[PATCH 0/6] drivers/dma: drop modular code from non modular drivers

[PATCH 0/6] drivers/dma: drop modular code from non modular drivers

[Paul Gortmaker]

This series of commits is a slice of a larger project to ensure
people don't have dead code for module removal in non-modular
drivers.  Overall there is roughly 5k lines of dead code in the
kernel due to this.

There is a quasi-separate theme, in that some of the drivers were
allowing an unbind implicitly since it is enabled by default.  But
for core DMA infrastructure drivers, this doesn't seem useful -- so
we also disable that here which allows us to delete any ".remove"
functions from the drivers that would otherwise be called during the
(impossible to trigger) module removal.

Since ARM covers these files the best of all architectures, each
file was build tested for allmodconfig on ARM, which at the same
time confirms that the files are not built with "CC [M]" -- hence
genuinely non-modular.

My testing and the larger patch series in general has been done
against the latest linux-next tree.

Paul.
---

Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: Daniel Mack <daniel@zonque.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: dmaengine@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-tegra@vger.kernel.org


Paul Gortmaker (6):
  drivers/dma: make edma.c explicitly non-modular
  drivers/dma: make mmp_pdma.c explicitly non-modular
  drivers/dma: make mmp_tdma.c explicitly non-modular
  drivers/dma: make pxa_dma.c explicitly non-modular
  drivers/dma: make sh/shdma-*.c explicitly non-modular
  drivers/dma: make tegra20-apb-dma.c explicitly non-modular

 drivers/dma/edma.c            | 37 ++++++-------------------------------
 drivers/dma/mmp_pdma.c        | 21 ++++-----------------
 drivers/dma/mmp_tdma.c        | 22 +++-------------------
 drivers/dma/pxa_dma.c         | 38 +++-----------------------------------
 drivers/dma/sh/shdma-base.c   | 14 ++------------
 drivers/dma/sh/shdma-of.c     | 11 +++--------
 drivers/dma/tegra20-apb-dma.c | 35 ++++-------------------------------
 7 files changed, 25 insertions(+), 153 deletions(-)

-- 
2.6.1


Paul Gortmaker (6):
  drivers/dma: make edma.c explicitly non-modular
  drivers/dma: make mmp_pdma.c explicitly non-modular
  drivers/dma: make mmp_tdma.c explicitly non-modular
  drivers/dma: make pxa_dma.c explicitly non-modular
  drivers/dma: make sh/shdma-*.c explicitly non-modular
  drivers/dma: make tegra20-apb-dma.c explicitly non-modular

 drivers/dma/edma.c            | 37 ++++++-------------------------------
 drivers/dma/mmp_pdma.c        | 21 ++++-----------------
 drivers/dma/mmp_tdma.c        | 22 +++-------------------
 drivers/dma/pxa_dma.c         | 38 +++-----------------------------------
 drivers/dma/sh/shdma-base.c   | 14 ++------------
 drivers/dma/sh/shdma-of.c     | 11 +++--------
 drivers/dma/tegra20-apb-dma.c | 35 ++++-------------------------------
 7 files changed, 25 insertions(+), 153 deletions(-)

-- 
2.6.1

[PATCH 1/6] drivers/dma: make edma.c explicitly non-modular

[Paul Gortmaker]

The Kconfig currently controlling compilation of this code is:

drivers/dma/Kconfig:config TI_EDMA
drivers/dma/Kconfig:    bool "TI EDMA support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_init wasn't being used by this driver, we've not any
issues worrying about the init ordering changing with this commit.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/dma/edma.c | 37 ++++++-------------------------------
 1 file changed, 6 insertions(+), 31 deletions(-)

diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
index 0675e268d577..1031a970b523 100644
--- a/drivers/dma/edma.c
+++ b/drivers/dma/edma.c
@@ -3,6 +3,8 @@
  *
  * Copyright 2012 Texas Instruments
  *
+ * Author: Matt Porter <matt.porter@linaro.org>
+ *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License as
  * published by the Free Software Foundation version 2.
@@ -20,7 +22,6 @@
 #include <linux/init.h>
 #include <linux/interrupt.h>
 #include <linux/list.h>
-#include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -2325,21 +2326,6 @@ err_reg1:
 	return ret;
 }
 
