diff mbox series

[2/2] btrfs: rename btrfs_folio_(set|start|end)_writer_lock()

Message ID d5f42da1109269ad9a4a88000e78eb3a66248591.1728338061.git.wqu@suse.com (mailing list archive)
State New
Headers show
Series btrfs: unify the read and writer locks for btrfs_subpage | expand

Commit Message

Qu Wenruo Oct. 7, 2024, 9:58 p.m. UTC 
Since there is no user of reader locks, rename the writer locks into a
more generic name, by removing the "_writer" part from the name.

And also rename btrfs_subpage::writer into btrfs_subpage::locked.

Signed-off-by: Qu Wenruo <wqu@suse.com>
---
 fs/btrfs/compression.c |  2 +-
 fs/btrfs/extent_io.c   | 14 ++++++-------
 fs/btrfs/subpage.c     | 46 +++++++++++++++++++++---------------------
 fs/btrfs/subpage.h     | 14 ++++++-------
 4 files changed, 38 insertions(+), 38 deletions(-)

Comments

David Sterba Oct. 8, 2024, 5:09 p.m. UTC | #1 
On Tue, Oct 08, 2024 at 08:28:45AM +1030, Qu Wenruo wrote:
> Since there is no user of reader locks, rename the writer locks into a
> more generic name, by removing the "_writer" part from the name.
> 
> And also rename btrfs_subpage::writer into btrfs_subpage::locked.

'locked' looks confusing in connection with atomics. It sounds like a
predicate but is in fact a counter, so I'd suggest to rename it to
nr_locked or nr_locks or something like that.
Qu Wenruo Oct. 8, 2024, 8:58 p.m. UTC | #2 
在 2024/10/9 03:39, David Sterba 写道:
> On Tue, Oct 08, 2024 at 08:28:45AM +1030, Qu Wenruo wrote:
>> Since there is no user of reader locks, rename the writer locks into a
>> more generic name, by removing the "_writer" part from the name.
>>
>> And also rename btrfs_subpage::writer into btrfs_subpage::locked.
>
> 'locked' looks confusing in connection with atomics. It sounds like a
> predicate but is in fact a counter, so I'd suggest to rename it to
> nr_locked or nr_locks or something like that.
>
nr_locked looks much better, and way better than my original
"sectors_locked".

Thanks,
Qu
diff mbox series

Patch

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 74799270eb78..dfa872cf09d5 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -545,7 +545,7 @@  static noinline int add_ra_bio_pages(struct inode *inode,
 		 * subpage::readers and to unlock the page.
 		 */
 		if (fs_info->sectorsize < PAGE_SIZE)
-			btrfs_folio_set_writer_lock(fs_info, folio, cur, add_size);
+			btrfs_folio_set_lock(fs_info, folio, cur, add_size);
 		folio_put(folio);
 		cur += add_size;
 	}
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 04b190bc047f..09c7f41555d8 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -190,7 +190,7 @@  static void process_one_folio(struct btrfs_fs_info *fs_info,
 		btrfs_folio_clamp_clear_writeback(fs_info, folio, start, len);
 
 	if (folio != locked_folio && (page_ops & PAGE_UNLOCK))
-		btrfs_folio_end_writer_lock(fs_info, folio, start, len);
+		btrfs_folio_end_lock(fs_info, folio, start, len);
 }
 
 static void __process_folios_contig(struct address_space *mapping,
@@ -274,7 +274,7 @@  static noinline int lock_delalloc_folios(struct inode *inode,
 				folio_unlock(folio);
 				goto out;
 			}
-			btrfs_folio_set_writer_lock(fs_info, folio, range_start, range_len);
+			btrfs_folio_set_lock(fs_info, folio, range_start, range_len);
 
 			processed_end = range_start + range_len - 1;
 		}
@@ -436,7 +436,7 @@  static void end_folio_read(struct folio *folio, bool uptodate, u64 start, u32 le
 	if (!btrfs_is_subpage(fs_info, folio->mapping))
 		folio_unlock(folio);
 	else
-		btrfs_folio_end_writer_lock(fs_info, folio, start, len);
+		btrfs_folio_end_lock(fs_info, folio, start, len);
 }
 
 /*
@@ -493,7 +493,7 @@  static void begin_folio_read(struct btrfs_fs_info *fs_info, struct folio *folio)
 		return;
 
 	ASSERT(folio_test_private(folio));
-	btrfs_folio_set_writer_lock(fs_info, folio, folio_pos(folio), PAGE_SIZE);
+	btrfs_folio_set_lock(fs_info, folio, folio_pos(folio), PAGE_SIZE);
 }
 
 /*
@@ -1175,7 +1175,7 @@  static noinline_for_stack int writepage_delalloc(struct btrfs_inode *inode,
 	for_each_set_bit(bit, &bio_ctrl->submit_bitmap, fs_info->sectors_per_page) {
 		u64 start = page_start + (bit << fs_info->sectorsize_bits);
 
