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-rw-r--r--drivers/hwtracing/stm/Kconfig16
-rw-r--r--drivers/hwtracing/stm/Makefile2
-rw-r--r--drivers/hwtracing/stm/core.c175
-rw-r--r--drivers/hwtracing/stm/dummy_stm.c71
-rw-r--r--drivers/hwtracing/stm/heartbeat.c130
-rw-r--r--drivers/hwtracing/stm/policy.c25
-rw-r--r--drivers/hwtracing/stm/stm.h2
7 files changed, 367 insertions, 54 deletions
diff --git a/drivers/hwtracing/stm/Kconfig b/drivers/hwtracing/stm/Kconfig
index 83e9f591a54b..847a39b35307 100644
--- a/drivers/hwtracing/stm/Kconfig
+++ b/drivers/hwtracing/stm/Kconfig
@@ -1,6 +1,7 @@
config STM
tristate "System Trace Module devices"
select CONFIGFS_FS
+ select SRCU
help
A System Trace Module (STM) is a device exporting data in System
Trace Protocol (STP) format as defined by MIPI STP standards.
@@ -8,6 +9,8 @@ config STM
Say Y here to enable System Trace Module device support.
+if STM
+
config STM_DUMMY
tristate "Dummy STM driver"
help
@@ -24,3 +27,16 @@ config STM_SOURCE_CONSOLE
If you want to send kernel console messages over STM devices,
say Y.
+
+config STM_SOURCE_HEARTBEAT
+ tristate "Heartbeat over STM devices"
+ help
+ This is a kernel space trace source that sends periodic
+ heartbeat messages to trace hosts over STM devices. It is
+ also useful for testing stm class drivers and the stm class
+ framework itself.
+
+ If you want to send heartbeat messages over STM devices,
+ say Y.
+
+endif
diff --git a/drivers/hwtracing/stm/Makefile b/drivers/hwtracing/stm/Makefile
index f9312c38dd7a..a9ce3d487e57 100644
--- a/drivers/hwtracing/stm/Makefile
+++ b/drivers/hwtracing/stm/Makefile
@@ -5,5 +5,7 @@ stm_core-y := core.o policy.o
obj-$(CONFIG_STM_DUMMY) += dummy_stm.o
obj-$(CONFIG_STM_SOURCE_CONSOLE) += stm_console.o
+obj-$(CONFIG_STM_SOURCE_HEARTBEAT) += stm_heartbeat.o
stm_console-y := console.o
+stm_heartbeat-y := heartbeat.o
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index b6445d9e5453..de80d45d8df9 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -113,6 +113,7 @@ struct stm_device *stm_find_device(const char *buf)
stm = to_stm_device(dev);
if (!try_module_get(stm->owner)) {
+ /* matches class_find_device() above */
put_device(dev);
return NULL;
}
@@ -125,7 +126,7 @@ struct stm_device *stm_find_device(const char *buf)
* @stm: stm device, previously acquired by stm_find_device()
*
* This drops the module reference and device reference taken by
- * stm_find_device().
+ * stm_find_device() or stm_char_open().
*/
void stm_put_device(struct stm_device *stm)
{
@@ -185,6 +186,9 @@ static void stm_output_claim(struct stm_device *stm, struct stm_output *output)
{
struct stp_master *master = stm_master(stm, output->master);
+ lockdep_assert_held(&stm->mc_lock);
+ lockdep_assert_held(&output->lock);
+
if (WARN_ON_ONCE(master->nr_free < output->nr_chans))
return;
@@ -199,6 +203,9 @@ stm_output_disclaim(struct stm_device *stm, struct stm_output *output)
{
struct stp_master *master = stm_master(stm, output->master);
+ lockdep_assert_held(&stm->mc_lock);
+ lockdep_assert_held(&output->lock);
+
bitmap_release_region(&master->chan_map[0], output->channel,
ilog2(output->nr_chans));
@@ -233,7 +240,7 @@ static int find_free_channels(unsigned long *bitmap, unsigned int start,
return -1;
}
-static unsigned int
+static int
stm_find_master_chan(struct stm_device *stm, unsigned int width,
unsigned int *mstart, unsigned int mend,
unsigned int *cstart, unsigned int cend)
@@ -288,12 +295,13 @@ static int stm_output_assign(struct stm_device *stm, unsigned int width,
}
spin_lock(&stm->mc_lock);
+ spin_lock(&output->lock);
/* output is already assigned -- shouldn't happen */
if (WARN_ON_ONCE(output->nr_chans))
goto unlock;
ret = stm_find_master_chan(stm, width, &midx, mend, &cidx, cend);
- if (ret)
+ if (ret < 0)
goto unlock;
