From: Shiyang Ruan <ruansy.fnst@fujitsu.com>
To: <linux-kernel@vger.kernel.org>, <linux-xfs@vger.kernel.org>,
<nvdimm@lists.linux.dev>, <linux-mm@kvack.org>,
<linux-fsdevel@vger.kernel.org>
Cc: <djwong@kernel.org>, <dan.j.williams@intel.com>,
<david@fromorbit.com>, <hch@infradead.org>, <jane.chu@oracle.com>,
Christoph Hellwig <hch@lst.de>
Subject: [PATCH v11 4/8] fsdax: Introduce dax_lock_mapping_entry()
Date: Sun, 27 Feb 2022 20:07:43 +0800 [thread overview]
Message-ID: <20220227120747.711169-5-ruansy.fnst@fujitsu.com> (raw)
In-Reply-To: <20220227120747.711169-1-ruansy.fnst@fujitsu.com>
The current dax_lock_page() locks dax entry by obtaining mapping and
index in page. To support 1-to-N RMAP in NVDIMM, we need a new function
to lock a specific dax entry corresponding to this file's mapping,index.
And output the page corresponding to the specific dax entry for caller
use.
Signed-off-by: Shiyang Ruan <ruansy.fnst@fujitsu.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
fs/dax.c | 63 +++++++++++++++++++++++++++++++++++++++++++++
include/linux/dax.h | 15 +++++++++++
2 files changed, 78 insertions(+)
diff --git a/fs/dax.c b/fs/dax.c
index cd03485867a7..653a2f390b72 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -455,6 +455,69 @@ void dax_unlock_page(struct page *page, dax_entry_t cookie)
dax_unlock_entry(&xas, (void *)cookie);
}
+/*
+ * dax_lock_mapping_entry - Lock the DAX entry corresponding to a mapping
+ * @mapping: the file's mapping whose entry we want to lock
+ * @index: the offset within this file
+ * @page: output the dax page corresponding to this dax entry
+ *
+ * Return: A cookie to pass to dax_unlock_mapping_entry() or 0 if the entry
+ * could not be locked.
+ */
+dax_entry_t dax_lock_mapping_entry(struct address_space *mapping, pgoff_t index,
+ struct page **page)
+{
+ XA_STATE(xas, NULL, 0);
+ void *entry;
+
+ rcu_read_lock();
+ for (;;) {
+ entry = NULL;
+ if (!dax_mapping(mapping))
+ break;
+
+ xas.xa = &mapping->i_pages;
+ xas_lock_irq(&xas);
+ xas_set(&xas, index);
+ entry = xas_load(&xas);
+ if (dax_is_locked(entry)) {
+ rcu_read_unlock();
+ wait_entry_unlocked(&xas, entry);
+ rcu_read_lock();
+ continue;
+ }
+ if (!entry ||
+ dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
+ /*
+ * Because we are looking for entry from file's mapping
+ * and index, so the entry may not be inserted for now,
+ * or even a zero/empty entry. We don't think this is
+ * an error case. So, return a special value and do
+ * not output @page.
