libflash/ipmi-hiomap: Overhaul event handling

Reworking the event handling was inspired by a bug report by Vasant
where the host would get wedged on multiple flash access attempts in the
face of a persistent error state on the BMC-side. The cause of this bug
was the early-exit based on ctx->update, which erronously assumed that
all events had been completely handled in prior calls to
ipmi_hiomap_handle_events(). This is not true if e.g.
HIOMAP_E_DAEMON_READY is clear in the prior calls.

Regardless, there were other correctness and efficiency problems with
the handling strategy:

* Ack-able event state was not restored in the face of errors in the
  process of re-establishing protocol state

* It forced needless window restoration with respect to the context in
  which ipmi_hiomap_handle_events() was called.

* Tests for HIOMAP_E_DAEMON_READY and HIOMAP_E_FLASH_LOST were redundant
  with the overhauled error handling introduced in the previous patch

Fix all of the above issues and add comments to explain the event
handling flow.

Tests for correctness follow later in the series.

Cc: stable
Cc: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Signed-off-by: Stewart Smith <stewart@linux.ibm.com>

1 files changed, 0 insertions, 1 deletions

diff --git a/libflash/ipmi-hiomap.h b/libflash/ipmi-hiomap.h
index f60f725..edd4ee0 100644
--- a/libflash/ipmi-hiomap.h
+++ b/libflash/ipmi-hiomap.h
@@ -48,7 +48,6 @@ struct ipmi_hiomap {
 	 * three variables are protected by lock to avoid conflict.
 	 */
 	struct lock lock;
-	bool update;
 	uint8_t bmc_state;
 	enum lpc_window_state window_state;
 };