From patchwork Wed May 8 17:18:43 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stanislav Fomichev X-Patchwork-Id: 56072 X-Patchwork-Delegate: sean@mess.org Received: from vger.kernel.org ([209.132.180.67]) by www.linuxtv.org with esmtp (Exim 4.84_2) (envelope-from ) id 1hOQDa-000424-Oc; Wed, 08 May 2019 17:18:59 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728956AbfEHRSz (ORCPT + 1 other); Wed, 8 May 2019 13:18:55 -0400 Received: from mail-qt1-f201.google.com ([209.85.160.201]:43327 "EHLO mail-qt1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728919AbfEHRSy (ORCPT ); Wed, 8 May 2019 13:18:54 -0400 Received: by mail-qt1-f201.google.com with SMTP id q32so10675883qtk.10 for ; Wed, 08 May 2019 10:18:53 -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=dBVF9tqLXphyriby2Sali7IJHS+SaCg6nJ2FY2lFxPo=; b=pANr7Ap0bi82ywW+IsBk6pG6XmeRA3aCL68H2DnzN+AKtyjvd7LsrJs7hy8JdHGnhU Bl8NMnwZoWlVOigv4u3XWznJ1JmeWFf39CuMEVJQbMhL94Gfh8nXH3B3pZB8b9wCd5u3 m8MdHX9C0varGlzBwzKIRstmEz6nr1XrWnkzd8D275SKuhQiGwRZur1kq6BLlluG/Egf Uxvwd9tS0JTuKxpNAiPg9CE/tf//Pwjegj2zI+QWlwu/jtnTVGByoqOgGL6RQ28DV9pl LDRmQKLs6GUcVSaWcmv1Ia39qEq4Lrbj92sqFZ+5euvQ0q3Qa+jh8NggfKFfdVa0diTs MwRA== 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=dBVF9tqLXphyriby2Sali7IJHS+SaCg6nJ2FY2lFxPo=; b=GkdiA/0Ad4x2L56IvDTNbkrA2EPcxhb0ghvKslCsDDpN1K0X4LtTSMP73OkyEK56Xl SlzLayoE0E4K/wy+uhTunNBWNgGR+iIJa0FVDI9l9X7HWQ5tNKEEc2JygPxd3A81hU5f YIP0Jp3Rh98Wp8IvYivWeH8pwfjaME11TOaUzXZ3sxo1/l+hISZt5QQxT0Rrcga5yGdV /o423OsOzVrw256rqQpB95/oyyx/80zb8fKzLDlNSha9uqG4h4dLaFc1lc2s6IdhhVng oRildPQuZKaMHBTZnl+vGf7N0aMsRzzg5Plak96ajasBzBZBvM/seKdb8qGrbi6JolYN lLRg== X-Gm-Message-State: APjAAAX14umZlrMGFX4pcht739E04Gr0JfCCDUQFDfELwrrmOzTZyHEH djDkirD/LlNn/OkpoTjg/QgPY+I= X-Google-Smtp-Source: APXvYqxR4fl9jIla2OhmLIzaZ6+WE2iEANBaN6rxOlayRJlxxKof7suMNC0Z0moEAiBEdZucFt7h+zI= X-Received: by 2002:a37:884:: with SMTP id 126mr1997936qki.67.1557335933118; Wed, 08 May 2019 10:18:53 -0700 (PDT) Date: Wed, 8 May 2019 10:18:43 -0700 In-Reply-To: <20190508171845.201303-1-sdf@google.com> Message-Id: <20190508171845.201303-3-sdf@google.com> Mime-Version: 1.0 References: <20190508171845.201303-1-sdf@google.com> X-Mailer: git-send-email 2.21.0.1020.gf2820cf01a-goog Subject: [PATCH bpf 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, Sean Young Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@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: Sean Young Signed-off-by: Stanislav Fomichev --- drivers/media/rc/bpf-lirc.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/drivers/media/rc/bpf-lirc.c b/drivers/media/rc/bpf-lirc.c index 390a722e6211..38d4c01174fc 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_dereference(p) \ + rcu_dereference_protected(p, lockdep_is_held(&ir_raw_handler_lock)) + /* * BPF interface for raw IR */ @@ -130,7 +133,7 @@ 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; @@ -148,12 +151,12 @@ 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_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; @@ -168,7 +171,7 @@ 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; @@ -186,7 +189,7 @@ static int lirc_bpf_detach(struct rc_dev *rcdev, struct bpf_prog *prog) goto unlock; } - old_array = raw->progs; + old_array = lirc_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 @@ -217,21 +220,25 @@ 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_dereference(rcdev->raw->progs); + if (!array) return; - item = rcu_dereference(rcdev->raw->progs)->items; + item = array->items; while (item->prog) { 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) @@ -284,7 +291,7 @@ 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; @@ -305,7 +312,7 @@ int lirc_prog_query(const union bpf_attr *attr, union bpf_attr __user *uattr) if (ret) goto put; - progs = rcdev->raw->progs; + progs = lirc_dereference(rcdev->raw->progs); cnt = progs ? bpf_prog_array_length(progs) : 0; if (copy_to_user(&uattr->query.prog_cnt, &cnt, sizeof(cnt))) {