From: Adrian Hunter <[email protected]> Other modules that may wish to write to persistent storage are supported by adding a notifier and write function.
The notifier has 3 events: PSTORE_BEGIN, PSTORE_DUMP and PSTORE_END. External writers use the PSTORE_DUMP event whereas the PSTORE_BEGIN and PSTORE_END can be used by platform code to ensure the back end is powered up. Signed-off-by: Adrian Hunter <[email protected]> -- fs/pstore/platform.c | 88 ++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/pstore.h | 43 +++++++++++++++++++---- 2 files changed, 124 insertions(+), 7 deletions(-) diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index 9d65723..63ff377 100644 -- a/fs/pstore/platform.c ++ b/fs/pstore/platform.c @@ -34,6 +34,7 @@ #include <linux/jiffies.h> #include <linux/workqueue.h> #include <linux/debugfs.h> #include <linux/notifier.h> #include "internal.h" @@ -74,6 +75,20 @@ void pstore_set_kmsg_bytes(int bytes) kmsg_bytes = bytes; } static ATOMIC_NOTIFIER_HEAD(pstore_notifiers); int pstore_notifier_register(struct notifier_block *n) { return atomic_notifier_chain_register(&pstore_notifiers, n); } EXPORT_SYMBOL_GPL(pstore_notifier_register); int pstore_notifier_unregister(struct notifier_block *n) { return atomic_notifier_chain_unregister(&pstore_notifiers, n); } EXPORT_SYMBOL_GPL(pstore_notifier_unregister); /* Tag each group of saved records with a sequence number */ static int oopscount; @@ -97,6 +112,26 @@ static const char *get_reason_str(enum kmsg_dump_reason reason) } } static int pstore_ext_flush(void) { int ret; if (!psinfo->ext_len) return 0; ret = psinfo->write(psinfo->ext_type, psinfo->ext_reason, &psinfo->ext_id, psinfo->ext_part++, psinfo->ext_len, psinfo); if (ret == 0 && psinfo->ext_reason == KMSG_DUMP_OOPS && pstore_is_mounted()) pstore_new_entry = 1; psinfo->ext_len = 0; return ret; } /* * callback from kmsg_dump. (s2,l2) has the most recently * written bytes, older bytes are in (s1,l1). Save as much @@ -122,6 +157,15 @@ static void pstore_dump(struct kmsg_dumper *dumper, } else spin_lock_irqsave(&psinfo->buf_lock, flags); oopscount++; psinfo->ext_id = 0; psinfo->ext_len = 0; psinfo->ext_part = 0; psinfo->ext_type = PSTORE_TYPE_UNKNOWN; psinfo->ext_reason = reason; atomic_notifier_call_chain(&pstore_notifiers, PSTORE_BEGIN, psinfo); while (total < kmsg_bytes) { char *dst; unsigned long size; @@ -148,6 +192,13 @@ static void pstore_dump(struct kmsg_dumper *dumper, total += hsize + len; part++; } atomic_notifier_call_chain(&pstore_notifiers, PSTORE_DUMP, psinfo); pstore_ext_flush(); atomic_notifier_call_chain(&pstore_notifiers, PSTORE_END, psinfo); if (in_nmi()) { if (is_locked) spin_unlock(&psinfo->buf_lock); @@ -368,5 +419,42 @@ static void pstore_timefunc(unsigned long dummy) mod_timer(&pstore_timer, jiffies + msecs_to_jiffies(pstore_update_ms)); } /* pstore_write must only be called from PSTORE_DUMP notifier callbacks */ int pstore_write(enum pstore_type_id type, const char *buf, size_t size) { size_t len; int err = 0, err2; if (!psinfo) return -ENODEV; /* * No locking is needed because pstore_write is called only from * PSTORE_DUMP notifier callbacks. */ if (type != psinfo->ext_type) { err = pstore_ext_flush(); psinfo->ext_type = type; psinfo->ext_part = 1; } while (size) { len = min(size, psinfo->bufsize - psinfo->ext_len); memcpy(psinfo->buf + psinfo->ext_len, buf, len); psinfo->ext_len += len; buf += len; size -= len; if (psinfo->ext_len == psinfo->bufsize) { err2 = pstore_ext_flush(); if (err2 && !err) err = err2; } } return err; } EXPORT_SYMBOL_GPL(pstore_write); module_param(backend, charp, 0444); MODULE_PARM_DESC(backend, "Pstore backend to use"); diff --git a/include/linux/pstore.h b/include/linux/pstore.h index 55ab23f..1bf7f4b 100644 -- a/include/linux/pstore.h ++ b/include/linux/pstore.h @@ -40,17 +40,27 @@ enum pstore_type_id { struct module; /* Notifier events */ #define PSTORE_BEGIN 1 #define PSTORE_DUMP 2 #define PSTORE_END 3 #define PSTORE_NO_HEADINGS BIT(0) #define PSTORE_MAX_KMSG_BYTES BIT(1) struct pstore_info { struct module *owner; char *name; unsigned int flags; spinlock_t buf_lock; /* serialize access to 'buf' */ char *buf; size_t bufsize; struct mutex read_mutex; /* serialize open/read/close */ struct module *owner; char *name; unsigned int flags; spinlock_t buf_lock; /* serialize access to 'buf' */ char *buf; size_t bufsize; struct mutex read_mutex; /* serialize open/read/close */ u64 ext_id; size_t ext_len; unsigned int ext_part; enum pstore_type_id ext_type; enum kmsg_dump_reason ext_reason; int (*open)(struct pstore_info *psi); int (*close)(struct pstore_info *psi); ssize_t (*read)(u64 *id, enum pstore_type_id *type, @@ -70,12 +80,31 @@ struct pstore_info { #ifdef CONFIG_PSTORE extern int pstore_register(struct pstore_info *); extern int pstore_notifier_register(struct notifier_block *n); extern int pstore_notifier_unregister(struct notifier_block *n); /* pstore_write must only be called from PSTORE_DUMP notifier callbacks */ extern int pstore_write(enum pstore_type_id type, const char *buf, size_t size); #else static inline int pstore_register(struct pstore_info *psi) { return -ENODEV; } static inline int pstore_notifier_register(struct notifier_block *n) { return 0; } static inline int pstore_notifier_unregister(struct notifier_block *n) { return 0; } static inline int pstore_write(enum pstore_type_id type, const char *buf, size_t size) { return 0; } #endif #endif /*_LINUX_PSTORE_H*/ - 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
