The code calling brightness_set() can't handle EINTR/ERESTARTSYS well, nor
is it checking brightness_set() return status properly.
Fix it.
Signed-off-by: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
---
drivers/misc/thinkpad_acpi.c | 34 +++++++++++++++++++++-------------
1 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/drivers/misc/thinkpad_acpi.c b/drivers/misc/thinkpad_acpi.c
index 306daa5..8c94307 100644
--- a/drivers/misc/thinkpad_acpi.c
+++ b/drivers/misc/thinkpad_acpi.c
@@ -3278,6 +3278,8 @@ static void brightness_exit(void)
static int brightness_update_status(struct backlight_device *bd)
{
+ /* it is the backlight class's job (caller) to handle
+ * EINTR and other errors properly */
return brightness_set(
(bd->props.fb_blank == FB_BLANK_UNBLANK &&
bd->props.power == FB_BLANK_UNBLANK) ?
@@ -3318,6 +3320,7 @@ static int brightness_get(struct backlight_device *bd)
return level;
}
+/* May return EINTR which can always be mapped to ERESTARTSYS */
static int brightness_set(int value)
{
int cmos_cmd, inc, i, res;
@@ -3381,29 +3384,34 @@ static int brightness_read(char *p)
static int brightness_write(char *buf)
{
int level;
- int new_level;
+ int rc;
char *cmd;
int max_level = (tp_features.bright_16levels) ? 15 : 7;
- while ((cmd = next_cmd(&buf))) {
- if ((level = brightness_get(NULL)) < 0)
- return level;
+ level = brightness_get(NULL);
+ if (level < 0)
+ return level;
+ while ((cmd = next_cmd(&buf))) {
if (strlencmp(cmd, "up") == 0) {
- new_level = level == (max_level)?
- max_level : level + 1;
+ if (level < max_level)
+ level++;
} else if (strlencmp(cmd, "down") == 0) {
- new_level = level == 0? 0 : level - 1;
- } else if (sscanf(cmd, "level %d", &new_level) == 1 &&
- new_level >= 0 && new_level <= max_level) {
- /* new_level set */
+ if (level > 0)
+ level--;
+ } else if (sscanf(cmd, "level %d", &level) == 1 &&
+ level >= 0 && level <= max_level) {
+ /* new level set */
} else
return -EINVAL;
-
- brightness_set(new_level);
}
- return 0;
+ /*
+ * Now we know what the final level should be, so we try to set it.
+ * Doing it this way makes the syscall restartable in case of EINTR
+ */
+ rc = brightness_set(level);
+ return (rc == -EINTR)? ERESTARTSYS : rc;
}
static struct ibm_struct brightness_driver_data = {
--
1.5.3.4
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