Re: [PATCH v7 18/27] mm: Introduce do_mmap_locked()

On Fri, 2019-06-07 at 09:47 +0200, Peter Zijlstra wrote:

On Fri, Jun 07, 2019 at 09:43:22AM +0200, Peter Zijlstra wrote:

quoted

On Thu, Jun 06, 2019 at 01:06:37PM -0700, Yu-cheng Yu wrote:

quoted

There are a few places that need do_mmap() with mm->mmap_sem held.
Create an in-line function for that.

Signed-off-by: Yu-cheng Yu <redacted>
---
 include/linux/mm.h | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 398f1e1c35e5..7cf014604848 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h

@@ -2411,6 +2411,24 @@ static inline void mm_populate(unsigned long addr,

unsigned long len)
 static inline void mm_populate(unsigned long addr, unsigned long len) {}
 #endif
 
+static inline unsigned long do_mmap_locked(unsigned long addr,
+	unsigned long len, unsigned long prot, unsigned long flags,
+	vm_flags_t vm_flags)
+{
+	struct mm_struct *mm = current->mm;
+	unsigned long populate;
+
+	down_write(&mm->mmap_sem);
+	addr = do_mmap(NULL, addr, len, prot, flags, vm_flags, 0,
+		       &populate, NULL);

Funny thing how do_mmap() takes a file pointer as first argument and
this thing explicitly NULLs that. That more or less invalidates the name
do_mmap_locked().

quoted

+	up_write(&mm->mmap_sem);
+
+	if (populate)
+		mm_populate(addr, populate);
+
+	return addr;
+}

You also don't retain that last @uf argument.

I'm thikning you're better off adding a helper to the cet.c file; call
it cet_mmap() or whatever.

Ok, I will fix that.

Yu-cheng