aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorHugo Villeneuve2023-12-21 18:18:08 -0500
committerGreg Kroah-Hartman2024-01-04 16:30:03 +0100
commit8a1060ce974919f2a79807527ad82ac39336eda2 (patch)
tree764763303a9c162c987c88a603dbd228b89ff406
parent0c2a5f471ce58bca8f8ab5fcb911aff91eaaa5eb (diff)
serial: sc16is7xx: fix invalid sc16is7xx_lines bitfield in case of probe error
If an error occurs during probing, the sc16is7xx_lines bitfield may be left in a state that doesn't represent the correct state of lines allocation. For example, in a system with two SC16 devices, if an error occurs only during probing of channel (port) B of the second device, sc16is7xx_lines final state will be 00001011b instead of the expected 00000011b. This is caused in part because of the "i--" in the for/loop located in the out_ports: error path. Fix this by checking the return value of uart_add_one_port() and set line allocation bit only if this was successful. This allows the refactor of the obfuscated for(i--...) loop in the error path, and properly call uart_remove_one_port() only when needed, and properly unset line allocation bits. Also use same mechanism in remove() when calling uart_remove_one_port(). Fixes: c64349722d14 ("sc16is7xx: support multiple devices") Cc: <stable@vger.kernel.org> Cc: Yury Norov <yury.norov@gmail.com> Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com> Link: https://lore.kernel.org/r/20231221231823.2327894-2-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/tty/serial/sc16is7xx.c44
1 files changed, 18 insertions, 26 deletions
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c
index e40e4a99277e..17b90f971f96 100644
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -407,19 +407,6 @@ static void sc16is7xx_port_update(struct uart_port *port, u8 reg,
regmap_update_bits(one->regmap, reg, mask, val);
}
-static int sc16is7xx_alloc_line(void)
-{
- int i;
-
- BUILD_BUG_ON(SC16IS7XX_MAX_DEVS > BITS_PER_LONG);
-
- for (i = 0; i < SC16IS7XX_MAX_DEVS; i++)
- if (!test_and_set_bit(i, &sc16is7xx_lines))
- break;
-
- return i;
-}
-
static void sc16is7xx_power(struct uart_port *port, int on)
{
sc16is7xx_port_update(port, SC16IS7XX_IER_REG,
@@ -1550,6 +1537,13 @@ static int sc16is7xx_probe(struct device *dev,
SC16IS7XX_IOCONTROL_SRESET_BIT);
for (i = 0; i < devtype->nr_uart; ++i) {
+ s->p[i].port.line = find_first_zero_bit(&sc16is7xx_lines,
+ SC16IS7XX_MAX_DEVS);
+ if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
+ ret = -ERANGE;
+ goto out_ports;
+ }
+
/* Initialize port data */
s->p[i].port.dev = dev;
s->p[i].port.irq = irq;
@@ -1569,14 +1563,8 @@ static int sc16is7xx_probe(struct device *dev,
s->p[i].port.rs485_supported = sc16is7xx_rs485_supported;
s->p[i].port.ops = &sc16is7xx_ops;
s->p[i].old_mctrl = 0;
- s->p[i].port.line = sc16is7xx_alloc_line();
s->p[i].regmap = regmaps[i];
- if (s->p[i].port.line >= SC16IS7XX_MAX_DEVS) {
- ret = -ENOMEM;
- goto out_ports;
- }
-
mutex_init(&s->p[i].efr_lock);
ret = uart_get_rs485_mode(&s->p[i].port);
@@ -1594,8 +1582,13 @@ static int sc16is7xx_probe(struct device *dev,
kthread_init_work(&s->p[i].tx_work, sc16is7xx_tx_proc);
kthread_init_work(&s->p[i].reg_work, sc16is7xx_reg_proc);
kthread_init_delayed_work(&s->p[i].ms_work, sc16is7xx_ms_proc);
+
/* Register port */
- uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
+ ret = uart_add_one_port(&sc16is7xx_uart, &s->p[i].port);
+ if (ret)
+ goto out_ports;
+
+ set_bit(s->p[i].port.line, &sc16is7xx_lines);
/* Enable EFR */
sc16is7xx_port_write(&s->p[i].port, SC16IS7XX_LCR_REG,
@@ -1653,10 +1646,9 @@ static int sc16is7xx_probe(struct device *dev,
#endif
out_ports:
- for (i--; i >= 0; i--) {
- uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
- clear_bit(s->p[i].port.line, &sc16is7xx_lines);
- }
+ for (i = 0; i < devtype->nr_uart; i++)
+ if (test_and_clear_bit(s->p[i].port.line, &sc16is7xx_lines))
+ uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
kthread_stop(s->kworker_task);
@@ -1678,8 +1670,8 @@ static void sc16is7xx_remove(struct device *dev)
for (i = 0; i < s->devtype->nr_uart; i++) {
kthread_cancel_delayed_work_sync(&s->p[i].ms_work);
- uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
- clear_bit(s->p[i].port.line, &sc16is7xx_lines);
+ if (test_and_clear_bit(s->p[i].port.line, &sc16is7xx_lines))
+ uart_remove_one_port(&sc16is7xx_uart, &s->p[i].port);
sc16is7xx_power(&s->p[i].port, 0);
}