-		btrfs_folio_set_writer_lock(fs_info, folio, start, fs_info->sectorsize);
+		btrfs_folio_set_lock(fs_info, folio, start, fs_info->sectorsize);
 	}
 
 	/* Lock all (subpage) delalloc ranges inside the folio first. */
@@ -1511,7 +1511,7 @@  static int extent_writepage(struct folio *folio, struct btrfs_bio_ctrl *bio_ctrl
 	 * Only unlock ranges that are submitted. As there can be some async
 	 * submitted ranges inside the folio.
 	 */
-	btrfs_folio_end_writer_lock_bitmap(fs_info, folio, bio_ctrl->submit_bitmap);
+	btrfs_folio_end_lock_bitmap(fs_info, folio, bio_ctrl->submit_bitmap);
 	ASSERT(ret <= 0);
 	return ret;
 }
@@ -2289,7 +2289,7 @@  void extent_write_locked_range(struct inode *inode, const struct folio *locked_f
 						       cur, cur_len, !ret);
 			mapping_set_error(mapping, ret);
 		}
-		btrfs_folio_end_writer_lock(fs_info, folio, cur, cur_len);
+		btrfs_folio_end_lock(fs_info, folio, cur, cur_len);
 		if (ret < 0)
 			found_error = true;
 next_page:
diff --git a/fs/btrfs/subpage.c b/fs/btrfs/subpage.c
index ed7f66963c0b..20ed766eaf5e 100644
--- a/fs/btrfs/subpage.c
+++ b/fs/btrfs/subpage.c
@@ -140,7 +140,7 @@  struct btrfs_subpage *btrfs_alloc_subpage(const struct btrfs_fs_info *fs_info,
 		return ERR_PTR(-ENOMEM);
 
 	spin_lock_init(&ret->lock);
-	atomic_set(&ret->writers, 0);
+	atomic_set(&ret->locked, 0);
 	if (type == BTRFS_SUBPAGE_METADATA)
 		atomic_set(&ret->eb_refs, 0);
 	return ret;
@@ -255,8 +255,8 @@  static void btrfs_subpage_clamp_range(struct folio *folio, u64 *start, u32 *len)
 			     orig_start + orig_len) - *start;
 }
 
-static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_info,
-					      struct folio *folio, u64 start, u32 len)
+static bool btrfs_subpage_end_and_test_lock(const struct btrfs_fs_info *fs_info,
+					    struct folio *folio, u64 start, u32 len)
 {
 	struct btrfs_subpage *subpage = folio_get_private(folio);
 	const int start_bit = subpage_calc_start_bit(fs_info, folio, locked, start, len);
@@ -274,9 +274,9 @@  static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_inf
 	 * extent_clear_unlock_delalloc() for compression path.
 	 *
 	 * This @locked_page is locked by plain lock_page(), thus its
-	 * subpage::writers is 0.  Handle them in a special way.
+	 * subpage::locked is 0.  Handle them in a special way.
 	 */
-	if (atomic_read(&subpage->writers) == 0) {
+	if (atomic_read(&subpage->locked) == 0) {
 		spin_unlock_irqrestore(&subpage->lock, flags);
 		return true;
 	}
@@ -285,8 +285,8 @@  static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_inf
 		clear_bit(bit, subpage->bitmaps);
 		cleared++;
 	}
-	ASSERT(atomic_read(&subpage->writers) >= cleared);
-	last = atomic_sub_and_test(cleared, &subpage->writers);
+	ASSERT(atomic_read(&subpage->locked) >= cleared);
+	last = atomic_sub_and_test(cleared, &subpage->locked);
 	spin_unlock_irqrestore(&subpage->lock, flags);
 	return last;
 }
@@ -307,8 +307,8 @@  static bool btrfs_subpage_end_and_test_writer(const struct btrfs_fs_info *fs_inf
  *   bitmap, reduce the writer lock number, and unlock the page if that's
  *   the last locked range.
  */
-void btrfs_folio_end_writer_lock(const struct btrfs_fs_info *fs_info,
-				 struct folio *folio, u64 start, u32 len)
+void btrfs_folio_end_lock(const struct btrfs_fs_info *fs_info,
+			  struct folio *folio, u64 start, u32 len)
 {
 	struct btrfs_subpage *subpage = folio_get_private(folio);
 
@@ -321,24 +321,24 @@  void btrfs_folio_end_writer_lock(const struct btrfs_fs_info *fs_info,
 
 	/*
 	 * For subpage case, there are two types of locked page.  With or
-	 * without writers number.
+	 * without locked number.
 	 *
-	 * Since we own the page lock, no one else could touch subpage::writers
+	 * Since we own the page lock, no one else could touch subpage::locked
 	 * and we are safe to do several atomic operations without spinlock.
 	 */
-	if (atomic_read(&subpage->writers) == 0) {
-		/* No writers, locked by plain lock_page(). */
+	if (atomic_read(&subpage->locked) == 0) {
+		/* No subpage lock, locked by plain lock_page(). */
 		folio_unlock(folio);
 		return;
 	}
 
 	btrfs_subpage_clamp_range(folio, &start, &len);
-	if (btrfs_subpage_end_and_test_writer(fs_info, folio, start, len))
+	if (btrfs_subpage_end_and_test_lock(fs_info, folio, start, len))
 		folio_unlock(folio);
 }
 
