From 063d99b4fa762cbae9324dbbf9b6bff4b3a8cfdc Mon Sep 17 00:00:00 2001
From: Michal Hocko <mhocko@suse.com>
Date: Thu, 15 Oct 2015 15:28:24 -0700
Subject: mm, fs: obey gfp_mapping for add_to_page_cache()

Commit 6afdb859b710 ("mm: do not ignore mapping_gfp_mask in page cache
allocation paths") has caught some users of hardcoded GFP_KERNEL used in
the page cache allocation paths.  This, however, wasn't complete and
there were others which went unnoticed.

Dave Chinner has reported the following deadlock for xfs on loop device:
: With the recent merge of the loop device changes, I'm now seeing
: XFS deadlock on my single CPU, 1GB RAM VM running xfs/073.
:
: The deadlocked is as follows:
:
: kloopd1: loop_queue_read_work
:       xfs_file_iter_read
:       lock XFS inode XFS_IOLOCK_SHARED (on image file)
:       page cache read (GFP_KERNEL)
:       radix tree alloc
:       memory reclaim
:       reclaim XFS inodes
:       log force to unpin inodes
:       <wait for log IO completion>
:
: xfs-cil/loop1: <does log force IO work>
:       xlog_cil_push
:       xlog_write
:       <loop issuing log writes>
:               xlog_state_get_iclog_space()
:               <blocks due to all log buffers under write io>
:               <waits for IO completion>
:
: kloopd1: loop_queue_write_work
:       xfs_file_write_iter
:       lock XFS inode XFS_IOLOCK_EXCL (on image file)
:       <wait for inode to be unlocked>
:
: i.e. the kloopd, with it's split read and write work queues, has
: introduced a dependency through memory reclaim. i.e. that writes
: need to be able to progress for reads make progress.
:
: The problem, fundamentally, is that mpage_readpages() does a
: GFP_KERNEL allocation, rather than paying attention to the inode's
: mapping gfp mask, which is set to GFP_NOFS.
:
: The didn't used to happen, because the loop device used to issue
: reads through the splice path and that does:
:
:       error = add_to_page_cache_lru(page, mapping, index,
:                       GFP_KERNEL & mapping_gfp_mask(mapping));

This has changed by commit aa4d86163e4 ("block: loop: switch to VFS
ITER_BVEC").

This patch changes mpage_readpage{s} to follow gfp mask set for the
mapping.  There are, however, other places which are doing basically the
same.

lustre:ll_dir_filler is doing GFP_KERNEL from the function which
apparently uses GFP_NOFS for other allocations so let's make this
consistent.

cifs:readpages_get_pages is called from cifs_readpages and
__cifs_readpages_from_fscache called from the same path obeys mapping
gfp.

ramfs_nommu_expand_for_mapping is hardcoding GFP_KERNEL as well
regardless it uses mapping_gfp_mask for the page allocation.

ext4_mpage_readpages is the called from the page cache allocation path
same as read_pages and read_cache_pages

As I've noticed in my previous post I cannot say I would be happy about
sprinkling mapping_gfp_mask all over the place and it sounds like we
should drop gfp_mask argument altogether and use it internally in
__add_to_page_cache_locked that would require all the filesystems to use
mapping gfp consistently which I am not sure is the case here.  From a
quick glance it seems that some file system use it all the time while
others are selective.

Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Dave Chinner <david@fromorbit.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Ming Lei <ming.lei@canonical.com>
Cc: Andreas Dilger <andreas.dilger@intel.com>
Cc: Oleg Drokin <oleg.drokin@intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 drivers/staging/lustre/lustre/llite/dir.c |  2 +-
 fs/cifs/file.c                            |  6 +++---
 fs/ext4/readpage.c                        |  4 ++--
 fs/mpage.c                                | 15 +++++++++------
 fs/ramfs/file-nommu.c                     |  5 +++--
 mm/readahead.c                            |  8 ++++----
 6 files changed, 22 insertions(+), 18 deletions(-)

diff --git a/drivers/staging/lustre/lustre/llite/dir.c b/drivers/staging/lustre/lustre/llite/dir.c
index 769b61193d87..a9bc6e23fc25 100644
--- a/drivers/staging/lustre/lustre/llite/dir.c
+++ b/drivers/staging/lustre/lustre/llite/dir.c
@@ -224,7 +224,7 @@ static int ll_dir_filler(void *_hash, struct page *page0)
 
 		prefetchw(&page->flags);
 		ret = add_to_page_cache_lru(page, inode->i_mapping, offset,
-					    GFP_KERNEL);
+					    GFP_NOFS);
 		if (ret == 0) {
 			unlock_page(page);
 		} else {
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index e2a6af1508af..62203c387db4 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -3380,6 +3380,7 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
 	struct page *page, *tpage;
 	unsigned int expected_index;
 	int rc;
+	gfp_t gfp = GFP_KERNEL & mapping_gfp_mask(mapping);
 
