From c0fdfb80382e4901473ce0e31d1e7833c1d297be Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 9 Feb 2014 20:59:04 -0500 Subject: tty: Fix ref counting for port krefs The tty core supports two models for handling tty_port lifetimes; the tty_port can use the kref supplied by tty_port (which will automatically destruct the tty_port when the ref count drops to zero) or it can destruct the tty_port manually. For tty drivers that choose to use the port kref to manage the tty_port lifetime, it is not possible to safely acquire a port reference conditionally. If the last reference is released after evaluating the condition but before acquiring the reference, a bogus reference will be held while the tty_port destruction commences. Rather, only acquire a port reference if the ref count is non-zero and allow the caller to distinguish if a reference has successfully been acquired. Cc: Jiri Slaby Signed-off-by: Peter Hurley Acked-by: Greg Kroah-Hartman Tested-By: Alexander Holler Signed-off-by: Marcel Holtmann --- include/linux/tty.h | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/include/linux/tty.h b/include/linux/tty.h index 90b4fdc8a61f..4781d7b27dd3 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -518,9 +518,9 @@ extern void tty_port_put(struct tty_port *port); static inline struct tty_port *tty_port_get(struct tty_port *port) { - if (port) - kref_get(&port->kref); - return port; + if (port && kref_get_unless_zero(&port->kref)) + return port; + return NULL; } /* If the cts flow control is enabled, return true. */ -- cgit From b075dd40c95d11c2c8690f6c4d6232fc0d9e7f56 Mon Sep 17 00:00:00 2001 From: Lucas De Marchi Date: Tue, 18 Feb 2014 02:19:26 -0300 Subject: Bluetooth: allocate static minor for vhci Commit bfacbb9 (Bluetooth: Use devname:vhci module alias for virtual HCI driver) added the module alias to hci_vhci module so it's possible to create the /dev/vhci node. However creating an alias without specifying the minor doesn't allow us to create the node ahead, triggerring module auto-load when it's first accessed. Starting with depmod from kmod 16 we started to warn if there's a devname alias without specifying the major and minor. Let's do the same done for uhid, kvm, fuse and others, specifying a fixed minor. In systems with systemd as the init the following will happen: on early boot systemd will call "kmod static-nodes" to read /lib/modules/$(uname -r)/modules.devname and then create the nodes. When first accessed these "dead" nodes will trigger the module loading. Signed-off-by: Lucas De Marchi Acked-by: Greg Kroah-Hartman Signed-off-by: Marcel Holtmann --- Documentation/devices.txt | 1 + drivers/bluetooth/hci_vhci.c | 3 ++- include/linux/miscdevice.h | 1 + 3 files changed, 4 insertions(+), 1 deletion(-) (limited to 'include/linux') diff --git a/Documentation/devices.txt b/Documentation/devices.txt index 10378cc48374..04356f5bc3af 100644 --- a/Documentation/devices.txt +++ b/Documentation/devices.txt @@ -353,6 +353,7 @@ Your cooperation is appreciated. 133 = /dev/exttrp External device trap 134 = /dev/apm_bios Advanced Power Management BIOS 135 = /dev/rtc Real Time Clock + 137 = /dev/vhci Bluetooth virtual HCI driver 139 = /dev/openprom SPARC OpenBoot PROM 140 = /dev/relay8 Berkshire Products Octal relay card 141 = /dev/relay16 Berkshire Products ISO-16 relay card diff --git a/drivers/bluetooth/hci_vhci.c b/drivers/bluetooth/hci_vhci.c index 1ef6990a5c7e..add1c6a72063 100644 --- a/drivers/bluetooth/hci_vhci.c +++ b/drivers/bluetooth/hci_vhci.c @@ -359,7 +359,7 @@ static const struct file_operations vhci_fops = { static struct miscdevice vhci_miscdev= { .name = "vhci", .fops = &vhci_fops, - .minor = MISC_DYNAMIC_MINOR, + .minor = VHCI_MINOR, }; static int __init vhci_init(void) @@ -385,3 +385,4 @@ MODULE_DESCRIPTION("Bluetooth virtual HCI driver ver " VERSION); MODULE_VERSION(VERSION); MODULE_LICENSE("GPL"); MODULE_ALIAS("devname:vhci"); +MODULE_ALIAS_MISCDEV(VHCI_MINOR); diff --git a/include/linux/miscdevice.h b/include/linux/miscdevice.h index 3737f7218f51..7bb6148d990f 100644 --- a/include/linux/miscdevice.h +++ b/include/linux/miscdevice.h @@ -23,6 +23,7 @@ #define TEMP_MINOR 131 /* Temperature Sensor */ #define RTC_MINOR 135 #define EFI_RTC_MINOR 136 /* EFI Time services */ +#define VHCI_MINOR 137 #define SUN_OPENPROM_MINOR 139 #define DMAPI_MINOR 140 /* DMAPI */ #define NVRAM_MINOR 144 -- cgit