-rw-r--r--mm/mlock.c785
1 files changed, 785 insertions, 0 deletions
diff --git a/mm/mlock.c b/mm/mlock.c
new file mode 100644
index 0000000000..06bdfab83b
--- /dev/null
+++ b/mm/mlock.c
@@ -0,0 +1,785 @@
+// 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->folios, folio_batch_count(fbatch));
+ folio_batch_reinit(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 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;
+
+ ptl = pmd_trans_huge_lock(pmd, vma);
+ if (ptl) {
+ if (!pmd_present(*pmd))
+ goto out;
+ if (is_huge_zero_pmd(*pmd))
+ goto out;
+ folio = page_folio(pmd_page(*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;
+ if (folio_test_large(folio))
+ continue;
+ if (vma->vm_flags & VM_LOCKED)
+ mlock_folio(folio);
+ else
+ munlock_folio(folio);
+ }
+ 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;
+ 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(vmi, 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(vmi, vma, start, 1);
+ if (ret)
+ goto out;
+ }
+
+ if (end != vma->vm_end) {
+ ret = split_vma(vmi, 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_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);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-28 01:38:44 +0000