Commit ee1d2674 authored by Geliang Tang's avatar Geliang Tang Committed by Tony Luck
Browse files

pstore: add pstore unregister



pstore 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) Unmap the memory and free it.
 4) Add a function to unregister pstore filesystem.
Signed-off-by: default avatarGeliang Tang <geliangtang@163.com>
Acked-by: default avatarKees Cook <keescook@chromium.org>
[Removed __exit annotation from ramoops_remove(). Reported by Arnd Bergmann]
Signed-off-by: default avatarTony Luck <tony.luck@intel.com>
parent 18730411
config PSTORE
bool "Persistent store support"
tristate "Persistent store support"
default n
select ZLIB_DEFLATE
select ZLIB_INFLATE
......
......@@ -2,12 +2,12 @@
# Makefile for the linux pstorefs routines.
#
obj-y += pstore.o
obj-$(CONFIG_PSTORE) += pstore.o
pstore-objs += inode.o platform.o
obj-$(CONFIG_PSTORE_FTRACE) += ftrace.o
pstore-$(CONFIG_PSTORE_FTRACE) += ftrace.o
obj-$(CONFIG_PSTORE_PMSG) += pmsg.o
pstore-$(CONFIG_PSTORE_PMSG) += pmsg.o
ramoops-objs += ram.o ram_core.o
obj-$(CONFIG_PSTORE_RAM) += ramoops.o
......@@ -104,22 +104,23 @@ static const struct file_operations pstore_knob_fops = {
.write = pstore_ftrace_knob_write,
};
static struct dentry *pstore_ftrace_dir;
void pstore_register_ftrace(void)
{
struct dentry *dir;
struct dentry *file;
if (!psinfo->write_buf)
return;
dir = debugfs_create_dir("pstore", NULL);
if (!dir) {
pstore_ftrace_dir = debugfs_create_dir("pstore", NULL);
if (!pstore_ftrace_dir) {
pr_err("%s: unable to create pstore directory\n", __func__);
return;
}
file = debugfs_create_file("record_ftrace", 0600, dir, NULL,
&pstore_knob_fops);
file = debugfs_create_file("record_ftrace", 0600, pstore_ftrace_dir,
NULL, &pstore_knob_fops);
if (!file) {
pr_err("%s: unable to create record_ftrace file\n", __func__);
goto err_file;
......@@ -127,5 +128,17 @@ void pstore_register_ftrace(void)
return;
err_file:
debugfs_remove(dir);
debugfs_remove(pstore_ftrace_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(pstore_ftrace_dir);
}
......@@ -178,6 +178,7 @@ static loff_t pstore_file_llseek(struct file *file, loff_t off, int whence)
}
static const struct file_operations pstore_file_operations = {
.owner = THIS_MODULE,
.open = pstore_file_open,
.read = pstore_file_read,
.llseek = pstore_file_llseek,
......@@ -456,6 +457,7 @@ static void pstore_kill_sb(struct super_block *sb)
}
static struct file_system_type pstore_fs_type = {
.owner = THIS_MODULE,
.name = "pstore",
.mount = pstore_mount,
.kill_sb = pstore_kill_sb,
......@@ -479,5 +481,12 @@ static int __init init_pstore_fs(void)
}
module_init(init_pstore_fs)
static void __exit exit_pstore_fs(void)
{
unregister_filesystem(&pstore_fs_type);
sysfs_remove_mount_point(fs_kobj, "pstore");
}
module_exit(exit_pstore_fs)
MODULE_AUTHOR("Tony Luck <tony.luck@intel.com>");
MODULE_LICENSE("GPL");
......@@ -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;
......
......@@ -237,6 +237,14 @@ static void allocate_buf_for_compression(void)
}
static void free_buf_for_compression(void)
{
kfree(stream.workspace);
stream.workspace = NULL;
kfree(big_oops_buf);
big_oops_buf = NULL;
}
/*
* Called when compression fails, since the printk buffer
* would be fetched for compression calling it again when
......@@ -358,6 +366,11 @@ 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)
{
......@@ -395,8 +408,14 @@ static void pstore_register_console(void)
{
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,
......@@ -467,12 +486,28 @@ int pstore_register(struct pstore_info *psi)
*/
backend = psi->name;
module_put(owner);
pr_info("Registered %s as persistent store backend\n", psi->name);
return 0;
}
EXPORT_SYMBOL_GPL(pstore_register);
void pstore_unregister(struct pstore_info *psi)
{
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
......
......@@ -114,3 +114,10 @@ void pstore_register_pmsg(void)
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);
}
......@@ -578,30 +578,27 @@ static int ramoops_probe(struct platform_device *pdev)
return err;
}
static int __exit ramoops_remove(struct platform_device *pdev)
static int 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);
pstore_unregister(&cxt->pstore);
cxt->max_dump_cnt = 0;
/* TODO(kees): When pstore supports unregistering, call it here. */
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",
},
......
......@@ -75,20 +75,8 @@ struct pstore_info {
#define PSTORE_FLAGS_FRAGILE 1
#ifdef CONFIG_PSTORE
extern int pstore_register(struct pstore_info *);
extern void pstore_unregister(struct pstore_info *);
extern bool pstore_cannot_block_path(enum kmsg_dump_reason reason);
#else
static inline int
pstore_register(struct pstore_info *psi)
{
return -ENODEV;
}
static inline bool
pstore_cannot_block_path(enum kmsg_dump_reason reason)
{
return false;
}
#endif
#endif /*_LINUX_PSTORE_H*/
......@@ -517,6 +517,7 @@ int check_syslog_permissions(int type, int source)
ok:
return security_syslog(type);
}
EXPORT_SYMBOL_GPL(check_syslog_permissions);
static void append_char(char **pp, char *e, char c)
{
......
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