+ */
+ entry = (void *)~0UL;
+ } else {
+ *page = pfn_to_page(dax_to_pfn(entry));
+ dax_lock_entry(&xas, entry);
+ }
+ xas_unlock_irq(&xas);
+ break;
+ }
+ rcu_read_unlock();
+ return (dax_entry_t)entry;
+}
+
+void dax_unlock_mapping_entry(struct address_space *mapping, pgoff_t index,
+ dax_entry_t cookie)
+{
+ XA_STATE(xas, &mapping->i_pages, index);
+
+ if (cookie == ~0UL)
+ return;
+
+ dax_unlock_entry(&xas, (void *)cookie);
+}
+
/*
* Find page cache entry at given index. If it is a DAX entry, return it
* with the entry locked. If the page cache doesn't contain an entry at
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 262d7bad131a..3ab253c82c75 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -158,6 +158,10 @@ struct page *dax_layout_busy_page(struct address_space *mapping);
struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
dax_entry_t dax_lock_page(struct page *page);
void dax_unlock_page(struct page *page, dax_entry_t cookie);
+dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
+ unsigned long index, struct page **page);
+void dax_unlock_mapping_entry(struct address_space *mapping,
+ unsigned long index, dax_entry_t cookie);
#else
static inline struct page *dax_layout_busy_page(struct address_space *mapping)
{
@@ -185,6 +189,17 @@ static inline dax_entry_t dax_lock_page(struct page *page)
static inline void dax_unlock_page(struct page *page, dax_entry_t cookie)
{
}
+
+static inline dax_entry_t dax_lock_mapping_entry(struct address_space *mapping,
+ unsigned long index, struct page **page)
+{
+ return 0;
+}
+
+static inline void dax_unlock_mapping_entry(struct address_space *mapping,
+ unsigned long index, dax_entry_t cookie)
+{
+}
#endif
int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
--
2.35.1
next prev parent reply other threads:[~2022-02-27 12:08 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-27 12:07 [PATCH v11 0/8] fsdax: introduce fs query to support reflink Shiyang Ruan
2022-02-27 12:07 ` [PATCH v11 1/8] dax: Introduce holder for dax_device Shiyang Ruan
2022-03-11 23:35 ` Dan Williams
2022-03-16 13:46 ` Shiyang Ruan
2022-03-30 5:41 ` Christoph Hellwig
2022-03-30 10:03 ` Shiyang Ruan
2022-03-30 10:13 ` Christoph Hellwig
2022-03-30 10:58 ` Shiyang Ruan
2022-03-30 15:49 ` Christoph Hellwig
2022-03-30 16:18 ` Darrick J. Wong
2022-04-06 0:55 ` Jane Chu
2022-04-06 1:22 ` Dan Williams
2022-04-06 20:39 ` Darrick J. Wong
2022-04-08 1:38 ` Dan Williams
2022-04-08 5:59 ` Shiyang Ruan
2022-03-30 5:41 ` Christoph Hellwig
2022-02-27 12:07 ` [PATCH v11 2/8] mm: factor helpers for memory_failure_dev_pagemap Shiyang Ruan
2022-02-27 12:07 ` [PATCH v11 3/8] pagemap,pmem: Introduce ->memory_failure() Shiyang Ruan
2022-02-27 12:07 ` Shiyang Ruan [this message]
2022-02-27 12:07 ` [PATCH v11 5/8] mm: move pgoff_address() to vma_pgoff_address() Shiyang Ruan
2022-03-30 5:46 ` Christoph Hellwig
2022-03-30 6:49 ` Shiyang Ruan
2022-02-27 12:07 ` [PATCH v11 6/8] mm: Introduce mf_dax_kill_procs() for fsdax case Shiyang Ruan
2022-03-30 5:51 ` Christoph Hellwig
2022-02-27 12:07 ` [PATCH v11 7/8] xfs: Implement ->notify_failure() for XFS Shiyang Ruan
2022-02-27 14:05 ` kernel test robot
2022-02-27 15:36 ` kernel test robot
2022-02-27 15:46 ` kernel test robot
2022-03-30 6:00 ` Christoph Hellwig
2022-03-30 15:16 ` Shiyang Ruan
2022-03-30 15:52 ` Christoph Hellwig
2022-04-08 6:04 ` Shiyang Ruan
2022-04-08 6:26 ` Dan Williams
2022-04-08 6:25 ` Dan Williams
2022-02-27 12:07 ` [PATCH v11 8/8] fsdax: set a CoW flag when associate reflink mappings Shiyang Ruan
2022-02-27 15:57 ` kernel test robot
2022-03-10 13:08 ` [PATCH v11 0/8] fsdax: introduce fs query to support reflink Shiyang Ruan
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