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TTY/n_gsm: potential double lock 

In gsm_dlci_data_kick() we call gsm_dlci_data_sweep() with the
"gsm->tx_lock" held so we can't lock it again inside
gsm_dlci_data_sweep().  I removed that lock from and added one to
gsmld_write_wakeup() instead.  The sweep function is only called from
those two places.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Dan Carpenter 2010-05-25 11:37:17 +02:00 committed by Greg Kroah-Hartman
parent e59e2bd9e8
commit 328be395a3
1 changed files with 5 additions and 4 deletions
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9
drivers/char/n_gsm.c
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@ -904,9 +904,7 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
int len;
/* Priority ordering: We should do priority with RR of the groups */
int i = 1;
unsigned long flags;
spin_lock_irqsave(&gsm->tx_lock, flags);
while (i < NUM_DLCI) {
struct gsm_dlci *dlci;
@ -927,7 +925,6 @@ static void gsm_dlci_data_sweep(struct gsm_mux *gsm)
if (len == 0)
i++;
}
spin_unlock_irqrestore(&gsm->tx_lock, flags);
}
/**
@ -2230,12 +2227,16 @@ static int gsmld_open(struct tty_struct *tty)
static void gsmld_write_wakeup(struct tty_struct *tty)
{
struct gsm_mux *gsm = tty->disc_data;
unsigned long flags;
/* Queue poll */
clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
gsm_data_kick(gsm);
if (gsm->tx_bytes < TX_THRESH_LO)
if (gsm->tx_bytes < TX_THRESH_LO) {
spin_lock_irqsave(&gsm->tx_lock, flags);
gsm_dlci_data_sweep(gsm);
spin_unlock_irqrestore(&gsm->tx_lock, flags);
}
}
/**