Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl...
authorLinus Torvalds <torvalds@linux-foundation.org>
Thu, 21 Feb 2013 17:38:18 +0000 (09:38 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 21 Feb 2013 17:38:18 +0000 (09:38 -0800)
Pull pstore patches from Tony Luck:
 "A few fixes to reduce places where pstore might hang a system in the
  crash path.  Plus a new mountpoint (/sys/fs/pstore ...  makes more
  sense then /dev/pstore)."

Fix up trivial conflict in drivers/firmware/efivars.c

* tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux:
  pstore: Create a convenient mount point for pstore
  efi_pstore: Introducing workqueue updating sysfs
  efivars: Disable external interrupt while holding efivars->lock
  efi_pstore: Avoid deadlock in non-blocking paths
  pstore: Avoid deadlock in panic and emergency-restart path

Documentation/ABI/testing/pstore
drivers/firmware/efivars.c
fs/pstore/inode.c
fs/pstore/platform.c
include/linux/efi.h
include/linux/pstore.h

index ff1df4e..5fca9f5 100644 (file)
@@ -1,4 +1,4 @@
-Where:         /dev/pstore/...
+Where:         /sys/fs/pstore/... (or /dev/pstore/...)
 Date:          March 2011
 Kernel Version: 2.6.39
 Contact:       tony.luck@intel.com
@@ -11,9 +11,9 @@ Description:  Generic interface to platform dependent persistent storage.
                of the console log is captured, but other interesting
                data can also be saved.
 
-               # mount -t pstore -o kmsg_bytes=8000 - /dev/pstore
+               # mount -t pstore -o kmsg_bytes=8000 - /sys/fs/pstore
 
-               $ ls -l /dev/pstore
+               $ ls -l /sys/fs/pstore/
                total 0
                -r--r--r-- 1 root root 7896 Nov 30 15:38 dmesg-erst-1
 
@@ -27,9 +27,9 @@ Description:  Generic interface to platform dependent persistent storage.
                the file will signal to the underlying persistent storage
                device that it can reclaim the space for later re-use.
 
-               $ rm /dev/pstore/dmesg-erst-1
+               $ rm /sys/fs/pstore/dmesg-erst-1
 
-               The expectation is that all files in /dev/pstore
+               The expectation is that all files in /sys/fs/pstore/
                will be saved elsewhere and erased from persistent store
                soon after boot to free up space ready for the next
                catastrophe.
index f5596db..fed08b6 100644 (file)
@@ -158,6 +158,13 @@ efivar_create_sysfs_entry(struct efivars *efivars,
                          efi_char16_t *variable_name,
                          efi_guid_t *vendor_guid);
 
+/*
+ * Prototype for workqueue functions updating sysfs entry
+ */
+
+static void efivar_update_sysfs_entries(struct work_struct *);
+static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
+
 /* Return the number of unicode characters in data */
 static unsigned long
 utf16_strnlen(efi_char16_t *s, size_t maxlength)
@@ -405,10 +412,11 @@ static efi_status_t
 get_var_data(struct efivars *efivars, struct efi_variable *var)
 {
        efi_status_t status;
+       unsigned long flags;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irqsave(&efivars->lock, flags);
        status = get_var_data_locked(efivars, var);
-       spin_unlock(&efivars->lock);
+       spin_unlock_irqrestore(&efivars->lock, flags);
 
        if (status != EFI_SUCCESS) {
                printk(KERN_WARNING "efivars: get_variable() failed 0x%lx!\n",
@@ -537,14 +545,14 @@ efivar_store_raw(struct efivar_entry *entry, const char *buf, size_t count)
                return -EINVAL;
        }
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
        status = efivars->ops->set_variable(new_var->VariableName,
                                            &new_var->VendorGuid,
                                            new_var->Attributes,
                                            new_var->DataSize,
                                            new_var->Data);
 
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        if (status != EFI_SUCCESS) {
                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
@@ -713,7 +721,7 @@ static ssize_t efivarfs_file_write(struct file *file,
         * amounts of memory. Pick a default size of 64K if
         * QueryVariableInfo() isn't supported by the firmware.
         */
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
 
        if (!efivars->ops->query_variable_info)
                status = EFI_UNSUPPORTED;
@@ -723,7 +731,7 @@ static ssize_t efivarfs_file_write(struct file *file,
                                                   &remaining_size, &max_size);
        }
 
