lkml.org 
[lkml]   [2019]   [May]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 07/14] fs: teach the mm about range locking
Date
Conversion is straightforward, mmap_sem is used within the
the same function context most of the time. No change in
semantics.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
---
fs/aio.c | 5 +++--
fs/coredump.c | 5 +++--
fs/exec.c | 19 +++++++++-------
fs/io_uring.c | 5 +++--
fs/proc/base.c | 23 ++++++++++++--------
fs/proc/internal.h | 2 ++
fs/proc/task_mmu.c | 32 +++++++++++++++------------
fs/proc/task_nommu.c | 22 +++++++++++--------
fs/userfaultfd.c | 50 ++++++++++++++++++++++++++-----------------
include/linux/userfaultfd_k.h | 5 +++--
10 files changed, 100 insertions(+), 68 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index 3490d1fa0e16..215d19dbbefa 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -461,6 +461,7 @@ static const struct address_space_operations aio_ctx_aops = {

static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
struct aio_ring *ring;
struct mm_struct *mm = current->mm;
unsigned long size, unused;
@@ -521,7 +522,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ctx->mmap_size = nr_pages * PAGE_SIZE;
pr_debug("attempting mmap of %lu bytes\n", ctx->mmap_size);

- if (down_write_killable(&mm->mmap_sem)) {
+ if (mm_write_lock_killable(mm, &mmrange)) {
ctx->mmap_size = 0;
aio_free_ring(ctx);
return -EINTR;
@@ -530,7 +531,7 @@ static int aio_setup_ring(struct kioctx *ctx, unsigned int nr_events)
ctx->mmap_base = do_mmap_pgoff(ctx->aio_ring_file, 0, ctx->mmap_size,
PROT_READ | PROT_WRITE,
MAP_SHARED, 0, &unused, NULL);
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
if (IS_ERR((void *)ctx->mmap_base)) {
ctx->mmap_size = 0;
aio_free_ring(ctx);
diff --git a/fs/coredump.c b/fs/coredump.c
index e42e17e55bfd..433713b63187 100644
--- a/fs/coredump.c
+++ b/fs/coredump.c
@@ -409,6 +409,7 @@ static int zap_threads(struct task_struct *tsk, struct mm_struct *mm,

static int coredump_wait(int exit_code, struct core_state *core_state)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
struct task_struct *tsk = current;
struct mm_struct *mm = tsk->mm;
int core_waiters = -EBUSY;
@@ -417,12 +418,12 @@ static int coredump_wait(int exit_code, struct core_state *core_state)
core_state->dumper.task = tsk;
core_state->dumper.next = NULL;

- if (down_write_killable(&mm->mmap_sem))
+ if (mm_write_lock_killable(mm, &mmrange))
return -EINTR;

if (!mm->core_state)
core_waiters = zap_threads(tsk, mm, core_state, exit_code);
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);

if (core_waiters > 0) {
struct core_thread *ptr;
diff --git a/fs/exec.c b/fs/exec.c
index e96fd5328739..fbcb36bc4fd1 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -241,6 +241,7 @@ static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,

static int __bprm_mm_init(struct linux_binprm *bprm)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
int err;
struct vm_area_struct *vma = NULL;
struct mm_struct *mm = bprm->mm;
@@ -250,7 +251,7 @@ static int __bprm_mm_init(struct linux_binprm *bprm)
return -ENOMEM;
vma_set_anonymous(vma);

- if (down_write_killable(&mm->mmap_sem)) {
+ if (mm_write_lock_killable(mm, &mmrange)) {
err = -EINTR;
goto err_free;
}
@@ -273,11 +274,11 @@ static int __bprm_mm_init(struct linux_binprm *bprm)

mm->stack_vm = mm->total_vm = 1;
arch_bprm_mm_init(mm, vma);
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
bprm->p = vma->vm_end - sizeof(void *);
return 0;
err:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
err_free:
bprm->vma = NULL;
vm_area_free(vma);
@@ -691,6 +692,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
unsigned long stack_top,
int executable_stack)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
unsigned long ret;
unsigned long stack_shift;
struct mm_struct *mm = current->mm;
@@ -738,7 +740,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
bprm->loader -= stack_shift;
bprm->exec -= stack_shift;

