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Subject[PATCH] hwmon: (occ) Fix poll rate limiting
Date
The poll rate limiter time was initialized at zero. This breaks the
comparison in time_after if jiffies is large. Switch to storing the
next update time rather than the previous time, and initialize the
time when the device is probed.

Fixes: c10e753d43eb ("hwmon (occ): Add sensor types and versions")
Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
drivers/hwmon/occ/common.c | 5 +++--
drivers/hwmon/occ/common.h | 2 +-
2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
index f1ac153d0b56..967532afb1c0 100644
--- a/drivers/hwmon/occ/common.c
+++ b/drivers/hwmon/occ/common.c
@@ -217,9 +217,9 @@ int occ_update_response(struct occ *occ)
return rc;

/* limit the maximum rate of polling the OCC */
- if (time_after(jiffies, occ->last_update + OCC_UPDATE_FREQUENCY)) {
+ if (time_after(jiffies, occ->next_update)) {
rc = occ_poll(occ);
- occ->last_update = jiffies;
+ occ->next_update = jiffies + OCC_UPDATE_FREQUENCY;
} else {
rc = occ->last_error;
}
@@ -1165,6 +1165,7 @@ int occ_setup(struct occ *occ, const char *name)
return rc;
}

+ occ->next_update = jiffies + OCC_UPDATE_FREQUENCY;
occ_parse_poll_response(occ);

rc = occ_setup_sensor_attrs(occ);
diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h
index 67e6968b8978..e6df719770e8 100644
--- a/drivers/hwmon/occ/common.h
+++ b/drivers/hwmon/occ/common.h
@@ -99,7 +99,7 @@ struct occ {
u8 poll_cmd_data; /* to perform OCC poll command */
int (*send_cmd)(struct occ *occ, u8 *cmd);

- unsigned long last_update;
+ unsigned long next_update;
struct mutex lock; /* lock OCC access */

struct device *hwmon;
--
2.27.0
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