KVM: Don't pre-reserve xarray entries when storing empty/NULL attributesgrafted

Skip the xarray reservation loop when clearing all memory attributes, as
storing NULL only erases the entry and never needs to allocate, so no
reservation (and no cleanup of a failed one) is required in that case.

Suggested-by: Sean Christopherson <seanjc@google.com>
Cc: David Ballesteros <davimaba.v@proton.me>
Signed-off-by: Zeng Chi <zengchi@kylinos.cn>
Link: https://patch.msgid.link/20260921102442.1232375-1-zeng_chi911@163.com
[sean: split to separate patch]
Signed-off-by: Sean Christopherson <seanjc@google.com>

1 files changed, 47 insertions, 0 deletions

diff --git a/drivers/md/bcache/request.h b/drivers/md/bcache/request.h
new file mode 100644
index 000000000..46bbef00a
--- /dev/null
+++ b/drivers/md/bcache/request.h
@@ -0,0 +1,47 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHE_REQUEST_H_
+#define _BCACHE_REQUEST_H_
+
+struct data_insert_op {
+	struct closure		cl;
+	struct cache_set	*c;
+	struct bio		*bio;
+	struct workqueue_struct *wq;
+
+	unsigned int		inode;
+	uint16_t		write_point;
+	uint16_t		write_prio;
+	blk_status_t		status;
+
+	union {
+		uint16_t	flags;
+
+	struct {
+		unsigned int	bypass:1;
+		unsigned int	writeback:1;
+		unsigned int	flush_journal:1;
+		unsigned int	csum:1;
+
+		unsigned int	replace:1;
+		unsigned int	replace_collision:1;
+
+		unsigned int	insert_data_done:1;
+	};
+	};
+
+	struct keylist		insert_keys;
+	BKEY_PADDED(replace_key);
+};
+
+unsigned int bch_get_congested(const struct cache_set *c);
+CLOSURE_CALLBACK(bch_data_insert);
+
+void bch_cached_dev_request_init(struct cached_dev *dc);
+void cached_dev_submit_bio(struct bio *bio);
+
+void bch_flash_dev_request_init(struct bcache_device *d);
+void flash_dev_submit_bio(struct bio *bio);
+
+extern struct kmem_cache *bch_search_cache;
+
+#endif /* _BCACHE_REQUEST_H_ */