[PATCH v5 11/12] pstore/blk: Support non-block storage devices
From: WeiXiong Liao
Date: Sat May 09 2020 - 07:15:24 EST
Add support for non-block devices (e.g. MTD). A non-block driver calls
pstore_blk_register_device() to register iself.
In addition, pstore/zone is updated to handle non-block devices,
where an erase must be done before a write. Without this, there is no
way to remove records stored to an MTD.
Signed-off-by: WeiXiong Liao <liaoweixiong@xxxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/1585126506-18635-11-git-send-email-liaoweixiong@xxxxxxxxxxxxxxxxx
Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
---
Documentation/admin-guide/pstore-blk.rst | 17 ++++++++---
fs/pstore/blk.c | 52 ++++++++++++--------------------
fs/pstore/zone.c | 8 ++++-
include/linux/pstore_blk.h | 37 +++++++++++++++++++++++
include/linux/pstore_zone.h | 6 ++++
5 files changed, 83 insertions(+), 37 deletions(-)
diff --git a/Documentation/admin-guide/pstore-blk.rst b/Documentation/admin-guide/pstore-blk.rst
index 484a1502fb49..2f3602397715 100644
--- a/Documentation/admin-guide/pstore-blk.rst
+++ b/Documentation/admin-guide/pstore-blk.rst
@@ -7,8 +7,8 @@ Introduction
------------
pstore block (pstore/blk) is an oops/panic logger that writes its logs to a
-block device before the system crashes. You can get these log files by
-mounting pstore filesystem like::
+block device and non-block device before the system crashes. You can get
+these log files by mounting pstore filesystem like::
mount -t pstore pstore /sys/fs/pstore
@@ -24,8 +24,8 @@ Configurations for user determine how pstore/blk works, such as pmsg_size,
kmsg_size and so on. All of them support both Kconfig and module parameters,
but module parameters have priority over Kconfig.
-Configurations for driver are all about block device, such as total_size
-of block device and read/write operations.
+Configurations for driver are all about block device and non-block device,
+such as total_size of block device and read/write operations.
Configurations for user
-----------------------
@@ -152,6 +152,15 @@ driver uses ``psblk_register_blkdev`` to register to pstore/blk.
.. kernel-doc:: fs/pstore/blk.c
:identifiers: psblk_register_blkdev
+A non-block device driver uses ``psblk_register_device`` with
+``struct psblk_device`` to register to pstore/blk.
+
+.. kernel-doc:: fs/pstore/blk.c
+ :identifiers: psblk_register_device
+
+.. kernel-doc:: include/linux/pstore_blk.h
+ :identifiers: psblk_device
+
Compression and header
----------------------
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index a6d578f9df2a..45f61d4ae105 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -98,36 +98,15 @@
})
/**
- * struct psblk_device - back-end pstore/blk driver structure.
+ * psblk_register_device() - register non-block device to pstore/blk
*
- * @total_size: The total size in bytes pstore/blk can use. It must be greater
- * than 4096 and be multiple of 4096.
- * @flags: Refer to macro starting with PSTORE_FLAGS defined in
- * linux/pstore.h. It means what front-ends this device support.
- * Zero means all backends for compatible.
- * @read: The general read operation. Both of the function parameters
- * @size and @offset are relative value to bock device (not the
- * whole disk).
- * On success, the number of bytes should be returned, others
- * means error.
- * @write: The same as @read, but the following error number:
- * -EBUSY means try to write again later.
- * -ENOMSG means to try next zone.
- * @panic_write:The write operation only used for panic case. It's optional
- * if you do not care panic log. The parameters are relative
- * value to storage.
- * On success, the number of bytes should be returned, others
- * excluding -ENOMSG mean error. -ENOMSG means to try next zone.
+ * @dev: non-block device information
+ *
+ * Return:
+ * * 0 - OK
+ * * Others - something error.
