selftests/xsk: do not close unused file descriptors

Do not close descriptors that have never been used. File descriptor
fields that are not in use are erroneously marked with the number 0,
which is a valid fd. Mark unused fds with -1 instead and do not close
these when deleting the socket.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Link: https://lore.kernel.org/r/20230111093526.11682-3-magnus.karlsson@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/testing/selftests/bpf/xsk.c b/tools/testing/selftests/bpf/xsk.c
index 39d349509ba462a684ea237785f73edf68daeb31..5e4a6552ed377b82b497fc7e66ccb007867a459d 100644 (file)
--- a/tools/testing/selftests/bpf/xsk.c
+++ b/tools/testing/selftests/bpf/xsk.c
@@ -35,6 +35,8 @@
 #include "xsk.h"
 #include "bpf_util.h"
 
+#define FD_NOT_USED (-1)
+
 #ifndef SOL_XDP
  #define SOL_XDP 283
 #endif
@@ -583,6 +585,9 @@ static void xsk_delete_bpf_maps(struct xsk_socket *xsk)
 {
        struct xsk_ctx *ctx = xsk->ctx;
 
+       if (ctx->xsks_map_fd == FD_NOT_USED)
+               return;
+
        bpf_map_delete_elem(ctx->xsks_map_fd, &ctx->queue_id);
        close(ctx->xsks_map_fd);
 }
@@ -941,6 +946,9 @@ static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk,
        ctx->umem = umem;
        ctx->queue_id = queue_id;
        bpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ);
+       ctx->prog_fd = FD_NOT_USED;
+       ctx->link_fd = FD_NOT_USED;
+       ctx->xsks_map_fd = FD_NOT_USED;
 
        ctx->fill = fill;
        ctx->comp = comp;
@@ -1221,8 +1229,9 @@ void xsk_socket__delete(struct xsk_socket *xsk)
 
        if (ctx->refcount == 1) {
                xsk_delete_bpf_maps(xsk);
-               close(ctx->prog_fd);
-               if (ctx->has_bpf_link)
+               if (ctx->prog_fd != FD_NOT_USED)
+                       close(ctx->prog_fd);
+               if (ctx->has_bpf_link && ctx->link_fd != FD_NOT_USED)
                        close(ctx->link_fd);
        }