From patchwork Wed May 22 20:53:51 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 1103668 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.b="YNNVPbSx"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 458Pxh3rkLz9sBK for ; Thu, 23 May 2019 06:54:00 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730195AbfEVUx7 (ORCPT ); Wed, 22 May 2019 16:53:59 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:55493 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729728AbfEVUx7 (ORCPT ); Wed, 22 May 2019 16:53:59 -0400 Received: by mail-qt1-f201.google.com with SMTP id v16so3253175qtk.22 for ; Wed, 22 May 2019 13:53:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=ukNWyZpQEscAlXdUip/QWXhs5cbXEziRRf5YyJhah4M=; b=YNNVPbSx7FsOwk16jCPbtBA2G+ZPpu8SLkw0MknnLWZEzpx3k3DQ24qU05oO58WL6/ Z3l/BWk0m2bqB2K7kjkcu2kFTiiSFUPaofTqH+Ct/OXdNXdY5jrYgET3PSnvoKLV6YsV HPayFURnBcfIEAK0D4VLrSsrs+q/kTNes9QTKFDjUVSpa/Yju1xDE7/Xlid8W0NEqX7I BRPnjfmY9tImK6Runjp2fQl0RHt53RpT1MPLuqRn333dWhZgbJRDa41ppTyfbyzAZ6fz URyIlnrJyVefkwaIo5PNLvNKJ8riAjHPlW1+VpMWGXP9P565Hqa4wpp1GScQEybwh+u2 hmlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=ukNWyZpQEscAlXdUip/QWXhs5cbXEziRRf5YyJhah4M=; b=DrEz5JlP6PqNDmSy6FfAvA6cLcByJ2LE8EeotMjf/UG5eXXrvb5lNvruba67njAiSI ovQRuofXEJY+9gx1B2Pm7r0F+R9+K/C2XxvKfyeRNCuEfKzrQe2FFUY2ADmzSUmzHvt+ B+QafjWp4k4pVHy2o2P8p+UvSkIPGgsWdGp6fs+krcFFBg7kJsvMi5AnTTzeXS98OIHr wmAtI3SGrrzTJB40R8HoTYS5W4s5tn4nYzXciwrqteQZ1d7C/AQdOd3TBTBNJkStEDxo wmv2mvdP/L2YKcs4q0XrTqqczA4P4mO99uUV5hwwojbGq2C/F+jp1HlFicjik+TZb+df ua5w== X-Gm-Message-State: APjAAAV/K3U6y5+gLwzydeNhd4oLpVFSQqnIRd4XiYJ8gOwglt0IQuvU vpgV+8ansO0B7PJv92UOVvDsIDk= X-Google-Smtp-Source: APXvYqx9x1/i9RddXIFy8UKRAw7tdSzqIGW+3fgcjqiypNTjBQ0QyE3Nol6HJXkiMDN9Q2UXUhI54Uo= X-Received: by 2002:ac8:1a04:: with SMTP id v4mr77233094qtj.63.1558558438027; Wed, 22 May 2019 13:53:58 -0700 (PDT) Date: Wed, 22 May 2019 13:53:51 -0700 In-Reply-To: <20190522205353.140648-1-sdf@google.com> Message-Id: <20190522205353.140648-2-sdf@google.com> Mime-Version: 1.0 References: <20190522205353.140648-1-sdf@google.com> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog Subject: [PATCH bpf-next v2 2/4] bpf: media: properly use bpf_prog_array api From: Stanislav Fomichev To: netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, daniel@iogearbox.net, Stanislav Fomichev , linux-media@vger.kernel.org, Mauro Carvalho Chehab , Sean Young Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Now that we don't have __rcu markers on the bpf_prog_array helpers, let's use proper rcu_dereference_protected to obtain array pointer under mutex. Cc: linux-media@vger.kernel.org Cc: Mauro Carvalho Chehab Cc: Sean Young Signed-off-by: Stanislav Fomichev --- drivers/media/rc/bpf-lirc.c | 30 +++++++++++++++++------------- 1 file changed, 17 insertions(+), 13 deletions(-) diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index ee657003c1a1..0a0ce620e4a2 100644 --- a/drivers/media/rc/bpf-lirc.c +++ b/drivers/media/rc/bpf-lirc.c @@ -8,6 +8,9 @@ #include #include "rc-core-priv.h" +#define lirc_rcu_dereference(p) \ + rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock)) + /* * BPF interface for raw IR */ @@ -136,7 +139,7 @@ const struct bpf_verifier_ops lirc_mode2_verifier_ops = { static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) { - struct bpf_prog_array __rcu *old_array; + struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; struct ir_raw_event_ctrl *raw; int ret; @@ -154,12 +157,12 @@ static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) goto unlock; } - if (raw->progs && bpf_prog_array_length(raw->progs) >= BPF_MAX_PROGS) { + old_array = lirc_rcu_dereference(raw->progs); + if (old_array && bpf_prog_array_length(old_array) >= BPF_MAX_PROGS) { ret = -E2BIG; goto unlock; } - old_array = raw->progs; ret = bpf_prog_array_copy(old_array, NULL, prog, &new_array); if (ret < 0) goto unlock; @@ -174,7 +177,7 @@ static int lirc_bpf_attach(struct rc_dev *rcdev, struct bpf_prog *prog) static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) { - struct bpf_prog_array __rcu *old_array; + struct bpf_prog_array *old_array; struct bpf_prog_array *new_array; struct ir_raw_event_ctrl *raw; int ret; @@ -192,7 +195,7 @@ static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) goto unlock; } - old_array = raw->progs; + old_array = lirc_rcu_dereference(raw->progs); ret = bpf_prog_array_copy(old_array, prog, NULL, &new_array); /* * Do not use bpf_prog_array_delete_safe() as we would end up @@ -223,21 +226,22 @@ void lirc_bpf_run(struct rc_dev *rcdev, u32 sample) /* * This should be called once the rc thread has been stopped, so there can be * no concurrent bpf execution. + * + * Should be called with the ir_raw_handler_lock held. */ void lirc_bpf_free(struct rc_dev *rcdev) { struct bpf_prog_array_item *item; + struct bpf_prog_array *array; - if (!rcdev->raw->progs) + array = lirc_rcu_dereference(rcdev->raw->progs); + if (!array) return; - item = rcu_dereference(rcdev->raw->progs)->items; - while (item->prog) { + for (item = array->items; item->prog; item++) bpf_prog_put(item->prog); - item++; - } - bpf_prog_array_free(rcdev->raw->progs); + bpf_prog_array_free(array); } int lirc_prog_attach(const union bpf_attr *attr, struct bpf_prog *prog) @@ -290,7 +294,7 @@ int lirc_prog_detach(const union bpf_attr *attr) int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) { __u32 __user *prog_ids = u64_to_user_ptr(attr->query.prog_ids); - struct bpf_prog_array __rcu *progs; + struct bpf_prog_array *progs; struct rc_dev *rcdev; u32 cnt, flags = 0; int ret; @@ -311,7 +315,7 @@ int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) if (ret) goto put; - progs = rcdev->raw->progs; + progs = lirc_rcu_dereference(rcdev->raw->progs); cnt = progs ? bpf_prog_array_length(progs) : 0; if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {