according to http://lwn.net/Articles/167034/ binary semaphores (which aren't given in interrupt context or locked/unlocked in different process contexts) should be converted to the new mutex API. this patch converts the semaphore used by the Smart Battery System ACPI interface driver to a mutex. please let me know your comments if i misinterpreted the article or if you see something wrong in the patch -- Smart Battery System ACPI driver: convert binary semaphore to mutex Signed-off-by: Matthias Kaehlcke <matthias.kaehlcke@xxxxxxxxx> -- diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c index 59640d9..7e90132 100644 --- a/drivers/acpi/sbs.c +++ b/drivers/acpi/sbs.c @@ -32,6 +32,7 @@ #include <linux/acpi.h> #include <linux/i2c.h> #include <linux/delay.h> +#include <linux/mutex.h> #include "i2c_ec.h" @@ -83,7 +84,7 @@ MODULE_AUTHOR("Rich Townsend"); MODULE_DESCRIPTION("Smart Battery System ACPI interface driver"); MODULE_LICENSE("GPL"); -static struct semaphore sbs_sem; +static DEFINE_MUTEX(sbs_mutex); #define UPDATE_MODE QUEUE_UPDATE_MODE /* REQUEST_UPDATE_MODE QUEUE_UPDATE_MODE */ @@ -930,7 +931,7 @@ static int acpi_battery_read_info(struct seq_file *seq, void *offset) return -ENODEV; } - down(&sbs_sem); + mutex_lock(&sbs_mutex); if (update_mode == REQUEST_UPDATE_MODE) { result = acpi_sbs_update_run(battery->sbs, DATA_TYPE_INFO); @@ -984,7 +985,7 @@ static int acpi_battery_read_info(struct seq_file *seq, void *offset) end: - up(&sbs_sem); + mutex_unlock(&sbs_mutex); return result; } @@ -1005,7 +1006,7 @@ static int acpi_battery_read_state(struct seq_file *seq, void *offset) return -ENODEV; } - down(&sbs_sem); + mutex_lock(&sbs_mutex); if (update_mode == REQUEST_UPDATE_MODE) { result = acpi_sbs_update_run(battery->sbs, DATA_TYPE_STATE); @@ -1061,7 +1062,7 @@ static int acpi_battery_read_state(struct seq_file *seq, void *offset) end: - up(&sbs_sem); + mutex_unlock(&sbs_mutex); return result; } @@ -1081,7 +1082,7 @@ static int acpi_battery_read_alarm(struct seq_file *seq, void *offset) return -ENODEV; } - down(&sbs_sem); + mutex_lock(&sbs_mutex); if (update_mode == REQUEST_UPDATE_MODE) { result = acpi_sbs_update_run(battery->sbs, DATA_TYPE_ALARM); @@ -1113,7 +1114,7 @@ static int acpi_battery_read_alarm(struct seq_file *seq, void *offset) end: - up(&sbs_sem); + mutex_unlock(&sbs_mutex); return result; } @@ -1131,7 +1132,7 @@ acpi_battery_write_alarm(struct file *file, const char __user * buffer, return -ENODEV; } - down(&sbs_sem); + mutex_lock(&sbs_mutex); if (!acpi_battery_is_present(battery)) { result = -ENODEV; @@ -1169,7 +1170,7 @@ acpi_battery_write_alarm(struct file *file, const char __user * buffer, } end: - up(&sbs_sem); + mutex_unlock(&sbs_mutex); if (result) { return result; @@ -1221,7 +1222,7 @@ static int acpi_ac_read_state(struct seq_file *seq, void *offset) return -ENODEV; } - down(&sbs_sem); + mutex_lock(&sbs_mutex); if (update_mode == REQUEST_UPDATE_MODE) { result = acpi_sbs_update_run(sbs, DATA_TYPE_AC_STATE); @@ -1234,7 +1235,7 @@ static int acpi_ac_read_state(struct seq_file *seq, void *offset) seq_printf(seq, "state: %s\n", sbs->ac_present ? "on-line" : "off-line"); - up(&sbs_sem); + mutex_unlock(&sbs_mutex); return 0; } @@ -1719,8 +1720,6 @@ static int __init acpi_sbs_init(void) if (acpi_disabled) return -ENODEV; - init_MUTEX(&sbs_sem); - if (capacity_mode != DEF_CAPACITY_UNIT && capacity_mode != MAH_CAPACITY_UNIT && capacity_mode != MWH_CAPACITY_UNIT) { -- Matthias Kaehlcke Linux Application Developer Barcelona Anyone who has never made a mistake has never tried anything new (Albert Einstein) .''`. using free software / Debian GNU/Linux | http://debian.org : :' : `. `'` gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4 `- - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
