From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f51.google.com (mail-ej1-f51.google.com [209.85.218.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3052141CB5C for ; Fri, 24 Jul 2026 09:44:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784886273; cv=none; b=mNh/YaPb4MiMA9pfzosX83UcuQ5Cxcynv4jfCzeWHXxiTWGs56zjAlIC28Tl79zXIzH4FHBxhhGKQB393BBmAOPCf+RymE7YZ5Emw4U/a7MVu/FbrWajTR6wI5phLeburwjRlbtm8ckNfrKXyLMHKEmJ9KM15VVuuEYwJJce6T0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784886273; c=relaxed/simple; bh=Dv+bY9RauteyeV/g853HpenpScE4tBDwQ8sOFX0Ybik=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References; b=QELG3bD2lXeEC0IjX5dDBD31yInKcud+rUeL9G5/ir6o+zMbPKqCgoSV3J441J2XUPJUHOBuubqk7lTdf9xdHuukCb/GOKdn9ONHOmkW7kJsZsNxHtCnj4BVnMPfJ8/nzLj3waFBrt9/iuO/gdVokQBiO2WkTj/TRnSWwVnKrgI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=YoFYNQ/Z; arc=none smtp.client-ip=209.85.218.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="YoFYNQ/Z" Received: by mail-ej1-f51.google.com with SMTP id a640c23a62f3a-c197f968b3cso36771366b.2 for ; Fri, 24 Jul 2026 02:44:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1784886268; x=1785491068; darn=vger.kernel.org; h=references:in-reply-to:message-id:date:subject:cc:to:from:from:to :cc:subject:date:message-id:reply-to:content-type; bh=h+OhafIneSQ53uhY2AzN2/or7dHkJV9E9pGuPyuaOKs=; b=YoFYNQ/ZyDIvPPYUSNWxxwGgPnkkbFPXLJpn9N2Uo+4gg3oW4X4x7cWnObAIWGgwGr rh6KttV5V+kF9maQhzIC0zsnL+iKNqVZkE3r103BWLT/7Y8U6MgfUOwRBr+6p8L7UF/Z BHJqybii3d+siP9fr5FNp2sVUk9nHrGKRBWE/uzxHZiQKMIM+tdSOLbTPI9UFa0k/7Yb 7KfelUPSZhh/7aIIm3Wb/ItPz8R+nDRTAI7XXb29Y4eG/CtgzRF0GXqrKqaQioycyTxU H8J0XMIuCz3HEVlh62PVbgtrJb3K3J80CfJiWlppf9noLo/edxQZqmb4YkLMcu92hTW6 lXEw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1784886268; x=1785491068; h=references:in-reply-to:message-id:date:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=h+OhafIneSQ53uhY2AzN2/or7dHkJV9E9pGuPyuaOKs=; b=JluHgoRnxcRzNV0rCNZVXlVxx0hATvM7vozBnSoP9F9THfgamFHX/V6fKZqIBWINVR VxiPDmNRV9aPUP0uL85P4h9IwhhtPs4tEn6dQK8Y8RE1maRLXLAbalzoonsxkqPsrFgn NBaCcUhyKQfAnlzzK80NxrABf1NR144qxe8lHR2fgw/2ZMQQSAKd3L8IyHFjq8BHRRqn d4qi29heOa4XKzXbTqXGc7lHc5zrvu0H59JYRhq1BTtgeLtuwIC5hUKXsr8S/UNcB0GG cakIZfHoovXcclgi7OKdAHqGScHyuMpvo4gUcVjzxNsCzAywvsFvVXgg3PeH1MJAkpZx PEWA== X-Forwarded-Encrypted: i=1; AHgh+Rq1tpPjqgSAXUXDZxpkSLdqsQk4WRKs3+vv1WZF0yA6Be4wTGk5KFib+d9Mrvou5t1FdP2ZWYrZj0nzJ1o=@vger.kernel.org X-Gm-Message-State: AOJu0Yx2QVIEImDiPRIF2RWd+QK36RLzqPRtkPmPns5giwpN4ZCKg+uK f1VGIlKQmfugdDeesZGQuYztbsFAEx/glYnwGcFTZaCds6bJdt9SE9Cq X-Gm-Gg: AR+sD13xBKWKXqFOiOLmYFTEvXfrcdC+2vpewqv7KFnyPrre8dad0f4RSc0Bjl2qx62 gllXFNRd+eTgygZl23yuMobk4TYroZMhfT/uWO7FMC+Rm+RBQSPhR44ru1xB5EmtDh+029vQMK1 wwK3TFxub0slVrPLiTU81th14wDVb1qjoko5S8kQoEnZi+gAoKG2+M8jmHI7XDFlOKNvtz8OTqm S8+f5FF8fsdiNnYWQV8RCVsbaSo1oaPxU++6vv6QqSmg1zf5YcpUhMIxoiu9dpC3nlNcrboKx4s TGGqQ8GUodDREK1SXC6GvKt/eXshCD3L2EK5r4qgmGJj4b5JwqA9GkG9c5hKNyOY8oD8iJn3XU8 qhsq2TAzItOoPlI8jf2xuT2Ya/CKccWJGhAYgynd55zKvLJr+HjMudd3fO+Nozi9bEvR4FTNpzJ lwMmr09rjGwg/H6wDjn3zT1NvkVy1P8A== X-Received: by 2002:a17:907:d09:b0:c15:c108:dcd with SMTP id a640c23a62f3a-c1c509bbd04mr362329466b.49.1784886268368; Fri, 24 Jul 2026 02:44:28 -0700 (PDT) Received: from localhost (c-85-228-45-68.bbcust.telenor.se. [85.228.45.68]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c1c32a798a5sm329410566b.9.2026.07.24.02.44.27 (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Fri, 24 Jul 2026 02:44:28 -0700 (PDT) From: Eli Billauer To: gregkh@linuxfoundation.org Cc: arnd@arndb.de, linux-kernel@vger.kernel.org, corbet@lwn.net, Eli Billauer Subject: [PATCH v3 4/7] char: xillybus: Use unsigned arithmetic for jiffies differences Date: Fri, 24 Jul 2026 11:42:59 +0200 Message-Id: <20260724094302.50761-5-eli.billauer@gmail.