From: Christoph Hellwig <hch@lst.de>
Date: Wed, 4 Aug 2021 11:56:20 +0200
Subject: [PATCH] bvec: add a bvec_virt helper
Git-commit: 1113f0b69c6a98ff4e733c306a6658a31f8cbc49
Patch-mainline: v5.15-rc1
References: jsc#PED-1183

Add a helper to get the virtual address for a bvec.  This avoids that
all callers need to know about the page + offset representation.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <kch@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Link: https://lore.kernel.org/r/20210804095634.460779-2-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Acked-by: Hannes Reinecke <hare@suse.com>
---
 include/linux/bvec.h | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index f9fa43b940ff..0e9bdd42dafb 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -229,4 +229,16 @@ static inline void memzero_bvec(struct bio_vec *bvec)
 	memzero_page(bvec->bv_page, bvec->bv_offset, bvec->bv_len);
 }
 
+/**
+ * bvec_virt - return the virtual address for a bvec
+ * @bvec: bvec to return the virtual address for
+ *
+ * Note: the caller must ensure that @bvec->bv_page is not a highmem page.
+ */
+static inline void *bvec_virt(struct bio_vec *bvec)
+{
+	WARN_ON_ONCE(PageHighMem(bvec->bv_page));
+	return page_address(bvec->bv_page) + bvec->bv_offset;
+}
+
 #endif /* __LINUX_BVEC_H */
-- 
2.35.3