Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[pandora-kernel.git] / fs / pstore / platform.c
index c5300ec..57bbf90 100644 (file)
 #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()
@@ -69,15 +87,22 @@ static void pstore_dump(struct kmsg_dumper *dumper,
        unsigned long   size, total = 0;
        char            *dst, *why;
        u64             id;
-       int             hsize;
+       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 (in_nmi()) {
+               is_locked = spin_trylock(&psinfo->buf_lock);
+               if (!is_locked)
+                       pr_err("pstore dump routine blocked in NMI, may corrupt error record\n");
+       } else
+               spin_lock_irqsave(&psinfo->buf_lock, flags);
        oopscount++;
        while (total < kmsg_bytes) {
                dst = psinfo->buf;
@@ -97,18 +122,20 @@ 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, part,
+               ret = psinfo->write(PSTORE_TYPE_DMESG, &id, part,
                                   hsize + l1_cpy + l2_cpy, psinfo);
-               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);
+               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 (in_nmi()) {
+               if (is_locked)
+                       spin_unlock(&psinfo->buf_lock);
+       } else
+               spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 }
 
 static struct kmsg_dumper pstore_dumper = {
@@ -140,6 +167,7 @@ int pstore_register(struct pstore_info *psi)
        }
 
        psinfo = psi;
+       mutex_init(&psinfo->read_mutex);
        spin_unlock(&pstore_lock);
 
        if (owner && !try_module_get(owner)) {
@@ -148,21 +176,27 @@ 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;
@@ -172,32 +206,52 @@ 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, psi)) > 0) {
-               if (pstore_mkfile(type, psi->name, id, psi->buf, (size_t)size,
-                                 time, psi))
+       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;
@@ -205,13 +259,13 @@ 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, 0, size, psinfo);
-       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);
-       mutex_unlock(&psinfo->buf_mutex);
+       spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 
        return 0;
 }