 	INIT_LIST_HEAD(tmplist);
 
@@ -3392,7 +3393,7 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
 	 */
 	__set_page_locked(page);
 	rc = add_to_page_cache_locked(page, mapping,
-				      page->index, GFP_KERNEL);
+				      page->index, gfp);
 
 	/* give up if we can't stick it in the cache */
 	if (rc) {
@@ -3418,8 +3419,7 @@ readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
 			break;
 
 		__set_page_locked(page);
-		if (add_to_page_cache_locked(page, mapping, page->index,
-								GFP_KERNEL)) {
+		if (add_to_page_cache_locked(page, mapping, page->index, gfp)) {
 			__clear_page_locked(page);
 			break;
 		}
diff --git a/fs/ext4/readpage.c b/fs/ext4/readpage.c
index e26803fb210d..560af0437704 100644
--- a/fs/ext4/readpage.c
+++ b/fs/ext4/readpage.c
@@ -165,8 +165,8 @@ int ext4_mpage_readpages(struct address_space *mapping,
 		if (pages) {
 			page = list_entry(pages->prev, struct page, lru);
 			list_del(&page->lru);
-			if (add_to_page_cache_lru(page, mapping,
-						  page->index, GFP_KERNEL))
+			if (add_to_page_cache_lru(page, mapping, page->index,
+					GFP_KERNEL & mapping_gfp_mask(mapping)))
 				goto next_page;
 		}
 
diff --git a/fs/mpage.c b/fs/mpage.c
index 778a4ddef77a..a7c34274f207 100644
--- a/fs/mpage.c
+++ b/fs/mpage.c
@@ -139,7 +139,8 @@ map_buffer_to_page(struct page *page, struct buffer_head *bh, int page_block)
 static struct bio *
 do_mpage_readpage(struct bio *bio, struct page *page, unsigned nr_pages,
 		sector_t *last_block_in_bio, struct buffer_head *map_bh,
-		unsigned long *first_logical_block, get_block_t get_block)
+		unsigned long *first_logical_block, get_block_t get_block,
+		gfp_t gfp)
 {
 	struct inode *inode = page->mapping->host;
 	const unsigned blkbits = inode->i_blkbits;
@@ -277,8 +278,7 @@ alloc_new:
 				goto out;
 		}
 		bio = mpage_alloc(bdev, blocks[0] << (blkbits - 9),
-				min_t(int, nr_pages, BIO_MAX_PAGES),
-				GFP_KERNEL);
+				min_t(int, nr_pages, BIO_MAX_PAGES), gfp);
 		if (bio == NULL)
 			goto confused;
 	}
@@ -361,6 +361,7 @@ mpage_readpages(struct address_space *mapping, struct list_head *pages,
 	sector_t last_block_in_bio = 0;
 	struct buffer_head map_bh;
 	unsigned long first_logical_block = 0;
+	gfp_t gfp = GFP_KERNEL & mapping_gfp_mask(mapping);
 
 	map_bh.b_state = 0;
 	map_bh.b_size = 0;
@@ -370,12 +371,13 @@ mpage_readpages(struct address_space *mapping, struct list_head *pages,
 		prefetchw(&page->flags);
 		list_del(&page->lru);
 		if (!add_to_page_cache_lru(page, mapping,
-					page->index, GFP_KERNEL)) {
+					page->index,
+					gfp)) {
 			bio = do_mpage_readpage(bio, page,
 					nr_pages - page_idx,
 					&last_block_in_bio, &map_bh,
 					&first_logical_block,
-					get_block);
+					get_block, gfp);
 		}
 		page_cache_release(page);
 	}
@@ -395,11 +397,12 @@ int mpage_readpage(struct page *page, get_block_t get_block)
 	sector_t last_block_in_bio = 0;
 	struct buffer_head map_bh;
 	unsigned long first_logical_block = 0;
+	gfp_t gfp = GFP_KERNEL & mapping_gfp_mask(page->mapping);
 
 	map_bh.b_state = 0;
 	map_bh.b_size = 0;
 	bio = do_mpage_readpage(bio, page, 1, &last_block_in_bio,
-			&map_bh, &first_logical_block, get_block);
+			&map_bh, &first_logical_block, get_block, gfp);
 	if (bio)
 		mpage_bio_submit(READ, bio);
 	return 0;
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
index ba1323a94924..a586467f6ff6 100644
--- a/fs/ramfs/file-nommu.c
+++ b/fs/ramfs/file-nommu.c
@@ -70,6 +70,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
 	unsigned order;
 	void *data;
 	int ret;
+	gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
 
 	/* make various checks */
 	order = get_order(newsize);
@@ -84,7 +85,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
 
 	/* allocate enough contiguous pages to be able to satisfy the
 	 * request */
-	pages = alloc_pages(mapping_gfp_mask(inode->i_mapping), order);
+	pages = alloc_pages(gfp, order);
 	if (!pages)
 		return -ENOMEM;
 
@@ -108,7 +109,7 @@ int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
 		struct page *page = pages + loop;
 
 		ret = add_to_page_cache_lru(page, inode->i_mapping, loop,
-					GFP_KERNEL);
+					gfp);
 		if (ret < 0)
 			goto add_error;
 
diff --git a/mm/readahead.c b/mm/readahead.c
index 60cd846a9a44..24682f6f4cfd 100644
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -89,8 +89,8 @@ int read_cache_pages(struct address_space *mapping, struct list_head *pages,
 	while (!list_empty(pages)) {
 		page = list_to_page(pages);
 		list_del(&page->lru);
-		if (add_to_page_cache_lru(page, mapping,
-					page->index, GFP_KERNEL)) {
+		if (add_to_page_cache_lru(page, mapping, page->index,
+				GFP_KERNEL & mapping_gfp_mask(mapping))) {
 			read_cache_pages_invalidate_page(mapping, page);
 			continue;
 		}
@@ -127,8 +127,8 @@ static int read_pages(struct address_space *mapping, struct file *filp,
 	for (page_idx = 0; page_idx < nr_pages; page_idx++) {
 		struct page *page = list_to_page(pages);
 		list_del(&page->lru);
-		if (!add_to_page_cache_lru(page, mapping,
-					page->index, GFP_KERNEL)) {
+		if (!add_to_page_cache_lru(page, mapping, page->index,
+				GFP_KERNEL & mapping_gfp_mask(mapping))) {
 			mapping->a_ops->readpage(filp, page);
 		}
 		page_cache_release(page);
-- 
cgit v1.2.3-70-g09d2


From 8d740a37b92f3d4a0435fe263b32efc7f61c5efb Mon Sep 17 00:00:00 2001
From: Riku Voipio <riku.voipio@linaro.org>
Date: Thu, 15 Oct 2015 15:28:26 -0700
Subject: builddeb: remove debian/files before build

Commit 3716001bcb7f ("deb-pkg: add source package") added the ability to
create a debian changelog file.  This exposed that previously the
builddeb script hasn't cleared debian/files between builds.

As debian/files keeps accumulating entries, the changes file will end up
growing indefinelty.  With outdated entries in debian/files, builddeb
script will exit with failure.  This regression impacts those who use
"make deb-pkg" target to build kernel into a .deb package and never use
"make mrproper" or other means to clean kernel tree from generated
directories.

To fix the regression, remove debian/files before starting build and in
the generated clean rule.

Fixes: 3716001bcb7f ("deb-pkg: add source package")
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Reported-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Doug Smythies <dsmythies@telus.net>
Tested-by: Kalle Valo <kvalo@codeaurora.org>
Acked-by: Ben Hutchings <ben@decadent.org.uk>
Cc: Michal Marek <mmarek@suse.cz>
Cc: maximilian attems <maks@stro.at>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 scripts/package/builddeb | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/package/builddeb b/scripts/package/builddeb
index 0cd46e129920..b967e4f9fed2 100755
--- a/scripts/package/builddeb
+++ b/scripts/package/builddeb
@@ -115,7 +115,7 @@ esac
 BUILD_DEBUG="$(grep -s '^CONFIG_DEBUG_INFO=y' $KCONFIG_CONFIG || true)"
 
