Re: [PATCH v13 19/26] mm: Re-introduce do_mmap_pgoff()

There was no more caller passing vm_flags to do_mmap(), and vm_flags was
removed from the function's input by:

     commit 45e55300f114 ("mm: remove unnecessary wrapper function
do_mmap_pgoff()").

There is a new user now.  Shadow stack allocation passes VM_SHSTK to
do_mmap().  Re-introduce vm_flags to do_mmap(), but without the old wrapper
do_mmap_pgoff().  Instead, fix all callers of the wrapper by passing a zero
vm_flags to do_mmap().

Signed-off-by: Yu-cheng Yu <redacted>
Cc: Peter Collingbourne <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: linux-mm@kvack.org
---
  fs/aio.c           |  2 +-
  include/linux/mm.h |  3 ++-
  ipc/shm.c          |  2 +-
  mm/mmap.c          | 10 +++++-----
  mm/nommu.c         |  4 ++--
  mm/util.c          |  2 +-
  6 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/fs/aio.c b/fs/aio.c
index d5ec30385566..ca8c11665eea 100644
--- a/fs/aio.c
+++ b/fs/aio.c

@@ -527,7 +527,7 @@ static int aio_setup_ring(struct kioctx *ctx,

unsigned int nr_events)

        ctx->mmap_base = do_mmap(ctx->aio_ring_file, 0, ctx->mmap_size,
                                 PROT_READ | PROT_WRITE,
-                                MAP_SHARED, 0, &unused, NULL);
+                                MAP_SHARED, 0, 0, &unused, NULL);
        mmap_write_unlock(mm);
        if (IS_ERR((void *)ctx->mmap_base)) {
                ctx->mmap_size = 0;

diff --git a/include/linux/mm.h b/include/linux/mm.h
index e09d13699bbe..e020eea33138 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -2560,7 +2560,8 @@ extern unsigned long mmap_region(struct file

*file, unsigned long addr,
        struct list_head *uf);
  extern unsigned long do_mmap(struct file *file, unsigned long addr,
        unsigned long len, unsigned long prot, unsigned long flags,
-       unsigned long pgoff, unsigned long *populate, struct list_head *uf);
+       vm_flags_t vm_flags, unsigned long pgoff, unsigned long *populate,
+       struct list_head *uf);
  extern int __do_munmap(struct mm_struct *, unsigned long, size_t,
                       struct list_head *uf, bool downgrade);
  extern int do_munmap(struct mm_struct *, unsigned long, size_t,

diff --git a/ipc/shm.c b/ipc/shm.c
index e25c7c6106bc..91474258933d 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c

@@ -1556,7 +1556,7 @@ long do_shmat(int shmid, char __user *shmaddr, int

shmflg,
                        goto invalid;
        }

-       addr = do_mmap(file, addr, size, prot, flags, 0, &populate, NULL);
+       addr = do_mmap(file, addr, size, prot, flags, 0, 0, &populate, NULL);
        *raddr = addr;
        err = 0;
        if (IS_ERR_VALUE(addr))

diff --git a/mm/mmap.c b/mm/mmap.c
index 574b3f273462..fc04184d2eae 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c

@@ -1365,11 +1365,11 @@ static inline bool file_mmap_ok(struct file

*file, struct inode *inode,
   */
  unsigned long do_mmap(struct file *file, unsigned long addr,
                        unsigned long len, unsigned long prot,
-                       unsigned long flags, unsigned long pgoff,
-                       unsigned long *populate, struct list_head *uf)
+                       unsigned long flags, vm_flags_t vm_flags,
+                       unsigned long pgoff, unsigned long *populate,
+                       struct list_head *uf)
  {
        struct mm_struct *mm = current->mm;
-       vm_flags_t vm_flags;
        int pkey = 0;

        *populate = 0;

@@ -1431,7 +1431,7 @@ unsigned long do_mmap(struct file *file, unsigned

long addr,
         * to. we assume access permissions have been handled by the open
         * of the memory object, so we don't do any here.
         */
-       vm_flags = calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
+       vm_flags |= calc_vm_prot_bits(prot, pkey) | calc_vm_flag_bits(flags) |
                        mm->def_flags | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;

        if (flags & MAP_LOCKED)

@@ -3007,7 +3007,7 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long,

start, unsigned long, size,

        file = get_file(vma->vm_file);
        ret = do_mmap(vma->vm_file, start, size,
-                       prot, flags, pgoff, &populate, NULL);
+                       prot, flags, 0, pgoff, &populate, NULL);
        fput(file);
  out:
        mmap_write_unlock(mm);

diff --git a/mm/nommu.c b/mm/nommu.c
index 75a327149af1..f67d6bcdfc9f 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c

@@ -1078,6 +1078,7 @@ unsigned long do_mmap(struct file *file,
                        unsigned long len,
                        unsigned long prot,
                        unsigned long flags,
+                       vm_flags_t vm_flags,
                        unsigned long pgoff,
                        unsigned long *populate,
                        struct list_head *uf)

@@ -1085,7 +1086,6 @@ unsigned long do_mmap(struct file *file,
        struct vm_area_struct *vma;
        struct vm_region *region;
        struct rb_node *rb;
-       vm_flags_t vm_flags;
        unsigned long capabilities, result;
        int ret;

@@ -1104,7 +1104,7 @@ unsigned long do_mmap(struct file *file,

        /* we've determined that we can make the mapping, now translate what we
         * now know into VMA flags */
-       vm_flags = determine_vm_flags(file, prot, flags, capabilities);
+       vm_flags |= determine_vm_flags(file, prot, flags, capabilities);

        /* we're going to need to record the mapping */
        region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);

diff --git a/mm/util.c b/mm/util.c
index 5ef378a2a038..beb8b881c080 100644
--- a/mm/util.c
+++ b/mm/util.c

@@ -503,7 +503,7 @@ unsigned long vm_mmap_pgoff(struct file *file,

unsigned long addr,
        if (!ret) {
                if (mmap_write_lock_killable(mm))
                        return -EINTR;
-               ret = do_mmap(file, addr, len, prot, flag, pgoff, &populate,
+               ret = do_mmap(file, addr, len, prot, flag, 0, pgoff, &populate,
                              &uf);
                mmap_write_unlock(mm);
                userfaultfd_unmap_complete(mm, &uf);
--
2.21.0