diff mbox series

[06/18] bvec: add a bvec_kmap_local helper

Message ID 20210615132456.753241-7-hch@lst.de (mailing list archive)
State Not Applicable
Headers show
Series [01/18] mm: add a kunmap_local_dirty helper | expand

Commit Message

Christoph Hellwig June 15, 2021, 1:24 p.m. UTC 
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: Ira Weiny <ira.weiny@intel.com>
---
 include/linux/bvec.h | 13 +++++++++++++
 1 file changed, 13 insertions(+)

Comments

Bart Van Assche June 16, 2021, 4:52 p.m. UTC | #1 
On 6/15/21 6:24 AM, Christoph Hellwig wrote:
> +/**
> + * 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;
> +}

Hi Christoph,

Would it be appropriate to add WARN_ON_ONCE(bvec->bv_offset >=
PAGE_SIZE) in this function?

Thanks,

Bart.
diff mbox series

Patch

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 */