-void btrfs_folio_end_writer_lock_bitmap(const struct btrfs_fs_info *fs_info,
-					struct folio *folio, unsigned long bitmap)
+void btrfs_folio_end_lock_bitmap(const struct btrfs_fs_info *fs_info,
+				 struct folio *folio, unsigned long bitmap)
 {
 	struct btrfs_subpage *subpage = folio_get_private(folio);
 	const int start_bit = fs_info->sectors_per_page * btrfs_bitmap_nr_locked;
@@ -352,8 +352,8 @@  void btrfs_folio_end_writer_lock_bitmap(const struct btrfs_fs_info *fs_info,
 		return;
 	}
 
-	if (atomic_read(&subpage->writers) == 0) {
-		/* No writers, locked by plain lock_page(). */
+	if (atomic_read(&subpage->locked) == 0) {
+		/* No subpage lock, locked by plain lock_page(). */
 		folio_unlock(folio);
 		return;
 	}
@@ -363,8 +363,8 @@  void btrfs_folio_end_writer_lock_bitmap(const struct btrfs_fs_info *fs_info,
 		if (test_and_clear_bit(bit + start_bit, subpage->bitmaps))
 			cleared++;
 	}
-	ASSERT(atomic_read(&subpage->writers) >= cleared);
-	last = atomic_sub_and_test(cleared, &subpage->writers);
+	ASSERT(atomic_read(&subpage->locked) >= cleared);
+	last = atomic_sub_and_test(cleared, &subpage->locked);
 	spin_unlock_irqrestore(&subpage->lock, flags);
 	if (last)
 		folio_unlock(folio);
@@ -685,8 +685,8 @@  void btrfs_folio_assert_not_dirty(const struct btrfs_fs_info *fs_info,
  * This populates the involved subpage ranges so that subpage helpers can
  * properly unlock them.
  */
-void btrfs_folio_set_writer_lock(const struct btrfs_fs_info *fs_info,
-				 struct folio *folio, u64 start, u32 len)
+void btrfs_folio_set_lock(const struct btrfs_fs_info *fs_info,
+			  struct folio *folio, u64 start, u32 len)
 {
 	struct btrfs_subpage *subpage;
 	unsigned long flags;
@@ -705,7 +705,7 @@  void btrfs_folio_set_writer_lock(const struct btrfs_fs_info *fs_info,
 	/* Target range should not yet be locked. */
 	assert_bitmap_range_all_zero(fs_info, folio, start, len);
 	bitmap_set(subpage->bitmaps, start_bit, nbits);
-	ret = atomic_add_return(nbits, &subpage->writers);
+	ret = atomic_add_return(nbits, &subpage->locked);
 	ASSERT(ret <= fs_info->sectors_per_page);
 	spin_unlock_irqrestore(&subpage->lock, flags);
 }
diff --git a/fs/btrfs/subpage.h b/fs/btrfs/subpage.h
index b6337543f7dd..96a405a90827 100644
--- a/fs/btrfs/subpage.h
+++ b/fs/btrfs/subpage.h
@@ -59,7 +59,7 @@  struct btrfs_subpage {
 		 *
 		 * How many sectors inside the page is locked.
 		 */
-		atomic_t writers;
+		atomic_t locked;
 	};
 	unsigned long bitmaps[];
 };
@@ -91,12 +91,12 @@  void btrfs_free_subpage(struct btrfs_subpage *subpage);
 void btrfs_folio_inc_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio);
 void btrfs_folio_dec_eb_refs(const struct btrfs_fs_info *fs_info, struct folio *folio);
 
-void btrfs_folio_end_writer_lock(const struct btrfs_fs_info *fs_info,
-				 struct folio *folio, u64 start, u32 len);
-void btrfs_folio_set_writer_lock(const struct btrfs_fs_info *fs_info,
-				 struct folio *folio, u64 start, u32 len);
-void btrfs_folio_end_writer_lock_bitmap(const struct btrfs_fs_info *fs_info,
-					struct folio *folio, unsigned long bitmap);
+void btrfs_folio_end_lock(const struct btrfs_fs_info *fs_info,
+			  struct folio *folio, u64 start, u32 len);
+void btrfs_folio_set_lock(const struct btrfs_fs_info *fs_info,
+			  struct folio *folio, u64 start, u32 len);
+void btrfs_folio_end_lock_bitmap(const struct btrfs_fs_info *fs_info,
+				 struct folio *folio, unsigned long bitmap);
 /*
  * Template for subpage related operations.
  *