- if (down_write_killable(&mm->mmap_sem))
+ if (mm_write_lock_killable(mm, &mmrange))
return -EINTR;

vm_flags = VM_STACK_FLAGS;
@@ -795,7 +797,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
ret = -EFAULT;

out_unlock:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
return ret;
}
EXPORT_SYMBOL(setup_arg_pages);
@@ -1010,6 +1012,7 @@ static int exec_mmap(struct mm_struct *mm)
{
struct task_struct *tsk;
struct mm_struct *old_mm, *active_mm;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

/* Notify parent that we're no longer interested in the old VM */
tsk = current;
@@ -1024,9 +1027,9 @@ static int exec_mmap(struct mm_struct *mm)
* through with the exec. We must hold mmap_sem around
* checking core_state and changing tsk->mm.
*/
- down_read(&old_mm->mmap_sem);
+ mm_read_lock(old_mm, &mmrange);
if (unlikely(old_mm->core_state)) {
- up_read(&old_mm->mmap_sem);
+ mm_read_unlock(old_mm, &mmrange);
return -EINTR;
}
}
@@ -1039,7 +1042,7 @@ static int exec_mmap(struct mm_struct *mm)
vmacache_flush(tsk);
task_unlock(tsk);
if (old_mm) {
- up_read(&old_mm->mmap_sem);
+ mm_read_unlock(old_mm, &mmrange);
BUG_ON(active_mm != old_mm);
setmax_mm_hiwater_rss(&tsk->signal->maxrss, old_mm);
mm_update_next_owner(old_mm);
diff --git a/fs/io_uring.c b/fs/io_uring.c
index e11d77181398..16c06811193b 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2597,6 +2597,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
struct page **pages = NULL;
int i, j, got_pages = 0;
int ret = -EINVAL;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

if (ctx->user_bufs)
return -EBUSY;
@@ -2671,7 +2672,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
}

ret = 0;
- down_read(&current->mm->mmap_sem);
+ mm_read_lock(current->mm, &mmrange);
pret = get_user_pages(ubuf, nr_pages,
FOLL_WRITE | FOLL_LONGTERM,
pages, vmas);
@@ -2689,7 +2690,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
} else {
ret = pret < 0 ? pret : -EFAULT;
}
- up_read(&current->mm->mmap_sem);
+ mm_read_unlock(current->mm, &mmrange);
if (ret) {
/*
* if we did partial map, or found file backed vmas,
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 9c8ca6cd3ce4..63d0fea104af 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -1962,9 +1962,11 @@ static int map_files_d_revalidate(struct dentry *dentry, unsigned int flags)
goto out;

if (!dname_to_vma_addr(dentry, &vm_start, &vm_end)) {
- down_read(&mm->mmap_sem);
+ DEFINE_RANGE_LOCK_FULL(mmrange);
+
+ mm_read_lock(mm, &mmrange);
exact_vma_exists = !!find_exact_vma(mm, vm_start, vm_end);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
}

mmput(mm);
@@ -1995,6 +1997,7 @@ static int map_files_get_link(struct dentry *dentry, struct path *path)
struct task_struct *task;
struct mm_struct *mm;
int rc;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

rc = -ENOENT;
task = get_proc_task(d_inode(dentry));
@@ -2011,14 +2014,14 @@ static int map_files_get_link(struct dentry *dentry, struct path *path)
goto out_mmput;

rc = -ENOENT;
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
vma = find_exact_vma(mm, vm_start, vm_end);
if (vma && vma->vm_file) {
*path = vma->vm_file->f_path;
path_get(path);
rc = 0;
}
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);

out_mmput:
mmput(mm);
@@ -2089,6 +2092,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
struct task_struct *task;
struct dentry *result;
struct mm_struct *mm;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

result = ERR_PTR(-ENOENT);
task = get_proc_task(dir);
@@ -2107,7 +2111,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
if (!mm)
goto out_put_task;

