linux-kernel - [PATCH v4 4/5] dax: remove DAX code from page_cache_tree

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Date:   Fri, 21 Jul 2017 16:39:54 -0600
From:   Ross Zwisler <ross.zwisler@...ux.intel.com>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        linux-kernel@...r.kernel.org
Cc:     Ross Zwisler <ross.zwisler@...ux.intel.com>,
        "Darrick J. Wong" <darrick.wong@...cle.com>,
        "Theodore Ts'o" <tytso@....edu>,
        Alexander Viro <viro@...iv.linux.org.uk>,
        Andreas Dilger <adilger.kernel@...ger.ca>,
        Christoph Hellwig <hch@....de>,
        Dan Williams <dan.j.williams@...el.com>,
        Dave Chinner <david@...morbit.com>,
        David Airlie <airlied@...ux.ie>,
        Ingo Molnar <mingo@...hat.com>,
        Inki Dae <inki.dae@...sung.com>, Jan Kara <jack@...e.cz>,
        Jonathan Corbet <corbet@....net>,
        Joonyoung Shim <jy0922.shim@...sung.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Kukjin Kim <kgene@...nel.org>,
        Kyungmin Park <kyungmin.park@...sung.com>,
        Matthew Wilcox <mawilcox@...rosoft.com>,
        Patrik Jakobsson <patrik.r.jakobsson@...il.com>,
        Rob Clark <robdclark@...il.com>,
        Seung-Woo Kim <sw0312.kim@...sung.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Tomi Valkeinen <tomi.valkeinen@...com>,
        dri-devel@...ts.freedesktop.org, freedreno@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, linux-doc@...r.kernel.org,
        linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org,
        linux-mm@...ck.org, linux-nvdimm@...ts.01.org,
        linux-samsung-soc@...r.kernel.org, linux-xfs@...r.kernel.org
Subject: [PATCH v4 4/5] dax: remove DAX code from page_cache_tree_insert()

Now that we no longer insert struct page pointers in DAX radix trees we can
remove the special casing for DAX in page_cache_tree_insert().  This also
allows us to make dax_wake_mapping_entry_waiter() local to fs/dax.c,
removing it from dax.h.

Signed-off-by: Ross Zwisler <ross.zwisler@...ux.intel.com>
Suggested-by: Jan Kara <jack@...e.cz>
---
 fs/dax.c            |  2 +-
 include/linux/dax.h |  2 --
 mm/filemap.c        | 13 ++-----------
 3 files changed, 3 insertions(+), 14 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index fb0e4c1..0e27d90 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -127,7 +127,7 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo
  * correct waitqueue where tasks might be waiting for that old 'entry' and
  * wake them.
  */
-void dax_wake_mapping_entry_waiter(struct address_space *mapping,
+static void dax_wake_mapping_entry_waiter(struct address_space *mapping,
 		pgoff_t index, void *entry, bool wake_all)
 {
 	struct exceptional_entry_key key;
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 29cced8..afa99bb 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -122,8 +122,6 @@ int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
 int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index);
 int dax_invalidate_mapping_entry_sync(struct address_space *mapping,
 				      pgoff_t index);
-void dax_wake_mapping_entry_waiter(struct address_space *mapping,
-		pgoff_t index, void *entry, bool wake_all);
 
 #ifdef CONFIG_FS_DAX
 int __dax_zero_page_range(struct block_device *bdev,
diff --git a/mm/filemap.c b/mm/filemap.c
index a497024..1bf1265 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -130,17 +130,8 @@ static int page_cache_tree_insert(struct address_space *mapping,
 			return -EEXIST;
 
 		mapping->nrexceptional--;
-		if (!dax_mapping(mapping)) {
-			if (shadowp)
-				*shadowp = p;
-		} else {
-			/* DAX can replace empty locked entry with a hole */
-			WARN_ON_ONCE(p !=
-				dax_radix_locked_entry(0, RADIX_DAX_EMPTY));
-			/* Wakeup waiters for exceptional entry lock */
-			dax_wake_mapping_entry_waiter(mapping, page->index, p,
-						      true);
-		}
+		if (shadowp)
+			*shadowp = p;
 	}
 	__radix_tree_replace(&mapping->page_tree, node, slot, page,
 			     workingset_update_node, mapping);
-- 
2.9.4