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Date: Fri, 16 Oct 2015 23:25:55 +0800
From: Geliang Tang <geliangtang@....com>
To: Anton Vorontsov <anton@...msg.org>,
Colin Cross <ccross@...roid.com>,
Kees Cook <keescook@...omium.org>,
Tony Luck <tony.luck@...el.com>
Cc: Geliang Tang <geliangtang@....com>, linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] pstore: add 'rmmod ramoops' support
ramoops doesn't support unregistering yet, it was marked as TODO.
This patch adds some code to fix it:
1) Add functions to unregister kmsg/console/ftrace/pmsg.
2) Add a function to free compression buffer.
3) Remove try_module_get() to allow this module can be unloaded.
4) Unmap the memory and free it.
5) Set console flags, make sure it can be registered again after
be unregistered.
Signed-off-by: Geliang Tang <geliangtang@....com>
---
fs/pstore/ftrace.c | 15 ++++++++++++++-
fs/pstore/internal.h | 4 ++++
fs/pstore/platform.c | 40 ++++++++++++++++++++++++++++++++--------
fs/pstore/pmsg.c | 7 +++++++
fs/pstore/ram.c | 19 ++++++++-----------
include/linux/pstore.h | 5 +++++
6 files changed, 70 insertions(+), 20 deletions(-)
diff --git a/fs/pstore/ftrace.c b/fs/pstore/ftrace.c
index 76a4eeb..554c1ce 100644
--- a/fs/pstore/ftrace.c
+++ b/fs/pstore/ftrace.c
@@ -104,9 +104,10 @@ static const struct file_operations pstore_knob_fops = {
.write = pstore_ftrace_knob_write,
};
+static struct dentry *dir;
+
void pstore_register_ftrace(void)
{
- struct dentry *dir;
struct dentry *file;
if (!psinfo->write_buf)
@@ -129,3 +130,15 @@ void pstore_register_ftrace(void)
err_file:
debugfs_remove(dir);
}
+
+void pstore_unregister_ftrace(void)
+{
+ mutex_lock(&pstore_ftrace_lock);
+ if (pstore_ftrace_enabled) {
+ unregister_ftrace_function(&pstore_ftrace_ops);
+ pstore_ftrace_enabled = 0;
+ }
+ mutex_unlock(&pstore_ftrace_lock);
+
+ debugfs_remove_recursive(dir);
+}
diff --git a/fs/pstore/internal.h b/fs/pstore/internal.h
index c36ba2c..96253c4 100644
--- a/fs/pstore/internal.h
+++ b/fs/pstore/internal.h
@@ -41,14 +41,18 @@ pstore_ftrace_decode_cpu(struct pstore_ftrace_record *rec)
#ifdef CONFIG_PSTORE_FTRACE
extern void pstore_register_ftrace(void);
+extern void pstore_unregister_ftrace(void);
#else
static inline void pstore_register_ftrace(void) {}
+static inline void pstore_unregister_ftrace(void) {}
#endif
#ifdef CONFIG_PSTORE_PMSG
extern void pstore_register_pmsg(void);
+extern void pstore_unregister_pmsg(void);
#else
static inline void pstore_register_pmsg(void) {}
+static inline void pstore_unregister_pmsg(void) {}
#endif
extern struct pstore_info *psinfo;
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c
index 1b11249..c474dc2 100644
--- a/fs/pstore/platform.c
+++ b/fs/pstore/platform.c
@@ -237,6 +237,12 @@ static void allocate_buf_for_compression(void)
}
+static void free_buf_for_compression(void)
+{
+ kfree(stream.workspace);
+ kfree(big_oops_buf);
+}
+
/*
* Called when compression fails, since the printk buffer
* would be fetched for compression calling it again when
@@ -358,6 +364,11 @@ static void pstore_register_kmsg(void)
kmsg_dump_register(&pstore_dumper);
}
+static void pstore_unregister_kmsg(void)
+{
+ kmsg_dump_unregister(&pstore_dumper);
+}
+
#ifdef CONFIG_PSTORE_CONSOLE
static void pstore_console_write(struct console *con, const char *s, unsigned c)
{
@@ -387,16 +398,22 @@ static void pstore_console_write(struct console *con, const char *s, unsigned c)
static struct console pstore_console = {
.name = "pstore",