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        if (status != EFI_SUCCESS) {
                if (status != EFI_UNSUPPORTED)
@@ -754,7 +762,7 @@ static ssize_t efivarfs_file_write(struct file *file,
         * set_variable call, and removal of the variable from the efivars
         * list (in the case of an authenticated delete).
         */
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
 
        status = efivars->ops->set_variable(var->var.VariableName,
                                            &var->var.VendorGuid,
@@ -762,7 +770,7 @@ static ssize_t efivarfs_file_write(struct file *file,
                                            data);
 
        if (status != EFI_SUCCESS) {
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                kfree(data);
 
                return efi_status_to_err(status);
@@ -783,21 +791,21 @@ static ssize_t efivarfs_file_write(struct file *file,
                                            NULL);
 
        if (status == EFI_BUFFER_TOO_SMALL) {
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                mutex_lock(&inode->i_mutex);
                i_size_write(inode, newdatasize + sizeof(attributes));
                mutex_unlock(&inode->i_mutex);
 
        } else if (status == EFI_NOT_FOUND) {
                list_del(&var->list);
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                efivar_unregister(var);
                drop_nlink(inode);
                d_delete(file->f_dentry);
                dput(file->f_dentry);
 
        } else {
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                pr_warn("efivarfs: inconsistent EFI variable implementation? "
                                "status = %lx\n", status);
        }
@@ -819,11 +827,11 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
        void *data;
        ssize_t size = 0;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
        status = efivars->ops->get_variable(var->var.VariableName,
                                            &var->var.VendorGuid,
                                            &attributes, &datasize, NULL);
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        if (status != EFI_BUFFER_TOO_SMALL)
                return efi_status_to_err(status);
@@ -833,12 +841,12 @@ static ssize_t efivarfs_file_read(struct file *file, char __user *userbuf,
        if (!data)
                return -ENOMEM;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
        status = efivars->ops->get_variable(var->var.VariableName,
                                            &var->var.VendorGuid,
                                            &attributes, &datasize,
                                            (data + sizeof(attributes)));
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        if (status != EFI_SUCCESS) {
                size = efi_status_to_err(status);
@@ -966,9 +974,9 @@ static int efivarfs_create(struct inode *dir, struct dentry *dentry,
                goto out;
 
        kobject_uevent(&var->kobj, KOBJ_ADD);
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
        list_add(&var->list, &efivars->list);
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
        d_instantiate(dentry, inode);
        dget(dentry);
 out:
@@ -985,7 +993,7 @@ static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
        struct efivars *efivars = var->efivars;
        efi_status_t status;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
 
        status = efivars->ops->set_variable(var->var.VariableName,
                                            &var->var.VendorGuid,
@@ -993,14 +1001,14 @@ static int efivarfs_unlink(struct inode *dir, struct dentry *dentry)
 
        if (status == EFI_SUCCESS || status == EFI_NOT_FOUND) {
                list_del(&var->list);
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                efivar_unregister(var);
                drop_nlink(dentry->d_inode);
                dput(dentry);
                return 0;
        }
 
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
        return -EINVAL;
 };
 
@@ -1066,13 +1074,13 @@ static int efivarfs_fill_super(struct super_block *sb, void *data, int silent)
                /* copied by the above to local storage in the dentry. */
                kfree(name);
 
-               spin_lock(&efivars->lock);
+               spin_lock_irq(&efivars->lock);
                efivars->ops->get_variable(entry->var.VariableName,
                                           &entry->var.VendorGuid,
                                           &entry->var.Attributes,
                                           &size,
                                           NULL);
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
 
                mutex_lock(&inode->i_mutex);
                inode->i_private = entry;
@@ -1123,7 +1131,7 @@ static int efi_pstore_open(struct pstore_info *psi)
 {
        struct efivars *efivars = psi->data;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
        efivars->walk_entry = list_first_entry(&efivars->list,
                                               struct efivar_entry, list);
        return 0;
@@ -1133,7 +1141,7 @@ static int efi_pstore_close(struct pstore_info *psi)
 {
        struct efivars *efivars = psi->data;
 
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
        return 0;
 }
 
@@ -1209,8 +1217,18 @@ static int efi_pstore_write(enum pstore_type_id type,
        int i, ret = 0;
        u64 storage_space, remaining_space, max_variable_size;
        efi_status_t status = EFI_NOT_FOUND;
-
-       spin_lock(&efivars->lock);
+       unsigned long flags;
+
+       if (pstore_cannot_block_path(reason)) {
+               /*
+                * If the lock is taken by another cpu in non-blocking path,
+                * this driver returns without entering firmware to avoid
+                * hanging up.
+                */
+               if (!spin_trylock_irqsave(&efivars->lock, flags))
+                       return -EBUSY;
+       } else
+               spin_lock_irqsave(&efivars->lock, flags);
 
        /*
         * Check if there is a space enough to log.
@@ -1222,7 +1240,7 @@ static int efi_pstore_write(enum pstore_type_id type,
                                                   &remaining_space,
                                                   &max_variable_size);
        if (status || remaining_space < size + DUMP_NAME_LEN * 2) {
-               spin_unlock(&efivars->lock);
+               spin_unlock_irqrestore(&efivars->lock, flags);
                *id = part;
                return -ENOSPC;
        }
@@ -1236,13 +1254,10 @@ static int efi_pstore_write(enum pstore_type_id type,
        efivars->ops->set_variable(efi_name, &vendor, PSTORE_EFI_ATTRIBUTES,
                                   size, psi->buf);
 
-       spin_unlock(&efivars->lock);
+       spin_unlock_irqrestore(&efivars->lock, flags);
 
-       if (size)
-               ret = efivar_create_sysfs_entry(efivars,
-                                         utf16_strsize(efi_name,
-                                                       DUMP_NAME_LEN * 2),
-                                         efi_name, &vendor);
+       if (reason == KMSG_DUMP_OOPS)
+               schedule_work(&efivar_work);
 
        *id = part;
        return ret;
@@ -1263,7 +1278,7 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
        sprintf(name, "dump-type%u-%u-%d-%lu", type, (unsigned int)id, count,
                time.tv_sec);
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
 
        for (i = 0; i < DUMP_NAME_LEN; i++)
                efi_name[i] = name[i];
@@ -1307,7 +1322,7 @@ static int efi_pstore_erase(enum pstore_type_id type, u64 id, int count,
        if (found)
                list_del(&found->list);
 
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        if (found)
                efivar_unregister(found);
@@ -1377,7 +1392,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
                return -EINVAL;
        }
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
 
        /*
         * Does this variable already exist?
@@ -1395,7 +1410,7 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
                }
        }
        if (found) {
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                return -EINVAL;
        }
 
@@ -1409,10 +1424,10 @@ static ssize_t efivar_create(struct file *filp, struct kobject *kobj,
        if (status != EFI_SUCCESS) {
                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
                        status);
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                return -EIO;
        }
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        /* Create the entry in sysfs.  Locking is not required here */
        status = efivar_create_sysfs_entry(efivars,
@@ -1440,7 +1455,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
        if (!capable(CAP_SYS_ADMIN))
                return -EACCES;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
 
        /*
         * Does this variable already exist?
@@ -1458,7 +1473,7 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
                }
        }
        if (!found) {
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                return -EINVAL;
        }
        /* force the Attributes/DataSize to 0 to ensure deletion */
@@ -1474,18 +1489,87 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
        if (status != EFI_SUCCESS) {
                printk(KERN_WARNING "efivars: set_variable() failed: status=%lx\n",
                        status);
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                return -EIO;
        }
        list_del(&search_efivar->list);
        /* We need to release this lock before unregistering. */
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
        efivar_unregister(search_efivar);
 
        /* It's dead Jim.... */
        return count;
 }
 
+static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
+{
+       struct efivar_entry *entry, *n;
+       struct efivars *efivars = &__efivars;
+       unsigned long strsize1, strsize2;
+       bool found = false;
+
+       strsize1 = utf16_strsize(variable_name, 1024);
+       list_for_each_entry_safe(entry, n, &efivars->list, list) {
+               strsize2 = utf16_strsize(entry->var.VariableName, 1024);
+               if (strsize1 == strsize2 &&
+                       !memcmp(variable_name, &(entry->var.VariableName),
+                               strsize2) &&
+                       !efi_guidcmp(entry->var.VendorGuid,
+                               *vendor)) {
+                       found = true;
+                       break;
+               }
+       }
+       return found;
+}
+
+static void efivar_update_sysfs_entries(struct work_struct *work)
+{
+       struct efivars *efivars = &__efivars;
+       efi_guid_t vendor;
+       efi_char16_t *variable_name;
+       unsigned long variable_name_size = 1024;
+       efi_status_t status = EFI_NOT_FOUND;
+       bool found;
+
+       /* Add new sysfs entries */
+       while (1) {
+               variable_name = kzalloc(variable_name_size, GFP_KERNEL);
+               if (!variable_name) {
+                       pr_err("efivars: Memory allocation failed.\n");
+                       return;
+               }
+
+               spin_lock_irq(&efivars->lock);
+               found = false;
+               while (1) {
+                       variable_name_size = 1024;
+                       status = efivars->ops->get_next_variable(
+                                                       &variable_name_size,
+                                                       variable_name,
+                                                       &vendor);
+                       if (status != EFI_SUCCESS) {
+                               break;
+                       } else {
+                               if (!variable_is_present(variable_name,
+                                   &vendor)) {
+                                       found = true;
+                                       break;
+                               }
+                       }
+               }
+               spin_unlock_irq(&efivars->lock);
+
+               if (!found) {
+                       kfree(variable_name);
+                       break;
+               } else
+                       efivar_create_sysfs_entry(efivars,
+                                                 variable_name_size,
+                                                 variable_name, &vendor);
+       }
+}
+
 /*
  * Let's not leave out systab information that snuck into
  * the efivars driver
@@ -1594,9 +1678,9 @@ efivar_create_sysfs_entry(struct efivars *efivars,
        kfree(short_name);
        short_name = NULL;
 
