Fix bug in module unloading.

Switch to always using spinlock over cmpxchg.
 Explicitly define pstore backend's supported modes.
 Remove bounce buffer from pmsg.
 Switch to using memcpy_to/fromio().
 Error checking improvements.
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Merge tag 'pstore-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux

Pull pstore updates from Kees Cook:

 - Fix bug in module unloading

 - Switch to always using spinlock over cmpxchg

 - Explicitly define pstore backend's supported modes

 - Remove bounce buffer from pmsg

 - Switch to using memcpy_to/fromio()

 - Error checking improvements

* tag 'pstore-v4.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  ramoops: move spin_lock_init after kmalloc error checking
  pstore/ram: Use memcpy_fromio() to save old buffer
  pstore/ram: Use memcpy_toio instead of memcpy
  pstore/pmsg: drop bounce buffer
  pstore/ram: Set pstore flags dynamically
  pstore: Split pstore fragile flags
  pstore/core: drop cmpxchg based updates
  pstore/ramoops: fixup driver removal

drivers/acpi/apei/erst.c

@@ -938,7 +938,7 @@ static int erst_clearer(enum pstore_type_id type, u64 id, int count,
 static struct pstore_info erst_info = {
 	.owner		= THIS_MODULE,
 	.name		= "erst",
-	.flags		= PSTORE_FLAGS_FRAGILE,
+	.flags		= PSTORE_FLAGS_DMESG,
 	.open		= erst_open_pstore,
 	.close		= erst_close_pstore,
 	.read		= erst_reader,