io_uring: fix xa_alloc_cycle() error return value check

We currently check for ret != 0 to indicate error, but '1' is a valid
return and just indicates that the allocation succeeded with a wrap.
Correct the check to be for < 0, like it was before the xarray
conversion.

Cc: stable@vger.kernel.org
Fixes: 61cf9370 ("io_uring: Convert personality_idr to XArray")
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/io_uring.c

@@ -9843,10 +9843,11 @@ static int io_register_personality(struct io_ring_ctx *ctx)
 
 	ret = xa_alloc_cyclic(&ctx->personalities, &id, (void *)creds,
 			XA_LIMIT(0, USHRT_MAX), &ctx->pers_next, GFP_KERNEL);
-	if (!ret)
-		return id;
+	if (ret < 0) {
 		put_cred(creds);
 		return ret;
+	}
+	return id;
 }
 
 static int io_register_restrictions(struct io_ring_ctx *ctx, void __user *arg,