-       spin_lock(&efivars->lock);
+       spin_lock_irq(&efivars->lock);
        list_add(&new_efivar->list, &efivars->list);
-       spin_unlock(&efivars->lock);
+       spin_unlock_irq(&efivars->lock);
 
        return 0;
 }
@@ -1665,9 +1749,9 @@ void unregister_efivars(struct efivars *efivars)
        struct efivar_entry *entry, *n;
 
        list_for_each_entry_safe(entry, n, &efivars->list, list) {
-               spin_lock(&efivars->lock);
+               spin_lock_irq(&efivars->lock);
                list_del(&entry->list);
-               spin_unlock(&efivars->lock);
+               spin_unlock_irq(&efivars->lock);
                efivar_unregister(entry);
        }
        if (efivars->new_var)
@@ -1823,6 +1907,8 @@ err_put:
 static void __exit
 efivars_exit(void)
 {
+       cancel_work_sync(&efivar_work);
+
        if (efi_enabled(EFI_RUNTIME_SERVICES)) {
                unregister_efivars(&__efivars);
                kobject_put(efi_kobj);
index 67de74c..e4bcb2c 100644 (file)
@@ -418,9 +418,25 @@ static struct file_system_type pstore_fs_type = {
        .kill_sb        = pstore_kill_sb,
 };
 
+static struct kobject *pstore_kobj;
+
 static int __init init_pstore_fs(void)
 {
-       return register_filesystem(&pstore_fs_type);
+       int err = 0;
+
+       /* Create a convenient mount point for people to access pstore */
+       pstore_kobj = kobject_create_and_add("pstore", fs_kobj);
+       if (!pstore_kobj) {
+               err = -ENOMEM;
+               goto out;
+       }
+
+       err = register_filesystem(&pstore_fs_type);
+       if (err < 0)
+               kobject_put(pstore_kobj);
+
+out:
+       return err;
 }
 module_init(init_pstore_fs)
 
index 5ea2e77..86d1038 100644 (file)
@@ -96,6 +96,27 @@ static const char *get_reason_str(enum kmsg_dump_reason reason)
        }
 }
 
+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
@@ -114,10 +135,12 @@ static void pstore_dump(struct kmsg_dumper *dumper,
 
        why = get_reason_str(reason);
 
-       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");
+       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++;
@@ -143,9 +166,9 @@ static void pstore_dump(struct kmsg_dumper *dumper,
                total += hsize + len;
                part++;
        }
-       if (in_nmi()) {
+       if (pstore_cannot_block_path(reason)) {
                if (is_locked)
-                       spin_unlock(&psinfo->buf_lock);
+                       spin_unlock_irqrestore(&psinfo->buf_lock, flags);
        } else
                spin_unlock_irqrestore(&psinfo->buf_lock, flags);
 }
index 7a9498a..9bf2f1f 100644 (file)
@@ -740,7 +740,8 @@ struct efivars {
         * 1) ->list - adds, removals, reads, writes
         * 2) ops.[gs]et_variable() calls.
         * It must not be held when creating sysfs entries or calling kmalloc.
-        * ops.get_next_variable() is only called from register_efivars(),
+        * ops.get_next_variable() is only called from register_efivars()
+        * or efivar_update_sysfs_entries(),
         * which is protected by the BKL, so that path is safe.
         */
        spinlock_t lock;
index 1788909..75d0176 100644 (file)
@@ -68,12 +68,18 @@ struct pstore_info {
 
 #ifdef CONFIG_PSTORE
 extern int pstore_register(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*/