output->master = midx;
@@ -304,6 +312,7 @@ static int stm_output_assign(struct stm_device *stm, unsigned int width,
ret = 0;
unlock:
+ spin_unlock(&output->lock);
spin_unlock(&stm->mc_lock);
return ret;
@@ -312,11 +321,18 @@ unlock:
static void stm_output_free(struct stm_device *stm, struct stm_output *output)
{
spin_lock(&stm->mc_lock);
+ spin_lock(&output->lock);
if (output->nr_chans)
stm_output_disclaim(stm, output);
+ spin_unlock(&output->lock);
spin_unlock(&stm->mc_lock);
}
+static void stm_output_init(struct stm_output *output)
+{
+ spin_lock_init(&output->lock);
+}
+
static int major_match(struct device *dev, const void *data)
{
unsigned int major = *(unsigned int *)data;
@@ -339,6 +355,7 @@ static int stm_char_open(struct inode *inode, struct file *file)
if (!stmf)
return -ENOMEM;
+ stm_output_init(&stmf->output);
stmf->stm = to_stm_device(dev);
if (!try_module_get(stmf->stm->owner))
@@ -349,6 +366,8 @@ static int stm_char_open(struct inode *inode, struct file *file)
return nonseekable_open(inode, file);
err_free:
+ /* matches class_find_device() above */
+ put_device(dev);
kfree(stmf);
return err;
@@ -357,9 +376,19 @@ err_free:
static int stm_char_release(struct inode *inode, struct file *file)
{
struct stm_file *stmf = file->private_data;
+ struct stm_device *stm = stmf->stm;
+
+ if (stm->data->unlink)
+ stm->data->unlink(stm->data, stmf->output.master,
+ stmf->output.channel);
- stm_output_free(stmf->stm, &stmf->output);
- stm_put_device(stmf->stm);
+ stm_output_free(stm, &stmf->output);
+
+ /*
+ * matches the stm_char_open()'s
+ * class_find_device() + try_module_get()
+ */
+ stm_put_device(stm);
kfree(stmf);
return 0;
@@ -380,8 +409,8 @@ static int stm_file_assign(struct stm_file *stmf, char *id, unsigned int width)
return ret;
}
-static void stm_write(struct stm_data *data, unsigned int master,
- unsigned int channel, const char *buf, size_t count)
+static ssize_t stm_write(struct stm_data *data, unsigned int master,
+ unsigned int channel, const char *buf, size_t count)
{
unsigned int flags = STP_PACKET_TIMESTAMPED;
const unsigned char *p = buf, nil = 0;
@@ -393,9 +422,14 @@ static void stm_write(struct stm_data *data, unsigned int master,
sz = data->packet(data, master, channel, STP_PACKET_DATA, flags,
sz, p);
flags = 0;
+
+ if (sz < 0)
+ break;
}
data->packet(data, master, channel, STP_PACKET_FLAG, 0, 0, &nil);
+
+ return pos;
}
static ssize_t stm_char_write(struct file *file, const char __user *buf,
@@ -406,6 +440,9 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf,
char *kbuf;
int err;
+ if (count + 1 > PAGE_SIZE)
+ count = PAGE_SIZE - 1;
+
/*
* if no m/c have been assigned to this writer up to this
* point, use "default" policy entry
@@ -430,8 +467,8 @@ static ssize_t stm_char_write(struct file *file, const char __user *buf,
return -EFAULT;
}
- stm_write(stm->data, stmf->output.master, stmf->output.channel, kbuf,
- count);
+ count = stm_write(stm->data, stmf->output.master, stmf->output.channel,
+ kbuf, count);
kfree(kbuf);
@@ -515,10 +552,8 @@ static int stm_char_policy_set_ioctl(struct stm_file *stmf, void __user *arg)
ret = stm->data->link(stm->data, stmf->output.master,
stmf->output.channel);
- if (ret) {
+ if (ret)
stm_output_free(stmf->stm, &stmf->output);
- stm_put_device(stmf->stm);
- }
err_free:
kfree(id);
@@ -618,7 +653,7 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data,
if (!stm_data->packet || !stm_data->sw_nchannels)
return -EINVAL;
- nmasters = stm_data->sw_end - stm_data->sw_start;
+ nmasters = stm_data->sw_end - stm_data->sw_start + 1;
stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
if (!stm)
return -ENOMEM;
@@ -641,6 +676,7 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data,
if (err)
goto err_device;
+ mutex_init(&stm->link_mutex);
spin_lock_init(&stm->link_lock);
