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