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
vma = find_exact_vma(mm, vm_start, vm_end);
if (!vma)
goto out_no_vma;
@@ -2117,7 +2121,7 @@ static struct dentry *proc_map_files_lookup(struct inode *dir,
(void *)(unsigned long)vma->vm_file->f_mode);

out_no_vma:
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
mmput(mm);
out_put_task:
put_task_struct(task);
@@ -2141,6 +2145,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
GENRADIX(struct map_files_info) fa;
struct map_files_info *p;
int ret;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

genradix_init(&fa);

@@ -2160,7 +2165,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
mm = get_task_mm(task);
if (!mm)
goto out_put_task;
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);

nr_files = 0;

@@ -2183,7 +2188,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
p = genradix_ptr_alloc(&fa, nr_files++, GFP_KERNEL);
if (!p) {
ret = -ENOMEM;
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
mmput(mm);
goto out_put_task;
}
@@ -2192,7 +2197,7 @@ proc_map_files_readdir(struct file *file, struct dir_context *ctx)
p->end = vma->vm_end;
p->mode = vma->vm_file->f_mode;
}
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
mmput(mm);

for (i = 0; i < nr_files; i++) {
diff --git a/fs/proc/internal.h b/fs/proc/internal.h
index d1671e97f7fe..df6f0ec84a8f 100644
--- a/fs/proc/internal.h
+++ b/fs/proc/internal.h
@@ -15,6 +15,7 @@
#include <linux/spinlock.h>
#include <linux/atomic.h>
#include <linux/binfmts.h>
+#include <linux/range_lock.h>
#include <linux/sched/coredump.h>
#include <linux/sched/task.h>

@@ -287,6 +288,7 @@ struct proc_maps_private {
#ifdef CONFIG_NUMA
struct mempolicy *task_mempolicy;
#endif
+ struct range_lock mmrange;
} __randomize_layout;

struct mm_struct *proc_mem_open(struct inode *inode, unsigned int mode);
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index a1c2ad9f960a..7ab5c6f5b8aa 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -128,7 +128,7 @@ static void vma_stop(struct proc_maps_private *priv)
struct mm_struct *mm = priv->mm;

release_task_mempolicy(priv);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &priv->mmrange);
mmput(mm);
}

@@ -166,7 +166,9 @@ static void *m_start(struct seq_file *m, loff_t *ppos)
if (!mm || !mmget_not_zero(mm))
return NULL;

- down_read(&mm->mmap_sem);
+ range_lock_init_full(&priv->mmrange);
+
+ mm_read_lock(mm, &priv->mmrange);
hold_task_mempolicy(priv);
priv->tail_vma = get_gate_vma(mm);

@@ -828,7 +830,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)

memset(&mss, 0, sizeof(mss));

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &priv->mmrange);
hold_task_mempolicy(priv);

for (vma = priv->mm->mmap; vma; vma = vma->vm_next) {
@@ -844,7 +846,7 @@ static int show_smaps_rollup(struct seq_file *m, void *v)
__show_smap(m, &mss);

release_task_mempolicy(priv);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &priv->mmrange);
mmput(mm);

out_put_task:
@@ -1080,6 +1082,7 @@ static int clear_refs_test_walk(unsigned long start, unsigned long end,
static ssize_t clear_refs_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
+ DEFINE_RANGE_LOCK_FULL(mmrange);
struct task_struct *task;
char buffer[PROC_NUMBUF];
struct mm_struct *mm;
@@ -1118,7 +1121,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
};

if (type == CLEAR_REFS_MM_HIWATER_RSS) {
- if (down_write_killable(&mm->mmap_sem)) {
+ if (mm_write_lock_killable(mm, &mmrange)) {
count = -EINTR;
goto out_mm;
}
@@ -1128,18 +1131,18 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
* resident set size to this mm's current rss value.
*/
reset_mm_hiwater_rss(mm);
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
goto out_mm;
}

