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misc: atmel-ssc: lock with mutex instead of spinlock 

commit b037d60a3b upstream.

Uninterruptible context is not needed in the driver and causes lockdep
warning because of mutex taken in of_alias_get_id(). Convert the lock to
mutex to avoid the issue.

Cc: stable@vger.kernel.org
Fixes: 099343c64e ("ARM: at91: atmel-ssc: add device tree support")
Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Link: https://lore.kernel.org/r/50f0d7fa107f318296afb49477c3571e4d6978c5.1592998403.git.mirq-linux@rere.qmqm.pl
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
5.4-rM2-2.2.x-imx-squashed
Michał Mirosław 2020-06-24 13:35:41 +02:00 committed by Greg Kroah-Hartman
parent 746930d17d
commit 0ab6b541c6
1 changed files with 12 additions and 12 deletions
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24
drivers/misc/atmel-ssc.c
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@ -10,7 +10,7 @@
#include <linux/clk.h> #include <linux/clk.h>
#include <linux/err.h> #include <linux/err.h>
#include <linux/io.h> #include <linux/io.h>
#include <linux/spinlock.h> #include <linux/mutex.h>
#include <linux/atmel-ssc.h> #include <linux/atmel-ssc.h>
#include <linux/slab.h> #include <linux/slab.h>
#include <linux/module.h> #include <linux/module.h>
@ -20,7 +20,7 @@
#include "../../sound/soc/atmel/atmel_ssc_dai.h" #include "../../sound/soc/atmel/atmel_ssc_dai.h"
/* Serialize access to ssc_list and user count */ /* Serialize access to ssc_list and user count */
static DEFINE_SPINLOCK(user_lock); static DEFINE_MUTEX(user_lock);
static LIST_HEAD(ssc_list); static LIST_HEAD(ssc_list);
struct ssc_device *ssc_request(unsigned int ssc_num) struct ssc_device *ssc_request(unsigned int ssc_num)
@ -28,7 +28,7 @@ struct ssc_device *ssc_request(unsigned int ssc_num)
int ssc_valid = 0; int ssc_valid = 0;
struct ssc_device *ssc; struct ssc_device *ssc;
spin_lock(&user_lock); mutex_lock(&user_lock);
list_for_each_entry(ssc, &ssc_list, list) { list_for_each_entry(ssc, &ssc_list, list) {
if (ssc->pdev->dev.of_node) { if (ssc->pdev->dev.of_node) {
if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc") if (of_alias_get_id(ssc->pdev->dev.of_node, "ssc")
@ -44,18 +44,18 @@ struct ssc_device *ssc_request(unsigned int ssc_num)
} }
if (!ssc_valid) { if (!ssc_valid) {
spin_unlock(&user_lock); mutex_unlock(&user_lock);
pr_err("ssc: ssc%d platform device is missing\n", ssc_num); pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
return ERR_PTR(-ENODEV); return ERR_PTR(-ENODEV);
} }
if (ssc->user) { if (ssc->user) {
spin_unlock(&user_lock); mutex_unlock(&user_lock);
dev_dbg(&ssc->pdev->dev, "module busy\n"); dev_dbg(&ssc->pdev->dev, "module busy\n");
return ERR_PTR(-EBUSY); return ERR_PTR(-EBUSY);
} }
ssc->user++; ssc->user++;
spin_unlock(&user_lock); mutex_unlock(&user_lock);
clk_prepare(ssc->clk); clk_prepare(ssc->clk);
@ -67,14 +67,14 @@ void ssc_free(struct ssc_device *ssc)
{ {
bool disable_clk = true; bool disable_clk = true;
spin_lock(&user_lock); mutex_lock(&user_lock);
if (ssc->user) if (ssc->user)
ssc->user--; ssc->user--;
else { else {
disable_clk = false; disable_clk = false;
dev_dbg(&ssc->pdev->dev, "device already free\n"); dev_dbg(&ssc->pdev->dev, "device already free\n");
} }
spin_unlock(&user_lock); mutex_unlock(&user_lock);
if (disable_clk) if (disable_clk)
clk_unprepare(ssc->clk); clk_unprepare(ssc->clk);
@ -237,9 +237,9 @@ static int ssc_probe(struct platform_device *pdev)
return -ENXIO; return -ENXIO;
} }
spin_lock(&user_lock); mutex_lock(&user_lock);
list_add_tail(&ssc->list, &ssc_list); list_add_tail(&ssc->list, &ssc_list);
spin_unlock(&user_lock); mutex_unlock(&user_lock);
platform_set_drvdata(pdev, ssc); platform_set_drvdata(pdev, ssc);
@ -258,9 +258,9 @@ static int ssc_remove(struct platform_device *pdev)
ssc_sound_dai_remove(ssc); ssc_sound_dai_remove(ssc);
spin_lock(&user_lock); mutex_lock(&user_lock);
list_del(&ssc->list); list_del(&ssc->list);
spin_unlock(&user_lock); mutex_unlock(&user_lock);
return 0; return 0;
} }