diff options
Diffstat (limited to 'fs/pstore/platform.c')
-rw-r--r-- | fs/pstore/platform.c | 139 |
1 files changed, 115 insertions, 24 deletions
diff --git a/fs/pstore/platform.c b/fs/pstore/platform.c index f2c3ff2..45d18d1 100644 --- a/fs/pstore/platform.c +++ b/fs/pstore/platform.c @@ -25,18 +25,38 @@ #include <linux/module.h> #include <linux/pstore.h> #include <linux/string.h> +#include <linux/timer.h> #include <linux/slab.h> #include <linux/uaccess.h> +#include <linux/hardirq.h> +#include <linux/workqueue.h> #include "internal.h" /* + * We defer making "oops" entries appear in pstore - see + * whether the system is actually still running well enough + * to let someone see the entry + */ +#define PSTORE_INTERVAL (60 * HZ) + +static int pstore_new_entry; + +static void pstore_timefunc(unsigned long); +static DEFINE_TIMER(pstore_timer, pstore_timefunc, 0, 0); + +static void pstore_dowork(struct work_struct *); +static DECLARE_WORK(pstore_work, pstore_dowork); + +/* * pstore_lock just protects "psinfo" during * calls to pstore_register() */ static DEFINE_SPINLOCK(pstore_lock); static struct pstore_info *psinfo; +static char *backend; + /* How much of the console log to snapshot */ static unsigned long kmsg_bytes = 10240; @@ -52,6 +72,27 @@ static char *reason_str[] = { "Oops", "Panic", "Kexec", "Restart", "Halt", "Poweroff", "Emergency" }; +bool pstore_cannot_block_path(enum kmsg_dump_reason reason) +{ + /* + * In case of NMI path, pstore shouldn't be blocked + * regardless of reason. + */ + if (in_nmi()) + return true; + + switch (reason) { + /* In panic case, other cpus are stopped by smp_send_stop(). */ + case KMSG_DUMP_PANIC: + /* Emergency restart shouldn't be blocked by spin lock. */ + case KMSG_DUMP_EMERG: + return true; + default: + return false; + } +} +EXPORT_SYMBOL_GPL(pstore_cannot_block_path); + /* * callback from kmsg_dump. (s2,l2) has the most recently * written bytes, older bytes are in (s1,l1). Save as much @@ -67,18 +108,28 @@ static void pstore_dump(struct kmsg_dumper *dumper, unsigned long size, total = 0; char *dst, *why; u64 id; - int hsize, part = 1; + int hsize, ret; + unsigned int part = 1; + unsigned long flags = 0; + int is_locked = 0; if (reason < ARRAY_SIZE(reason_str)) why = reason_str[reason]; else why = "Unknown"; - mutex_lock(&psinfo->buf_mutex); + if (pstore_cannot_block_path(reason)) { + is_locked = spin_trylock_irqsave(&psinfo->buf_lock, flags); + if (!is_locked) { + pr_err("pstore dump routine blocked in %s path, may corrupt error record\n" + , in_nmi() ? "NMI" : why); + } + } else + spin_lock_irqsave(&psinfo->buf_lock, flags); oopscount++; while (total < kmsg_bytes) { dst = psinfo->buf; - hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part++); + hsize = sprintf(dst, "%s#%d Part%d\n", why, oopscount, part); size = psinfo->bufsize - hsize; dst += hsize; @@ -94,16 +145,20 @@ static void pstore_dump(struct kmsg_dumper *dumper, memcpy(dst, s1 + s1_start, l1_cpy); memcpy(dst + l1_cpy, s2 + s2_start, l2_cpy); - id = psinfo->write(PSTORE_TYPE_DMESG, hsize + l1_cpy + l2_cpy); - if (reason == KMSG_DUMP_OOPS && pstore_is_mounted()) - pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, - psinfo->buf, hsize + l1_cpy + l2_cpy, - CURRENT_TIME, psinfo->erase); + ret = psinfo->write(PSTORE_TYPE_DMESG, &id, part, + hsize + l1_cpy + l2_cpy, psinfo); + if (ret == 0 && reason == KMSG_DUMP_OOPS && pstore_is_mounted()) + pstore_new_entry = 