-static int edma_remove(struct platform_device *pdev)
-{
-	struct device *dev = &pdev->dev;
-	struct edma_cc *ecc = dev_get_drvdata(dev);
-
-	if (dev->of_node)
-		of_dma_controller_free(dev->of_node);
-	dma_async_device_unregister(&ecc->dma_slave);
-	if (ecc->dma_memcpy)
-		dma_async_device_unregister(ecc->dma_memcpy);
-	edma_free_slot(ecc, ecc->dummy_slot);
-
-	return 0;
-}
-
 #ifdef CONFIG_PM_SLEEP
 static int edma_pm_suspend(struct device *dev)
 {
@@ -2396,11 +2382,11 @@ static const struct dev_pm_ops edma_pm_ops = {
 
 static struct platform_driver edma_driver = {
 	.probe		= edma_probe,
-	.remove		= edma_remove,
 	.driver = {
-		.name	= "edma",
-		.pm	= &edma_pm_ops,
-		.of_match_table = edma_of_ids,
+		.name			= "edma",
+		.pm			= &edma_pm_ops,
+		.of_match_table		= edma_of_ids,
+		.suppress_bind_attrs	= true,
 	},
 };
 
@@ -2439,14 +2425,3 @@ static int edma_init(void)
 	return platform_driver_register(&edma_driver);
 }
 subsys_initcall(edma_init);
-
-static void __exit edma_exit(void)
-{
-	platform_driver_unregister(&edma_driver);
-	platform_driver_unregister(&edma_tptc_driver);
-}
-module_exit(edma_exit);
-
-MODULE_AUTHOR("Matt Porter <matt.porter@linaro.org>");
-MODULE_DESCRIPTION("TI EDMA DMA engine driver");
-MODULE_LICENSE("GPL v2");
-- 
2.6.1

[PATCH 2/6] drivers/dma: make mmp_pdma.c explicitly non-modular

[Paul Gortmaker]

The Kconfig currently controlling compilation of this code is:

drivers/dma/Kconfig:config MMP_PDMA
drivers/dma/Kconfig:    bool "MMP PDMA support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/dma/mmp_pdma.c | 21 ++++-----------------
 1 file changed, 4 insertions(+), 17 deletions(-)

diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c
index e39457f13d4d..d41b74b6e852 100644
--- a/drivers/dma/mmp_pdma.c
+++ b/drivers/dma/mmp_pdma.c
@@ -1,5 +1,7 @@
 /*
+ * MARVELL MMP Peripheral DMA Driver
  * Copyright 2012 Marvell International Ltd.
+ * Author: Marvell International Ltd.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
@@ -7,7 +9,6 @@
  */
 
 #include <linux/err.h>
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/interrupt.h>
@@ -929,14 +930,6 @@ static void dma_do_tasklet(unsigned long data)
 	}
 }
 
-static int mmp_pdma_remove(struct platform_device *op)
-{
-	struct mmp_pdma_device *pdev = platform_get_drvdata(op);
-
-	dma_async_device_unregister(&pdev->device);
-	return 0;
-}
-
 static int mmp_pdma_chan_init(struct mmp_pdma_device *pdev, int idx, int irq)
 {
 	struct mmp_pdma_phy *phy  = &pdev->phy[idx];
@@ -976,7 +969,6 @@ static const struct of_device_id mmp_pdma_dt_ids[] = {
 	{ .compatible = "marvell,pdma-1.0", },
 	{}
 };
-MODULE_DEVICE_TABLE(of, mmp_pdma_dt_ids);
 
 static struct dma_chan *mmp_pdma_dma_xlate(struct of_phandle_args *dma_spec,
 					   struct of_dma *ofdma)
@@ -1110,12 +1102,13 @@ static const struct platform_device_id mmp_pdma_id_table[] = {
 static struct platform_driver mmp_pdma_driver = {
 	.driver		= {
 		.name	= "mmp-pdma",
+		.suppress_bind_attrs = true,
 		.of_match_table = mmp_pdma_dt_ids,
 	},
 	.id_table	= mmp_pdma_id_table,
 	.probe		= mmp_pdma_probe,
-	.remove		= mmp_pdma_remove,
 };
+builtin_platform_driver(mmp_pdma_driver);
 
