ipmi: ssif_bmc: Fix new request loss when bmc ready for a response

Cosmo found that when there is a new request comes in while BMC is
ready for a response, the complete_response(), which is called to
complete the pending response, would accidentally clear out that new
request and force ssif_bmc to move back to abort state again.

This commit is to address that issue.

Fixes: dd2bc5c ("ipmi: ssif_bmc: Add SSIF BMC driver")
Reported-by: Cosmo Chou <chou.cosmo@gmail.com>
Closes: https://lore.kernel.org/lkml/20250101165431.2113407-1-chou.cosmo@gmail.com/
Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com>
Message-ID: <20250107034734.1842247-1-quan@os.amperecomputing.com>
Signed-off-by: Corey Minyard <corey@minyard.net>

Author: qnguyen-ampere

drivers/char/ipmi/ssif_bmc.c

@@ -292,7 +292,6 @@ static void complete_response(struct ssif_bmc_ctx *ssif_bmc)
 	ssif_bmc->nbytes_processed = 0;
 	ssif_bmc->remain_len = 0;
 	ssif_bmc->busy = false;
-	memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
 	wake_up_all(&ssif_bmc->wait_queue);
 }
 
@@ -744,9 +743,11 @@ static void on_stop_event(struct ssif_bmc_ctx *ssif_bmc, u8 *val)
 			ssif_bmc->aborting = true;
 		}
 	} else if (ssif_bmc->state == SSIF_RES_SENDING) {
-		if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF)
+		if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num == 0xFF) {
+			memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
 			/* Invalidate response buffer to denote it is sent */
 			complete_response(ssif_bmc);
+		}
 		ssif_bmc->state = SSIF_READY;
 	}