[PATCH 1/2] block: add a bvec_phys helper

Christoph Hellwig
2024-07-06T07:52:34Z

Get callers out of poking into bvec internals a bit more. Not a huge win
right now, but with the proposed new DMA mapping API we might end up with
a lot more of this otherwise.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
arch/m68k/emu/nfblock.c | 2 +-
block/bio.c | 2 +-
block/blk.h | 4 ++--
include/linux/bvec.h | 14 ++++++++++++++
4 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/arch/m68k/emu/nfblock.c b/arch/m68k/emu/nfblock.c
index 8eea7ef9115146..874fe958877388 100644
--- a/arch/m68k/emu/nfblock.c
+++ b/arch/m68k/emu/nfblock.c
@@ -71,7 +71,7 @@ static void nfhd_submit_bio(struct bio *bio)
len = bvec.bv_len;
len >>= 9;
nfhd_read_write(dev->id, 0, dir, sec >> shift, len >> shift,
- page_to_phys(bvec.bv_page) + bvec.bv_offset);
+ bvec_phys(&bvec));
sec += len;
}
bio_endio(bio);
diff --git a/block/bio.c b/block/bio.c
index e9e809a63c5975..a3b1b2266c50be 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -953,7 +953,7 @@ bool bvec_try_merge_hw_page(struct request_queue *q, struct bio_vec *bv,
bool *same_page)
{
unsigned long mask = queue_segment_boundary(q);
- phys_addr_t addr1 = page_to_phys(bv->bv_page) + bv->bv_offset;
+ phys_addr_t addr1 = bvec_phys(bv);
phys_addr_t addr2 = page_to_phys(page) + offset + len - 1;

if ((addr1 | mask) != (addr2 | mask))
diff --git a/block/blk.h b/block/blk.h
index 8c27d524303aa7..d099ef1df5f64a 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -109,8 +109,8 @@ static inline bool biovec_phys_mergeable(struct request_queue *q,
struct bio_vec *vec1, struct bio_vec *vec2)
{
unsigned long mask = queue_segment_boundary(q);
- phys_addr_t addr1 = page_to_phys(vec1->bv_page) + vec1->bv_offset;
- phys_addr_t addr2 = page_to_phys(vec2->bv_page) + vec2->bv_offset;
+ phys_addr_t addr1 = bvec_phys(vec1);
+ phys_addr_t addr2 = bvec_phys(vec2);

/*
* Merging adjacent physical pages may not work correctly under KMSAN
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
index bd1e361b351c5a..f41c7f0ef91ed5 100644
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -280,4 +280,18 @@ static inline void *bvec_virt(struct bio_vec *bvec)
return page_address(bvec->bv_page) + bvec->bv_offset;
}

+/**
+ * bvec_phys - return the physical address for a bvec
+ * @bvec: bvec to return the physical address for
+ */
+static inline phys_addr_t bvec_phys(const struct bio_vec *bvec)
+{
+ /*
+ * Note this open codes page_to_phys because page_to_phys is defined in
+ * <asm/io.h>, which we don't want to pull in here. If it ever moves to
+ * a sensible place we should start using it.
+ */
+ return PFN_PHYS(page_to_pfn(bvec->bv_page)) + bvec->bv_offset;
+}
+
#endif /* __LINUX_BVEC_H */
--
2.43.0