INIT_LIST_HEAD(&stm->link_list);
@@ -654,6 +690,7 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data,
return 0;
err_device:
+ /* matches device_initialize() above */
put_device(&stm->dev);
err_free:
kfree(stm);
@@ -662,20 +699,28 @@ err_free:
}
EXPORT_SYMBOL_GPL(stm_register_device);
-static void __stm_source_link_drop(struct stm_source_device *src,
- struct stm_device *stm);
+static int __stm_source_link_drop(struct stm_source_device *src,
+ struct stm_device *stm);
void stm_unregister_device(struct stm_data *stm_data)
{
struct stm_device *stm = stm_data->stm;
struct stm_source_device *src, *iter;
- int i;
+ int i, ret;
- spin_lock(&stm->link_lock);
+ mutex_lock(&stm->link_mutex);
list_for_each_entry_safe(src, iter, &stm->link_list, link_entry) {
- __stm_source_link_drop(src, stm);
+ ret = __stm_source_link_drop(src, stm);
+ /*
+ * src <-> stm link must not change under the same
+ * stm::link_mutex, so complain loudly if it has;
+ * also in this situation ret!=0 means this src is
+ * not connected to this stm and it should be otherwise
+ * safe to proceed with the tear-down of stm.
+ */
+ WARN_ON_ONCE(ret);
}
- spin_unlock(&stm->link_lock);
+ mutex_unlock(&stm->link_mutex);
synchronize_srcu(&stm_source_srcu);
@@ -686,7 +731,7 @@ void stm_unregister_device(struct stm_data *stm_data)
stp_policy_unbind(stm->policy);
mutex_unlock(&stm->policy_mutex);
- for (i = 0; i < stm->sw_nmasters; i++)
+ for (i = stm->data->sw_start; i <= stm->data->sw_end; i++)
stp_master_free(stm, i);
device_unregister(&stm->dev);
@@ -694,6 +739,17 @@ void stm_unregister_device(struct stm_data *stm_data)
}
EXPORT_SYMBOL_GPL(stm_unregister_device);
+/*
+ * stm::link_list access serialization uses a spinlock and a mutex; holding
+ * either of them guarantees that the list is stable; modification requires
+ * holding both of them.
+ *
+ * Lock ordering is as follows:
+ * stm::link_mutex
+ * stm::link_lock
+ * src::link_lock
+ */
+
/**
* stm_source_link_add() - connect an stm_source device to an stm device
* @src: stm_source device
@@ -710,6 +766,7 @@ static int stm_source_link_add(struct stm_source_device *src,
char *id;
int err;
+ mutex_lock(&stm->link_mutex);
spin_lock(&stm->link_lock);
spin_lock(&src->link_lock);
@@ -719,6 +776,7 @@ static int stm_source_link_add(struct stm_source_device *src,
spin_unlock(&src->link_lock);
spin_unlock(&stm->link_lock);
+ mutex_unlock(&stm->link_mutex);
id = kstrdup(src->data->name, GFP_KERNEL);
if (id) {
@@ -753,9 +811,9 @@ static int stm_source_link_add(struct stm_source_device *src,
fail_free_output:
stm_output_free(stm, &src->output);
- stm_put_device(stm);
fail_detach:
+ mutex_lock(&stm->link_mutex);
spin_lock(&stm->link_lock);
spin_lock(&src->link_lock);
@@ -764,6 +822,7 @@ fail_detach:
spin_unlock(&src->link_lock);
spin_unlock(&stm->link_lock);
+ mutex_unlock(&stm->link_mutex);
return err;
}
@@ -776,28 +835,55 @@ fail_detach:
* If @stm is @src::link, disconnect them from one another and put the
* reference on the @stm device.
*
- * Caller must hold stm::link_lock.
+ * Caller must hold stm::link_mutex.
*/
-static void __stm_source_link_drop(struct stm_source_device *src,
- struct stm_device *stm)
+static int __stm_source_link_drop(struct stm_source_device *src,
+ struct stm_device *stm)
{
struct stm_device *link;
+ int ret = 0;
+
+ lockdep_assert_held(&stm->link_mutex);
+ /* for stm::link_list modification, we hold both mutex and spinlock */
+ spin_lock(&stm->link_lock);
spin_lock(&src->link_lock);
link = srcu_dereference_check(src->link, &stm_source_srcu, 1);
- if (WARN_ON_ONCE(link != stm)) {
- spin_unlock(&src->link_lock);
- return;
+
+ /*
+ * The linked device may have changed since we last looked, because
+ * we weren't holding the src::link_lock back then; if this is the
+ * case, tell the caller to retry.
