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List:       git-commits-head
Subject:    HID: cp2112: fix sleep-while-atomic
From:       "Linux Kernel Mailing List" <linux-kernel () vger ! kernel ! org>
Date:       2017-01-31 21:57:06
Message-ID: 20170131215706.89A31660FC8 () gitolite ! kernel ! org
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Web:        https://git.kernel.org/torvalds/c/7a7b5df84b6b4e5d599c7289526eed96541a0654
Commit:     7a7b5df84b6b4e5d599c7289526eed96541a0654
Parent:     877a021e08ccb6434718c0cc781fdf943c884cc0
Refname:    refs/heads/master
Author:     Johan Hovold <johan@kernel.org>
AuthorDate: Mon Jan 30 11:26:38 2017 +0100
Committer:  Jiri Kosina <jkosina@suse.cz>
CommitDate: Tue Jan 31 12:59:32 2017 +0100

    HID: cp2112: fix sleep-while-atomic
    
    A recent commit fixing DMA-buffers on stack added a shared transfer
    buffer protected by a spinlock. This is broken as the USB HID request
    callbacks can sleep. Fix this up by replacing the spinlock with a mutex.
    
    Fixes: 1ffb3c40ffb5 ("HID: cp2112: make transfer buffers DMA capable")
    Cc: stable <stable@vger.kernel.org>     # 4.9
    Signed-off-by: Johan Hovold <johan@kernel.org>
    Reviewed-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>
    Signed-off-by: Jiri Kosina <jkosina@suse.cz>
---
 drivers/hid/hid-cp2112.c | 26 +++++++++++---------------
 1 file changed, 11 insertions(+), 15 deletions(-)

diff --git a/drivers/hid/hid-cp2112.c b/drivers/hid/hid-cp2112.c
index f31a778..3e0b6ba 100644
--- a/drivers/hid/hid-cp2112.c
+++ b/drivers/hid/hid-cp2112.c
@@ -168,7 +168,7 @@ struct cp2112_device {
 	atomic_t xfer_avail;
 	struct gpio_chip gc;
 	u8 *in_out_buffer;
-	spinlock_t lock;
+	struct mutex lock;
 
 	struct gpio_desc *desc[8];
 	bool gpio_poll;
@@ -186,10 +186,9 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
@@ -213,7 +212,7 @@ static int cp2112_gpio_direction_input(struct gpio_chip *chip, unsigned offset)
 	ret = 0;
 
 exit:
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 	return ret <= 0 ? ret : -EIO;
 }
 
@@ -222,10 +221,9 @@ static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	buf[0] = CP2112_GPIO_SET;
 	buf[1] = value ? 0xff : 0;
@@ -237,7 +235,7 @@ static void cp2112_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
 	if (ret < 0)
 		hid_err(hdev, "error setting GPIO values: %d\n", ret);
 
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 }
 
 static int cp2112_gpio_get_all(struct gpio_chip *chip)
@@ -245,10 +243,9 @@ static int cp2112_gpio_get_all(struct gpio_chip *chip)
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_GET, buf,
 				 CP2112_GPIO_GET_LENGTH, HID_FEATURE_REPORT,
@@ -262,7 +259,7 @@ static int cp2112_gpio_get_all(struct gpio_chip *chip)
 	ret = buf[1];
 
 exit:
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 
 	return ret;
 }
@@ -284,10 +281,9 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 	struct cp2112_device *dev = gpiochip_get_data(chip);
 	struct hid_device *hdev = dev->hdev;
 	u8 *buf = dev->in_out_buffer;
-	unsigned long flags;
 	int ret;
 
-	spin_lock_irqsave(&dev->lock, flags);
+	mutex_lock(&dev->lock);
 
 	ret = hid_hw_raw_request(hdev, CP2112_GPIO_CONFIG, buf,
 				 CP2112_GPIO_CONFIG_LENGTH, HID_FEATURE_REPORT,
@@ -308,7 +304,7 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 		goto fail;
 	}
 
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 
 	/*
 	 * Set gpio value when output direction is already set,
@@ -319,7 +315,7 @@ static int cp2112_gpio_direction_output(struct gpio_chip *chip,
 	return 0;
 
 fail:
-	spin_unlock_irqrestore(&dev->lock, flags);
+	mutex_unlock(&dev->lock);
 	return ret < 0 ? ret : -EIO;
 }
 
@@ -1235,7 +1231,7 @@ static int cp2112_probe(struct hid_device *hdev, const struct hid_device_id *id)
 	if (!dev->in_out_buffer)
 		return -ENOMEM;
 
-	spin_lock_init(&dev->lock);
+	mutex_init(&dev->lock);
 
 	ret = hid_parse(hdev);
 	if (ret) {
--
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