[PATCH v4 2/4] io_uring/rsrc: store folio shift and mask into imu

[Chenliang Li <cliang01.li@samsung.com>]

Store the folio shift and folio mask into imu struct and use it in
iov_iter adjust, as we will have non PAGE_SIZE'd chunks if a
multi-hugepage buffer get coalesced.

Signed-off-by: Chenliang Li <cliang01.li@samsung.com>
---
 io_uring/rsrc.c | 6 ++++--
 io_uring/rsrc.h | 2 ++
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index d08224c0c5b0..578d382ca9bc 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1015,6 +1015,8 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 	imu->ubuf = (unsigned long) iov->iov_base;
 	imu->ubuf_end = imu->ubuf + iov->iov_len;
 	imu->nr_bvecs = nr_pages;
+	imu->folio_shift = PAGE_SHIFT;
+	imu->folio_mask = PAGE_MASK;
 	*pimu = imu;
 	ret = 0;
 
@@ -1153,12 +1155,12 @@ int io_import_fixed(int ddir, struct iov_iter *iter,
 
 			/* skip first vec */
 			offset -= bvec->bv_len;
-			seg_skip = 1 + (offset >> PAGE_SHIFT);
+			seg_skip = 1 + (offset >> imu->folio_shift);
 
 			iter->bvec = bvec + seg_skip;
 			iter->nr_segs -= seg_skip;
 			iter->count -= bvec->bv_len + offset;
-			iter->iov_offset = offset & ~PAGE_MASK;
+			iter->iov_offset = offset & ~imu->folio_mask;
 		}
 	}
 
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index b2a9d66b76dd..93da02e652bc 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -46,7 +46,9 @@ struct io_mapped_ubuf {
 	u64		ubuf;
 	u64		ubuf_end;
 	unsigned int	nr_bvecs;
+	unsigned int	folio_shift;
 	unsigned long	acct_pages;
+	unsigned long	folio_mask;
 	struct bio_vec	bvec[] __counted_by(nr_bvecs);
 };
 
-- 
2.34.1