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
tlb_gather_mmu(&tlb, mm, 0, -1);
if (type == CLEAR_REFS_SOFT_DIRTY) {
for (vma = mm->mmap; vma; vma = vma->vm_next) {
if (!(vma->vm_flags & VM_SOFTDIRTY))
continue;
- up_read(&mm->mmap_sem);
- if (down_write_killable(&mm->mmap_sem)) {
+ mm_read_unlock(mm, &mmrange);
+ if (mm_write_lock_killable(mm, &mmrange)) {
count = -EINTR;
goto out_mm;
}
@@ -1158,14 +1161,14 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
* failed like if
* get_proc_task() fails?
*/
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
goto out_mm;
}
for (vma = mm->mmap; vma; vma = vma->vm_next) {
vma->vm_flags &= ~VM_SOFTDIRTY;
vma_set_page_prot(vma);
}
- downgrade_write(&mm->mmap_sem);
+ mm_downgrade_write(mm, &mmrange);
break;
}

@@ -1177,7 +1180,7 @@ static ssize_t clear_refs_write(struct file *file, const char __user *buf,
if (type == CLEAR_REFS_SOFT_DIRTY)
mmu_notifier_invalidate_range_end(&range);
tlb_finish_mmu(&tlb, 0, -1);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
out_mm:
mmput(mm);
}
@@ -1484,6 +1487,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
unsigned long start_vaddr;
unsigned long end_vaddr;
int ret = 0, copied = 0;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

if (!mm || !mmget_not_zero(mm))
goto out;
@@ -1539,9 +1543,9 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
/* overflow ? */
if (end < start_vaddr || end > end_vaddr)
end = end_vaddr;
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
ret = walk_page_range(start_vaddr, end, &pagemap_walk);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
start_vaddr = end;

len = min(count, PM_ENTRY_BYTES * pm.pos);
diff --git a/fs/proc/task_nommu.c b/fs/proc/task_nommu.c
index 36bf0f2e102e..32bf2860eff3 100644
--- a/fs/proc/task_nommu.c
+++ b/fs/proc/task_nommu.c
@@ -23,9 +23,10 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
struct vm_area_struct *vma;
struct vm_region *region;
struct rb_node *p;
+ DEFINE_RANGE_LOCK_FULL(mmrange);
unsigned long bytes = 0, sbytes = 0, slack = 0, size;

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
vma = rb_entry(p, struct vm_area_struct, vm_rb);

@@ -77,7 +78,7 @@ void task_mem(struct seq_file *m, struct mm_struct *mm)
"Shared:\t%8lu bytes\n",
bytes, slack, sbytes);

- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
}

unsigned long task_vsize(struct mm_struct *mm)
@@ -85,13 +86,14 @@ unsigned long task_vsize(struct mm_struct *mm)
struct vm_area_struct *vma;
struct rb_node *p;
unsigned long vsize = 0;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
vma = rb_entry(p, struct vm_area_struct, vm_rb);
vsize += vma->vm_end - vma->vm_start;
}
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
return vsize;
}

@@ -103,8 +105,9 @@ unsigned long task_statm(struct mm_struct *mm,
struct vm_region *region;
struct rb_node *p;
unsigned long size = kobjsize(mm);
+ DEFINE_RANGE_LOCK_FULL(mmrange);

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
for (p = rb_first(&mm->mm_rb); p; p = rb_next(p)) {
vma = rb_entry(p, struct vm_area_struct, vm_rb);
size += kobjsize(vma);
@@ -119,7 +122,7 @@ unsigned long task_statm(struct mm_struct *mm,
>> PAGE_SHIFT;
*data = (PAGE_ALIGN(mm->start_stack) - (mm->start_data & PAGE_MASK))
>> PAGE_SHIFT;
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
size >>= PAGE_SHIFT;
size += *text + *data;
*resident = size;
@@ -201,6 +204,7 @@ static void *m_start(struct seq_file *m, loff_t *pos)
struct mm_struct *mm;
struct rb_node *p;
loff_t n = *pos;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

