pstore improvements and refactorings

- Improve compression handling
 - Refactor argument handling during initialization
 - Avoid needless locking for saner EFI backend handling
 - Add more kern-doc and improve debugging output
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 Comment: Kees Cook <[email protected]>
 
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Merge tag 'pstore-v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:
 "Improvements and refactorings:

   - Improve compression handling

   - Refactor argument handling during initialization

   - Avoid needless locking for saner EFI backend handling

   - Add more kern-doc and improve debugging output"

* tag 'pstore-v4.21-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  pstore/ram: Avoid NULL deref in ftrace merging failure path
  pstore: Convert buf_lock to semaphore
  pstore: Fix bool initialization/comparison
  pstore/ram: Do not treat empty buffers as valid
  pstore/ram: Simplify ramoops_get_next_prz() arguments
  pstore: Map PSTORE_TYPE_* to strings
  pstore: Replace open-coded << with BIT()
  pstore: Improve and update some comments and status output
  pstore/ram: Add kern-doc for struct persistent_ram_zone
  pstore/ram: Report backend assignments with finer granularity
  pstore/ram: Standardize module name in ramoops
  pstore: Avoid duplicate call of persistent_ram_zap()
  pstore: Remove needless lock during console writes
  pstore: Do not use crash buffer for decompression

drivers/acpi/apei/erst.c

@@ -1035,7 +1035,7 @@ skip:
 			     CPER_SECTION_TYPE_MCE) == 0)
 		record->type = PSTORE_TYPE_MCE;
 	else
-		record->type = PSTORE_TYPE_UNKNOWN;
+		record->type = PSTORE_TYPE_MAX;
 
 	if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
 		record->time.tv_sec = rcd->hdr.timestamp;
@@ -1176,7 +1176,6 @@ static int __init erst_init(void)
 	"Error Record Serialization Table (ERST) support is initialized.\n");
 
 	buf = kmalloc(erst_erange.size, GFP_KERNEL);
-	spin_lock_init(&erst_info.buf_lock);
 	if (buf) {
 		erst_info.buf = buf + sizeof(struct cper_pstore_record);
 		erst_info.bufsize = erst_erange.size -