 bool mmp_pdma_filter_fn(struct dma_chan *chan, void *param)
 {
@@ -1129,9 +1122,3 @@ bool mmp_pdma_filter_fn(struct dma_chan *chan, void *param)
 	return true;
 }
 EXPORT_SYMBOL_GPL(mmp_pdma_filter_fn);
-
-module_platform_driver(mmp_pdma_driver);
-
-MODULE_DESCRIPTION("MARVELL MMP Peripheral DMA Driver");
-MODULE_AUTHOR("Marvell International Ltd.");
-MODULE_LICENSE("GPL v2");
-- 
2.6.1

[PATCH 3/6] drivers/dma: make mmp_tdma.c explicitly non-modular

[Paul Gortmaker]

The Kconfig currently controlling compilation of this code is:

drivers/dma/Kconfig:config MMP_TDMA
drivers/dma/Kconfig:    bool "MMP Two-Channel DMA support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/dma/mmp_tdma.c | 22 +++-------------------
 1 file changed, 3 insertions(+), 19 deletions(-)

diff --git a/drivers/dma/mmp_tdma.c b/drivers/dma/mmp_tdma.c
index 3df0422607d5..e231a0e79562 100644
--- a/drivers/dma/mmp_tdma.c
+++ b/drivers/dma/mmp_tdma.c
@@ -1,6 +1,7 @@
 /*
  * Driver For Marvell Two-channel DMA Engine
  *
+ * Authors: Leo Yan <leoy@marvell.com>  Zhangfei Gao <zhangfei.gao@marvell.com>
  * Copyright: Marvell International Ltd.
  *
  * The code contained herein is licensed under the GNU General Public
@@ -10,7 +11,6 @@
  */
 
 #include <linux/err.h>
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/interrupt.h>
@@ -530,14 +530,6 @@ static void mmp_tdma_issue_pending(struct dma_chan *chan)
 	mmp_tdma_enable_chan(tdmac);
 }
 
-static int mmp_tdma_remove(struct platform_device *pdev)
-{
-	struct mmp_tdma_device *tdev = platform_get_drvdata(pdev);
-
-	dma_async_device_unregister(&tdev->device);
-	return 0;
-}
-
 static int mmp_tdma_chan_init(struct mmp_tdma_device *tdev,
 					int idx, int irq,
 					int type, struct gen_pool *pool)
@@ -617,7 +609,6 @@ static const struct of_device_id mmp_tdma_dt_ids[] = {
 	{ .compatible = "marvell,pxa910-squ", .data = (void *)PXA910_SQU},
 	{}
 };
-MODULE_DEVICE_TABLE(of, mmp_tdma_dt_ids);
 
 static int mmp_tdma_probe(struct platform_device *pdev)
 {
@@ -728,17 +719,10 @@ static const struct platform_device_id mmp_tdma_id_table[] = {
 static struct platform_driver mmp_tdma_driver = {
 	.driver		= {
 		.name	= "mmp-tdma",
+		.suppress_bind_attrs = true,
 		.of_match_table = mmp_tdma_dt_ids,
 	},
 	.id_table	= mmp_tdma_id_table,
 	.probe		= mmp_tdma_probe,
-	.remove		= mmp_tdma_remove,
 };
-
-module_platform_driver(mmp_tdma_driver);
-
-MODULE_LICENSE("GPL");
-MODULE_DESCRIPTION("MMP Two-Channel DMA Driver");
-MODULE_ALIAS("platform:mmp-tdma");
-MODULE_AUTHOR("Leo Yan <leoy@marvell.com>");
-MODULE_AUTHOR("Zhangfei Gao <zhangfei.gao@marvell.com>");
+builtin_platform_driver(mmp_tdma_driver);
-- 
2.6.1

[PATCH 4/6] drivers/dma: make pxa_dma.c explicitly non-modular

[Paul Gortmaker]