+ */
+ if (link != stm) {
+ ret = -EAGAIN;
+ goto unlock;
}
stm_output_free(link, &src->output);
- /* caller must hold stm::link_lock */
list_del_init(&src->link_entry);
/* matches stm_find_device() from stm_source_link_store() */
stm_put_device(link);
rcu_assign_pointer(src->link, NULL);
+unlock:
spin_unlock(&src->link_lock);
+ spin_unlock(&stm->link_lock);
+
+ /*
+ * Call the unlink callbacks for both source and stm, when we know
+ * that we have actually performed the unlinking.
+ */
+ if (!ret) {
+ if (src->data->unlink)
+ src->data->unlink(src->data);
+
+ if (stm->data->unlink)
+ stm->data->unlink(stm->data, src->output.master,
+ src->output.channel);
+ }
+
+ return ret;
}
/**
@@ -813,21 +899,29 @@ static void __stm_source_link_drop(struct stm_source_device *src,
static void stm_source_link_drop(struct stm_source_device *src)
{
struct stm_device *stm;
- int idx;
+ int idx, ret;
+retry:
idx = srcu_read_lock(&stm_source_srcu);
+ /*
+ * The stm device will be valid for the duration of this
+ * read section, but the link may change before we grab
+ * the src::link_lock in __stm_source_link_drop().
+ */
stm = srcu_dereference(src->link, &stm_source_srcu);
+ ret = 0;
if (stm) {
- if (src->data->unlink)
- src->data->unlink(src->data);
-
- spin_lock(&stm->link_lock);
- __stm_source_link_drop(src, stm);
- spin_unlock(&stm->link_lock);
+ mutex_lock(&stm->link_mutex);
+ ret = __stm_source_link_drop(src, stm);
+ mutex_unlock(&stm->link_mutex);
}
srcu_read_unlock(&stm_source_srcu, idx);
+
+ /* if it did change, retry */
+ if (ret == -EAGAIN)
+ goto retry;
}
static ssize_t stm_source_link_show(struct device *dev,
@@ -862,8 +956,10 @@ static ssize_t stm_source_link_store(struct device *dev,
return -EINVAL;
err = stm_source_link_add(src, link);
- if (err)
+ if (err) {
+ /* matches the stm_find_device() above */
stm_put_device(link);
+ }
return err ? : count;
}
@@ -925,6 +1021,7 @@ int stm_source_register_device(struct device *parent,
if (err)
goto err;
+ stm_output_init(&src->output);
spin_lock_init(&src->link_lock);
INIT_LIST_HEAD(&src->link_entry);
src->data = data;
@@ -973,9 +1070,9 @@ int stm_source_write(struct stm_source_data *data, unsigned int chan,
stm = srcu_dereference(src->link, &stm_source_srcu);
if (stm)
- stm_write(stm->data, src->output.master,
- src->output.channel + chan,
- buf, count);
+ count = stm_write(stm->data, src->output.master,
+ src->output.channel + chan,
+ buf, count);
else
count = -ENODEV;
diff --git a/drivers/hwtracing/stm/dummy_stm.c b/drivers/hwtracing/stm/dummy_stm.c
index 3709bef0b21f..310adf57e7a1 100644
--- a/drivers/hwtracing/stm/dummy_stm.c
+++ b/drivers/hwtracing/stm/dummy_stm.c
@@ -40,22 +40,75 @@ dummy_stm_packet(struct stm_data *stm_data, unsigned int master,
return size;
}
-static struct stm_data dummy_stm = {
- .name = "dummy_stm",
- .sw_start = 0x0000,
- .sw_end = 0xffff,
- .sw_nchannels = 0xffff,
- .packet = dummy_stm_packet,
-};
+#define DUMMY_STM_MAX 32
+
+static struct stm_data dummy_stm[DUMMY_STM_MAX];
+
+static int nr_dummies = 4;
+
+module_param(nr_dummies, int, 0600);
+
+static unsigned int dummy_stm_nr;
+
+static unsigned int fail_mode;
+
+module_param(fail_mode, int, 0600);
+
+static int dummy_stm_link(struct stm_data *data, unsigned int master,
+ unsigned int channel)
+{
+ if (fail_mode && (channel & fail_mode))
+ return -EINVAL;
+
+ return 0;
+}
static int dummy_stm_init(void)
{
- return stm_register_device(NULL, &dummy_stm, THIS_MODULE);
+ int i, ret = -ENOMEM, __nr_dummies = ACCESS_ONCE(nr_dummies);
+
+ if (__nr_dummies < 0 || __nr_dummies > DUMMY_STM_MAX)
+ return -EINVAL;
+
+ for (i = 0; i < __nr_dummies; i++) {
+ dummy_stm[i].name = kasprintf(GFP_KERNEL, "dummy_stm.%d", i);
+ if (!dummy_stm[i].name)
+ goto fail_unregister;
+
+ dummy_stm[i].sw_start = 0x0000;
+ dummy_stm[i].sw_end = 0xffff;
+ dummy_stm[i].sw_nchannels = 0xffff;
+ dummy_stm[i].packet = dummy_stm_packet;
+ dummy_stm[i].link = dummy_stm_link;
+
+ ret = stm_register_device(NULL, &dummy_stm[i], THIS_MODULE);
+ if (ret)
+ goto fail_free;
+ }
+
+ dummy_stm_nr = __nr_dummies;
+
+ return 0;
+
+fail_unregister:
+ for (i--; i >= 0; i--) {
+ stm_unregister_device(&dummy_stm[i]);
+fail_free:
+ kfree(dummy_stm[i].name);
+ }
+
+ return ret;
+
}
static void dummy_stm_exit(void)
{
- stm_unregister_device(&dummy_stm);
+ int i;
+
+ for (i = 0; i < dummy_stm_nr; i++) {
+ stm_unregister_device(&dummy_stm[i]);
+ kfree(dummy_stm[i].name);
+ }
}
module_init(dummy_stm_init);
diff --git a/drivers/hwtracing/stm/heartbeat.c b/drivers/hwtracing/stm/heartbeat.c
new file mode 100644
index 000000000000..0133571b506f
--- /dev/null
+++ b/drivers/hwtracing/stm/heartbeat.c
@@ -0,0 +1,130 @@
+/*
+ * Simple heartbeat STM source driver
+ * Copyright (c) 2016, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * Heartbeat STM source will send repetitive messages over STM devices to a
+ * trace host.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/hrtimer.h>
+#include <linux/slab.h>
+#include <linux/stm.h>
+
+#define STM_HEARTBEAT_MAX 32
+
+static int nr_devs = 4;
+static int interval_ms = 10;
+
+module_param(nr_devs, int, 0600);
+module_param(interval_ms, int, 0600);
+
+static struct stm_heartbeat {
+ struct stm_source_data data;
+ struct hrtimer hrtimer;
+ unsigned int active;
+} stm_heartbeat[STM_HEARTBEAT_MAX];
+
+static unsigned int nr_instances;
+
+static const char str[] = "heartbeat stm source driver is here to serve you";
+
+static enum hrtimer_restart stm_heartbeat_hrtimer_handler(struct hrtimer *hr)
+{
+ struct stm_heartbeat *heartbeat = container_of(hr, struct stm_heartbeat,
+ hrtimer);
+
+ stm_source_write(&heartbeat->data, 0, str, sizeof str);
+ if (heartbeat->active)
+ hrtimer_forward_now(hr, ms_to_ktime(interval_ms));
+
+ return heartbeat->active ? HRTIMER_RESTART : HRTIMER_NORESTART;
+}
+
+static int stm_heartbeat_link(struct stm_source_data *data)
+{
+ struct stm_heartbeat *heartbeat =
+ container_of(data, struct stm_heartbeat, data);
+
+ heartbeat->active = 1;
+ hrtimer_start(&heartbeat->hrtimer, ms_to_ktime(interval_ms),
+ HRTIMER_MODE_ABS);
+
+ return 0;
+}
+
+static void stm_heartbeat_unlink(struct stm_source_data *data)
+{
+ struct stm_heartbeat *heartbeat =
+ container_of(data, struct stm_heartbeat, data);
+
+ heartbeat->active = 0;
+ hrtimer_cancel(&heartbeat->hrtimer);
+}
+
+static int stm_heartbeat_init(void)
+{
+ int i, ret = -ENOMEM, __nr_instances = ACCESS_ONCE(nr_devs);
+
+ if (__nr_instances < 0 || __nr_instances > STM_HEARTBEAT_MAX)
+ return -EINVAL;
+
+ for (i = 0; i < __nr_instances; i++) {
+ stm_heartbeat[i].data.name =
+ kasprintf(GFP_KERNEL, "heartbeat.%d", i);
+ if (!stm_heartbeat[i].data.name)
+ goto fail_unregister;
+
+ stm_heartbeat[i].data.nr_chans = 1;
+ stm_heartbeat[i].data.link = stm_heartbeat_link;
+ stm_heartbeat[i].data.unlink = stm_heartbeat_unlink;
+ hrtimer_init(&stm_heartbeat[i].hrtimer, CLOCK_MONOTONIC,
+ HRTIMER_MODE_ABS);
+ stm_heartbeat[i].hrtimer.function =
+ stm_heartbeat_hrtimer_handler;
+
+ ret = stm_source_register_device(NULL, &stm_heartbeat[i].data);
+ if (ret)
+ goto fail_free;
+ }
+
+ nr_instances = __nr_instances;
+
+ return 0;
+
+fail_unregister:
+ for (i--; i >= 0; i--) {
+ stm_source_unregister_device(&stm_heartbeat[i].data);
+fail_free:
+ kfree(stm_heartbeat[i].data.name);
+ }
+
+ return ret;
+}
+
+static void stm_heartbeat_exit(void)
+{
+ int i;
+
+ for (i = 0; i < nr_instances; i++) {
+ stm_source_unregister_device(&stm_heartbeat[i].data);
+ kfree(stm_heartbeat[i].data.name);
+ }
+}
+
+module_init(stm_heartbeat_init);
+module_exit(stm_heartbeat_exit);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("stm_heartbeat driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@linux.intel.com>");
diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
index 11ab6d01adf6..1db189657b2b 100644
--- a/drivers/hwtracing/stm/policy.c
+++ b/drivers/hwtracing/stm/policy.c
@@ -272,13 +272,17 @@ void stp_policy_unbind(struct stp_policy *policy)
{
struct stm_device *stm = policy->stm;
+ /*
+ * stp_policy_release() will not call here if the policy is already
+ * unbound; other users should not either, as no link exists between
+ * this policy and anything else in that case
+ */
if (WARN_ON_ONCE(!policy->stm))
return;
- mutex_lock(&stm->policy_mutex);
- stm->policy = NULL;
- mutex_unlock(&stm->policy_mutex);
+ lockdep_assert_held(&stm->policy_mutex);
+ stm->policy = NULL;
policy->stm = NULL;
stm_put_device(stm);
@@ -287,8 +291,16 @@ void stp_policy_unbind(struct stp_policy *policy)
static void stp_policy_release(struct config_item *item)
{
struct stp_policy *policy = to_stp_policy(item);
+ struct stm_device *stm = policy->stm;
+ /* a policy *can* be unbound and still exist in configfs tree */
+ if (!stm)
+ return;
+
+ mutex_lock(&stm->policy_mutex);
stp_policy_unbind(policy);
+ mutex_unlock(&stm->policy_mutex);
+
kfree(policy);
}
@@ -320,10 +332,11 @@ stp_policies_make(struct config_group *group, const char *name)
/*
* node must look like <device_name>.<policy_name>, where
- * <device_name> is the name of an existing stm device and
- * <policy_name> is an arbitrary string
+ * <device_name> is the name of an existing stm device; may
+ * contain dots;
+ * <policy_name> is an arbitrary string; may not contain dots
*/
- p = strchr(devname, '.');
+ p = strrchr(devname, '.');
if (!p) {
kfree(devname);
return ERR_PTR(-EINVAL);
diff --git a/drivers/hwtracing/stm/stm.h b/drivers/hwtracing/stm/stm.h
index 95ece0292c99..4e8c6926260f 100644
--- a/drivers/hwtracing/stm/stm.h
+++ b/drivers/hwtracing/stm/stm.h
@@ -45,6 +45,7 @@ struct stm_device {
int major;
unsigned int sw_nmasters;
struct stm_data *data;
+ struct mutex link_mutex;
spinlock_t link_lock;
struct list_head link_list;
/* master allocation */
@@ -56,6 +57,7 @@ struct stm_device {
container_of((_d), struct stm_device, dev)
struct stm_output {
+ spinlock_t lock;
unsigned int master;
unsigned int channel;
unsigned int nr_chans;
generated by cgit v1.2.3 (git 2.25.1) at 2024-12-25 12:10:37 +0000