.write = pstore_console_write,
- .flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME,
.index = -1,
};
static void pstore_register_console(void)
{
+ pstore_console.flags = CON_PRINTBUFFER | CON_ENABLED | CON_ANYTIME;
register_console(&pstore_console);
}
+
+static void pstore_unregister_console(void)
+{
+ unregister_console(&pstore_console);
+}
#else
static void pstore_register_console(void) {}
+static void pstore_unregister_console(void) {}
#endif
static int pstore_write_compat(enum pstore_type_id type,
@@ -420,8 +437,6 @@ static int pstore_write_compat(enum pstore_type_id type,
*/
int pstore_register(struct pstore_info *psi)
{
- struct module *owner = psi->owner;
-
if (backend && strcmp(backend, psi->name))
return -EPERM;
@@ -437,11 +452,6 @@ int pstore_register(struct pstore_info *psi)
mutex_init(&psinfo->read_mutex);
spin_unlock(&pstore_lock);
- if (owner && !try_module_get(owner)) {
- psinfo = NULL;
- return -EINVAL;
- }
-
allocate_buf_for_compression();
if (pstore_is_mounted())
@@ -473,6 +483,20 @@ int pstore_register(struct pstore_info *psi)
}
EXPORT_SYMBOL_GPL(pstore_register);
+void pstore_unregister(void)
+{
+ pstore_unregister_pmsg();
+ pstore_unregister_ftrace();
+ pstore_unregister_console();
+ pstore_unregister_kmsg();
+
+ free_buf_for_compression();
+
+ psinfo = NULL;
+ backend = NULL;
+}
+EXPORT_SYMBOL_GPL(pstore_unregister);
+
/*
* Read all the records from the persistent store. Create
* files in our filesystem. Don't warn about -EEXIST errors
diff --git a/fs/pstore/pmsg.c b/fs/pstore/pmsg.c
index 5a2f05a..7de20cd 100644
--- a/fs/pstore/pmsg.c
+++ b/fs/pstore/pmsg.c
@@ -114,3 +114,10 @@ err_class:
err:
return;
}
+
+void pstore_unregister_pmsg(void)
+{
+ device_destroy(pmsg_class, MKDEV(pmsg_major, 0));
+ class_destroy(pmsg_class);
+ unregister_chrdev(pmsg_major, PMSG_NAME);
+}
diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c
index 6c26c4d..d938bc1 100644
--- a/fs/pstore/ram.c
+++ b/fs/pstore/ram.c
@@ -580,28 +580,25 @@ fail_out:
static int __exit ramoops_remove(struct platform_device *pdev)
{
-#if 0
- /* TODO(kees): We cannot unload ramoops since pstore doesn't support
- * unregistering yet.
- */
struct ramoops_context *cxt = &oops_cxt;
- iounmap(cxt->virt_addr);
- release_mem_region(cxt->phys_addr, cxt->size);
- cxt->max_dump_cnt = 0;
+ pstore_unregister();
- /* TODO(kees): When pstore supports unregistering, call it here. */
+ cxt->max_dump_cnt = 0;
kfree(cxt->pstore.buf);
cxt->pstore.bufsize = 0;
+ persistent_ram_free(cxt->mprz);
+ persistent_ram_free(cxt->fprz);
+ persistent_ram_free(cxt->cprz);
+ ramoops_free_przs(cxt);
+
return 0;
-#endif
- return -EBUSY;
}
static struct platform_driver ramoops_driver = {
.probe = ramoops_probe,
- .remove = __exit_p(ramoops_remove),
+ .remove = ramoops_remove,
.driver = {
.name = "ramoops",
},
diff --git a/include/linux/pstore.h b/include/linux/pstore.h
index 8e7a25b..34e4a6d 100644
--- a/include/linux/pstore.h
+++ b/include/linux/pstore.h
@@ -77,6 +77,7 @@ struct pstore_info {
#ifdef CONFIG_PSTORE
extern int pstore_register(struct pstore_info *);
+extern void pstore_unregister(void);
extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
#else
static inline int
@@ -84,6 +85,10 @@ pstore_register(struct pstore_info *psi)
{
return -ENODEV;
}
+static inline void
+pstore_unregister(void)
+{
+}
static inline bool
pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
--
2.5.0
--
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