kernel/net/bluetooth/rfcomm/tty.c, branch linux-4.1.y

Bluetooth: Convert RFCOMM spinlocks into mutexes

2014-05-06T02:25:06Z

Enabling CONFIG_DEBUG_ATOMIC_SLEEP has shown that some rfcomm functions acquiring spinlocks call sleeping locks further in the chain. Converting the offending spinlocks into mutexes makes sleeping safe. Signed-off-by: Libor Pechacek Signed-off-by: Marcel Holtmann

Bluetooth: Fix write_room() calculation

2014-02-14T21:39:32Z

The skb truesize of a 12-byte payload with a 10-byte head/tail reserve is 768 bytes. Consequently, even with 40 tx_credits, at most 6 packets could be queued at any one time: 40 tx_credits * 127-byte mtu < 768-byte truesize * 7 This error could also cause the tx queue to apparently stall if credit flow control is disabled (where tx_credits is fixed at 5), or if the receiver only granted a limited number of tx credits (eg., less than 7). Instead, track the outstanding number of queued packets not yet sent in wmem_alloc and allow for a maximum of 40 queued packets. Report the space avail for a single write() as the mtu * number of packets left before reaching the maximum. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Refactor write_room() calculation

2014-02-14T21:39:32Z

Compute the amount of space available for a single write() within rfcomm_room(); clamp to 0 for negative values. Note this patch does not change the result of the computation. Report the amount of room returned in the debug printk. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Don't fail RFCOMM tty writes

2014-02-14T21:39:32Z

The tty driver api design prefers no-fail writes if the driver write_room() method has previously indicated space is available to accept writes. Since this is trivially possible for the RFCOMM tty driver, do so. Introduce rfcomm_dlc_send_noerror(), which queues but does not schedule the krfcomm thread if the dlc is not yet connected (and thus does not error based on the connection state). The mtu size test is also unnecessary since the caller already chunks the written data into mtu size. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Force -EIO from tty read/write if .activate() fails

2014-02-14T21:39:32Z

If rfcomm_dlc_open() fails, set tty into error state which returns -EIO from reads and writes. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Cleanup RFCOMM device registration error handling

2014-02-14T21:39:32Z

If RFCOMM tty device registration fails, cleanup by releasing the tty_port reference to trigger rfcomm_dev destruction (rather than open-coding it). The dlc reference release is moved into rfcomm_dev_add(), which ensures cleanup in both error paths -- ie., if __rfcomm_dev_add() fails or if tty_port_register_device() fails. Fixes releasing the module reference if device registration fails. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Refactor rfcomm_dev_add()

2014-02-14T21:39:31Z

Move rfcomm_dev allocation and initialization into new function, __rfcomm_dev_add(), to simplify resource release in error handling. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Serialize RFCOMMCREATEDEV and RFCOMMRELEASEDEV ioctls

2014-02-14T21:39:31Z

At least two different race conditions exist with multiple concurrent RFCOMMCREATEDEV and RFCOMMRELEASEDEV ioctls: * Multiple concurrent RFCOMMCREATEDEVs with RFCOMM_REUSE_DLC can mistakenly share the same DLC. * RFCOMMRELEASEDEV can destruct the rfcomm_dev still being constructed by RFCOMMCREATEDEV. Introduce rfcomm_ioctl_mutex to serialize these add/remove operations. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Rename __rfcomm_dev_get() to __rfcomm_dev_lookup()

2014-02-14T21:39:31Z

Functions which search lists for matching id's are more commonly named *_lookup, which is the convention in the bluetooth core as well. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann

Bluetooth: Fix RFCOMM parent device for reused dlc

2014-02-14T21:39:31Z

The RFCOMM tty device is parented to the acl link device when the dlc state_change(BT_CONNECTED) notification is received. However, if the dlc from the RFCOMM socket is being reused (RFCOMM_REUSE_DLC is set), then the dlc may already be connected, and no notification will occur. Instead, always parent the RFCOMM tty device to the acl link device at registration time. If the acl link device is not available (eg, because the dlc is not connected) then the tty will remain unparented until the BT_CONNECTED notification is received. Fixes regression with ModemManager when the rfcomm device is created with the flag RFCOMM_REUSE_DLC. Signed-off-by: Peter Hurley Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann