linux-kernel - [PATCH v2 12/26] dmaengine: dw-edma: Stop checking debugfs_create

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Message-ID: <20220503225104.12108-13-Sergey.Semin@baikalelectronics.ru>
Date:   Wed, 4 May 2022 01:50:50 +0300
From:   Serge Semin <Sergey.Semin@...kalelectronics.ru>
To:     Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
        Vinod Koul <vkoul@...nel.org>,
        Jingoo Han <jingoohan1@...il.com>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
        Frank Li <Frank.Li@....com>,
        Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
CC:     Serge Semin <Sergey.Semin@...kalelectronics.ru>,
        Serge Semin <fancer.lancer@...il.com>,
        Alexey Malahov <Alexey.Malahov@...kalelectronics.ru>,
        Pavel Parkhomenko <Pavel.Parkhomenko@...kalelectronics.ru>,
        Rob Herring <robh@...nel.org>,
        Krzysztof Wilczyński <kw@...ux.com>,
        <linux-pci@...r.kernel.org>, <dmaengine@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH v2 12/26] dmaengine: dw-edma: Stop checking debugfs_create_*() return value

First of all they never return NULL. So checking their return value for
being not NULL just pointless. Secondly the DebugFS subsystem is designed
in a way to be used as simple as possible. So if one of the
debugfs_create_*() method in a hierarchy fails, the following methods will
just silently return the passed erroneous parental dentry. Finally the
code is supposed to be working no matter whether anything DebugFS-related
fails. So in order to make code simpler and DebugFS-independent let's drop
the debugfs_create_*() methods return value checking in the same way as
the most of the kernel drivers do.

Note in order to preserve some memory space we suggest to skip the DebugFS
nodes initialization if the file system in unavailable.

Signed-off-by: Serge Semin <Sergey.Semin@...kalelectronics.ru>
Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
---
 drivers/dma/dw-edma/dw-edma-v0-debugfs.c | 20 +++++---------------
 1 file changed, 5 insertions(+), 15 deletions(-)

diff --git a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
index 8e61810dea4b..6e7f3ef60ca7 100644
--- a/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
+++ b/drivers/dma/dw-edma/dw-edma-v0-debugfs.c
@@ -100,9 +100,8 @@ static void dw_edma_debugfs_create_x32(const struct debugfs_entries entries[],
 	int i;
 
 	for (i = 0; i < nr_entries; i++) {
-		if (!debugfs_create_file_unsafe(entries[i].name, 0444, dir,
-						entries[i].reg,	&fops_x32))
-			break;
+		debugfs_create_file_unsafe(entries[i].name, 0444, dir,
+					   entries[i].reg, &fops_x32);
 	}
 }
 
@@ -168,8 +167,6 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 	char name[16];
 
 	regs_dir = debugfs_create_dir(WRITE_STR, dir);
-	if (!regs_dir)
-		return;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
@@ -184,8 +181,6 @@ static void dw_edma_debugfs_regs_wr(struct dentry *dir)
 		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
 
 		ch_dir = debugfs_create_dir(name, regs_dir);
-		if (!ch_dir)
-			return;
 
 		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].wr, ch_dir);
 
@@ -237,8 +232,6 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 	char name[16];
 
 	regs_dir = debugfs_create_dir(READ_STR, dir);
-	if (!regs_dir)
-		return;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
@@ -253,8 +246,6 @@ static void dw_edma_debugfs_regs_rd(struct dentry *dir)
 		snprintf(name, sizeof(name), "%s:%d", CHANNEL_STR, i);
 
 		ch_dir = debugfs_create_dir(name, regs_dir);
-		if (!ch_dir)
-			return;
 
 		dw_edma_debugfs_regs_ch(&regs->type.unroll.ch[i].rd, ch_dir);
 
@@ -273,8 +264,6 @@ static void dw_edma_debugfs_regs(void)
 	int nr_entries;
 
 	regs_dir = debugfs_create_dir(REGISTERS_STR, dw->debugfs);
-	if (!regs_dir)
-		return;
 
 	nr_entries = ARRAY_SIZE(debugfs_regs);
 	dw_edma_debugfs_create_x32(debugfs_regs, nr_entries, regs_dir);
@@ -285,6 +274,9 @@ static void dw_edma_debugfs_regs(void)
 
 void dw_edma_v0_debugfs_on(struct dw_edma *_dw)
 {
+	if (!debugfs_initialized())
+		return;
+
 	dw = _dw;
 	if (!dw)
 		return;
@@ -294,8 +286,6 @@ void dw_edma_v0_debugfs_on(struct dw_edma *_dw)
 		return;
 
 	dw->debugfs = debugfs_create_dir(dw->name, NULL);
-	if (!dw->debugfs)
-		return;
 
 	debugfs_create_u32("mf", 0444, dw->debugfs, &dw->chip->mf);
 	debugfs_create_u16("wr_ch_cnt", 0444, dw->debugfs, &dw->wr_ch_cnt);
-- 
2.35.1