From: WeiXiong Liao <liaoweixiong@xxxxxxxxxxxxxxxxx> 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 | 94 +++++++++++++----------- fs/pstore/zone.c | 8 +- include/linux/pstore_blk.h | 38 ++++++++++ include/linux/pstore_zone.h | 6 ++ 5 files changed, 115 insertions(+), 48 deletions(-) diff --git a/Documentation/admin-guide/pstore-blk.rst b/Documentation/admin-guide/pstore-blk.rst index bef8c7436721..d45341e55e82 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 ``register_pstore_blk`` to register to pstore/blk. .. kernel-doc:: fs/pstore/blk.c :identifiers: register_pstore_blk +A non-block device driver uses ``register_pstore_device`` with +``struct pstore_device_info`` to register to pstore/blk. + +.. kernel-doc:: fs/pstore/blk.c + :identifiers: register_pstore_device + +.. kernel-doc:: include/linux/pstore_blk.h + :identifiers: pstore_device_info + Compression and header ---------------------- diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c index 95436cff8976..a1bd7c1fdfa0 100644 --- a/fs/pstore/blk.c +++ b/fs/pstore/blk.c @@ -105,55 +105,23 @@ struct bdev_info { _##name_; \ }) -/** - * struct pstore_device_info - 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. - * @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 pstore_device_info { - unsigned long total_size; - unsigned int flags; - pstore_zone_read_op read; - pstore_zone_write_op write; - pstore_zone_write_op panic_write; -}; - -static int psblk_register_do(struct pstore_device_info *dev) +static int __register_pstore_device(struct pstore_device_info *dev) { int ret; - if (!dev || !dev->total_size || !dev->read || !dev->write) + if (WARN_ON(!mutex_is_locked(&pstore_blk_lock))) return -EINVAL; - mutex_lock(&pstore_blk_lock); + if (!dev || !dev->total_size || !dev->read || !dev->write) + return -EINVAL; /* someone already registered before */ - if (pstore_zone_info) { - mutex_unlock(&pstore_blk_lock); + if (pstore_zone_info) return -EBUSY; - } + pstore_zone_info = kzalloc(sizeof(struct pstore_zone_info), GFP_KERNEL); - if (!pstore_zone_info) { - mutex_unlock(&pstore_blk_lock); + if (!pstore_zone_info) return -ENOMEM; - } /* zero means not limit on which backends to attempt to store. */ if (!dev->flags) @@ -179,6 +147,7 @@ static int psblk_register_do(struct pstore_device_info *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 = KBUILD_MODNAME; pstore_zone_info->owner = THIS_MODULE; @@ -188,20 +157,51 @@ static int psblk_register_do(struct pstore_device_info *dev) kfree(pstore_zone_info); pstore_zone_info = NULL; } + return ret; +} +/** + * register_pstore_device() - register non-block device to pstore/blk + * + * @dev: non-block device information + * + * Return: + * * 0 - OK + * * Others - something error. + */ +int register_pstore_device(struct pstore_device_info *dev) +{ + int ret; + + mutex_lock(&pstore_blk_lock); + ret = __register_pstore_device(dev); mutex_unlock(&pstore_blk_lock); + return ret; } +EXPORT_SYMBOL_GPL(register_pstore_device); -static void psblk_unregister_do(struct pstore_device_info *dev) +static void __unregister_pstore_device(struct pstore_device_info *dev) { - mutex_lock(&pstore_blk_lock); + WARN_ON(!mutex_is_locked(&pstore_blk_lock)); if (pstore_zone_info && pstore_zone_info->read == dev->read) { unregister_pstore_zone(pstore_zone_info); kfree(pstore_zone_info); pstore_zone_info = NULL; } +} + +/** + * unregister_pstore_device() - unregister non-block device from pstore/blk + * + * @dev: non-block device information + */ +void unregister_pstore_device(struct pstore_device_info *dev) +{ + mutex_lock(&pstore_blk_lock); + __unregister_pstore_device(dev); mutex_unlock(&pstore_blk_lock); } +EXPORT_SYMBOL_GPL(unregister_pstore_device); /** * psblk_get_bdev() - open block device @@ -399,9 +399,10 @@ static int __register_pstore_blk(struct pstore_blk_info *info) dev.flags = info->flags; dev.read = psblk_generic_blk_read; dev.write = psblk_generic_blk_write; + dev.erase = NULL; dev.panic_write = info->panic_write ? psblk_blk_panic_write : NULL; - ret = psblk_register_do(&dev); + ret = __register_pstore_device(&dev); if (ret) goto err_put_bdev; @@ -445,7 +446,7 @@ static void __unregister_pstore_blk(unsigned int major) WARN_ON(!mutex_is_locked(&pstore_blk_lock)); if (psblk_bdev && MAJOR(psblk_bdev->bd_dev) == major) { - psblk_unregister_do(&dev); + __unregister_pstore_device(&dev); psblk_put_bdev(psblk_bdev, holder); blkdev_panic_write = NULL; psblk_bdev = NULL; @@ -484,6 +485,13 @@ static void __exit pstore_blk_exit(void) mutex_lock(&pstore_blk_lock); if (psblk_bdev) __unregister_pstore_blk(MAJOR(psblk_bdev->bd_dev)); + else { + struct pstore_device_info dev = { }; + + if (pstore_zone_info) + dev.read = pstore_zone_info->read; + __unregister_pstore_device(&dev); + } mutex_unlock(&pstore_blk_lock); } module_exit(pstore_blk_exit); diff --git a/fs/pstore/zone.c b/fs/pstore/zone.c index 110a38242f74..bd8e194110fc 100644 --- a/fs/pstore/zone.c +++ b/fs/pstore/zone.c @@ -661,15 +661,21 @@ static inline int psz_kmsg_erase(struct psz_context *cxt, struct psz_buffer *buffer = zone->buffer; struct psz_kmsg_header *hdr = (struct psz_kmsg_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 0c40774e71e0..61e914522b01 100644 --- a/include/linux/pstore_blk.h +++ b/include/linux/pstore_blk.h @@ -49,6 +49,44 @@ struct pstore_blk_info { int register_pstore_blk(struct pstore_blk_info *info); void unregister_pstore_blk(unsigned int major); +/** + * struct pstore_device_info - 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 pstore_device_info { + unsigned long total_size; + unsigned int flags; + pstore_zone_read_op read; + pstore_zone_write_op write; + pstore_zone_erase_op erase; + pstore_zone_write_op panic_write; +}; + +int register_pstore_device(struct pstore_device_info *dev); +void unregister_pstore_device(struct pstore_device_info *dev); + /** * struct pstore_blk_config - the pstore_blk backend configuration * diff --git a/include/linux/pstore_zone.h b/include/linux/pstore_zone.h index e79a18e41064..1e35eaa33e5e 100644 --- a/include/linux/pstore_zone.h +++ b/include/linux/pstore_zone.h @@ -7,6 +7,7 @@ typedef ssize_t (*pstore_zone_read_op)(char *, size_t, loff_t); typedef ssize_t (*pstore_zone_write_op)(const char *, size_t, loff_t); +typedef ssize_t (*pstore_zone_erase_op)(size_t, loff_t); /** * struct pstore_zone_info - pstore/zone back-end driver structure * @@ -27,6 +28,10 @@ typedef ssize_t (*pstore_zone_write_op)(const char *, size_t, loff_t); * @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; pstore_zone_read_op read; pstore_zone_write_op write; + pstore_zone_erase_op erase; pstore_zone_write_op panic_write; }; -- 2.20.1