 # Setup the directory structure
-rm -rf "$tmpdir" "$fwdir" "$kernel_headers_dir" "$libc_headers_dir" "$dbg_dir"
+rm -rf "$tmpdir" "$fwdir" "$kernel_headers_dir" "$libc_headers_dir" "$dbg_dir" $objtree/debian/files
 mkdir -m 755 -p "$tmpdir/DEBIAN"
 mkdir -p "$tmpdir/lib" "$tmpdir/boot"
 mkdir -p "$fwdir/lib/firmware/$version/"
@@ -408,7 +408,7 @@ binary-arch:
 	\$(MAKE) KDEB_SOURCENAME=${sourcename} KDEB_PKGVERSION=${packageversion} bindeb-pkg
 
 clean:
-	rm -rf debian/*tmp
+	rm -rf debian/*tmp debian/files
 	mv debian/ debian.backup # debian/ might be cleaned away
 	\$(MAKE) clean
 	mv debian.backup debian
-- 
cgit v1.2.3-70-g09d2


From 424cdc14138088ada1b0e407a2195b2783c6e5ef Mon Sep 17 00:00:00 2001
From: Shaohua Li <shli@fb.com>
Date: Thu, 15 Oct 2015 15:28:29 -0700
Subject: memcg: convert threshold to bytes

page_counter_memparse() returns pages for the threshold, while
mem_cgroup_usage() returns bytes for memory usage.  Convert the
threshold to bytes.

Fixes: 3e32cb2e0a12b6915 ("memcg: rename cgroup_event to mem_cgroup_event").
Signed-off-by: Shaohua Li <shli@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 mm/memcontrol.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1fedbde68f59..d9b5c817dce8 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3387,6 +3387,7 @@ static int __mem_cgroup_usage_register_event(struct mem_cgroup *memcg,
 	ret = page_counter_memparse(args, "-1", &threshold);
 	if (ret)
 		return ret;
+	threshold <<= PAGE_SHIFT;
 
 	mutex_lock(&memcg->thresholds_lock);
 
-- 
cgit v1.2.3-70-g09d2


From 0f90cc6609c72b0bdf2aad0cb0456194dd896e19 Mon Sep 17 00:00:00 2001
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Date: Thu, 15 Oct 2015 15:28:32 -0700
Subject: mm, dax: fix DAX deadlocks

The following two locking commits in the DAX code:

commit 843172978bb9 ("dax: fix race between simultaneous faults")
commit 46c043ede471 ("mm: take i_mmap_lock in unmap_mapping_range() for DAX")

introduced a number of deadlocks and other issues which need to be fixed
for the v4.3 kernel.  The list of issues in DAX after these commits
(some newly introduced by the commits, some preexisting) can be found
here:

  https://lkml.org/lkml/2015/9/25/602 (Subject: "Re: [PATCH] dax: fix deadlock in __dax_fault").

This undoes most of the changes introduced by those two commits,
essentially returning us to the DAX locking scheme that was used in
v4.2.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dave Chinner <dchinner@redhat.com>
Cc: Jan Kara <jack@suse.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 fs/dax.c    | 70 +++++++++++++++++++++++++------------------------------------
 mm/memory.c |  2 ++
 2 files changed, 31 insertions(+), 41 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index bcfb14bfc1e4..a86d3cc2b389 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -285,6 +285,7 @@ static int copy_user_bh(struct page *to, struct buffer_head *bh,
 static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
 			struct vm_area_struct *vma, struct vm_fault *vmf)
 {
+	struct address_space *mapping = inode->i_mapping;
 	sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9);
 	unsigned long vaddr = (unsigned long)vmf->virtual_address;
 	void __pmem *addr;
@@ -292,6 +293,8 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
 	pgoff_t size;
 	int error;
 
