From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ej1-f43.google.com (mail-ej1-f43.google.com [209.85.218.43]) (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 1FA3717BC9 for ; Fri, 9 Aug 2024 14:48:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.218.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723214922; cv=none; b=mHLKovB0j6Gzx4Tw8NvYrAgQCzVwDo8I6AQQ9YOjOL6k8IOJZ0+/gTcJWw8JS3oHnocd5EvqhHPate+Rs2Wq7+IWDNzgOyzkVspxc1jOhu7wF7msnBPi09Q50H4EYJ4lubtVOp1Tpi0/4h/XXPNOOm0Ik5HD+xQ30QKuWvfE6gM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723214922; c=relaxed/simple; bh=4I5b2H9NUEiAhmrSpLhpqMq35zTGGlKoTm2KVgYDd8c=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=NaC0RZBpgGMHSEnxSeDB70zLdlaToznCXAqucNH3RpUtR8MZiFJ1W9EWzEHMfM0Sub3eCQZOIBTZ9gimZPLM/MI1hqY0PpFk0G6QE7k/5tFvfFYj9S2zoScQThAvkb4BfnYWTUQ1Z0IyUuhwhay1Z/rk10M/sA3fAHC1Feg6rko= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org; spf=pass smtp.mailfrom=linaro.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b=xGRZ2EY8; arc=none smtp.client-ip=209.85.218.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linaro.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linaro.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="xGRZ2EY8" Received: by mail-ej1-f43.google.com with SMTP id a640c23a62f3a-a7d638a1f27so90311966b.2 for ; Fri, 09 Aug 2024 07:48:40 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1723214919; x=1723819719; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=tFtgPj7cDJPPMnEzJqYuz4oTx2v5U6jmL1KNLX38x4Q=; b=xGRZ2EY84cWKdcwGaBmL4Do9kjrLYeq3e3nNsKqv4TFpGAiy+K8u4RCVWzlD170hOy KFZh6VFfBBfqLNNSYoSPswFKt+ieVqPLhOOCXc3IevlUD/ervn+hVOKrTfNZOpkwoq9p tyWTQuMovkhxYlOaciC31JlXsFz65Q1H6GCKHfidhiCPE7RGG5zOqKNwtxXgckquJ7W5 IcbTF02mI0Wx+JEsVaFfWhQ7iYnq36eh+s1g7c3xSX+c1BCODJS/2q2drZCmJeSCadxo cRsWAmc4xJXi/jsJ7KQy0Z4UGi22ja0luL2nCzQlA36PwaK9ZOslp3gYy34U2a4j89Lx o3zg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1723214919; x=1723819719; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=tFtgPj7cDJPPMnEzJqYuz4oTx2v5U6jmL1KNLX38x4Q=; b=HthUdd+QIuyOaNgnIASmCb/O1EWHX9MtSnoUfyWDFlY0sAygyUXGCmr5f6Mjr1AuVl etN/5wIhvI7MTLiZpTjKyRM4EnSYpxY8otWZiVpZF/b8wvQjTjUK7lAxpsSxZXrzqBC7 Tk5CqHz5IRwOblQ/MnXSZYEqZp5Bdnm6AWHM1wgFJS48seecpPuHdozefsdikKBdAXxx bRb5JxvMGobAEtf3h6hnd2QS1THsbOCJRXo996g5uDLKN3hkP+tUfosi1oE2CAnJf0fQ kXf59c29+dGWhY+GxGfDe5Zb00o6H5gvPtk/YFk0h7l22UhDuS8iLm0hWiFax6KE+x5e x7sQ== X-Forwarded-Encrypted: i=1; AJvYcCX5p0yIbnSGqKq0t9lfqhHG/aLpLPG1bHIncNvtXTsWkALbv0Vv7io0L9NvPdScu7Nxt62nAsSHLfvsMZnrMrqUmfTULo4sOINYdtk= X-Gm-Message-State: AOJu0Yy3adcbHf0uFK5QXwhmxBC0RCgV6QCGwshjAzFx/XQVAIpP0K/+ RwYlhwRsuVAVyeIeCg2nYR0CXGb/nb9s01kkHn2LSn9fe/RG0Y+h1jk1VNrQbOQ= X-Google-Smtp-Source: AGHT+IFBY2Fa09LrgoQHpcmAJetlamh86kOIIRg78Yt85HeAsUAmRa90xiVBDSWmTBmcEOH2cLKoNw== X-Received: by 2002:a05:6402:510e:b0:5a1:b6d8:b561 with SMTP id 4fb4d7f45d1cf-5bd0a535c1emr1850330a12.9.1723214919081; Fri, 09 Aug 2024 07:48:39 -0700 (PDT) Received: from localhost ([196.207.164.177]) by smtp.gmail.com with ESMTPSA id 4fb4d7f45d1cf-5bbb2e5c8edsm1596620a12.81.2024.08.09.07.48.