msm: sysmon: Handle races between probe/removal and API calls.
It is possible that clients of the sysmon may call its APIs
before the associated device has probed, after it has been
removed, or while it is in the process of being added or
removed. Handle these scenarios and return -ENODEV when
external APIs are called at illegal times.
(cherry picked from commit 9319017b803cca3fd479e589db3d8d3560e19511)
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
Change-Id: Idb7bfd410957efe63ab4917d9481922de25287c4
Signed-off-by: Neha Pandey <nehap@codeaurora.org>
diff --git a/arch/arm/mach-msm/sysmon.c b/arch/arm/mach-msm/sysmon.c
index 1677713..fc5c3a9 100644
--- a/arch/arm/mach-msm/sysmon.c
+++ b/arch/arm/mach-msm/sysmon.c
@@ -44,6 +44,7 @@
struct completion resp_ready;
char rx_buf[RX_BUF_SIZE];
enum transports transport;
+ struct device *dev;
};
static struct sysmon_subsys subsys[SYSMON_NUM_SS] = {
@@ -139,6 +140,9 @@
char tx_buf[TX_BUF_SIZE];
int ret;
+ if (ss->dev == NULL)
+ return -ENODEV;
+
if (dest_ss < 0 || dest_ss >= SYSMON_NUM_SS ||
notif < 0 || notif >= SUBSYS_NOTIF_TYPE_COUNT ||
event_ss == NULL)
@@ -179,6 +183,9 @@
size_t prefix_len = ARRAY_SIZE(expect) - 1;
int ret;
+ if (ss->dev == NULL)
+ return -ENODEV;
+
if (dest_ss < 0 || dest_ss >= SYSMON_NUM_SS)
return -EINVAL;
@@ -215,6 +222,9 @@
size_t prefix_len = ARRAY_SIZE(expect) - 1;
int ret;
+ if (ss->dev == NULL)
+ return -ENODEV;
+
if (dest_ss < 0 || dest_ss >= SYSMON_NUM_SS ||
buf == NULL || len == 0)
return -EINVAL;
@@ -301,6 +311,7 @@
default:
return -EINVAL;
}
+ ss->dev = &pdev->dev;
return 0;
}
@@ -309,6 +320,9 @@
{
struct sysmon_subsys *ss = &subsys[pdev->id];
+ ss->dev = NULL;
+
+ mutex_lock(&ss->lock);
switch (ss->transport) {
case TRANSPORT_SMD:
smd_close(ss->chan);
@@ -317,6 +331,7 @@
hsic_sysmon_close(HSIC_SYSMON_DEV_EXT_MODEM);
break;
}
+ mutex_unlock(&ss->lock);
return 0;
}