Commit bfc0aa7a authored by Jens Axboe's avatar Jens Axboe
Browse files

io_uring/rsrc: add reference count to struct io_mapped_ubuf 



Currently there's a single ring owner of a mapped buffer, and hence the
reference count will always be 1 when it's torn down and freed. However,
in preparation for being able to link io_mapped_ubuf to different spots,
add a reference count to manage the lifetime of it.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 021b153f

io_uring/rsrc.c

+3 −0
Original line number Diff line number Diff line
@@ -116,6 +116,8 @@ static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slo 


	*slot = NULL;

	if (imu != &dummy_ubuf) {

		if (!refcount_dec_and_test(&imu->refs))

			return;

		for (i = 0; i < imu->nr_bvecs; i++)

			unpin_user_page(imu->bvec[i].bv_page);

		if (imu->acct_pages)
@@ -990,6 +992,7 @@ static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 
		imu->folio_shift = data.folio_shift;

		imu->folio_mask = ~((1UL << data.folio_shift) - 1);

	}

	refcount_set(&imu->refs, 1);

	off = (unsigned long) iov->iov_base & ~imu->folio_mask;

	*pimu = imu;

	ret = 0;

io_uring/rsrc.h

+1 −0
Original line number Diff line number Diff line
@@ -47,6 +47,7 @@ struct io_mapped_ubuf { 
	unsigned int    folio_shift;

	unsigned long	acct_pages;

	unsigned long   folio_mask;

	refcount_t	refs;

	struct bio_vec	bvec[] __counted_by(nr_bvecs);

};