The Kconfig currently controlling compilation of this code is:

drivers/dma/Kconfig:config PXA_DMA
drivers/dma/Kconfig:    bool "PXA DMA support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Daniel Mack <daniel@zonque.org>
Cc: Haojian Zhuang <haojian.zhuang@gmail.com>
Cc: Robert Jarzmik <robert.jarzmik@free.fr>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: dmaengine@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/dma/pxa_dma.c | 38 +++-----------------------------------
 1 file changed, 3 insertions(+), 35 deletions(-)

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index f2a0310ae771..5d6ab9ff2222 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -1,4 +1,5 @@
 /*
+ * Marvell PXA Peripheral DMA Driver
  * Copyright 2015 Robert Jarzmik <robert.jarzmik@free.fr>
  *
  * This program is free software; you can redistribute it and/or modify
@@ -7,7 +8,6 @@
  */
 
 #include <linux/err.h>
-#include <linux/module.h>
 #include <linux/init.h>
 #include <linux/types.h>
 #include <linux/interrupt.h>
@@ -400,13 +400,8 @@ err_root:
 	pr_err("pxad: debugfs is not available\n");
 }
 
-static void pxad_cleanup_debugfs(struct pxad_device *pdev)
-{
-	debugfs_remove_recursive(pdev->dbgfs_root);
-}
 #else
 static inline void pxad_init_debugfs(struct pxad_device *pdev) {}
-static inline void pxad_cleanup_debugfs(struct pxad_device *pdev) {}
 #endif
 
 /*
@@ -1246,27 +1241,6 @@ static enum dma_status pxad_tx_status(struct dma_chan *dchan,
 	return ret;
 }
 
-static void pxad_free_channels(struct dma_device *dmadev)
-{
-	struct pxad_chan *c, *cn;
-
-	list_for_each_entry_safe(c, cn, &dmadev->channels,
-				 vc.chan.device_node) {
-		list_del(&c->vc.chan.device_node);
-		tasklet_kill(&c->vc.task);
-	}
-}
-
-static int pxad_remove(struct platform_device *op)
-{
-	struct pxad_device *pdev = platform_get_drvdata(op);
-
-	pxad_cleanup_debugfs(pdev);
-	pxad_free_channels(&pdev->slave);
-	dma_async_device_unregister(&pdev->slave);
-	return 0;
-}
-
 static int pxad_init_phys(struct platform_device *op,
 			  struct pxad_device *pdev,
 			  unsigned int nb_phy_chans)
@@ -1315,7 +1289,6 @@ static const struct of_device_id const pxad_dt_ids[] = {
 	{ .compatible = "marvell,pdma-1.0", },
 	{}
 };
-MODULE_DEVICE_TABLE(of, pxad_dt_ids);
 
 static struct dma_chan *pxad_dma_xlate(struct of_phandle_args *dma_spec,
 					   struct of_dma *ofdma)
@@ -1448,12 +1421,13 @@ static const struct platform_device_id pxad_id_table[] = {
 static struct platform_driver pxad_driver = {
 	.driver		= {
 		.name	= "pxa-dma",
+		.suppress_bind_attrs = true,
 		.of_match_table = pxad_dt_ids,
 	},
 	.id_table	= pxad_id_table,
 	.probe		= pxad_probe,
-	.remove		= pxad_remove,
 };
+builtin_platform_driver(pxad_driver);
 
 bool pxad_filter_fn(struct dma_chan *chan, void *param)
 {
@@ -1478,9 +1452,3 @@ int pxad_toggle_reserved_channel(int legacy_channel)
 	return 0;
 }
 EXPORT_SYMBOL_GPL(pxad_toggle_reserved_channel);
-
-module_platform_driver(pxad_driver);
-
-MODULE_DESCRIPTION("Marvell PXA Peripheral DMA Driver");
-MODULE_AUTHOR("Robert Jarzmik <robert.jarzmik@free.fr>");
-MODULE_LICENSE("GPL v2");
-- 
2.6.1

[PATCH 5/6] drivers/dma: make sh/shdma-*.c explicitly non-modular

[Paul Gortmaker]

The Kconfig currently controlling compilation of these files is:

config SH_DMAE_BASE
     bool "Renesas SuperH DMA Engine support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

In one file, we explicitly disallow a driver unbind, since that
doesn't have a sensible use case anyway, and there was not a
".remove" code assigned in the struct for it either.

