Differential D24459 Diff 147476 sys/kern/tty_outq.c

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sys/kern/tty_outq.c

Show First 20 Lines • Show All 87 Lines • ▼ Show 20 Lines	ttyoutq_flush(struct ttyoutq *to)
to->to_end = 0;		to->to_end = 0;
}		}

int		int
ttyoutq_setsize(struct ttyoutq to, struct tty tp, size_t size)		ttyoutq_setsize(struct ttyoutq to, struct tty tp, size_t size)
{		{
struct ttyoutq_block *tob;		struct ttyoutq_block *tob;

		tty_assert_locked(tp);
		ttydisc_assert_locked(tp);
to->to_quota = howmany(size, TTYOUTQ_DATASIZE);		to->to_quota = howmany(size, TTYOUTQ_DATASIZE);

while (to->to_quota > to->to_nblocks) {		while (to->to_quota > to->to_nblocks) {
/*		/*
* List is getting bigger.		* List is getting bigger.
* Add new blocks to the tail of the list.		* Add new blocks to the tail of the list.
*		*
* We must unlock the TTY temporarily, because we need		* We must unlock the ttydisc, but we're still holding on to
* to allocate memory. This won't be a problem, because		* the tty lock so we should avoid problems.
* in the worst case, another thread ends up here, which
* may cause us to allocate too many blocks, but this
* will be caught by the loop below.
*/		*/
tty_unlock(tp);		ttydisc_unlock(tp);
tob = uma_zalloc(ttyoutq_zone, M_WAITOK);		tob = uma_zalloc(ttyoutq_zone, M_WAITOK);
tty_lock(tp);		ttydisc_lock(tp);

if (tty_gone(tp)) {
uma_zfree(ttyoutq_zone, tob);
return (ENXIO);
}

TTYOUTQ_INSERT_TAIL(to, tob);		TTYOUTQ_INSERT_TAIL(to, tob);
}		}
return (0);		return (0);
}		}

void		void
ttyoutq_free(struct ttyoutq *to)		ttyoutq_free(struct ttyoutq *to)
{		{
▲ Show 20 Lines • Show All 70 Lines • ▼ Show 20 Lines
* back to the user, because we temporarily remove the block from the		* back to the user, because we temporarily remove the block from the
* queue. Otherwise we need to copy it to a temporary buffer first, to		* queue. Otherwise we need to copy it to a temporary buffer first, to
* make sure data remains in the correct order.		* make sure data remains in the correct order.
*/		*/
int		int
ttyoutq_read_uio(struct ttyoutq to, struct tty tp, struct uio *uio)		ttyoutq_read_uio(struct ttyoutq to, struct tty tp, struct uio *uio)
{		{

		ttydisc_assert_locked(tp);
while (uio->uio_resid > 0) {		while (uio->uio_resid > 0) {
int error;		int error;
struct ttyoutq_block *tob;		struct ttyoutq_block *tob;
size_t cbegin, cend, clen;		size_t cbegin, cend, clen;

/* See if there still is data. */		/* See if there still is data. */
if (to->to_begin == to->to_end)		if (to->to_begin == to->to_end)
return (0);		return (0);
Show All 27 Lines	if (cend == TTYOUTQ_DATASIZE \|\| cend == to->to_end) {
TTYOUTQ_REMOVE_HEAD(to);		TTYOUTQ_REMOVE_HEAD(to);
to->to_begin = 0;		to->to_begin = 0;
if (to->to_end <= TTYOUTQ_DATASIZE)		if (to->to_end <= TTYOUTQ_DATASIZE)
to->to_end = 0;		to->to_end = 0;
else		else
to->to_end -= TTYOUTQ_DATASIZE;		to->to_end -= TTYOUTQ_DATASIZE;

/* Temporary unlock and copy the data to userspace. */		/* Temporary unlock and copy the data to userspace. */
tty_unlock(tp);		ttydisc_unlock(tp);
error = uiomove(tob->tob_data + cbegin, clen, uio);		error = uiomove(tob->tob_data + cbegin, clen, uio);
tty_lock(tp);		ttydisc_lock(tp);

/* Block can now be readded to the list. */		/* Block can now be readded to the list. */
TTYOUTQ_RECYCLE(to, tob);		TTYOUTQ_RECYCLE(to, tob);
} else {		} else {
char ob[TTYOUTQ_DATASIZE - 1];		char ob[TTYOUTQ_DATASIZE - 1];

/*		/*
* Slow path: store data in a temporary buffer.		* Slow path: store data in a temporary buffer.
*/		*/
memcpy(ob, tob->tob_data + cbegin, clen);		memcpy(ob, tob->tob_data + cbegin, clen);
to->to_begin += clen;		to->to_begin += clen;
MPASS(to->to_begin < TTYOUTQ_DATASIZE);		MPASS(to->to_begin < TTYOUTQ_DATASIZE);

/* Temporary unlock and copy the data to userspace. */		/* Temporary unlock and copy the data to userspace. */
tty_unlock(tp);		ttydisc_unlock(tp);
error = uiomove(ob, clen, uio);		error = uiomove(ob, clen, uio);
tty_lock(tp);		ttydisc_lock(tp);
}		}

if (error != 0)		if (error != 0)
return (error);		return (error);
}		}

return (0);		return (0);
}		}
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