Commit 024e4ec1 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

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
parents 850cb82b fb0af3f2

Documentation/ABI/testing/pstore

+5 −5
Original line number Diff line number Diff line 
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.

drivers/firmware/efivars.c

+133 −47
Original line number Diff line number Diff line
@@ -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;

	unsigned long flags;



	spin_lock(&efivars->lock);

	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);

fs/pstore/inode.c

+17 −1
Original line number Diff line number Diff line
@@ -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)

fs/pstore/platform.c

+29 −6
Original line number Diff line number Diff line
@@ -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);

}

include/linux/efi.h

+2 −1
Original line number Diff line number Diff line
@@ -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;

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