Merge tag 'please-pull-pstore' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux

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

1 files changed, 133 insertions, 47 deletions

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index f5596db0cf58..fed08b661711 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -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);