/* pin the task and mm whilst we play with them */
priv->task = get_proc_task(priv->inode);
@@ -211,13 +215,13 @@ static void *m_start(struct seq_file *m, loff_t *pos)
if (!mm || !mmget_not_zero(mm))
return NULL;

- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, &mmrange);
/* start from the Nth VMA */
for (p = rb_first(&mm->mm_rb); p; p = rb_next(p))
if (n-- == 0)
return p;

- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, &mmrange);
mmput(mm);
return NULL;
}
@@ -227,7 +231,7 @@ static void m_stop(struct seq_file *m, void *_vml)
struct proc_maps_private *priv = m->private;

if (!IS_ERR_OR_NULL(_vml)) {
- up_read(&priv->mm->mmap_sem);
+ mm_read_unlock(priv->mm, &mmrange);
mmput(priv->mm);
}
if (priv->task) {
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 3b30301c90ec..3592f6d71778 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -220,13 +220,14 @@ static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
struct vm_area_struct *vma,
unsigned long address,
unsigned long flags,
- unsigned long reason)
+ unsigned long reason,
+ struct range_lock *mmrange)
{
struct mm_struct *mm = ctx->mm;
pte_t *ptep, pte;
bool ret = true;

- VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+ VM_BUG_ON(!mm_is_locked(mm, mmrange));

ptep = huge_pte_offset(mm, address, vma_mmu_pagesize(vma));

@@ -252,7 +253,9 @@ static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
struct vm_area_struct *vma,
unsigned long address,
unsigned long flags,
- unsigned long reason)
+ unsigned long reason,
+ struct range_lock *mmrange)
+
{
return false; /* should never get here */
}
@@ -268,7 +271,8 @@ static inline bool userfaultfd_huge_must_wait(struct userfaultfd_ctx *ctx,
static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
unsigned long address,
unsigned long flags,
- unsigned long reason)
+ unsigned long reason,
+ struct range_lock *mmrange)
{
struct mm_struct *mm = ctx->mm;
pgd_t *pgd;
@@ -278,7 +282,7 @@ static inline bool userfaultfd_must_wait(struct userfaultfd_ctx *ctx,
pte_t *pte;
bool ret = true;

- VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+ VM_BUG_ON(!mm_is_locked(mm, mmrange));

pgd = pgd_offset(mm, address);
if (!pgd_present(*pgd))
@@ -368,7 +372,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
* Coredumping runs without mmap_sem so we can only check that
* the mmap_sem is held, if PF_DUMPCORE was not set.
*/
- WARN_ON_ONCE(!rwsem_is_locked(&mm->mmap_sem));
+ WARN_ON_ONCE(!mm_is_locked(mm, vmf->lockrange));

ctx = vmf->vma->vm_userfaultfd_ctx.ctx;
if (!ctx)
@@ -476,12 +480,13 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)

if (!is_vm_hugetlb_page(vmf->vma))
must_wait = userfaultfd_must_wait(ctx, vmf->address, vmf->flags,
- reason);
+ reason, vmf->lockrange);
else
must_wait = userfaultfd_huge_must_wait(ctx, vmf->vma,
vmf->address,
- vmf->flags, reason);
- up_read(&mm->mmap_sem);
+ vmf->flags, reason,
+ vmf->lockrange);
+ mm_read_unlock(mm, vmf->lockrange);

if (likely(must_wait && !READ_ONCE(ctx->released) &&
(return_to_userland ? !signal_pending(current) :
@@ -535,7 +540,7 @@ vm_fault_t handle_userfault(struct vm_fault *vmf, unsigned long reason)
* and there's no need to retake the mmap_sem
* in such case.
*/
- down_read(&mm->mmap_sem);
+ mm_read_lock(mm, vmf->lockrange);
ret = VM_FAULT_NOPAGE;
}
}
@@ -628,9 +633,10 @@ static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
if (release_new_ctx) {
struct vm_area_struct *vma;
struct mm_struct *mm = release_new_ctx->mm;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

