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| author | Peter Hurley <peter@hurleysoftware.com> | 2016-04-09 17:53:20 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-04-30 09:26:55 -0700 |
| commit | e4d38f334ad24f80229a8ebab26950de8e8f34d7 (patch) | |
| tree | 700de742e06c9ef1df41d6d79b59a91d095abb4d | |
| parent | 97ef38b8210d7459d4cb51668cdf3983772ac6b7 (diff) | |
| download | linux-e4d38f334ad24f80229a8ebab26950de8e8f34d7.tar.gz linux-e4d38f334ad24f80229a8ebab26950de8e8f34d7.tar.bz2 linux-e4d38f334ad24f80229a8ebab26950de8e8f34d7.zip | |
tty: Define ASYNC_ replacement bits
Prepare for relocating kernel private state bits out of tty_port::flags
field; tty_port::flags field is not atomic and can become corrupted
by concurrent updates. It also suffers from the complication of sharing
in a userspace-visible field which must be masked.
Define new tty_port::iflags field and new, substitute bit definitions
for the former ASYNC_* flags.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/tty.h | 16 | ||||
| -rw-r--r-- | include/uapi/linux/tty_flags.h | 9 |
2 files changed, 23 insertions, 2 deletions
diff --git a/include/linux/tty.h b/include/linux/tty.h index 89f9c91b40f5..4e0dbda05180 100644 --- a/include/linux/tty.h +++ b/include/linux/tty.h @@ -228,7 +228,8 @@ struct tty_port { int count; /* Usage count */ wait_queue_head_t open_wait; /* Open waiters */ wait_queue_head_t delta_msr_wait; /* Modem status change */ - unsigned long flags; /* TTY flags ASY_*/ + unsigned long flags; /* User TTY flags ASYNC_ */ + unsigned long iflags; /* Internal flags TTY_PORT_ */ unsigned char console:1, /* port is a console */ low_latency:1; /* optional: tune for latency */ struct mutex mutex; /* Locking */ @@ -242,6 +243,19 @@ struct tty_port { struct kref kref; /* Ref counter */ }; +/* tty_port::iflags bits -- use atomic bit ops */ +#define TTY_PORT_INITIALIZED 0 /* device is initialized */ +#define TTY_PORT_SUSPENDED 1 /* device is suspended */ +#define TTY_PORT_ACTIVE 2 /* device is open */ + +/* + * uart drivers: use the uart_port::status field and the UPSTAT_* defines + * for s/w-based flow control steering and carrier detection status + */ +#define TTY_PORT_CTS_FLOW 3 /* h/w flow control enabled */ +#define TTY_PORT_CHECK_CD 4 /* carrier detect enabled */ + + /* * Where all of the state associated with a tty is kept while the tty * is open. Since the termios state should be kept even if the tty diff --git a/include/uapi/linux/tty_flags.h b/include/uapi/linux/tty_flags.h index 072e41e45ee2..8e1a4365259f 100644 --- a/include/uapi/linux/tty_flags.h +++ b/include/uapi/linux/tty_flags.h @@ -32,7 +32,12 @@ #define ASYNCB_MAGIC_MULTIPLIER 16 /* Use special CLK or divisor */ #define ASYNCB_LAST_USER 16 -/* Internal flags used only by kernel */ +/* + * Internal flags used only by kernel (read-only) + * + * WARNING: These flags are no longer used and have been superceded by the + * TTY_PORT_ flags in the iflags field (and not userspace-visible) + */ #define ASYNCB_INITIALIZED 31 /* Serial port was initialized */ #define ASYNCB_SUSPENDED 30 /* Serial port is suspended */ #define ASYNCB_NORMAL_ACTIVE 29 /* Normal device is active */ @@ -44,6 +49,7 @@ #define ASYNCB_CONS_FLOW 23 /* flow control for console */ #define ASYNCB_FIRST_KERNEL 22 +/* Masks */ #define ASYNC_HUP_NOTIFY (1U << ASYNCB_HUP_NOTIFY) #define ASYNC_SUSPENDED (1U << ASYNCB_SUSPENDED) #define ASYNC_FOURPORT (1U << ASYNCB_FOURPORT) @@ -72,6 +78,7 @@ #define ASYNC_SPD_WARP (ASYNC_SPD_HI|ASYNC_SPD_SHI) #define ASYNC_SPD_MASK (ASYNC_SPD_HI|ASYNC_SPD_VHI|ASYNC_SPD_SHI) +/* These flags are no longer used (and were always masked from userspace) */ #define ASYNC_INITIALIZED (1U << ASYNCB_INITIALIZED) #define ASYNC_NORMAL_ACTIVE (1U << ASYNCB_NORMAL_ACTIVE) #define ASYNC_BOOT_AUTOCONF (1U << ASYNCB_BOOT_AUTOCONF) |