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From: Matthew Wilcox <willy@infradead.org>
To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org
Cc: Matthew Wilcox <willy@infradead.org>, Jan Kara <jack@suse.cz>,
	Jeff Layton <jlayton@redhat.com>,
	Lukas Czerner <lczerner@redhat.com>,
	Ross Zwisler <ross.zwisler@linux.intel.com>,
	Christoph Hellwig <hch@lst.de>,
	Goldwyn Rodrigues <rgoldwyn@suse.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>,
	linux-nilfs@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
	Chao Yu <yuchao0@huawei.com>,
	linux-f2fs-devel@lists.sourceforge.net
Subject: [PATCH v14 68/74] dax: Convert dax_lock_page to XArray
Date: Sat, 16 Jun 2018 19:00:46 -0700	[thread overview]
Message-ID: <20180617020052.4759-69-willy@infradead.org> (raw)
In-Reply-To: <20180617020052.4759-1-willy@infradead.org>

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
 fs/dax.c | 96 +++++++++++++++++++++++++++++---------------------------
 1 file changed, 50 insertions(+), 46 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 08595ffde566..54a01380527a 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -99,6 +99,22 @@ static void *dax_make_locked(unsigned long pfn, unsigned long flags)
 			DAX_LOCKED);
 }
 
+static unsigned long dax_is_pmd_entry(void *entry)
+{
+	return xa_to_value(entry) & DAX_PMD;
+}
+
+static void *dax_make_entry(pfn_t pfn, unsigned long flags)
+{
+	return xa_mk_value(flags | (pfn_t_to_pfn(pfn) << DAX_SHIFT));
+}
+
+static void *dax_make_page_entry(struct page *page, void *entry)
+{
+	pfn_t pfn = page_to_pfn_t(page);
+	return dax_make_entry(pfn, dax_is_pmd_entry(entry));
+}
+
 static bool dax_is_locked(void *entry)
 {
 	return xa_to_value(entry) & DAX_LOCKED;
@@ -111,11 +127,6 @@ static unsigned int dax_entry_order(void *entry)
 	return 0;
 }
 
-static int dax_is_pmd_entry(void *entry)
-{
-	return xa_to_value(entry) & DAX_PMD;
-}
-
 static int dax_is_pte_entry(void *entry)
 {
 	return !(xa_to_value(entry) & DAX_PMD);
@@ -466,78 +477,71 @@ static struct page *dax_busy_page(void *entry)
 
 struct page *dax_lock_page(unsigned long pfn)
 {
-	pgoff_t index;
-	struct inode *inode;
-	wait_queue_head_t *wq;
-	void *entry = NULL, **slot;
+	struct page *page = pfn_to_page(pfn);
+	XA_STATE(xas, NULL, 0);
+	void *entry;
 	struct address_space *mapping;
-	struct wait_exceptional_entry_queue ewait;
-	struct page *ret = NULL, *page = pfn_to_page(pfn);
 
-	rcu_read_lock();
 	for (;;) {
+		rcu_read_lock();
 		mapping = READ_ONCE(page->mapping);
 
-		if (!mapping || !IS_DAX(mapping->host))
+		if (!mapping || !IS_DAX(mapping->host)) {
+			page = NULL;
 			break;
+		}
 
 		/*
 		 * In the device-dax case there's no need to lock, a
 		 * struct dev_pagemap pin is sufficient to keep the
 		 * inode alive.
 		 */
-		inode = mapping->host;
-		if (S_ISCHR(inode->i_mode)) {
-			ret = page;
+		if (S_ISCHR(mapping->host->i_mode))
 			break;
-		}
 
-		xa_lock_irq(&mapping->i_pages);
+		xas.xa = &mapping->i_pages;
+		xas_lock_irq(&xas);
+		rcu_read_unlock();
 		if (mapping != page->mapping) {
 			xa_unlock_irq(&mapping->i_pages);
 			continue;
 		}
-		index = page->index;
-
-		init_wait(&ewait.wait);
-		ewait.wait.func = wake_exceptional_entry_func;
-
-		entry = __radix_tree_lookup(&mapping->i_pages, index, NULL,
-				&slot);
-		if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) {
-			xa_unlock_irq(&mapping->i_pages);
-			break;
-		} else if (!slot_locked(mapping, slot)) {
-			lock_slot(mapping, slot);
-			ret = page;
-			xa_unlock_irq(&mapping->i_pages);
-			break;
+		xas_set(&xas, page->index);
+		entry = xas_load(&xas);
+		if (dax_is_locked(entry)) {
+			entry = get_unlocked_entry(&xas);
+			/* Did the page move while we slept? */
+			if (dax_to_pfn(entry) != pfn) {
+				xas_unlock_irq(&xas);
+				continue;
+			}
 		}
-
-		wq = dax_entry_waitqueue(&mapping->i_pages, index, entry,
-				&ewait.key);
-		prepare_to_wait_exclusive(wq, &ewait.wait,
-				TASK_UNINTERRUPTIBLE);
-		xa_unlock_irq(&mapping->i_pages);
-		rcu_read_unlock();
-		schedule();
-		finish_wait(wq, &ewait.wait);
-		rcu_read_lock();
+		dax_lock_entry(&xas, entry);
+		xas_unlock_irq(&xas);
+		goto out;
 	}
 	rcu_read_unlock();
 
+out:
 	return page;
 }
 
 void dax_unlock_page(struct page *page)
 {
 	struct address_space *mapping = page->mapping;
-	struct inode *inode = mapping->host;
+	XA_STATE(xas, &mapping->i_pages, page->index);
+	void *entry;
 
-	if (S_ISCHR(inode->i_mode))
+	if (S_ISCHR(mapping->host->i_mode))
 		return;
 
