[RFC PATCH 03/12] io_uring: extend io_mapped_ubuf to cover external bvec table

[Ming Lei <ming.lei@redhat.com>]

Extend io_mapped_ubuf to cover external bvec table for supporting
fused command kbuf, in which the bvec table could be from one IO
request.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
---
 io_uring/rsrc.c | 5 +++--
 io_uring/rsrc.h | 3 ++-
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c
index a59fc02de598..c41edd197b0a 100644
--- a/io_uring/rsrc.c
+++ b/io_uring/rsrc.c
@@ -1221,7 +1221,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 		goto done;
 	}
 
-	imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL);
+	imu = kvmalloc(struct_size(imu, __bvec, nr_pages), GFP_KERNEL);
 	if (!imu)
 		goto done;
 
@@ -1237,7 +1237,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov,
 		size_t vec_len;
 
 		vec_len = min_t(size_t, size, PAGE_SIZE - off);
-		bvec_set_page(&imu->bvec[i], pages[i], vec_len, off);
+		bvec_set_page(&imu->__bvec[i], pages[i], vec_len, off);
 		off = 0;
 		size -= vec_len;
 	}
@@ -1245,6 +1245,7 @@ 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->bvec = imu->__bvec;
 	*pimu = imu;
 	ret = 0;
 done:
diff --git a/io_uring/rsrc.h b/io_uring/rsrc.h
index 774aca20326c..24329eca49ef 100644
--- a/io_uring/rsrc.h
+++ b/io_uring/rsrc.h
@@ -50,7 +50,8 @@ struct io_mapped_ubuf {
 	u64		ubuf_end;
 	unsigned int	nr_bvecs;
 	unsigned int	acct_pages;
-	struct bio_vec	bvec[];
+	struct bio_vec	*bvec;
+	struct bio_vec	__bvec[];
 };
 
 void io_rsrc_put_tw(struct callback_head *cb);
-- 
2.31.1