Since module_init translates to device_initcall in the non-modular
case, the init ordering remains unchanged with this commit.

Similarly builtin_platform_driver and module_platform_driver use
device_initcall, so the init ordering remains unchanged there too.

In one file, We replace module.h with moduleparam.h since the file does
have one module_param already.

We also delete the MODULE_LICENSE tag etc. since all that information
is already contained at the top of the file in the comments.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: dmaengine@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/dma/sh/shdma-base.c | 14 ++------------
 drivers/dma/sh/shdma-of.c   | 11 +++--------
 2 files changed, 5 insertions(+), 20 deletions(-)

diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
index 10fcabad80f3..69097a860fc8 100644
--- a/drivers/dma/sh/shdma-base.c
+++ b/drivers/dma/sh/shdma-base.c
@@ -18,7 +18,7 @@
 #include <linux/dmaengine.h>
 #include <linux/init.h>
 #include <linux/interrupt.h>
-#include <linux/module.h>
+#include <linux/moduleparam.h>
 #include <linux/pm_runtime.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -1051,14 +1051,4 @@ static int __init shdma_enter(void)
 		return -ENOMEM;
 	return 0;
 }
-module_init(shdma_enter);
-
-static void __exit shdma_exit(void)
-{
-	kfree(shdma_slave_used);
-}
-module_exit(shdma_exit);
-
-MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("SH-DMA driver base library");
-MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
+device_initcall(shdma_enter);
diff --git a/drivers/dma/sh/shdma-of.c b/drivers/dma/sh/shdma-of.c
index f999f9b0d314..888bd8761333 100644
--- a/drivers/dma/sh/shdma-of.c
+++ b/drivers/dma/sh/shdma-of.c
@@ -10,7 +10,7 @@
  */
 
 #include <linux/dmaengine.h>
-#include <linux/module.h>
+#include <linux/init.h>
 #include <linux/of.h>
 #include <linux/of_dma.h>
 #include <linux/of_platform.h>
@@ -62,18 +62,13 @@ static const struct of_device_id shdma_of_match[] = {
 	{ .compatible = "renesas,shdma-mux", },
 	{ }
 };
-MODULE_DEVICE_TABLE(of, sh_dmae_of_match);
 
 static struct platform_driver shdma_of = {
 	.driver		= {
 		.name	= "shdma-of",
+		.suppress_bind_attrs = true,
 		.of_match_table = shdma_of_match,
 	},
 	.probe		= shdma_of_probe,
 };
-
-module_platform_driver(shdma_of);
-
-MODULE_LICENSE("GPL v2");
-MODULE_DESCRIPTION("SH-DMA driver DT glue");
-MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
+builtin_platform_driver(shdma_of);
-- 
2.6.1

Re: [PATCH 5/6] drivers/dma: make sh/shdma-*.c explicitly non-modular

[Geert Uytterhoeven]