-	dax_unlock_mapping_entry(mapping, page->index);
+	xas_lock_irq(&xas);
+	entry = xas_load(&xas);
+	BUG_ON(!dax_is_locked(entry));
+	entry = dax_make_page_entry(page, entry);
+	xas_store(&xas, entry);
+	dax_wake_entry(&xas, entry, false);
+	xas_unlock_irq(&xas);
 }
 
 /*
-- 
2.17.1

  parent reply	other threads:[~2018-06-17  2:01 UTC|newest]

Thread overview: 90+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-17  1:59 [PATCH v14 00/74] Convert page cache " Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 01/74] Update email address Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 02/74] radix tree test suite: Enable ubsan Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 03/74] dax: Fix use of zero page Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 04/74] xarray: Replace exceptional entries Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 05/74] xarray: Change definition of sibling entries Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 06/74] xarray: Add definition of struct xarray Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 07/74] xarray: Define struct xa_node Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 08/74] xarray: Add documentation Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 09/74] xarray: Add XArray load operation Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 10/74] xarray: Add XArray tags Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 11/74] xarray: Add XArray unconditional store operations Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 12/74] xarray: Add XArray conditional " Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 13/74] xarray: Add XArray iterators Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 14/74] xarray: Extract entries from an XArray Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 15/74] xarray: Destroy " Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 16/74] xarray: Step through " Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 17/74] xarray: Add xas_for_each_conflict Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 18/74] xarray: Add xas_create_range Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 19/74] xarray: Add MAINTAINERS entry Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 20/74] page cache: Rearrange address_space Matthew Wilcox
2018-06-17  1:59 ` [PATCH v14 21/74] page cache: Convert hole search to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 22/74] page cache: Add and replace pages using the XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 23/74] page cache: Convert page deletion to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 24/74] page cache: Convert find_get_entry " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 25/74] page cache: Convert find_get_entries " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 26/74] page cache: Convert find_get_pages_range " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 27/74] page cache: Convert find_get_pages_contig " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 28/74] page cache; Convert find_get_pages_range_tag " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 29/74] page cache: Convert find_get_entries_tag " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 30/74] page cache: Convert filemap_map_pages " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 31/74] radix tree test suite: Convert regression1 " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 32/74] page cache: Convert delete_batch " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 33/74] page cache: Remove stray radix comment Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 34/74] page cache: Convert filemap_range_has_page to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 35/74] mm: Convert page-writeback " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 36/74] mm: Convert workingset " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 37/74] mm: Convert truncate " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 38/74] mm: Convert add_to_swap_cache " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 39/74] mm: Convert delete_from_swap_cache " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 40/74] mm: Convert __do_page_cache_readahead " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 41/74] mm: Convert page migration " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 42/74] mm: Convert huge_memory " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 43/74] mm: Convert collapse_shmem " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 44/74] mm: Convert khugepaged_scan_shmem " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 45/74] mm: Convert is_page_cache_freeable " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 46/74] pagevec: Use xa_tag_t Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 47/74] shmem: Convert shmem_radix_tree_replace to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 48/74] shmem: Convert shmem_confirm_swap " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 49/74] shmem: Convert find_swap_entry " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 50/74] shmem: Convert shmem_add_to_page_cache " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 51/74] shmem: Convert shmem_alloc_hugepage " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 52/74] shmem: Convert shmem_free_swap " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 53/74] shmem: Convert shmem_partial_swap_usage " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 54/74] memfd: Convert memfd_wait_for_pins " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 55/74] memfd: Convert memfd_tag_pins " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 56/74] shmem: Comment fixups Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 57/74] btrfs: Convert page cache to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 58/74] fs: Convert buffer " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 59/74] fs: Convert writeback " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 60/74] nilfs2: Convert " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 61/74] f2fs: " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 62/74] dax: Rename some functions Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 63/74] dax: Hash on XArray instead of mapping Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 64/74] dax: Convert dax_insert_pfn_mkwrite to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 65/74] dax: Convert dax_layout_busy_page " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 66/74] dax: Convert __dax_invalidate_entry " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 67/74] dax: Convert dax writeback " Matthew Wilcox
2018-06-17  2:00 ` Matthew Wilcox [this message]
2018-06-29 17:30   ` [PATCH v14 68/74] dax: Convert dax_lock_page " Ross Zwisler
2018-07-06 11:54     ` [PATCH] fs/dax: remove unused function Anders Roxell
2018-07-06 13:04     ` [PATCH v14 68/74] dax: Convert dax_lock_page to XArray Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 69/74] dax: Convert page fault handlers " Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 70/74] page cache: Finish XArray conversion Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 71/74] radix tree: Remove radix_tree_update_node_t Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 72/74] radix tree: Remove split/join code Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 73/74] radix tree: Remove radix_tree_maybe_preload_order Matthew Wilcox
2018-06-17  2:00 ` [PATCH v14 74/74] radix tree: Remove radix_tree_clear_tags Matthew Wilcox
2018-06-19  3:12 ` [PATCH v14 00/74] Convert page cache to XArray Ross Zwisler
2018-06-19  9:22   ` Matthew Wilcox
2018-06-19 16:40     ` Ross Zwisler
2018-06-19 17:16       ` Matthew Wilcox
2018-06-27 11:05         ` Matthew Wilcox
2018-06-27 19:44           ` Ross Zwisler
2018-06-28  8:39             ` Matthew Wilcox
2018-06-28 16:30               ` Ross Zwisler
2018-07-25 21:03             ` Matthew Wilcox
2018-07-25 21:12               ` Ross Zwisler
2018-07-27 17:20               ` Ross Zwisler
2018-07-30 15:43                 ` Matthew Wilcox

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