From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A59051E47B4; Thu, 30 Jan 2025 14:02:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738245766; cv=none; b=mOyxsgUGJlUGxu4NFKGw3/N2bzv65YwLb1VnAOX5Q3NYF23LX1y9+js5e8h9xPvKyyLXnmepi5D4wOrMvTYgzQYoLKP/ldyzdmAPiNIkDgtBHKBJYHqD/IKfm9Bs15SJxz8EBIdrpqeuCWl/tRU181/IY3Qa80Vqg+WX18ewRiw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738245766; c=relaxed/simple; bh=IP0ruFvqMl7BuVbld4MZ3F/YzBp2XziHT/trF6XKCu0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=El63Vuz/NrPHUVZYjlXteryqQG6i37wawF8GRtKfPiH03mPZgz2pPe3A/wZLrB4ITjB8LdAYDoDw/IhhSfwcetUzrGMylpzXtSDwTdNOPVu5x04TwG5xlQWRQ7tK3eR6E46ZqPcP7rVJvGMoq9UWzBWuKVUygaYWGqW+BW3ffSA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=RNhsWD+n; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="RNhsWD+n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2D680C4CED2; Thu, 30 Jan 2025 14:02:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738245766; bh=IP0ruFvqMl7BuVbld4MZ3F/YzBp2XziHT/trF6XKCu0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=RNhsWD+ntH91S1O2q/Kq3R37vp+IuHCMJX+s4S0rHiyP8GFSJCQ2NAuBef4kvyMc6 D7rY7sGQLKgKohCWsyBrU4TdPI8gwYocJ0wXQR4QEmsG2UpYMbWKVmysXhOTWzHSXy vJ3zFSsmy2xdqijuJwLnn50EoKnNa3HMkOUAKzgs= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kalesh AP , Chandramohan Akula , Selvin Xavier , Jason Gunthorpe , Alva Lan Subject: [PATCH 6.6 13/43] RDMA/bnxt_re: Avoid CPU lockups due fifo occupancy check loop Date: Thu, 30 Jan 2025 14:59:20 +0100 Message-ID: <20250130133459.436063588@linuxfoundation.org> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250130133458.903274626@linuxfoundation.org> References: <20250130133458.903274626@linuxfoundation.org> User-Agent: quilt/0.68 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Selvin Xavier commit 8be3e5b0c96beeefe9d5486b96575d104d3e7d17 upstream. Driver waits indefinitely for the fifo occupancy to go below a threshold as soon as the pacing interrupt is received. This can cause soft lockup on one of the processors, if the rate of DB is very high. Add a loop count for FPGA and exit the __wait_for_fifo_occupancy_below_th if the loop is taking more time. Pacing will be continuing until the occupancy is below the threshold. This is ensured by the checks in bnxt_re_pacing_timer_exp and further scheduling the work for pacing based on the fifo occupancy. Fixes: 2ad4e6303a6d ("RDMA/bnxt_re: Implement doorbell pacing algorithm") Link: https://patch.msgid.link/r/1728373302-19530-7-git-send-email-selvin.xavier@broadcom.com Reviewed-by: Kalesh AP Reviewed-by: Chandramohan Akula Signed-off-by: Selvin Xavier Signed-off-by: Jason Gunthorpe [ Add the declaration of variable pacing_data to make it work on 6.6.y ] Signed-off-by: Alva Lan Signed-off-by: Greg Kroah-Hartman --- drivers/infiniband/hw/bnxt_re/main.c | 10 ++++++++++ 1 file changed, 10 insertions(+) --- a/drivers/infiniband/hw/bnxt_re/main.c +++ b/drivers/infiniband/hw/bnxt_re/main.c @@ -485,6 +485,8 @@ static void bnxt_re_set_default_pacing_d static void __wait_for_fifo_occupancy_below_th(struct bnxt_re_dev *rdev) { u32 read_val, fifo_occup; + struct bnxt_qplib_db_pacing_data *pacing_data = rdev->qplib_res.pacing_data; + u32 retry_fifo_check = 1000; /* loop shouldn't run infintely as the occupancy usually goes * below pacing algo threshold as soon as pacing kicks in. @@ -500,6 +502,14 @@ static void __wait_for_fifo_occupancy_be if (fifo_occup < rdev->qplib_res.pacing_data->pacing_th) break; + if (!retry_fifo_check--) { + dev_info_once(rdev_to_dev(rdev), + "%s: fifo_occup = 0x%xfifo_max_depth = 0x%x pacing_th = 0x%x\n", + __func__, fifo_occup, pacing_data->fifo_max_depth, + pacing_data->pacing_th); + break; + } + } }