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From:   Christoph Hellwig <hch@lst.de>
To:     Jens Axboe <axboe@kernel.dk>, Thomas Gleixner <tglx@linutronix.de>
Cc:     Thomas Bogendoerfer <tsbogend@alpha.franken.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Geoff Levand <geoff@infradead.org>,
        Ilya Dryomov <idryomov@gmail.com>,
        Dongsheng Yang <dongsheng.yang@easystack.cn>,
        Mike Snitzer <snitzer@redhat.com>,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        Ira Weiny <ira.weiny@intel.com>, dm-devel@redhat.com,
        linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-block@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
        ceph-devel@vger.kernel.org, linux-arch@vger.kernel.org,
        Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>,
        "Martin K . Petersen" <martin.petersen@oracle.com>
Subject: [PATCH 03/15] bvec: add a bvec_kmap_local helper
Date:   Tue, 27 Jul 2021 07:56:34 +0200
Message-Id: <20210727055646.118787-4-hch@lst.de>
In-Reply-To: <20210727055646.118787-1-hch@lst.de>
References: <20210727055646.118787-1-hch@lst.de>
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Add a helper to call kmap_local_page on a bvec.  There is no need for
an unmap helper given that kunmap_local accept any address in the mapped
page.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
---
 include/linux/bvec.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index 883faf5f1523..f8710af18eef 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -7,6 +7,7 @@
 #ifndef __LINUX_BVEC_H
 #define __LINUX_BVEC_H
 
+#include <linux/highmem.h>
 #include <linux/bug.h>
 #include <linux/errno.h>
 #include <linux/limits.h>
@@ -183,4 +184,16 @@ static inline void bvec_advance(const struct bio_vec *bvec,
 	}
 }
 
+/**
+ * bvec_kmap_local - map a bvec into the kernel virtual address space
+ * @bvec: bvec to map
+ *
+ * Must be called on single-page bvecs only.  Call kunmap_local on the returned
+ * address to unmap.
+ */
+static inline void *bvec_kmap_local(struct bio_vec *bvec)
+{
+	return kmap_local_page(bvec->bv_page) + bvec->bv_offset;
+}
+
 #endif /* __LINUX_BVEC_H */
-- 
2.30.2