[merged] mm-gup-protect-unpin_user_pages-against-npages==-errno.patch removed from -mm tree

[akpm@linux-foundation.org]

The patch titled
     Subject: mm/gup: protect unpin_user_pages() against npages==-ERRNO
has been removed from the -mm tree.  Its filename was
     mm-gup-protect-unpin_user_pages-against-npages==-errno.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: John Hubbard <jhubbard@nvidia.com>
Subject: mm/gup: protect unpin_user_pages() against npages==-ERRNO

As suggested by Dan Carpenter, fortify unpin_user_pages() just a bit,
against a typical caller mistake: check if the npages arg is really a
-ERRNO value, which would blow up the unpinning loop: WARN and return.

If this new WARN_ON() fires, then the system *might* be leaking pages (by
leaving them pinned), but probably not.  More likely, gup/pup returned a
hard -ERRNO error to the caller, who erroneously passed it here.

Link: https://lkml.kernel.org/r/20200917065706.409079-1-jhubbard@nvidia.com
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/gup.c |    7 +++++++
 1 file changed, 7 insertions(+)

--- a/mm/gup.c~mm-gup-protect-unpin_user_pages-against-npages==-errno
+++ a/mm/gup.c
@@ -329,6 +329,13 @@ void unpin_user_pages(struct page **page
 	unsigned long index;
 
 	/*
+	 * If this WARN_ON() fires, then the system *might* be leaking pages (by
+	 * leaving them pinned), but probably not. More likely, gup/pup returned
+	 * a hard -ERRNO error to the caller, who erroneously passed it here.
+	 */
+	if (WARN_ON(IS_ERR_VALUE(npages)))
+		return;
+	/*
 	 * TODO: this can be optimized for huge pages: if a series of pages is
 	 * physically contiguous and part of the same compound page, then a
 	 * single operation to the head page should suffice.
_

Patches currently in -mm which might be from jhubbard@nvidia.com are

mm-gup_benchmark-rename-to-mm-gup_test.patch
selftests-vm-use-a-common-gup_testh.patch
selftests-vm-rename-run_vmtests-run_vmtestssh.patch
selftests-vm-minor-cleanup-makefile-and-gup_testc.patch
selftests-vm-only-some-gup_test-items-are-really-benchmarks.patch
selftests-vm-gup_test-introduce-the-dump_pages-sub-test.patch
selftests-vm-run_vmtestsh-update-and-clean-up-gup_test-invocation.patch
selftests-vm-hmm-tests-remove-the-libhugetlbfs-dependency.patch
selftests-vm-hmm-tests-remove-the-libhugetlbfs-dependency-fix.patch
selftests-vm-10x-speedup-for-hmm-tests.patch