CC linux-sh

On Thu, Dec 10, 2015 at 12:22 AM, Paul Gortmaker
<paul.gortmaker@windriver.com> wrote:
> The Kconfig currently controlling compilation of these files is:
>
> config SH_DMAE_BASE
>      bool "Renesas SuperH DMA Engine support"
>
> ...meaning that it currently is not being built as a module by anyone.
>
> Lets remove the modular code that is essentially orphaned, so that
> when reading the driver there is no doubt it is builtin-only.
>
> In one file, we explicitly disallow a driver unbind, since that
> doesn't have a sensible use case anyway, and there was not a
> ".remove" code assigned in the struct for it either.
>
> Since module_init translates to device_initcall in the non-modular
> case, the init ordering remains unchanged with this commit.
>
> Similarly builtin_platform_driver and module_platform_driver use
> device_initcall, so the init ordering remains unchanged there too.
>
> In one file, We replace module.h with moduleparam.h since the file does
> have one module_param already.
>
> We also delete the MODULE_LICENSE tag etc. since all that information
> is already contained at the top of the file in the comments.
>
> Cc: Vinod Koul <vinod.koul@intel.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: dmaengine@vger.kernel.org
> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
> ---
>  drivers/dma/sh/shdma-base.c | 14 ++------------
>  drivers/dma/sh/shdma-of.c   | 11 +++--------
>  2 files changed, 5 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/dma/sh/shdma-base.c b/drivers/dma/sh/shdma-base.c
> index 10fcabad80f3..69097a860fc8 100644
> --- a/drivers/dma/sh/shdma-base.c
> +++ b/drivers/dma/sh/shdma-base.c
> @@ -18,7 +18,7 @@
>  #include <linux/dmaengine.h>
>  #include <linux/init.h>
>  #include <linux/interrupt.h>
> -#include <linux/module.h>
> +#include <linux/moduleparam.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/slab.h>
>  #include <linux/spinlock.h>
> @@ -1051,14 +1051,4 @@ static int __init shdma_enter(void)
>                 return -ENOMEM;
>         return 0;
>  }
> -module_init(shdma_enter);
> -
> -static void __exit shdma_exit(void)
> -{
> -       kfree(shdma_slave_used);
> -}
> -module_exit(shdma_exit);
> -
> -MODULE_LICENSE("GPL v2");
> -MODULE_DESCRIPTION("SH-DMA driver base library");
> -MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
> +device_initcall(shdma_enter);
> diff --git a/drivers/dma/sh/shdma-of.c b/drivers/dma/sh/shdma-of.c
> index f999f9b0d314..888bd8761333 100644
> --- a/drivers/dma/sh/shdma-of.c
> +++ b/drivers/dma/sh/shdma-of.c
> @@ -10,7 +10,7 @@
>   */
>
>  #include <linux/dmaengine.h>
> -#include <linux/module.h>
> +#include <linux/init.h>
>  #include <linux/of.h>
>  #include <linux/of_dma.h>
>  #include <linux/of_platform.h>
> @@ -62,18 +62,13 @@ static const struct of_device_id shdma_of_match[] = {
>         { .compatible = "renesas,shdma-mux", },
>         { }
>  };
> -MODULE_DEVICE_TABLE(of, sh_dmae_of_match);
>
>  static struct platform_driver shdma_of = {
>         .driver         = {
>                 .name   = "shdma-of",
> +               .suppress_bind_attrs = true,
>                 .of_match_table = shdma_of_match,
>         },
>         .probe          = shdma_of_probe,
>  };
> -
> -module_platform_driver(shdma_of);
> -
> -MODULE_LICENSE("GPL v2");
> -MODULE_DESCRIPTION("SH-DMA driver DT glue");
> -MODULE_AUTHOR("Guennadi Liakhovetski <g.liakhovetski@gmx.de>");
> +builtin_platform_driver(shdma_of);
> --
> 2.6.1

[PATCH 6/6] drivers/dma: make tegra20-apb-dma.c explicitly non-modular

[Paul Gortmaker]

The Kconfig currently controlling compilation of this code is:

drivers/dma/Kconfig:config TEGRA20_APB_DMA
drivers/dma/Kconfig:    bool "NVIDIA Tegra20 APB DMA support"

...meaning that it currently is not being built as a module by anyone.

Lets remove the modular code that is essentially orphaned, so that
when reading the driver there is no doubt it is builtin-only.

We explicitly disallow a driver unbind, since that doesn't have a
sensible use case anyway, and it allows us to drop the ".remove"
code for non-modular drivers.

Since module_platform_driver() uses the same init level priority as
builtin_platform_driver() the init ordering remains unchanged with
this commit.

We don't replace module.h with init.h since the file already has that.

Also note that MODULE_DEVICE_TABLE is a no-op for non-modular code.

We also delete the MODULE_LICENSE tag etc. since all that information
was (or is now) contained at the top of the file in the comments.

