mm: remove VM_DENYWRITE

All in-tree users of MAP_DENYWRITE are gone. MAP_DENYWRITE cannot be
set from user space, so all users are gone; let's remove it.

Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Christian König <christian.koenig@amd.com>
Signed-off-by: David Hildenbrand <david@redhat.com>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index eb97468..cf25be3 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -619,7 +619,6 @@ static void show_smap_vma_flags(struct seq_file *m, struct vm_area_struct *vma)
                [ilog2(VM_MAYSHARE)]    = "ms",
                [ilog2(VM_GROWSDOWN)]   = "gd",
                [ilog2(VM_PFNMAP)]      = "pf",
-               [ilog2(VM_DENYWRITE)]   = "dw",
                [ilog2(VM_LOCKED)]      = "lo",
                [ilog2(VM_IO)]          = "io",
                [ilog2(VM_SEQ_READ)]    = "sr",

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 56b1cd4..257995f 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -281,7 +281,6 @@ extern unsigned int kobjsize(const void *objp);
 #define VM_GROWSDOWN   0x00000100      /* general info on the segment */
 #define VM_UFFD_MISSING        0x00000200      /* missing pages tracking */
 #define VM_PFNMAP      0x00000400      /* Page-ranges managed without "struct page", just pure PFN */
-#define VM_DENYWRITE   0x00000800      /* ETXTBSY on write attempts.. */
 #define VM_UFFD_WP     0x00001000      /* wrprotect pages tracking */
 
 #define VM_LOCKED      0x00002000

diff --git a/include/linux/mman.h b/include/linux/mman.h
index ebb09a9..bd9aadd 100644 (file)
--- a/include/linux/mman.h
+++ b/include/linux/mman.h
@@ -153,7 +153,6 @@ static inline unsigned long
 calc_vm_flag_bits(unsigned long flags)
 {
        return _calc_vm_trans(flags, MAP_GROWSDOWN,  VM_GROWSDOWN ) |
-              _calc_vm_trans(flags, MAP_DENYWRITE,  VM_DENYWRITE ) |
               _calc_vm_trans(flags, MAP_LOCKED,     VM_LOCKED    ) |
               _calc_vm_trans(flags, MAP_SYNC,       VM_SYNC      ) |
               arch_calc_vm_flag_bits(flags);

diff --git a/include/trace/events/mmflags.h b/include/trace/events/mmflags.h
index f160484..0b53e85 100644 (file)
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h
@@ -165,7 +165,6 @@ IF_HAVE_PG_SKIP_KASAN_POISON(PG_skip_kasan_poison, "skip_kasan_poison")
        {VM_UFFD_MISSING,               "uffd_missing"  },              \
 IF_HAVE_UFFD_MINOR(VM_UFFD_MINOR,      "uffd_minor"    )               \
        {VM_PFNMAP,                     "pfnmap"        },              \
-       {VM_DENYWRITE,                  "denywrite"     },              \
        {VM_UFFD_WP,                    "uffd_wp"       },              \
        {VM_LOCKED,                     "locked"        },              \
        {VM_IO,                         "io"            },              \

diff --git a/kernel/events/core.c b/kernel/events/core.c
index 1cb1f9b..19767bb 100644 (file)
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8307,8 +8307,6 @@ static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
        else
                flags = MAP_PRIVATE;
 
-       if (vma->vm_flags & VM_DENYWRITE)
-               flags |= MAP_DENYWRITE;
        if (vma->vm_flags & VM_LOCKED)
                flags |= MAP_LOCKED;
        if (is_vm_hugetlb_page(vma))

diff --git a/kernel/fork.c b/kernel/fork.c
index 7677f89..feef105 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -570,12 +570,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
                tmp->vm_flags &= ~(VM_LOCKED | VM_LOCKONFAULT);
                file = tmp->vm_file;
                if (file) {
-                       struct inode *inode = file_inode(file);
                        struct address_space *mapping = file->f_mapping;
 
                        get_file(file);
-                       if (tmp->vm_flags & VM_DENYWRITE)
-                               put_write_access(inode);
                        i_mmap_lock_write(mapping);
                        if (tmp->vm_flags & VM_SHARED)
                                mapping_allow_writable(mapping);

diff --git a/lib/test_printf.c b/lib/test_printf.c
index 8ac71ae..8a48b61 100644 (file)
--- a/lib/test_printf.c
+++ b/lib/test_printf.c
@@ -675,9 +675,8 @@ flags(void)
                        "uptodate|dirty|lru|active|swapbacked",
                        cmp_buffer);
 
-       flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC
-                       | VM_DENYWRITE;
-       test("read|exec|mayread|maywrite|mayexec|denywrite", "%pGv", &flags);
+       flags = VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
+       test("read|exec|mayread|maywrite|mayexec", "%pGv", &flags);
 
        gfp = GFP_TRANSHUGE;
        test("GFP_TRANSHUGE", "%pGg", &gfp);

diff --git a/mm/mmap.c b/mm/mmap.c
index ca54d36..589dc1d 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -148,8 +148,6 @@ void vma_set_page_prot(struct vm_area_struct *vma)
 static void __remove_shared_vm_struct(struct vm_area_struct *vma,
                struct file *file, struct address_space *mapping)
 {
-       if (vma->vm_flags & VM_DENYWRITE)
-               allow_write_access(file);
        if (vma->vm_flags & VM_SHARED)
                mapping_unmap_writable(mapping);
 
@@ -666,8 +664,6 @@ static void __vma_link_file(struct vm_area_struct *vma)
        if (file) {
                struct address_space *mapping = file->f_mapping;
 
-               if (vma->vm_flags & VM_DENYWRITE)
-                       put_write_access(file_inode(file));
                if (vma->vm_flags & VM_SHARED)
                        mapping_allow_writable(mapping);
 
@@ -1788,22 +1784,12 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
        vma->vm_pgoff = pgoff;
 
        if (file) {
-               if (vm_flags & VM_DENYWRITE) {
-                       error = deny_write_access(file);
-                       if (error)
-                               goto free_vma;
-               }
                if (vm_flags & VM_SHARED) {
                        error = mapping_map_writable(file->f_mapping);
                        if (error)
-                               goto allow_write_and_free_vma;
+                               goto free_vma;
                }
 
-               /* ->mmap() can change vma->vm_file, but must guarantee that
-                * vma_link() below can deny write-access if VM_DENYWRITE is set
-                * and map writably if VM_SHARED is set. This usually means the
-                * new file must not have been exposed to user-space, yet.
-                */
                vma->vm_file = get_file(file);
                error = call_mmap(file, vma);
                if (error)
@@ -1860,13 +1846,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 
        vma_link(mm, vma, prev, rb_link, rb_parent);
        /* Once vma denies write, undo our temporary denial count */
-       if (file) {
 unmap_writable:
-               if (vm_flags & VM_SHARED)
-                       mapping_unmap_writable(file->f_mapping);
-               if (vm_flags & VM_DENYWRITE)
-                       allow_write_access(file);
-       }
+       if (file && vm_flags & VM_SHARED)
+               mapping_unmap_writable(file->f_mapping);
        file = vma->vm_file;
 out:
        perf_event_mmap(vma);
@@ -1906,9 +1888,6 @@ unmap_and_free_vma:
        charged = 0;
        if (vm_flags & VM_SHARED)
                mapping_unmap_writable(file->f_mapping);
-allow_write_and_free_vma:
-       if (vm_flags & VM_DENYWRITE)
-               allow_write_access(file);
 free_vma:
        vm_area_free(vma);
 unacct_error: