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Commit d4ccb132 authored by Eric Lapuyade's avatar Eric Lapuyade Committed by John W. Linville
Browse files

NFC: Specify usage for targets found and target lost events 



It is now specified that nfc_target_found() and nfc_target_lost() core
functions must not be called from an atomic context. This allow us to
serialize calls and protect the targets table using the nfc device lock
instead of a spinlock.

Signed-off-by: default avatarEric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: default avatarSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent addfabf9

include/net/nfc/nfc.h

+0 −1
Original line number Original line Diff line number Diff line
@@ -97,7 +97,6 @@ struct nfc_dev { 
	struct nfc_target *targets;

	struct nfc_target *targets;

	int n_targets;

	int n_targets;

	int targets_generation;

	int targets_generation;

	spinlock_t targets_lock;

	struct device dev;

	struct device dev;

	bool dev_up;

	bool dev_up;

	bool polling;

	bool polling;

net/nfc/core.c

+26 −9
Original line number Original line Diff line number Diff line
@@ -501,6 +501,9 @@ EXPORT_SYMBOL(nfc_alloc_recv_skb); 
 * The device driver must call this function when one or many nfc targets

 * The device driver must call this function when one or many nfc targets

 * are found. After calling this function, the device driver must stop

 * are found. After calling this function, the device driver must stop

 * polling for targets.

 * polling for targets.

 * IMPORTANT: this function must not be called from an atomic context.

 * In addition, it must also not be called from a context that would prevent

 * the NFC Core to call other nfc ops entry point concurrently.

 */

 */

int nfc_targets_found(struct nfc_dev *dev,

int nfc_targets_found(struct nfc_dev *dev,

		      struct nfc_target *targets, int n_targets)

		      struct nfc_target *targets, int n_targets)
@@ -514,7 +517,7 @@ int nfc_targets_found(struct nfc_dev *dev, 
	for (i = 0; i < n_targets; i++)

	for (i = 0; i < n_targets; i++)

		targets[i].idx = dev->target_next_idx++;

		targets[i].idx = dev->target_next_idx++;





	spin_lock_bh(&dev->targets_lock);

	device_lock(&dev->dev);





	dev->targets_generation++;

	dev->targets_generation++;
@@ -524,12 +527,12 @@ int nfc_targets_found(struct nfc_dev *dev, 




	if (!dev->targets) {

	if (!dev->targets) {

		dev->n_targets = 0;

		dev->n_targets = 0;

		spin_unlock_bh(&dev->targets_lock);

		device_unlock(&dev->dev);

		return -ENOMEM;

		return -ENOMEM;

	}

	}





	dev->n_targets = n_targets;

	dev->n_targets = n_targets;

	spin_unlock_bh(&dev->targets_lock);

	device_unlock(&dev->dev);





	nfc_genl_targets_found(dev);

	nfc_genl_targets_found(dev);
@@ -537,6 +540,18 @@ int nfc_targets_found(struct nfc_dev *dev, 
}

}

EXPORT_SYMBOL(nfc_targets_found);

EXPORT_SYMBOL(nfc_targets_found);





/**

 * nfc_target_lost - inform that an activated target went out of field

 *

 * @dev: The nfc device that had the activated target in field

 * @target_idx: the nfc index of the target

 *

 * The device driver must call this function when the activated target

 * goes out of the field.

 * IMPORTANT: this function must not be called from an atomic context.

 * In addition, it must also not be called from a context that would prevent

 * the NFC Core to call other nfc ops entry point concurrently.

 */

int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)

int nfc_target_lost(struct nfc_dev *dev, u32 target_idx)

{

{

	struct nfc_target *tg;

	struct nfc_target *tg;
@@ -544,7 +559,7 @@ int nfc_target_lost(struct nfc_dev *dev, u32 target_idx) 




	pr_debug("dev_name %s n_target %d\n", dev_name(&dev->dev), target_idx);

	pr_debug("dev_name %s n_target %d\n", dev_name(&dev->dev), target_idx);





	spin_lock_bh(&dev->targets_lock);

	device_lock(&dev->dev);





	for (i = 0; i < dev->n_targets; i++) {

	for (i = 0; i < dev->n_targets; i++) {

		tg = &dev->targets[i];

		tg = &dev->targets[i];
@@ -553,7 +568,7 @@ int nfc_target_lost(struct nfc_dev *dev, u32 target_idx) 
	}

	}





	if (i == dev->n_targets) {

	if (i == dev->n_targets) {

		spin_unlock_bh(&dev->targets_lock);

		device_unlock(&dev->dev);

		return -EINVAL;

		return -EINVAL;

	}

	}
@@ -569,7 +584,7 @@ int nfc_target_lost(struct nfc_dev *dev, u32 target_idx) 
		dev->targets = NULL;

		dev->targets = NULL;

	}

	}





	spin_unlock_bh(&dev->targets_lock);

	device_unlock(&dev->dev);





	nfc_genl_target_lost(dev, target_idx);

	nfc_genl_target_lost(dev, target_idx);
@@ -607,8 +622,10 @@ static void nfc_check_pres_work(struct work_struct *work) 
			mod_timer(&dev->check_pres_timer, jiffies +

			mod_timer(&dev->check_pres_timer, jiffies +

				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));

				  msecs_to_jiffies(NFC_CHECK_PRES_FREQ_MS));

		} else {

		} else {

			nfc_target_lost(dev, dev->active_target->idx);

			u32 active_target_idx = dev->active_target->idx;

			dev->active_target = NULL;

			device_unlock(&dev->dev);

			nfc_target_lost(dev, active_target_idx);

			return;

		}

		}

	}

	}
@@ -681,9 +698,9 @@ struct nfc_dev *nfc_allocate_device(struct nfc_ops *ops, 
	dev->tx_headroom = tx_headroom;

	dev->tx_headroom = tx_headroom;

	dev->tx_tailroom = tx_tailroom;

	dev->tx_tailroom = tx_tailroom;





	spin_lock_init(&dev->targets_lock);

	nfc_genl_data_init(&dev->genl_data);

	nfc_genl_data_init(&dev->genl_data);







	/* first generation must not be 0 */

	/* first generation must not be 0 */

	dev->targets_generation = 1;

	dev->targets_generation = 1;

net/nfc/netlink.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -128,7 +128,7 @@ static int nfc_genl_dump_targets(struct sk_buff *skb, 
		cb->args[1] = (long) dev;

		cb->args[1] = (long) dev;

	}

	}





	spin_lock_bh(&dev->targets_lock);

	device_lock(&dev->dev);





	cb->seq = dev->targets_generation;

	cb->seq = dev->targets_generation;
@@ -141,7 +141,7 @@ static int nfc_genl_dump_targets(struct sk_buff *skb, 
		i++;

		i++;

	}

	}





	spin_unlock_bh(&dev->targets_lock);

	device_unlock(&dev->dev);





	cb->args[0] = i;

	cb->args[0] = i;