[PATCH 3/3] blockconsole: Allow to be a module

Takashi Iwai
2013-03-07T18:52:00Z

Move the partition checker code into blockconsole driver so that it
can be built as a module, too. linux/blockconsole.h is removed since
all stuff is found locally in drivers/block/blockconsole.c. Also some
functions are marked as static for the same reason.

A new linked list is added to blockconsole instance for managing the
proper unregistration at unloading the module on the fly.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
block/partitions/Makefile | 1 -
block/partitions/blockconsole.c | 22 -----------
block/partitions/check.c | 3 --
block/partitions/check.h | 4 --
drivers/block/Kconfig | 2 +-
drivers/block/blockconsole.c | 84 +++++++++++++++++++++++++++++++++++++++--
include/linux/blockconsole.h | 7 ----
7 files changed, 81 insertions(+), 42 deletions(-)
delete mode 100644 block/partitions/blockconsole.c
delete mode 100644 include/linux/blockconsole.h

diff --git a/block/partitions/Makefile b/block/partitions/Makefile
index bf26d4a..03af8ea 100644
--- a/block/partitions/Makefile
+++ b/block/partitions/Makefile
@@ -18,4 +18,3 @@ obj-$(CONFIG_IBM_PARTITION) += ibm.o
obj-$(CONFIG_EFI_PARTITION) += efi.o
obj-$(CONFIG_KARMA_PARTITION) += karma.o
obj-$(CONFIG_SYSV68_PARTITION) += sysv68.o
-obj-$(CONFIG_BLOCKCONSOLE) += blockconsole.o
diff --git a/block/partitions/blockconsole.c b/block/partitions/blockconsole.c
deleted file mode 100644
index 79796a8..0000000
--- a/block/partitions/blockconsole.c
+++ /dev/null
@@ -1,22 +0,0 @@
-#include <linux/blockconsole.h>
-
-#include "check.h"
-
-int blockconsole_partition(struct parsed_partitions *state)
-{
- Sector sect;
- void *data;
- int err = 0;
-
- data = read_part_sector(state, 0, &sect);
- if (!data)
- return -EIO;
- if (!bcon_magic_present(data))
- goto out;
-
- bcon_add(state->name);
- err = 1;
-out:
- put_dev_sector(sect);
- return err;
-}
diff --git a/block/partitions/check.c b/block/partitions/check.c
index d71cb02..d9e9324 100644
--- a/block/partitions/check.c
+++ b/block/partitions/check.c
@@ -43,9 +43,6 @@ static int (*check_part[])(struct parsed_partitions *) = {
* Probe partition formats with tables at disk address 0
* that also have an ADFS boot block at 0xdc0.
*/
-#ifdef CONFIG_BLOCKCONSOLE
- blockconsole_partition,
-#endif
#ifdef CONFIG_ACORN_PARTITION_ICS
adfspart_check_ICS,
#endif
diff --git a/block/partitions/check.h b/block/partitions/check.h
index 53c8508..886ed32 100644
--- a/block/partitions/check.h
+++ b/block/partitions/check.h
@@ -52,10 +52,6 @@ put_partition(struct parsed_partitions *p, int n, sector_t from, sector_t size)

extern int warn_no_part;

-#ifdef CONFIG_BLOCKCONSOLE
-int blockconsole_partition(struct parsed_partitions *state);
-#endif
-
struct partition_checker {
int (*check)(struct parsed_partitions *);
struct list_head list;
diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
index 7da1360..2049ad4 100644
--- a/drivers/block/Kconfig
+++ b/drivers/block/Kconfig
@@ -542,7 +542,7 @@ config BLK_DEV_RSXX
module will be called rsxx.

config BLOCKCONSOLE
- bool "Block device console logging support"
+ tristate "Block device console logging support"
help
This enables logging to block devices.
See <file:Documentation/block/blockconsole.txt> for details.
diff --git a/drivers/block/blockconsole.c b/drivers/block/blockconsole.c
index 86744cc..5fc192a 100644
--- a/drivers/block/blockconsole.c
+++ b/drivers/block/blockconsole.c
@@ -4,13 +4,13 @@
* Copyright (C) 2012 Joern Engel <joern@logfs.org>
*/
#include <linux/bio.h>
-#include <linux/blockconsole.h>
#include <linux/console.h>
#include <linux/fs.h>
#include <linux/kref.h>
#include <linux/kthread.h>
#include <linux/mm.h>
#include <linux/mount.h>
+#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/string.h>
@@ -18,6 +18,7 @@
#include <linux/sched.h>
#include <linux/sched/rt.h>
#include <linux/ctype.h>
+#include "../../block/partitions/check.h"

#define BLOCKCONSOLE_MAGIC "\nLinux blockconsole version 1.1\n"
#define BCON_UUID_OFS (32)
@@ -68,8 +69,15 @@ struct blockconsole {
struct work_struct release_work;
struct task_struct *writeback_thread;
struct notifier_block panic_block;
+ struct list_head list;
};

