Merge tag 'tty-4.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial fixes from Greg KH:
 "Here are some tty/serial driver fixes for 4.4-rc6 that resolve some
  reported problems.  All of these have been in linux-next.  The details
  are in the shortlog"

* tag 'tty-4.4-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty:
  tty: Fix GPF in flush_to_ldisc()
  serial: earlycon: Add missing spinlock initialization
  serial: sh-sci: Fix length of scatterlist
  n_tty: Fix poll() after buffer-limited eof push read
  serial: 8250_uniphier: fix dl_read and dl_write functions

5 files changed, 19 insertions, 17 deletions

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index ed776149261e..e49c2bce551d 100644
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2054,13 +2054,13 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
         size_t eol;
         size_t tail;
         int ret, found = 0;
-        bool eof_push = 0;
 
         /* N.B. avoid overrun if nr == 0 */
-        n = min(*nr, smp_load_acquire(&ldata->canon_head) - ldata->read_tail);
-        if (!n)
+        if (!*nr)
                 return 0;
 
+        n = min(*nr + 1, smp_load_acquire(&ldata->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);
 
@@ -2081,12 +2081,11 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
         n = eol - tail;
         if (n > N_TTY_BUF_SIZE)
                 n += N_TTY_BUF_SIZE;
-        n += found;
-        c = n;
+        c = n + found;
 
-        if (found && !ldata->push && read_buf(ldata, eol) == __DISABLED_CHAR) {
-                n--;
-                eof_push = !n && ldata->read_tail != ldata->line_start;
+        if (!found || read_buf(ldata, eol) != __DISABLED_CHAR) {
+                c = min(*nr, c);
+                n = c;
         }
 
         n_tty_trace("%s: eol:%zu found:%d n:%zu c:%zu size:%zu more:%zu\n",
@@ -2116,7 +2115,7 @@ static int canon_copy_from_read_buf(struct tty_struct *tty,
                         ldata->push = 0;
                 tty_audit_push(tty);
         }
-        return eof_push ? -EAGAIN : 0;
+        return 0;
 }
 
 extern ssize_t redirected_tty_write(struct file *, const char __user *,
@@ -2273,10 +2272,7 @@ static ssize_t n_tty_read(struct tty_struct *tty, struct file *file,
 
                 if (ldata->icanon && !L_EXTPROC(tty)) {
                         retval = canon_copy_from_read_buf(tty, &b, &nr);
-                        if (retval == -EAGAIN) {
-                                retval = 0;
-                                continue;
-                        } else if (retval)
+                        if (retval)
                                 break;
                 } else {
                         int uncopied;
diff --git a/drivers/tty/serial/8250/8250_uniphier.c b/drivers/tty/serial/8250/8250_uniphier.c
index d11621e2cf1d..245edbb68d4b 100644
--- a/drivers/tty/serial/8250/8250_uniphier.c
+++ b/drivers/tty/serial/8250/8250_uniphier.c
@@ -115,12 +115,16 @@ static void uniphier_serial_out(struct uart_port *p, int offset, int value)
  */
 static int uniphier_serial_dl_read(struct uart_8250_port *up)
 {
-        return readl(up->port.membase + UNIPHIER_UART_DLR);
+        int offset = UNIPHIER_UART_DLR << up->port.regshift;
+
+        return readl(up->port.membase + offset);
 }
 
 static void uniphier_serial_dl_write(struct uart_8250_port *up, int value)
 {
-        writel(value, up->port.membase + UNIPHIER_UART_DLR);
+        int offset = UNIPHIER_UART_DLR << up->port.regshift;
+
+        writel(value, up->port.membase + offset);
 }
 
 static int uniphier_of_serial_setup(struct device *dev, struct uart_port *port,
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
index f09636083426..b5b2f2be6be7 100644
--- a/drivers/tty/serial/earlycon.c
+++ b/drivers/tty/serial/earlycon.c
@@ -115,6 +115,7 @@ static int __init register_earlycon(char *buf, const struct earlycon_id *match)
         if (buf && !parse_options(&early_console_dev, buf))
                 buf = NULL;
 
+        spin_lock_init(&port->lock);
         port->uartclk = BASE_BAUD * 16;
         if (port->mapbase)
                 port->membase = earlycon_map(port->mapbase, 64);
@@ -202,6 +203,7 @@ int __init of_setup_earlycon(unsigned long addr,
         int err;
         struct uart_port *port = &early_console_dev.port;
 
+        spin_lock_init(&port->lock);
         port->iotype = UPIO_MEM;
         port->mapbase = addr;
         port->uartclk = BASE_BAUD * 16;
diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c
index 960e50a97558..51c7507b0444 100644
--- a/drivers/tty/serial/sh-sci.c
+++ b/drivers/tty/serial/sh-sci.c
@@ -1437,7 +1437,7 @@ static void sci_request_dma(struct uart_port *port)
                         sg_init_table(sg, 1);
                         s->rx_buf[i] = buf;
                         sg_dma_address(sg) = dma;
-                        sg->length = s->buf_len_rx;
+                        sg_dma_len(sg) = s->buf_len_rx;
 
                         buf += s->buf_len_rx;
                         dma += s->buf_len_rx;
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c
index 9a479e61791a..3cd31e0d4bd9 100644
--- a/drivers/tty/tty_buffer.c
+++ b/drivers/tty/tty_buffer.c
@@ -450,7 +450,7 @@ receive_buf(struct tty_struct *tty, struct tty_buffer *head, int count)
                 count = disc->ops->receive_buf2(tty, p, f, count);
         else {
                 count = min_t(int, count, tty->receive_room);
-                if (count)
+                if (count && disc->ops->receive_buf)
                         disc->ops->receive_buf(tty, p, f, count);
         }
         return count;