gpiolib: Fix incorrect use of find_next_zero_bit()

Commit b17566a6b08b ("gpiolib: Implement fast processing path in
get/set array"), already fixed to some extent with commit 5d581d7e8cdc
("gpiolib: Fix missing updates of bitmap index"), introduced a new mode
of processing bitmaps where bits applicable for fast bitmap processing
path are supposed to be skipped while iterating bits which don't apply.
Unfortunately, find_next_zero_bit() function supposed to skip over
those fast bits is always called with a 'start' argument equal to an
index of last zero bit found and returns that index value again an
again, causing an infinite loop.

Fix it by incrementing the index uncoditionally before
find_next_zero_bit() is optionally called.

Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Janusz Krzysztofik <jmkrzyszt@gmail.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 4ce402f9fc69247443ff123a3b2111e8635f78d4..a293f14ba75cb34c54a86d901403faa922063a36 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2920,12 +2920,11 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
                        int hwgpio = gpio_chip_hwgpio(desc);
 
                        __set_bit(hwgpio, mask);
+                       i++;
 
                        if (array_info)
                                i = find_next_zero_bit(array_info->get_mask,
                                                       array_size, i);
-                       else
-                               i++;
                } while ((i < array_size) &&
                         (desc_array[i]->gdev->chip == chip));
 
@@ -2945,12 +2944,11 @@ int gpiod_get_array_value_complex(bool raw, bool can_sleep,
                                value = !value;
                        __assign_bit(j, value_bitmap, value);
                        trace_gpio_value(desc_to_gpio(desc), 1, value);
+                       j++;
 
                        if (array_info)
                                j = find_next_zero_bit(array_info->get_mask, i,
                                                       j);
-                       else
-                               j++;
                }
 
                if (mask != fastpath)
@@ -3233,12 +3231,11 @@ int gpiod_set_array_value_complex(bool raw, bool can_sleep,
                                        __clear_bit(hwgpio, bits);
                                count++;
                        }
+                       i++;
 
                        if (array_info)
                                i = find_next_zero_bit(array_info->set_mask,
                                                       array_size, i);
-                       else
-                               i++;
                } while ((i < array_size) &&
                         (desc_array[i]->gdev->chip == chip));
                /* push collected bits to outputs */