mmap locking API: convert mmap_sem comments

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Author: walken-google

Documentation/admin-guide/mm/numa_memory_policy.rst

@@ -364,19 +364,19 @@ follows:
 
 2) for querying the policy, we do not need to take an extra reference on the
    target task's task policy nor vma policies because we always acquire the
-   task's mm's mmap_sem for read during the query.  The set_mempolicy() and
-   mbind() APIs [see below] always acquire the mmap_sem for write when
+   task's mm's mmap_lock for read during the query.  The set_mempolicy() and
+   mbind() APIs [see below] always acquire the mmap_lock for write when
    installing or replacing task or vma policies.  Thus, there is no possibility
    of a task or thread freeing a policy while another task or thread is
    querying it.
 
 3) Page allocation usage of task or vma policy occurs in the fault path where
-   we hold them mmap_sem for read.  Again, because replacing the task or vma
-   policy requires that the mmap_sem be held for write, the policy can't be
+   we hold them mmap_lock for read.  Again, because replacing the task or vma
+   policy requires that the mmap_lock be held for write, the policy can't be
    freed out from under us while we're using it for page allocation.
 
 4) Shared policies require special consideration.  One task can replace a
-   shared memory policy while another task, with a distinct mmap_sem, is
+   shared memory policy while another task, with a distinct mmap_lock, is
    querying or allocating a page based on the policy.  To resolve this
    potential race, the shared policy infrastructure adds an extra reference
    to the shared policy during lookup while holding a spin lock on the shared

Documentation/admin-guide/mm/userfaultfd.rst

@@ -33,7 +33,7 @@ memory ranges) provides two primary functionalities:
 The real advantage of userfaults if compared to regular virtual memory
 management of mremap/mprotect is that the userfaults in all their
 operations never involve heavyweight structures like vmas (in fact the
-``userfaultfd`` runtime load never takes the mmap_sem for writing).
+``userfaultfd`` runtime load never takes the mmap_lock for writing).
 
 Vmas are not suitable for page- (or hugepage) granular fault tracking
 when dealing with virtual address spaces that could span

Documentation/filesystems/locking.rst

@@ -615,7 +615,7 @@ prototypes::
 locking rules:
 
 =============	========	===========================
-ops		mmap_sem	PageLocked(page)
+ops		mmap_lock	PageLocked(page)
 =============	========	===========================
 open:		yes
 close:		yes

Documentation/vm/transhuge.rst

@@ -98,9 +98,9 @@ split_huge_page() or split_huge_pmd() has a cost.
 
 To make pagetable walks huge pmd aware, all you need to do is to call
 pmd_trans_huge() on the pmd returned by pmd_offset. You must hold the
-mmap_sem in read (or write) mode to be sure a huge pmd cannot be
+mmap_lock in read (or write) mode to be sure a huge pmd cannot be
 created from under you by khugepaged (khugepaged collapse_huge_page
-takes the mmap_sem in write mode in addition to the anon_vma lock). If
+takes the mmap_lock in write mode in addition to the anon_vma lock). If
 pmd_trans_huge returns false, you just fallback in the old code
 paths. If instead pmd_trans_huge returns true, you have to take the
 page table lock (pmd_lock()) and re-run pmd_trans_huge. Taking the

arch/arc/mm/fault.c

@@ -141,7 +141,7 @@ void do_page_fault(unsigned long address, struct pt_regs *regs)
 	}
 
 	/*
-	 * Fault retry nuances, mmap_sem already relinquished by core mm
+	 * Fault retry nuances, mmap_lock already relinquished by core mm
 	 */
 	if (unlikely((fault & VM_FAULT_RETRY) &&
 		     (flags & FAULT_FLAG_ALLOW_RETRY))) {

arch/arm/kernel/vdso.c

@@ -240,7 +240,7 @@ static int install_vvar(struct mm_struct *mm, unsigned long addr)
 	return PTR_ERR_OR_ZERO(vma);
 }
 
-/* assumes mmap_sem is write-locked */
+/* assumes mmap_lock is write-locked */
 void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
 {
 	struct vm_area_struct *vma;

arch/arm/mm/fault.c

@@ -293,7 +293,7 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 	fault = __do_page_fault(mm, addr, fsr, flags, tsk);
 
 	/* If we need to retry but a fatal signal is pending, handle the
-	 * signal first. We do not need to release the mmap_sem because
+	 * signal first. We do not need to release the mmap_lock because
 	 * it would already be released in __lock_page_or_retry in
 	 * mm/filemap.c. */
 	if (fault_signal_pending(fault, regs)) {

arch/ia64/mm/fault.c

@@ -86,7 +86,7 @@ ia64_do_page_fault (unsigned long address, unsigned long isr, struct pt_regs *re
 #ifdef CONFIG_VIRTUAL_MEM_MAP
 	/*
 	 * If fault is in region 5 and we are in the kernel, we may already
-	 * have the mmap_sem (pfn_valid macro is called during mmap). There
+	 * have the mmap_lock (pfn_valid macro is called during mmap). There
 	 * is no vma for region 5 addr's anyway, so skip getting the semaphore
 	 * and go directly to the exception handling code.
 	 */

arch/microblaze/mm/fault.c

@@ -124,7 +124,7 @@ void do_page_fault(struct pt_regs *regs, unsigned long address,
 	/* When running in the kernel we expect faults to occur only to
 	 * addresses in user space.  All other faults represent errors in the
 	 * kernel and should generate an OOPS.  Unfortunately, in the case of an
-	 * erroneous fault occurring in a code path which already holds mmap_sem
+	 * erroneous fault occurring in a code path which already holds mmap_lock
 	 * we will deadlock attempting to validate the fault against the
 	 * address space.  Luckily the kernel only validly references user
 	 * space from well defined areas of code, which are listed in the

arch/nds32/mm/fault.c

@@ -210,7 +210,7 @@ void do_page_fault(unsigned long entry, unsigned long addr,
 
 	/*
 	 * If we need to retry but a fatal signal is pending, handle the
-	 * signal first. We do not need to release the mmap_sem because it
+	 * signal first. We do not need to release the mmap_lock because it
 	 * would already be released in __lock_page_or_retry in mm/filemap.c.
 	 */
 	if (fault_signal_pending(fault, regs)) {