[PATCH RFC 5/7] mm: remove VM_DENYWRITE
From: David Hildenbrand <hidden>
Date: 2021-04-23 13:18:36
Also in:
linux-fsdevel, linux-mm, lkml
Subsystem:
exec & binfmt api, elf, filesystems (vfs and infrastructure), library code, memory management, memory management - core, memory mapping, performance events subsystem, proc filesystem, scheduler, the rest, tracing · Maintainers:
Kees Cook, Alexander Viro, Christian Brauner, Andrew Morton, David Hildenbrand, Liam R. Howlett, Lorenzo Stoakes, Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Juri Lelli, Vincent Guittot, Linus Torvalds, Steven Rostedt, Masami Hiramatsu
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. Signed-off-by: David Hildenbrand <redacted> --- fs/proc/task_mmu.c | 1 - include/linux/mm.h | 1 - include/linux/mman.h | 1 - include/trace/events/mmflags.h | 1 - kernel/events/core.c | 2 -- kernel/fork.c | 3 --- lib/test_printf.c | 5 ++--- mm/mmap.c | 27 +++------------------------ 8 files changed, 5 insertions(+), 36 deletions(-)
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e862cab69583..2710703c39b0 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c@@ -621,7 +621,6 @@ 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 043702972e5f..cdad125af9fa 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -274,7 +274,6 @@ 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 ebb09a964272..bd9aadda047b 100644
--- 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 67018d367b9f..e1721ce6381d 100644
--- a/include/trace/events/mmflags.h
+++ b/include/trace/events/mmflags.h@@ -149,7 +149,6 @@ IF_HAVE_PG_ARCH_2(PG_arch_2, "arch_2" ) {VM_GROWSDOWN, "growsdown" }, \ {VM_UFFD_MISSING, "uffd_missing" }, \ {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 3dfd463f1831..1ed3eb7aa4c9 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c@@ -8184,8 +8184,6 @@ 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 0681f2973667..fda43ba05d91 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c@@ -556,12 +556,9 @@ 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 95a2f82427c7..54f0583dc45d 100644
--- a/lib/test_printf.c
+++ b/lib/test_printf.c@@ -596,9 +596,8 @@ flags(void) test("uptodate|dirty|lru|active|swapbacked", "%pGp", &flags); - 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 882f8ee4af1f..b335f8907568 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c@@ -142,8 +142,6 @@ 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);
@@ -660,8 +658,6 @@ 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);
@@ -1785,22 +1781,12 @@ 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)
@@ -1857,13 +1843,9 @@ 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);
@@ -1903,9 +1885,6 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 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:
--
2.30.2