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20260724094302.50761-1-eli.billauer@gmail.com> References: <20260724094302.50761-1-eli.billauer@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Change the type of jiffies-related deadline variables from long to unsigned long, and remove unnecessary casts when computing time remaining as deadline - jiffies. No functional change is expected: although signed overflow is undefined in the C standard, processors perform the calculation correctly in practice. Using unsigned arithmetic is nevertheless the proper way to handle jiffies differences. Assisted-by: Deepseek:v4-pro Kimi:K2.6 ChatGPT:GPT-5.5 Claude:Sonnet-4.6 Signed-off-by: Eli Billauer --- Notes: Changes v2->v3: -- Add Assisted-by tag to description No change on v1->v2. drivers/char/xillybus/xillybus_core.c | 5 +++-- drivers/char/xillybus/xillyusb.c | 17 ++++++++++------- 2 files changed, 13 insertions(+), 9 deletions(-) diff --git a/drivers/char/xillybus/xillybus_core.c b/drivers/char/xillybus/xillybus_core.c index 952ef149aba1..7acebc1e6050 100644 --- a/drivers/char/xillybus/xillybus_core.c +++ b/drivers/char/xillybus/xillybus_core.c @@ -694,7 +694,8 @@ static ssize_t xillybus_read(struct file *filp, char __user *userbuf, unsigned long flags; int bytes_done = 0; int no_time_left = 0; - long deadline, left_to_sleep; + unsigned long deadline; + long left_to_sleep; struct xilly_channel *channel = filp->private_data; int empty, reached_eof, exhausted, ready; @@ -938,7 +939,7 @@ static ssize_t xillybus_read(struct file *filp, char __user *userbuf, return -EINTR; } - left_to_sleep = deadline - ((long) jiffies); + left_to_sleep = deadline - jiffies; /* * If our time is out, skip the waiting. We may miss wr_sleepy diff --git a/drivers/char/xillybus/xillyusb.c b/drivers/char/xillybus/xillyusb.c index 7d2434c02fa7..aa08206a18ef 100644 --- a/drivers/char/xillybus/xillyusb.c +++ b/drivers/char/xillybus/xillyusb.c @@ -1127,12 +1127,13 @@ static int xillyusb_send_opcode(struct xillyusb_dev *xdev, */ static int flush_downstream(struct xillyusb_channel *chan, - long timeout, + unsigned long timeout, bool interruptible) { struct xillyusb_dev *xdev = chan->xdev; int chan_num = chan->chan_idx << 1; - long deadline, left_to_sleep; + unsigned long deadline; + long left_to_sleep; int rc; if (chan->flushed) @@ -1141,7 +1142,8 @@ static int flush_downstream(struct xillyusb_channel *chan, deadline = jiffies + 1 + timeout; if (chan->flushing) { - long cancel_deadline = jiffies + 1 + XILLY_RESPONSE_TIMEOUT; + unsigned long cancel_deadline = + jiffies + 1 + XILLY_RESPONSE_TIMEOUT; chan->canceled = 0; rc = xillyusb_send_opcode(xdev, chan_num, @@ -1152,7 +1154,7 @@ static int flush_downstream(struct xillyusb_channel *chan, /* Ignoring interrupts. Cancellation must be handled */ while (!chan->canceled) { - left_to_sleep = cancel_deadline - ((long)jiffies); + left_to_sleep = cancel_deadline - jiffies; if (left_to_sleep <= 0) { report_io_error(xdev, -EIO); @@ -1202,7 +1204,7 @@ static int flush_downstream(struct xillyusb_channel *chan, } while (chan->flushing) { - left_to_sleep = deadline - ((long)jiffies); + left_to_sleep = deadline - jiffies; if (left_to_sleep <= 0) return -ETIMEDOUT; @@ -1435,7 +1437,8 @@ static ssize_t xillyusb_read(struct file *filp, char __user *userbuf, struct xillyfifo *fifo = chan->in_fifo; int chan_num = (chan->chan_idx << 1) | 1; - long deadline, left_to_sleep; + unsigned long deadline; + long left_to_sleep; int bytes_done = 0; bool sent_set_push = false; int rc; @@ -1464,7 +1467,7 @@ static ssize_t xillyusb_read(struct file *filp, char __user *userbuf, bytes_done += rc; chan->in_consumed_bytes += rc; - left_to_sleep = deadline - ((long)jiffies); + left_to_sleep = deadline - jiffies; /* * Some 32-bit arithmetic that may wrap. Note that -- 2.34.1