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authorWeiXiong Liao <liaoweixiong@allwinnertech.com>2020-03-25 16:55:05 +0800
committerKees Cook <keescook@chromium.org>2020-05-31 19:49:00 -0700
commit7dcb7848ba110ff192efc917d1a6de66b4c9ca4f (patch)
tree53e7bdd3c266bbadeb9b7091889a736f5c76897a /fs/pstore
parent1525fb3bb6d69028b3941d34363397c28345ffab (diff)
downloadlinux-7dcb7848ba110ff192efc917d1a6de66b4c9ca4f.tar.bz2
pstore/blk: Support non-block storage devices
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@allwinnertech.com> Link: https://lore.kernel.org/lkml/20200511233229.27745-10-keescook@chromium.org/ Co-developed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'fs/pstore')
-rw-r--r--fs/pstore/blk.c93
-rw-r--r--fs/pstore/zone.c8
2 files changed, 57 insertions, 44 deletions
diff --git a/fs/pstore/blk.c b/fs/pstore/blk.c
index 631bc27c8661..881b40ed8142 100644
--- a/fs/pstore/blk.c
+++ b/fs/pstore/blk.c
@@ -105,55 +105,22 @@ 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;
+ lockdep_assert_held(&pstore_blk_lock);
+
if (!dev || !dev->total_size || !dev->read || !dev->write)
return -EINVAL;
- mutex_lock(&pstore_blk_lock);
-
/* 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 +146,7 @@ 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 +156,51 @@ 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);
+ lockdep_assert_held(&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
@@ -396,9 +395,10 @@ 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;
@@ -442,7 +442,7 @@ static void __unregister_pstore_blk(unsigned int major)
lockdep_assert_held(&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;
@@ -481,6 +481,13 @@ 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 add26b125984..819428dfa32f 100644
--- a/fs/pstore/zone.c
+++ b/fs/pstore/zone.c
@@ -660,15 +660,21 @@ 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,