Merge branch 'gup_flag-cleanups'

Merge the gup_flags cleanups from Lorenzo Stoakes:
 "This patch series adjusts functions in the get_user_pages* family such
  that desired FOLL_* flags are passed as an argument rather than
  implied by flags.

  The purpose of this change is to make the use of FOLL_FORCE explicit
  so it is easier to grep for and clearer to callers that this flag is
  being used.  The use of FOLL_FORCE is an issue as it overrides missing
  VM_READ/VM_WRITE flags for the VMA whose pages we are reading
  from/writing to, which can result in surprising behaviour.

  The patch series came out of the discussion around commit 38e088546522
  ("mm: check VMA flags to avoid invalid PROT_NONE NUMA balancing"),
  which addressed a BUG_ON() being triggered when a page was faulted in
  with PROT_NONE set but having been overridden by FOLL_FORCE.
  do_numa_page() was run on the assumption the page _must_ be one marked
  for NUMA node migration as an actual PROT_NONE page would have been
  dealt with prior to this code path, however FOLL_FORCE introduced a
  situation where this assumption did not hold.

  See

      https://marc.info/?l=linux-mm&m=147585445805166

  for the patch proposal"

Additionally, there's a fix for an ancient bug related to FOLL_FORCE and
FOLL_WRITE by me.

[ This branch was rebased recently to add a few more acked-by's and
  reviewed-by's ]

* gup_flag-cleanups:
  mm: replace access_process_vm() write parameter with gup_flags
  mm: replace access_remote_vm() write parameter with gup_flags
  mm: replace __access_remote_vm() write parameter with gup_flags
  mm: replace get_user_pages_remote() write/force parameters with gup_flags
  mm: replace get_user_pages() write/force parameters with gup_flags
  mm: replace get_vaddr_frames() write/force parameters with gup_flags
  mm: replace get_user_pages_locked() write/force parameters with gup_flags
  mm: replace get_user_pages_unlocked() write/force parameters with gup_flags
  mm: remove write/force parameters from __get_user_pages_unlocked()
  mm: remove write/force parameters from __get_user_pages_locked()
  mm: remove gup_flags FOLL_WRITE games from __get_user_pages()

5 files changed, 9 insertions, 7 deletions

diff --git a/arch/x86/kernel/step.c b/arch/x86/kernel/step.c
index c9a073866ca7..a23ce84a3f6c 100644
--- a/arch/x86/kernel/step.c
+++ b/arch/x86/kernel/step.c
@@ -57,7 +57,8 @@ static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs)
 	unsigned char opcode[15];
 	unsigned long addr = convert_ip_to_linear(child, regs);
 
-	copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0);
+	copied = access_process_vm(child, addr, opcode, sizeof(opcode),
+			FOLL_FORCE);
 	for (i = 0; i < copied; i++) {
 		switch (opcode[i]) {
 		/* popf and iret */
diff --git a/arch/x86/mm/gup.c b/arch/x86/mm/gup.c
index b8b6a60b32cf..0d4fb3ebbbac 100644
--- a/arch/x86/mm/gup.c
+++ b/arch/x86/mm/gup.c
@@ -435,7 +435,7 @@ slow_irqon:
 
 		ret = get_user_pages_unlocked(start,
 					      (end - start) >> PAGE_SHIFT,
-					      write, 0, pages);
+					      pages, write ? FOLL_WRITE : 0);
 
 		/* Have to be a bit careful with return values */
 		if (nr > 0) {
diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c
index 80476878eb4c..e4f800999b32 100644
--- a/arch/x86/mm/mpx.c
+++ b/arch/x86/mm/mpx.c
@@ -544,10 +544,9 @@ static int mpx_resolve_fault(long __user *addr, int write)
 {
 	long gup_ret;
 	int nr_pages = 1;
-	int force = 0;
 
-	gup_ret = get_user_pages((unsigned long)addr, nr_pages, write,
-			force, NULL, NULL);
+	gup_ret = get_user_pages((unsigned long)addr, nr_pages,
+			write ? FOLL_WRITE : 0,	NULL, NULL);
 	/*
 	 * get_user_pages() returns number of pages gotten.
 	 * 0 means we failed to fault in and get anything,
diff --git a/arch/x86/um/ptrace_32.c b/arch/x86/um/ptrace_32.c
index 5766ead6fdb9..60a5a5a85505 100644
--- a/arch/x86/um/ptrace_32.c
+++ b/arch/x86/um/ptrace_32.c
@@ -36,7 +36,8 @@ int is_syscall(unsigned long addr)
 		 * slow, but that doesn't matter, since it will be called only
 		 * in case of singlestepping, if copy_from_user failed.
 		 */
-		n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
+		n = access_process_vm(current, addr, &instr, sizeof(instr),
+				FOLL_FORCE);
 		if (n != sizeof(instr)) {
 			printk(KERN_ERR "is_syscall : failed to read "
 			       "instruction from 0x%lx\n", addr);
diff --git a/arch/x86/um/ptrace_64.c b/arch/x86/um/ptrace_64.c
index 0b5c184dd5b3..e30202b1716e 100644
--- a/arch/x86/um/ptrace_64.c
+++ b/arch/x86/um/ptrace_64.c
@@ -212,7 +212,8 @@ int is_syscall(unsigned long addr)
 		 * slow, but that doesn't matter, since it will be called only
 		 * in case of singlestepping, if copy_from_user failed.
 		 */
-		n = access_process_vm(current, addr, &instr, sizeof(instr), 0);
+		n = access_process_vm(current, addr, &instr, sizeof(instr),
+				FOLL_FORCE);
 		if (n != sizeof(instr)) {
 			printk("is_syscall : failed to read instruction from "
 			       "0x%lx\n", addr);