gpiolib: Fix incorrect use of find_next_zero_bit()

Commit b17566a ("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 <[email protected]> Signed-off-by: Janusz Krzysztofik <[email protected]> Tested-by: Marek Szyprowski <[email protected]> Signed-off-by: Linus Walleij <[email protected]>
dabrace · Oct 1, 2018 · 799d5eb · 799d5eb
1 parent be8c8fa
commit 799d5eb
Showing 1 changed file with 3 additions and 6 deletions.
diff --git 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 */