+	i_mmap_lock_read(mapping);
+
 	/*
 	 * Check truncate didn't happen while we were allocating a block.
 	 * If it did, this block may or may not be still allocated to the
@@ -321,6 +324,8 @@ static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh,
 	error = vm_insert_mixed(vma, vaddr, pfn);
 
  out:
+	i_mmap_unlock_read(mapping);
+
 	return error;
 }
 
@@ -382,17 +387,15 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 			 * from a read fault and we've raced with a truncate
 			 */
 			error = -EIO;
-			goto unlock;
+			goto unlock_page;
 		}
-	} else {
-		i_mmap_lock_write(mapping);
 	}
 
 	error = get_block(inode, block, &bh, 0);
 	if (!error && (bh.b_size < PAGE_SIZE))
 		error = -EIO;		/* fs corruption? */
 	if (error)
-		goto unlock;
+		goto unlock_page;
 
 	if (!buffer_mapped(&bh) && !buffer_unwritten(&bh) && !vmf->cow_page) {
 		if (vmf->flags & FAULT_FLAG_WRITE) {
@@ -403,9 +406,8 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 			if (!error && (bh.b_size < PAGE_SIZE))
 				error = -EIO;
 			if (error)
-				goto unlock;
+				goto unlock_page;
 		} else {
-			i_mmap_unlock_write(mapping);
 			return dax_load_hole(mapping, page, vmf);
 		}
 	}
@@ -417,15 +419,17 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 		else
 			clear_user_highpage(new_page, vaddr);
 		if (error)
-			goto unlock;
+			goto unlock_page;
 		vmf->page = page;
 		if (!page) {
+			i_mmap_lock_read(mapping);
 			/* Check we didn't race with truncate */
 			size = (i_size_read(inode) + PAGE_SIZE - 1) >>
 								PAGE_SHIFT;
 			if (vmf->pgoff >= size) {
+				i_mmap_unlock_read(mapping);
 				error = -EIO;
-				goto unlock;
+				goto out;
 			}
 		}
 		return VM_FAULT_LOCKED;
@@ -461,8 +465,6 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 			WARN_ON_ONCE(!(vmf->flags & FAULT_FLAG_WRITE));
 	}
 
-	if (!page)
-		i_mmap_unlock_write(mapping);
  out:
 	if (error == -ENOMEM)
 		return VM_FAULT_OOM | major;
@@ -471,14 +473,11 @@ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf,
 		return VM_FAULT_SIGBUS | major;
 	return VM_FAULT_NOPAGE | major;
 
- unlock:
+ unlock_page:
 	if (page) {
 		unlock_page(page);
 		page_cache_release(page);
-	} else {
-		i_mmap_unlock_write(mapping);
 	}
-
 	goto out;
 }
 EXPORT_SYMBOL(__dax_fault);
@@ -556,10 +555,10 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 	block = (sector_t)pgoff << (PAGE_SHIFT - blkbits);
 
 	bh.b_size = PMD_SIZE;
-	i_mmap_lock_write(mapping);
 	length = get_block(inode, block, &bh, write);
 	if (length)
 		return VM_FAULT_SIGBUS;
+	i_mmap_lock_read(mapping);
 
 	/*
 	 * If the filesystem isn't willing to tell us the length of a hole,
@@ -569,36 +568,14 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 	if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE)
 		goto fallback;
 
-	sector = bh.b_blocknr << (blkbits - 9);
-
-	if (buffer_unwritten(&bh) || buffer_new(&bh)) {
-		int i;
-
-		length = bdev_direct_access(bh.b_bdev, sector, &kaddr, &pfn,
-						bh.b_size);
-		if (length < 0) {
-			result = VM_FAULT_SIGBUS;
-			goto out;
-		}
-		if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
-			goto fallback;
-
-		for (i = 0; i < PTRS_PER_PMD; i++)
-			clear_pmem(kaddr + i * PAGE_SIZE, PAGE_SIZE);
-		wmb_pmem();
-		count_vm_event(PGMAJFAULT);
-		mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
-		result |= VM_FAULT_MAJOR;
-	}
-
 	/*
 	 * If we allocated new storage, make sure no process has any
 	 * zero pages covering this hole
 	 */
 	if (buffer_new(&bh)) {
-		i_mmap_unlock_write(mapping);
+		i_mmap_unlock_read(mapping);
 		unmap_mapping_range(mapping, pgoff << PAGE_SHIFT, PMD_SIZE, 0);
-		i_mmap_lock_write(mapping);
+		i_mmap_lock_read(mapping);
 	}
 
