[PATCH 3/5] fs: add ki_bio_cache pointer to struct kiocb

[Jens Axboe <axboe@kernel.dk>]

This allows an issuer (and owner of a kiocb) to pass in a bio allocation
cache that can be used to improve the efficiency of the churn of repeated
bio allocations and frees.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
---
 include/linux/fs.h | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/include/linux/fs.h b/include/linux/fs.h
index 640574294216..5f17d10ddc2d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -291,6 +291,7 @@ struct page;
 struct address_space;
 struct writeback_control;
 struct readahead_control;
+struct bio_alloc_cache;
 
 /*
  * Write life time hint values.
@@ -319,6 +320,8 @@ enum rw_hint {
 /* iocb->ki_waitq is valid */
 #define IOCB_WAITQ		(1 << 19)
 #define IOCB_NOIO		(1 << 20)
+/* iocb->ki_bio_cache is valid */
+#define IOCB_ALLOC_CACHE	(1 << 21)
 
 struct kiocb {
 	struct file		*ki_filp;
@@ -337,6 +340,14 @@ struct kiocb {
 		struct wait_page_queue	*ki_waitq; /* for async buffered IO */
 	};
 
+	/*
+	 * If set, owner of iov_iter can pass in a fast-cache for bio
+	 * allocations.
+	 */
+#ifdef CONFIG_BLOCK
+	struct bio_alloc_cache	*ki_bio_cache;
+#endif
+
 	randomized_struct_fields_end
 };
 
-- 
2.32.0