Cc: Laxman Dewangan <ldewangan@nvidia.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: dmaengine@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
 drivers/dma/tegra20-apb-dma.c | 35 ++++-------------------------------
 1 file changed, 4 insertions(+), 31 deletions(-)

diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c
index 935da8192f59..eee783cee45b 100644
--- a/drivers/dma/tegra20-apb-dma.c
+++ b/drivers/dma/tegra20-apb-dma.c
@@ -3,6 +3,8 @@
  *
  * Copyright (c) 2012-2013, NVIDIA CORPORATION.  All rights reserved.
  *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
  * version 2, as published by the Free Software Foundation.
@@ -26,7 +28,6 @@
 #include <linux/interrupt.h>
 #include <linux/io.h>
 #include <linux/mm.h>
-#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/of_dma.h>
@@ -1309,7 +1310,6 @@ static const struct of_device_id tegra_dma_of_match[] = {
 	}, {
 	},
 };
-MODULE_DEVICE_TABLE(of, tegra_dma_of_match);
 
 static int tegra_dma_probe(struct platform_device *pdev)
 {
@@ -1488,27 +1488,6 @@ err_irq:
 	return ret;
 }
 
-static int tegra_dma_remove(struct platform_device *pdev)
-{
-	struct tegra_dma *tdma = platform_get_drvdata(pdev);
-	int i;
-	struct tegra_dma_channel *tdc;
-
-	dma_async_device_unregister(&tdma->dma_dev);
-
-	for (i = 0; i < tdma->chip_data->nr_channels; ++i) {
-		tdc = &tdma->channels[i];
-		free_irq(tdc->irq, tdc);
-		tasklet_kill(&tdc->tasklet);
-	}
-
-	pm_runtime_disable(&pdev->dev);
-	if (!pm_runtime_status_suspended(&pdev->dev))
-		tegra_dma_runtime_suspend(&pdev->dev);
-
-	return 0;
-}
-
 static int tegra_dma_runtime_suspend(struct device *dev)
 {
 	struct tegra_dma *tdma = dev_get_drvdata(dev);
@@ -1616,15 +1595,9 @@ static struct platform_driver tegra_dmac_driver = {
 	.driver = {
 		.name	= "tegra-apbdma",
 		.pm	= &tegra_dma_dev_pm_ops,
+		.suppress_bind_attrs = true,
 		.of_match_table = tegra_dma_of_match,
 	},
 	.probe		= tegra_dma_probe,
-	.remove		= tegra_dma_remove,
 };
-
-module_platform_driver(tegra_dmac_driver);
-
-MODULE_ALIAS("platform:tegra20-apbdma");
-MODULE_DESCRIPTION("NVIDIA Tegra APB DMA Controller driver");
-MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
-MODULE_LICENSE("GPL v2");
+builtin_platform_driver(tegra_dmac_driver);
-- 
2.6.1

Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers

[Arnd Bergmann]

On Wednesday 09 December 2015 18:21:56 Paul Gortmaker wrote:
> This series of commits is a slice of a larger project to ensure
> people don't have dead code for module removal in non-modular
> drivers.  Overall there is roughly 5k lines of dead code in the
> kernel due to this.
> 
> There is a quasi-separate theme, in that some of the drivers were
> allowing an unbind implicitly since it is enabled by default.  But
> for core DMA infrastructure drivers, this doesn't seem useful -- so
> we also disable that here which allows us to delete any ".remove"
> functions from the drivers that would otherwise be called during the
> (impossible to trigger) module removal.
> 
> Since ARM covers these files the best of all architectures, each
> file was build tested for allmodconfig on ARM, which at the same
> time confirms that the files are not built with "CC [M]" -- hence
> genuinely non-modular.
> 
> My testing and the larger patch series in general has been done
> against the latest linux-next tree.
> 
> 

We are in the process of changing the DMA drivers to a new way of
passing the "filter" function around. We can soon build them
all as loadable modules again.

	Arnd

Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers

[Paul Gortmaker]

[Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers] On 10/12/2015 (Thu 00:29) Arnd Bergmann wrote:

> On Wednesday 09 December 2015 18:21:56 Paul Gortmaker wrote:
> > This series of commits is a slice of a larger project to ensure
> > people don't have dead code for module removal in non-modular
> > drivers.  Overall there is roughly 5k lines of dead code in the
> > kernel due to this.
> > 
> > There is a quasi-separate theme, in that some of the drivers were
> > allowing an unbind implicitly since it is enabled by default.  But
> > for core DMA infrastructure drivers, this doesn't seem useful -- so
> > we also disable that here which allows us to delete any ".remove"
> > functions from the drivers that would otherwise be called during the
> > (impossible to trigger) module removal.
> > 
> > Since ARM covers these files the best of all architectures, each
> > file was build tested for allmodconfig on ARM, which at the same
> > time confirms that the files are not built with "CC [M]" -- hence
> > genuinely non-modular.
> > 
> > My testing and the larger patch series in general has been done
> > against the latest linux-next tree.
> > 
> > 
> 
> We are in the process of changing the DMA drivers to a new way of
> passing the "filter" function around. We can soon build them
> all as loadable modules again.