 	/*
@@ -635,6 +612,7 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 		result = VM_FAULT_NOPAGE;
 		spin_unlock(ptl);
 	} else {
+		sector = bh.b_blocknr << (blkbits - 9);
 		length = bdev_direct_access(bh.b_bdev, sector, &kaddr, &pfn,
 						bh.b_size);
 		if (length < 0) {
@@ -644,15 +622,25 @@ int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address,
 		if ((length < PMD_SIZE) || (pfn & PG_PMD_COLOUR))
 			goto fallback;
 
+		if (buffer_unwritten(&bh) || buffer_new(&bh)) {
+			int i;
+			for (i = 0; i < PTRS_PER_PMD; i++)
+				clear_pmem(kaddr + i * PAGE_SIZE, PAGE_SIZE);
+			wmb_pmem();
+			count_vm_event(PGMAJFAULT);
+			mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT);
+			result |= VM_FAULT_MAJOR;
+		}
+
 		result |= vmf_insert_pfn_pmd(vma, address, pmd, pfn, write);
 	}
 
  out:
+	i_mmap_unlock_read(mapping);
+
 	if (buffer_unwritten(&bh))
 		complete_unwritten(&bh, !(result & VM_FAULT_ERROR));
 
-	i_mmap_unlock_write(mapping);
-
 	return result;
 
  fallback:
diff --git a/mm/memory.c b/mm/memory.c
index 9cb27470fee9..deb679c31f2a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2426,6 +2426,8 @@ void unmap_mapping_range(struct address_space *mapping,
 	if (details.last_index < details.first_index)
 		details.last_index = ULONG_MAX;
 
+
+	/* DAX uses i_mmap_lock to serialise file truncate vs page fault */
 	i_mmap_lock_write(mapping);
 	if (unlikely(!RB_EMPTY_ROOT(&mapping->i_mmap)))
 		unmap_mapping_range_tree(&mapping->i_mmap, &details);
-- 
cgit v1.2.3-70-g09d2


From 1fd4e5c347bfcef6ae2c31f6a2abce00f6ecaa3f Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@linux-foundation.org>
Date: Thu, 15 Oct 2015 15:28:35 -0700
Subject: lib/Kconfig: ZLIB_DEFLATE must select BITREVERSE

lib/built-in.o: In function `__bitrev32':
deftree.c:(.text+0x1e799): undefined reference to `byte_rev_table'
deftree.c:(.text+0x1e7a0): undefined reference to `byte_rev_table'
deftree.c:(.text+0x1e7b4): undefined reference to `byte_rev_table'
deftree.c:(.text+0x1e7c1): undefined reference to `byte_rev_table'

Anything which uses bitrevX() has to select BITREVERSE, to grab
lib/bitrev.o.

Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 lib/Kconfig | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/Kconfig b/lib/Kconfig
index 2e491ac15622..f0df318104e7 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -220,6 +220,7 @@ config ZLIB_INFLATE
 
 config ZLIB_DEFLATE
 	tristate
+	select BITREVERSE
 
 config LZO_COMPRESS
 	tristate
-- 
cgit v1.2.3-70-g09d2


From 934ed25ea505859cec5236dcb1769be5f998dd25 Mon Sep 17 00:00:00 2001
From: Ross Zwisler <ross.zwisler@linux.intel.com>
Date: Thu, 15 Oct 2015 15:28:38 -0700
Subject: sh: add copy_user_page() alias for __copy_user()

copy_user_page() is needed by DAX.  Without this we get a compile error
for DAX on SH:

  fs/dax.c:280:2: error: implicit declaration of function `copy_user_page' [-Werror=implicit-function-declaration]
    copy_user_page(vto, (void __force *)vfrom, vaddr, to);
      ^

This was done with a random config that happened to include DAX support.

This patch has only been compile tested.

Signed-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Reported-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
 arch/sh/include/asm/page.h | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/sh/include/asm/page.h b/arch/sh/include/asm/page.h
index fe20d14ae051..ceb5201a30ed 100644
--- a/arch/sh/include/asm/page.h
+++ b/arch/sh/include/asm/page.h
@@ -59,6 +59,7 @@ pages_do_alias(unsigned long addr1, unsigned long addr2)
 
 #define clear_page(page)	memset((void *)(page), 0, PAGE_SIZE)
 extern void copy_page(void *to, void *from);
+#define copy_user_page(to, from, vaddr, pg)  __copy_user(to, from, PAGE_SIZE)
 
 struct page;
 struct vm_area_struct;
-- 
cgit v1.2.3-70-g09d2