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 09 Aug 2024 07:48:38 -0700 (PDT) Date: Fri, 9 Aug 2024 17:48:35 +0300 From: Dan Carpenter To: Christophe JAILLET Cc: Helge Deller , linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org, linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org Subject: Re: [PATCH] fbdev: omapfb: panel-sony-acx565akm: Simplify show_cabc_available_modes() Message-ID: References: <91fc9049558a4865d441930c8f4732461f478eca.1723110340.git.christophe.jaillet@wanadoo.fr> Precedence: bulk X-Mailing-List: linux-fbdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Fri, Aug 09, 2024 at 05:42:32PM +0300, Dan Carpenter wrote: > On Thu, Aug 08, 2024 at 11:46:11AM +0200, Christophe JAILLET wrote: > > Use sysfs_emit_at() instead of snprintf() + custom logic. > > Using sysfs_emit_at() is much more simple. > > > > Also, sysfs_emit() is already used in this function, so using > > sysfs_emit_at() is more consistent. > > > > Also simplify the logic: > > - always add a space after an entry > > - change the last space into a '\n' > > > > Finally it is easy to see that, given the size of cabc_modes, PAGE_SIZE > > can not be reached. > > So better keep everything simple (and correct). > > > > Signed-off-by: Christophe JAILLET > > --- > > .../omap2/omapfb/displays/panel-sony-acx565akm.c | 15 ++++++++------- > > 1 file changed, 8 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c b/drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c > > index 71d2e015960c..fc975615d5c9 100644 > > --- a/drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c > > +++ b/drivers/video/fbdev/omap2/omapfb/displays/panel-sony-acx565akm.c > > @@ -466,19 +466,20 @@ static ssize_t show_cabc_available_modes(struct device *dev, > > char *buf) > > { > > struct panel_drv_data *ddata = dev_get_drvdata(dev); > > - int len; > > + int len = 0; > > int i; > > > > if (!ddata->has_cabc) > > return sysfs_emit(buf, "%s\n", cabc_modes[0]); > > > > - for (i = 0, len = 0; > > - len < PAGE_SIZE && i < ARRAY_SIZE(cabc_modes); i++) > > - len += snprintf(&buf[len], PAGE_SIZE - len, "%s%s%s", > > - i ? " " : "", cabc_modes[i], > > - i == ARRAY_SIZE(cabc_modes) - 1 ? "\n" : ""); > > + for (i = 0; i < ARRAY_SIZE(cabc_modes); i++) > > + len += sysfs_emit_at(buf, len, "%s ", cabc_modes[i]); > > + > > + /* Remove the trailing space */ > > + if (len) > > + buf[len - 1] = '\n'; > > I'm uncomfortable with this line. It assumes we don't overflow PAGE_SIZE where > the original code was careful about checking. Probably easiest to do what the > original code did and say: > > for (i = 0; i < ARRAY_SIZE(cabc_modes); i++) > len += sysfs_emit_at(buf, len, "%s%s", cabc_modes[i], > i == ARRAY_SIZE(cabc_modes) - 1 ? "\n" : ""); Or you could change it to: if (len) sysfs_emit_at(buf, len - 1, "\n"); But that feels weird. regards, dan carpenter