Commit 9c6e6a80 authored by lic121's avatar lic121 Committed by Andrii Nakryiko
Browse files

libbpf: Unmap rings when umem deleted 



xsk_umem__create() does mmap for fill/comp rings, but xsk_umem__delete()
doesn't do the unmap. This works fine for regular cases, because
xsk_socket__delete() does unmap for the rings. But for the case that
xsk_socket__create_shared() fails, umem rings are not unmapped.

fill_save/comp_save are checked to determine if rings have already be
unmapped by xsk. If fill_save and comp_save are NULL, it means that the
rings have already been used by xsk. Then they are supposed to be
unmapped by xsk_socket__delete(). Otherwise, xsk_umem__delete() does the
unmap.

Fixes: 2f6324a3 ("libbpf: Support shared umems between queues and devices")
Signed-off-by: default avatarCheng Li <lic121@chinatelecom.cn>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220301132623.GA19995@vscode.7~
parent c344b9fc

tools/lib/bpf/xsk.c

+11 −0
Original line number Diff line number Diff line
@@ -1193,12 +1193,23 @@ int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname, 


int xsk_umem__delete(struct xsk_umem *umem)

{

	struct xdp_mmap_offsets off;

	int err;



	if (!umem)

		return 0;



	if (umem->refcount)

		return -EBUSY;



	err = xsk_get_mmap_offsets(umem->fd, &off);

	if (!err && umem->fill_save && umem->comp_save) {

		munmap(umem->fill_save->ring - off.fr.desc,

		       off.fr.desc + umem->config.fill_size * sizeof(__u64));

		munmap(umem->comp_save->ring - off.cr.desc,

		       off.cr.desc + umem->config.comp_size * sizeof(__u64));

	}



	close(umem->fd);

	free(umem);