1; l1 -= l1_cpy; l2 -= l2_cpy; total += l1_cpy + l2_cpy; + part++; } - mutex_unlock(&psinfo->buf_mutex); + if (pstore_cannot_block_path(reason)) { + if (is_locked) + spin_unlock_irqrestore(&psinfo->buf_lock, flags); + } else + spin_unlock_irqrestore(&psinfo->buf_lock, flags); } static struct kmsg_dumper pstore_dumper = { @@ -128,7 +183,14 @@ int pstore_register(struct pstore_info *psi) spin_unlock(&pstore_lock); return -EBUSY; } + + if (backend && strcmp(backend, psi->name)) { + spin_unlock(&pstore_lock); + return -EINVAL; + } + psinfo = psi; + mutex_init(&psinfo->read_mutex); spin_unlock(&pstore_lock); if (owner && !try_module_get(owner)) { @@ -137,21 +199,27 @@ int pstore_register(struct pstore_info *psi) } if (pstore_is_mounted()) - pstore_get_records(); + pstore_get_records(0); kmsg_dump_register(&pstore_dumper); + pstore_timer.expires = jiffies + PSTORE_INTERVAL; + add_timer(&pstore_timer); + return 0; } EXPORT_SYMBOL_GPL(pstore_register); /* - * Read all the records from the persistent store. Create and - * file files in our filesystem. + * Read all the records from the persistent store. Create + * files in our filesystem. Don't warn about -EEXIST errors + * when we are re-scanning the backing store looking to add new + * error records. */ -void pstore_get_records(void) +void pstore_get_records(int quiet) { struct pstore_info *psi = psinfo; + char *buf = NULL; ssize_t size; u64 id; enum pstore_type_id type; @@ -161,32 +229,52 @@ void pstore_get_records(void) if (!psi) return; - mutex_lock(&psinfo->buf_mutex); + mutex_lock(&psi->read_mutex); rc = psi->open(psi); if (rc) goto out; - while ((size = psi->read(&id, &type, &time)) > 0) { - if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size, - time, psi->erase)) + while ((size = psi->read(&id, &type, &time, &buf, psi)) > 0) { + rc = pstore_mkfile(type, psi->name, id, buf, (size_t)size, + time, psi); + kfree(buf); + buf = NULL; + if (rc && (rc != -EEXIST || !quiet)) failed++; } psi->close(psi); out: - mutex_unlock(&psinfo->buf_mutex); + mutex_unlock(&psi->read_mutex); if (failed) printk(KERN_WARNING "pstore: failed to load %d record(s) from '%s'\n", failed, psi->name); } +static void pstore_dowork(struct work_struct *work) +{ + pstore_get_records(1); +} + +static void pstore_timefunc(unsigned long dummy) +{ + if (pstore_new_entry) { + pstore_new_entry = 0; + schedule_work(&pstore_work); + } + + mod_timer(&pstore_timer, jiffies + PSTORE_INTERVAL); +} + /* * Call platform driver to write a record to the * persistent store. */ int pstore_write(enum pstore_type_id type, char *buf, size_t size) { - u64 id; + u64 id; + int ret; + unsigned long flags; if (!psinfo) return -ENODEV; @@ -194,14 +282,17 @@ int pstore_write(enum pstore_type_id type, char *buf, size_t size) if (size > psinfo->bufsize) return -EFBIG; - mutex_lock(&psinfo->buf_mutex); + spin_lock_irqsave(&psinfo->buf_lock, flags); memcpy(psinfo->buf, buf, size); - id = psinfo->write(type, size); - if (pstore_is_mounted()) + ret = psinfo->write(type, &id, 0, size, psinfo); + if (ret == 0 && pstore_is_mounted()) pstore_mkfile(PSTORE_TYPE_DMESG, psinfo->name, id, psinfo->buf, - size, CURRENT_TIME, psinfo->erase); - mutex_unlock(&psinfo->buf_mutex); + size, CURRENT_TIME, psinfo); + spin_unlock_irqrestore(&psinfo->buf_lock, flags); return 0; } EXPORT_SYMBOL_GPL(pstore_write); + +module_param(backend, charp, 0444); +MODULE_PARM_DESC(backend, "Pstore backend to use"); |