Hi Arnd,

Thanks for the feedback -- just to clarify, you are suggesting I hold
on the series until I see what emerges in the next merge window?

Paul.
--

> 
> 	Arnd

Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers

[Vinod Koul]

On Wed, Dec 09, 2015 at 07:17:42PM -0500, Paul Gortmaker wrote:
> [Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers] On 10/12/2015 (Thu 00:29) Arnd Bergmann wrote:
> 
> > On Wednesday 09 December 2015 18:21:56 Paul Gortmaker wrote:
> > > This series of commits is a slice of a larger project to ensure
> > > people don't have dead code for module removal in non-modular
> > > drivers.  Overall there is roughly 5k lines of dead code in the
> > > kernel due to this.
> > > 
> > > There is a quasi-separate theme, in that some of the drivers were
> > > allowing an unbind implicitly since it is enabled by default.  But
> > > for core DMA infrastructure drivers, this doesn't seem useful -- so
> > > we also disable that here which allows us to delete any ".remove"
> > > functions from the drivers that would otherwise be called during the
> > > (impossible to trigger) module removal.
> > > 
> > > Since ARM covers these files the best of all architectures, each
> > > file was build tested for allmodconfig on ARM, which at the same
> > > time confirms that the files are not built with "CC [M]" -- hence
> > > genuinely non-modular.
> > > 
> > > My testing and the larger patch series in general has been done
> > > against the latest linux-next tree.
> > > 
> > > 
> > 
> > We are in the process of changing the DMA drivers to a new way of
> > passing the "filter" function around. We can soon build them
> > all as loadable modules again.
> 
> Hi Arnd,
> 
> Thanks for the feedback -- just to clarify, you are suggesting I hold
> on the series until I see what emerges in the next merge window?

Yes, with this we should be able to have loadable modules for *most* so we
may not require this

Thanks
-- 
~Vinod

Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers

[Arnd Bergmann]

On Wednesday 09 December 2015 19:17:42 Paul Gortmaker wrote:
> [Re: [PATCH 0/6] drivers/dma: drop modular code from non modular drivers] On 10/12/2015 (Thu 00:29) Arnd Bergmann wrote:
> 
> > On Wednesday 09 December 2015 18:21:56 Paul Gortmaker wrote:
> > > This series of commits is a slice of a larger project to ensure
> > > people don't have dead code for module removal in non-modular
> > > drivers.  Overall there is roughly 5k lines of dead code in the
> > > kernel due to this.
> > > 
> > > There is a quasi-separate theme, in that some of the drivers were
> > > allowing an unbind implicitly since it is enabled by default.  But
> > > for core DMA infrastructure drivers, this doesn't seem useful -- so
> > > we also disable that here which allows us to delete any ".remove"
> > > functions from the drivers that would otherwise be called during the
> > > (impossible to trigger) module removal.
> > > 
> > > Since ARM covers these files the best of all architectures, each
> > > file was build tested for allmodconfig on ARM, which at the same
> > > time confirms that the files are not built with "CC [M]" -- hence
> > > genuinely non-modular.
> > > 
> > > My testing and the larger patch series in general has been done
> > > against the latest linux-next tree.
> > > 
> > > 
> > 
> > We are in the process of changing the DMA drivers to a new way of
> > passing the "filter" function around. We can soon build them
> > all as loadable modules again.
> 
> Hi Arnd,
> 
> Thanks for the feedback -- just to clarify, you are suggesting I hold
> on the series until I see what emerges in the next merge window?
> 
> 

It may take a few cycles, but I think we'll get there and should not
remove the unload logic from any of these drivers. When we're done,
there is no reason for a dmaengine driver to be built-in.

	Arnd