X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=mm%2Fmlock.c;h=45eb650b9654ed09bebe3b4de3c203442538792d;hb=3701b0332330ca1add3e5d56513ef201ff7efdbb;hp=a6da2aee940af0873f46bd1b88b24a36242979b3;hpb=8891d6da17db0f9bb507d3a017f130b9970c3087;p=safe%2Fjmp%2Flinux-2.6 diff --git a/mm/mlock.c b/mm/mlock.c index a6da2ae..45eb650 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -31,7 +31,6 @@ int can_do_mlock(void) } EXPORT_SYMBOL(can_do_mlock); -#ifdef CONFIG_UNEVICTABLE_LRU /* * Mlocked pages are marked with PageMlocked() flag for efficient testing * in vmscan and, possibly, the fault path; and to support semi-accurate @@ -162,7 +161,7 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long addr = start; struct page *pages[16]; /* 16 gives a reasonable batch */ int nr_pages = (end - start) / PAGE_SIZE; - int ret; + int ret = 0; int gup_flags = 0; VM_BUG_ON(start & ~PAGE_MASK); @@ -173,12 +172,13 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma, (atomic_read(&mm->mm_users) != 0)); /* - * mlock: don't page populate if page has PROT_NONE permission. - * munlock: the pages always do munlock althrough - * its has PROT_NONE permission. + * mlock: don't page populate if vma has PROT_NONE permission. + * munlock: always do munlock although the vma has PROT_NONE + * permission, or SIGKILL is pending. */ if (!mlock) - gup_flags |= GUP_FLAGS_IGNORE_VMA_PERMISSIONS; + gup_flags |= GUP_FLAGS_IGNORE_VMA_PERMISSIONS | + GUP_FLAGS_IGNORE_SIGKILL; if (vma->vm_flags & VM_WRITE) gup_flags |= GUP_FLAGS_WRITE; @@ -260,27 +260,6 @@ static int __mlock_posix_error_return(long retval) return retval; } -#else /* CONFIG_UNEVICTABLE_LRU */ - -/* - * Just make pages present if VM_LOCKED. No-op if unlocking. - */ -static long __mlock_vma_pages_range(struct vm_area_struct *vma, - unsigned long start, unsigned long end, - int mlock) -{ - if (mlock && (vma->vm_flags & VM_LOCKED)) - return make_pages_present(start, end); - return 0; -} - -static inline int __mlock_posix_error_return(long retval) -{ - return 0; -} - -#endif /* CONFIG_UNEVICTABLE_LRU */ - /** * mlock_vma_pages_range() - mlock pages in specified vma range. * @vma - the vma containing the specfied address range @@ -293,14 +272,10 @@ static inline int __mlock_posix_error_return(long retval) * * return number of pages [> 0] to be removed from locked_vm on success * of "special" vmas. - * - * return negative error if vma spanning @start-@range disappears while - * mmap semaphore is dropped. Unlikely? */ long mlock_vma_pages_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { - struct mm_struct *mm = vma->vm_mm; int nr_pages = (end - start) / PAGE_SIZE; BUG_ON(!(vma->vm_flags & VM_LOCKED)); @@ -313,20 +288,11 @@ long mlock_vma_pages_range(struct vm_area_struct *vma, if (!((vma->vm_flags & (VM_DONTEXPAND | VM_RESERVED)) || is_vm_hugetlb_page(vma) || vma == get_gate_vma(current))) { - long error; - downgrade_write(&mm->mmap_sem); - - error = __mlock_vma_pages_range(vma, start, end, 1); - up_read(&mm->mmap_sem); - /* vma can change or disappear */ - down_write(&mm->mmap_sem); - vma = find_vma(mm, start); - /* non-NULL vma must contain @start, but need to check @end */ - if (!vma || end > vma->vm_end) - return -ENOMEM; + __mlock_vma_pages_range(vma, start, end, 1); - return 0; /* hide other errors from mmap(), et al */ + /* Hide errors from mmap() and other callers */ + return 0; } /* @@ -437,41 +403,14 @@ success: vma->vm_flags = newflags; if (lock) { - /* - * mmap_sem is currently held for write. Downgrade the write - * lock to a read lock so that other faults, mmap scans, ... - * while we fault in all pages. - */ - downgrade_write(&mm->mmap_sem); - ret = __mlock_vma_pages_range(vma, start, end, 1); - /* - * Need to reacquire mmap sem in write mode, as our callers - * expect this. We have no support for atomically upgrading - * a sem to write, so we need to check for ranges while sem - * is unlocked. - */ - up_read(&mm->mmap_sem); - /* vma can change or disappear */ - down_write(&mm->mmap_sem); - *prev = find_vma(mm, start); - /* non-NULL *prev must contain @start, but need to check @end */ - if (!(*prev) || end > (*prev)->vm_end) - ret = -ENOMEM; - else if (ret > 0) { + if (ret > 0) { mm->locked_vm -= ret; ret = 0; } else ret = __mlock_posix_error_return(ret); /* translate if needed */ } else { - /* - * TODO: for unlocking, pages will already be resident, so - * we don't need to wait for allocations/reclaim/pagein, ... - * However, unlocking a very large region can still take a - * while. Should we downgrade the semaphore for both lock - * AND unlock ? - */ __mlock_vma_pages_range(vma, start, end, 0); } @@ -529,7 +468,7 @@ static int do_mlock(unsigned long start, size_t len, int on) return error; } -asmlinkage long sys_mlock(unsigned long start, size_t len) +SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len) { unsigned long locked; unsigned long lock_limit; @@ -557,7 +496,7 @@ asmlinkage long sys_mlock(unsigned long start, size_t len) return error; } -asmlinkage long sys_munlock(unsigned long start, size_t len) +SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len) { int ret; @@ -594,7 +533,7 @@ out: return 0; } -asmlinkage long sys_mlockall(int flags) +SYSCALL_DEFINE1(mlockall, int, flags) { unsigned long lock_limit; int ret = -EINVAL; @@ -622,7 +561,7 @@ out: return ret; } -asmlinkage long sys_munlockall(void) +SYSCALL_DEFINE0(munlockall) { int ret; @@ -667,3 +606,44 @@ void user_shm_unlock(size_t size, struct user_struct *user) spin_unlock(&shmlock_user_lock); free_uid(user); } + +int account_locked_memory(struct mm_struct *mm, struct rlimit *rlim, + size_t size) +{ + unsigned long lim, vm, pgsz; + int error = -ENOMEM; + + pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT; + + down_write(&mm->mmap_sem); + + lim = rlim[RLIMIT_AS].rlim_cur >> PAGE_SHIFT; + vm = mm->total_vm + pgsz; + if (lim < vm) + goto out; + + lim = rlim[RLIMIT_MEMLOCK].rlim_cur >> PAGE_SHIFT; + vm = mm->locked_vm + pgsz; + if (lim < vm) + goto out; + + mm->total_vm += pgsz; + mm->locked_vm += pgsz; + + error = 0; + out: + up_write(&mm->mmap_sem); + return error; +} + +void refund_locked_memory(struct mm_struct *mm, size_t size) +{ + unsigned long pgsz = PAGE_ALIGN(size) >> PAGE_SHIFT; + + down_write(&mm->mmap_sem); + + mm->total_vm -= pgsz; + mm->locked_vm -= pgsz; + + up_write(&mm->mmap_sem); +}