Hi Christoph,
On Fri, Jul 5, 2024 at 10:15 AM Christoph Hellwig <hch@xxxxxx> wrote:
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@xxxxxx>
Thanks for your patch!
arch/m68k/emu/nfblock.c | 2 +-
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -255,8 +255,7 @@ static bool bvec_split_segs(const struct queue_limits *lim,
unsigned seg_size = 0;
while (len && *nsegs < max_segs) {
- seg_size = get_max_segment_size(lim, page_to_phys(bv->bv_page) +
- bv->bv_offset + total_len);
+ seg_size = get_max_segment_size(lim, bvec_phys(bv) + total_len);
seg_size = min(seg_size, len);
(*nsegs)++;
@@ -492,8 +491,7 @@ static unsigned blk_bvec_map_sg(struct request_queue *q,
while (nbytes > 0) {
unsigned offset = bvec->bv_offset + total;
unsigned len = min(get_max_segment_size(&q->limits,
- page_to_phys(bvec->bv_page) + offset),
- nbytes);
+ bvec_phys(bvec) + total), nbytes);
struct page *page = bvec->bv_page;
/*
If you would have introduce bvec_phys() first, you could fold the above
two hunks into [PATCH 1/2].
--- a/include/linux/bvec.h
+++ b/include/linux/bvec.h
@@ -280,4 +280,19 @@ 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
Which suggests this is arch-specific, and may not always be defined
the same? I checked a few (but not all) that seem to differ from the
above at first sight, but end up doing the same...
I think it would be good to make sure they are identical, and if
they are, move them to a common place first, to any subtle breakages.
+ * a sensible place we should start using it.
+ */
+ return ((phys_addr_t)page_to_pfn(bvec->bv_page) << PAGE_SHIFT) +
+ bvec->bv_offset;
+}
+
#endif /* __LINUX_BVEC_H */
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
