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| author | Peter Hurley <peter@hurleysoftware.com> | 2014-11-05 12:12:55 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-05 18:41:22 -0800 |
| commit | deb287e7401bbbf7803731805acbda1d983d1999 (patch) | |
| tree | a190857e293df1c08a6627b8c9a42f5e5f6ddbcc /drivers/tty/tty_io.c | |
| parent | d5e370a4eeb701201bd441b4ec089091dd6f2ce0 (diff) | |
| download | lwn-deb287e7401bbbf7803731805acbda1d983d1999.tar.gz lwn-deb287e7401bbbf7803731805acbda1d983d1999.zip | |
tty: Document check_tty_count() requires tty_lock held
Holding the tty_lock() is necessary to prevent concurrent changes
to the tty count that may cause it to differ from the open file
list count. The tty_lock() is already held at all call sites.
NB: Note that the check for the pty master tty count is safe because
the slave's tty_lock() is held while decrementing the pty master
tty count.
Reviewed-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/tty_io.c')
| -rw-r--r-- | drivers/tty/tty_io.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c index b008e2b38d54..adbd9acf817f 100644 --- a/drivers/tty/tty_io.c +++ b/drivers/tty/tty_io.c @@ -275,6 +275,7 @@ int tty_paranoia_check(struct tty_struct *tty, struct inode *inode, return 0; } +/* Caller must hold tty_lock */ static int check_tty_count(struct tty_struct *tty, const char *routine) { #ifdef CHECK_TTY_COUNT |