linux-kernel - Re: [1/3] mfd/omap-usb-tll: Delete two error messages for a failed memory allocation in usbtll_omap

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Date:   Mon, 15 Jan 2018 19:30:59 +0100
From:   Ladislav Michl <ladis@...ux-mips.org>
To:     SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:     linux-omap@...r.kernel.org, Lee Jones <lee.jones@...aro.org>,
        Tony Lindgren <tony@...mide.com>,
        Roger Quadros <rogerq@...com>,
        LKML <linux-kernel@...r.kernel.org>,
        kernel-janitors@...r.kernel.org
Subject: Re: [1/3] mfd/omap-usb-tll: Delete two error messages for a failed
 memory allocation in usbtll_omap_probe()

On Mon, Jan 15, 2018 at 07:12:37PM +0100, SF Markus Elfring wrote:
> Thanks for this clarification. - So I hope that your solution approach
> will be also fine. Will it supersede my proposal?

Who knows, perhaps it would be the best if you could judge yourself...

8<--------

Subject: [PATCH] mfd/omap-usb-tll: Allocate driver data at once

Allocating memory to store clk array together with driver
data simplifies error unwinding and allows deleting memory
allocation failure message as there is now only single point
where allocation could fail.

Signed-off-by: Ladislav Michl <ladis@...ux-mips.org>
---
 drivers/mfd/omap-usb-tll.c | 57 +++++++++++++++++++---------------------------
 1 file changed, 24 insertions(+), 33 deletions(-)

diff --git a/drivers/mfd/omap-usb-tll.c b/drivers/mfd/omap-usb-tll.c
index 44a5d66314c6..f327fe6d3292 100644
--- a/drivers/mfd/omap-usb-tll.c
+++ b/drivers/mfd/omap-usb-tll.c
@@ -108,9 +108,9 @@
 					 (x) != OMAP_EHCI_PORT_MODE_PHY)
 
 struct usbtll_omap {
-	int					nch;	/* num. of channels */
-	struct clk				**ch_clk;
-	void __iomem				*base;
+	void __iomem	*base;
+	int		nch;		/* num. of channels */
+	struct clk	*ch_clk[0];	/* must be the last member */
 };
 
 /*-------------------------------------------------------------------------*/
@@ -216,53 +216,50 @@ static int usbtll_omap_probe(struct platform_device *pdev)
 	struct device				*dev =  &pdev->dev;
 	struct resource				*res;
 	struct usbtll_omap			*tll;
-	int					ret = 0;
-	int					i, ver;
+	void __iomem				*base;
+	int					i, nch, ver;
 
 	dev_dbg(dev, "starting TI HSUSB TLL Controller\n");
 
-	tll = devm_kzalloc(dev, sizeof(struct usbtll_omap), GFP_KERNEL);
-	if (!tll) {
-		dev_err(dev, "Memory allocation failed\n");
-		return -ENOMEM;
-	}
-
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	tll->base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(tll->base))
-		return PTR_ERR(tll->base);
+	base = devm_ioremap_resource(dev, res);
+	if (IS_ERR(base))
+		return PTR_ERR(base);
 
-	platform_set_drvdata(pdev, tll);
 	pm_runtime_enable(dev);
 	pm_runtime_get_sync(dev);
 
-	ver =  usbtll_read(tll->base, OMAP_USBTLL_REVISION);
+	ver = usbtll_read(base, OMAP_USBTLL_REVISION);
 	switch (ver) {
 	case OMAP_USBTLL_REV1:
 	case OMAP_USBTLL_REV4:
-		tll->nch = OMAP_TLL_CHANNEL_COUNT;
+		nch = OMAP_TLL_CHANNEL_COUNT;
 		break;
 	case OMAP_USBTLL_REV2:
 	case OMAP_USBTLL_REV3:
-		tll->nch = OMAP_REV2_TLL_CHANNEL_COUNT;
+		nch = OMAP_REV2_TLL_CHANNEL_COUNT;
 		break;
 	default:
-		tll->nch = OMAP_TLL_CHANNEL_COUNT;
+		nch = OMAP_TLL_CHANNEL_COUNT;
 		dev_dbg(dev,
 		 "USB TLL Rev : 0x%x not recognized, assuming %d channels\n",
-			ver, tll->nch);
+			ver, nch);
 		break;
 	}
 
-	tll->ch_clk = devm_kzalloc(dev, sizeof(struct clk *) * tll->nch,
-						GFP_KERNEL);
-	if (!tll->ch_clk) {
-		ret = -ENOMEM;
-		dev_err(dev, "Couldn't allocate memory for channel clocks\n");
-		goto err_clk_alloc;
+	tll = devm_kzalloc(dev, sizeof(*tll) + sizeof(tll->ch_clk[nch]),
+			   GFP_KERNEL);
+	if (!tll) {
+		pm_runtime_put_sync(dev);
+		pm_runtime_disable(dev);
+		return -ENOMEM;
 	}
 
-	for (i = 0; i < tll->nch; i++) {
+	tll->base = base;
+	tll->nch = nch;
+	platform_set_drvdata(pdev, tll);
+
+	for (i = 0; i < nch; i++) {
 		char clkname[] = "usb_tll_hs_usb_chx_clk";
 
 		snprintf(clkname, sizeof(clkname),
@@ -282,12 +279,6 @@ static int usbtll_omap_probe(struct platform_device *pdev)
 	spin_unlock(&tll_lock);
 
 	return 0;
-
-err_clk_alloc:
-	pm_runtime_put_sync(dev);
-	pm_runtime_disable(dev);
-
-	return ret;
 }
 
 /**
-- 
2.15.1