/* the various vma->vm_userfaultfd_ctx still points to it */
- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
/* no task can run (and in turn coredump) yet */
VM_WARN_ON(!mmget_still_valid(mm));
for (vma = mm->mmap; vma; vma = vma->vm_next)
@@ -638,7 +644,7 @@ static void userfaultfd_event_wait_completion(struct userfaultfd_ctx *ctx,
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
vma->vm_flags &= ~(VM_UFFD_WP | VM_UFFD_MISSING);
}
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);

userfaultfd_ctx_put(release_new_ctx);
}
@@ -780,7 +786,8 @@ void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *vm_ctx,
}

bool userfaultfd_remove(struct vm_area_struct *vma,
- unsigned long start, unsigned long end)
+ unsigned long start, unsigned long end,
+ struct range_lock *mmrange)
{
struct mm_struct *mm = vma->vm_mm;
struct userfaultfd_ctx *ctx;
@@ -792,7 +799,7 @@ bool userfaultfd_remove(struct vm_area_struct *vma,

userfaultfd_ctx_get(ctx);
WRITE_ONCE(ctx->mmap_changing, true);
- up_read(&mm->mmap_sem);
+ mm_read_unlock(mm, mmrange);

msg_init(&ewq.msg);

@@ -872,6 +879,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
/* len == 0 means wake all */
struct userfaultfd_wake_range range = { .len = 0, };
unsigned long new_flags;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

WRITE_ONCE(ctx->released, true);

@@ -886,7 +894,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
* it's critical that released is set to true (above), before
* taking the mmap_sem for writing.
*/
- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
if (!mmget_still_valid(mm))
goto skip_mm;
prev = NULL;
@@ -912,7 +920,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
vma->vm_userfaultfd_ctx = NULL_VM_UFFD_CTX;
}
skip_mm:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
mmput(mm);
wakeup:
/*
@@ -1299,6 +1307,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
unsigned long vm_flags, new_flags;
bool found;
bool basic_ioctls;
+ DEFINE_RANGE_LOCK_FULL(mmrange);
unsigned long start, end, vma_end;

user_uffdio_register = (struct uffdio_register __user *) arg;
@@ -1339,7 +1348,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
if (!mmget_not_zero(mm))
goto out;

- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
if (!mmget_still_valid(mm))
goto out_unlock;
vma = find_vma_prev(mm, start, &prev);
@@ -1483,7 +1492,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
out_unlock:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
mmput(mm);
if (!ret) {
/*
@@ -1511,6 +1520,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
bool found;
unsigned long start, end, vma_end;
const void __user *buf = (void __user *)arg;
+ DEFINE_RANGE_LOCK_FULL(mmrange);

ret = -EFAULT;
if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
@@ -1528,7 +1538,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
if (!mmget_not_zero(mm))
goto out;

- down_write(&mm->mmap_sem);
+ mm_write_lock(mm, &mmrange);
if (!mmget_still_valid(mm))
goto out_unlock;
vma = find_vma_prev(mm, start, &prev);
@@ -1645,7 +1655,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
vma = vma->vm_next;
} while (vma && vma->vm_start < end);
out_unlock:
- up_write(&mm->mmap_sem);
+ mm_write_unlock(mm, &mmrange);
mmput(mm);
out:
return ret;
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index ac9d71e24b81..c8d3c102ce5e 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -68,7 +68,7 @@ extern void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *,

extern bool userfaultfd_remove(struct vm_area_struct *vma,
unsigned long start,
- unsigned long end);
+ unsigned long end, struct range_lock *mmrange);

extern int userfaultfd_unmap_prep(struct vm_area_struct *vma,
unsigned long start, unsigned long end,
@@ -125,7 +125,8 @@ static inline void mremap_userfaultfd_complete(struct vm_userfaultfd_ctx *ctx,

static inline bool userfaultfd_remove(struct vm_area_struct *vma,
unsigned long start,
- unsigned long end)
+ unsigned long end,
+ struct range_lock *mmrange)
{
return true;
}
--
2.16.4
\
 
 \ /
  Last update: 2019-05-21 06:54    [W:0.073 / U:19.364 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site