+static DEFINE_SPINLOCK(bc_device_lock);
+static LIST_HEAD(bc_list_head);
+static atomic_t bc_list_count = ATOMIC_INIT(0);
+
+static int bcon_magic_present(const void *data);
+
static void bcon_get(struct blockconsole *bc)
{
kref_get(&bc->kref);
@@ -85,6 +93,7 @@ static void __bcon_release(struct work_struct *work)
invalidate_mapping_pages(bc->bdev->bd_inode->i_mapping, 0, -1);
blkdev_put(bc->bdev, FMODE_READ|FMODE_WRITE);
kfree(bc);
+ atomic_dec(&bc_list_count);
}

static void bcon_release(struct kref *kref)
@@ -285,6 +294,11 @@ static void bcon_unregister(struct work_struct *work)
del_timer_sync(&bc->pad_timer);
kthread_stop(bc->writeback_thread);
/* No new io will be scheduled anymore now */
+
+ spin_lock(&bc_device_lock);
+ list_del_init(&bc->list);
+ spin_unlock(&bc_device_lock);
+
bcon_put(bc);
}

@@ -515,7 +529,13 @@ static int bcon_create(const char *devname)
bc->panic_block.notifier_call = blockconsole_panic;
bc->panic_block.priority = INT_MAX;
atomic_notifier_chain_register(&panic_notifier_list, &bc->panic_block);
+
+ spin_lock(&bc_device_lock);
+ list_add(&bc->list, &bc_list_head);
+ spin_unlock(&bc_device_lock);
+
pr_info("now logging to %s at %llx\n", devname, bc->console_bytes >> 20);
+ atomic_inc(&bc_list_count);

return 0;

@@ -546,13 +566,13 @@ static void bcon_create_fuzzy(const char *name)
}
}

-static DEFINE_SPINLOCK(bc_device_lock);
static char scanned_devices[80];

static void bcon_do_add(struct work_struct *work)
{
char local_devices[80], *name, *remainder = local_devices;

+ atomic_inc(&bc_list_count);
spin_lock(&bc_device_lock);
memcpy(local_devices, scanned_devices, sizeof(local_devices));
memset(scanned_devices, 0, sizeof(scanned_devices));
@@ -562,11 +582,12 @@ static void bcon_do_add(struct work_struct *work)
name = strsep(&remainder, ",");
bcon_create_fuzzy(name);
}
+ atomic_dec(&bc_list_count);
}

static DECLARE_WORK(bcon_add_work, bcon_do_add);

-void bcon_add(const char *name)
+static void bcon_add(const char *name)
{
/*
* We add each name to a small static buffer and ask for a workqueue
@@ -602,7 +623,7 @@ static bool is_four_byte_hex(const void *data)
return true;
}

-int bcon_magic_present(const void *data)
+static int bcon_magic_present(const void *data)
{
size_t len = strlen(BLOCKCONSOLE_MAGIC);

@@ -616,3 +637,58 @@ int bcon_magic_present(const void *data)
return 0;
return 11;
}
+
+static int blockconsole_partition(struct parsed_partitions *state)
+{
+ Sector sect;
+ void *data;
+ int err = 0;
+
+ data = read_part_sector(state, 0, &sect);
+ if (!data)
+ return -EIO;
+ if (!bcon_magic_present(data))
+ goto out;
+
+ bcon_add(state->name);
+ err = 1;
+out:
+ put_dev_sector(sect);
+ return err;
+}
+
+static struct partition_checker bc_part_checker = {
+ .check = blockconsole_partition
+};
+
+static int __init bcon_module_init(void)
+{
+ append_partition_checker(&bc_part_checker);
+ return 0;
+}
+
+static void __exit bcon_module_exit(void)
+{
+ remove_partition_checker(&bc_part_checker);
+ cancel_work_sync(&bcon_add_work);
+
+ /* unregister all pending consoles */
+ spin_lock(&bc_device_lock);
+ while (!list_empty(&bc_list_head)) {
+ struct blockconsole *bc;
+ bc = list_first_entry(&bc_list_head, struct blockconsole, list);
+ schedule_work(&bc->unregister_work);
+ list_del_init(&bc->list);
+ }
+ spin_unlock(&bc_device_lock);
+
+ while (atomic_read(&bc_list_count)) {
+ flush_scheduled_work();
+ schedule_timeout(1);
+ }
+}
+
+MODULE_LICENSE("GPL");
+
+module_init(bcon_module_init);
+module_exit(bcon_module_exit);
diff --git a/include/linux/blockconsole.h b/include/linux/blockconsole.h
deleted file mode 100644
index 114f7c5..0000000
--- a/include/linux/blockconsole.h
+++ /dev/null
@@ -1,7 +0,0 @@
-#ifndef LINUX_BLOCKCONSOLE_H
-#define LINUX_BLOCKCONSOLE_H
-
-int bcon_magic_present(const void *data);
-void bcon_add(const char *name);
-
-#endif
--
1.8.1.4