diff options
Diffstat (limited to 'drivers/tty/n_tty.c')
| -rw-r--r-- | drivers/tty/n_tty.c | 26 |
1 files changed, 19 insertions, 7 deletions
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index b89308d52ade..9e546d0cc55c 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -2009,21 +2009,22 @@ static bool copy_from_read_buf(struct tty_struct *tty, * read_tail published */ -static void canon_copy_from_read_buf(struct tty_struct *tty, +static bool canon_copy_from_read_buf(struct tty_struct *tty, unsigned char **kbp, size_t *nr) { struct n_tty_data *ldata = tty->disc_data; size_t n, size, more, c; size_t eol; - size_t tail; + size_t tail, canon_head; int found = 0; /* N.B. avoid overrun if nr == 0 */ if (!*nr) - return; + return false; - n = min(*nr + 1, smp_load_acquire(&ldata->canon_head) - ldata->read_tail); + canon_head = smp_load_acquire(&ldata->canon_head); + n = min(*nr + 1, canon_head - ldata->read_tail); tail = ldata->read_tail & (N_TTY_BUF_SIZE - 1); size = min_t(size_t, tail + n, N_TTY_BUF_SIZE); @@ -2067,7 +2068,11 @@ static void canon_copy_from_read_buf(struct tty_struct *tty, else ldata->push = 0; tty_audit_push(); + return false; } + + /* No EOL found - do a continuation retry if there is more data */ + return ldata->read_tail != canon_head; } extern ssize_t redirected_tty_write(struct file *, const char __user *, @@ -2141,8 +2146,13 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, * termios_rwsem, and can just continue to copy data. */ if (*cookie) { - if (copy_from_read_buf(tty, &kb, &nr)) - return kb - kbuf; + if (ldata->icanon && !L_EXTPROC(tty)) { + if (canon_copy_from_read_buf(tty, &kb, &nr)) + return kb - kbuf; + } else { + if (copy_from_read_buf(tty, &kb, &nr)) + return kb - kbuf; + } /* No more data - release locks and stop retries */ n_tty_kick_worker(tty); @@ -2239,7 +2249,8 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, } if (ldata->icanon && !L_EXTPROC(tty)) { - canon_copy_from_read_buf(tty, &kb, &nr); + if (canon_copy_from_read_buf(tty, &kb, &nr)) + goto more_to_be_read; } else { /* Deal with packet mode. */ if (packet && kb == kbuf) { @@ -2257,6 +2268,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file, * will release them when done. */ if (copy_from_read_buf(tty, &kb, &nr) && kb - kbuf >= minimum) { +more_to_be_read: remove_wait_queue(&tty->read_wait, &wait); *cookie = cookie; return kb - kbuf; |