*/
-struct psblk_device {
- unsigned long total_size;
- unsigned int flags;
- psz_read_op read;
- psz_write_op write;
- psz_write_op panic_write;
-};
-
-static int psblk_register_do(struct psblk_device *dev)
+int psblk_register_device(struct psblk_device *dev)
{
int ret;
@@ -170,6 +149,7 @@ static int psblk_register_do(struct psblk_device *dev)
pstore_zone_info->max_reason = max_reason;
pstore_zone_info->read = dev->read;
pstore_zone_info->write = dev->write;
+ pstore_zone_info->erase = dev->erase;
pstore_zone_info->panic_write = dev->panic_write;
pstore_zone_info->name = MODNAME;
pstore_zone_info->owner = THIS_MODULE;
@@ -182,8 +162,14 @@ static int psblk_register_do(struct psblk_device *dev)
mutex_unlock(&psz_lock);
return ret;
}
+EXPORT_SYMBOL_GPL(psblk_register_device);
-static void psblk_unregister_do(struct psblk_device *dev)
+/**
+ * psblk_unregister_blkdev() - unregister block device from pstore/blk
+ *
+ * @dev: non-block device information
+ */
+void psblk_unregister_device(struct psblk_device *dev)
{
mutex_lock(&psz_lock);
if (pstore_zone_info && pstore_zone_info->read == dev->read) {
@@ -193,6 +179,7 @@ static void psblk_unregister_do(struct psblk_device *dev)
}
mutex_unlock(&psz_lock);
}
+EXPORT_SYMBOL_GPL(psblk_unregister_device);
/**
* psblk_get_bdev() - open block device
@@ -406,11 +393,12 @@ int psblk_register_blkdev(unsigned int major, unsigned int flags,
dev.total_size = psblk_bdev_size(bdev);
dev.flags = flags;
- dev.panic_write = panic_write ? psblk_blk_panic_write : NULL;
dev.read = psblk_generic_blk_read;
dev.write = psblk_generic_blk_write;
+ dev.erase = NULL;
+ dev.panic_write = panic_write ? psblk_blk_panic_write : NULL;
- ret = psblk_register_do(&dev);
+ ret = psblk_register_device(&dev);
if (ret)
goto err_put_bdev;
@@ -436,7 +424,7 @@ void psblk_unregister_blkdev(unsigned int major)
void *holder = blkdev;
if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) {
- psblk_unregister_do(&dev);
+ psblk_unregister_device(&dev);
psblk_put_bdev(psblk_bdev, holder);
blkdev_panic_write = NULL;
psblk_bdev = NULL;
diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c
index 9a9a4a7134d0..bc4d4f3041b8 100644
--- a/fs/pstore/zone.c
+++ b/fs/pstore/zone.c
@@ -659,15 +659,21 @@ static inline int psz_oops_erase(struct psz_context *cxt,
struct psz_buffer *buffer = zone->buffer;
struct psz_oops_header *hdr =
(struct psz_oops_header *)buffer->data;
+ size_t size;
if (unlikely(!psz_ok(zone)))
return 0;
+
/* this zone is already updated, no need to erase */
if (record->count != hdr->counter)
return 0;
+ size = buffer_datalen(zone) + sizeof(*zone->buffer);
atomic_set(&zone->buffer->datalen, 0);
- return psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
+ if (cxt->pstore_zone_info->erase)
+ return cxt->pstore_zone_info->erase(size, zone->off);
+ else
+ return psz_zone_write(zone, FLUSH_META, NULL, 0, 0);
}
static inline int psz_record_erase(struct psz_context *cxt,
diff --git a/include/linux/pstore_blk.h b/include/linux/pstore_blk.h
index dd5213044e21..43242e343dad 100644
--- a/include/linux/pstore_blk.h
+++ b/include/linux/pstore_blk.h
@@ -8,6 +8,41 @@
#include <linux/pstore_zone.h>
/**
+ * struct psblk_device - back-end pstore/blk driver structure.
+ *
+ * @total_size: The total size in bytes pstore/blk can use. It must be greater
+ * than 4096 and be multiple of 4096.
+ * @flags: Refer to macro starting with PSTORE_FLAGS defined in
+ * linux/pstore.h. It means what front-ends this device support.
+ * Zero means all backends for compatible.
+ * @read: The general read operation. Both of the function parameters
+ * @size and @offset are relative value to bock device (not the
+ * whole disk).
+ * On success, the number of bytes should be returned, others
+ * means error.
+ * @write: The same as @read, but the following error number:
+ * -EBUSY means try to write again later.
+ * -ENOMSG means to try next zone.
+ * @erase: The general erase operation for device with special removing
+ * job. Both of the function parameters @size and @offset are
+ * relative value to storage.
+ * Return 0 on success and others on failure.
+ * @panic_write:The write operation only used for panic case. It's optional
+ * if you do not care panic log. The parameters are relative
+ * value to storage.
+ * On success, the number of bytes should be returned, others
+ * excluding -ENOMSG mean error. -ENOMSG means to try next zone.
+ */
+struct psblk_device {
+ unsigned long total_size;
+ unsigned int flags;
+ psz_read_op read;
+ psz_write_op write;
+ psz_erase_op erase;
+ psz_write_op panic_write;
+};
+
+/**
* typedef psblk_panic_write_op - panic write operation to block device
*
* @buf: the data to write
@@ -22,6 +57,8 @@
typedef int (*psblk_panic_write_op)(const char *buf, sector_t start_sect,
sector_t sects);
+int psblk_register_device(struct psblk_device *dev);
+void psblk_unregister_device(struct psblk_device *dev);
int psblk_register_blkdev(unsigned int major, unsigned int flags,
psblk_panic_write_op panic_write);
void psblk_unregister_blkdev(unsigned int major);
diff --git a/include/linux/pstore_zone.h b/include/linux/pstore_zone.h
index ddb3dfea4ea6..2c031a25ee5f 100644
--- a/include/linux/pstore_zone.h
+++ b/include/linux/pstore_zone.h
@@ -7,6 +7,7 @@
typedef ssize_t (*psz_read_op)(char *, size_t, loff_t);
typedef ssize_t (*psz_write_op)(const char *, size_t, loff_t);
+typedef ssize_t (*psz_erase_op)(size_t, loff_t);
/**
* struct pstore_zone_info - pstore/zone back-end driver structure
*
@@ -27,6 +28,10 @@
* @write: The same as @read, but the following error number:
* -EBUSY means try to write again later.
* -ENOMSG means to try next zone.
+ * @erase: The general erase operation for device with special removing
+ * job. Both of the function parameters @size and @offset are
+ * relative value to storage.
+ * Return 0 on success and others on failure.
* @panic_write:The write operation only used for panic case. It's optional
* if you do not care panic log. The parameters are relative
* value to storage.
@@ -45,6 +50,7 @@ struct pstore_zone_info {
unsigned long ftrace_size;
psz_read_op read;
psz_write_op write;
+ psz_erase_op erase;
psz_write_op panic_write;
};
--
1.9.1