Patch "megaraid_sas: Do not fire MR_DCMD_PD_LIST_QUERY to controllers which do not support it" has been added to the 4.7-stable tree

This is a note to let you know that I've just added the patch titled

megaraid_sas: Do not fire MR_DCMD_PD_LIST_QUERY to controllers which do not support it

to the 4.7-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
megaraid_sas-do-not-fire-mr_dcmd_pd_list_query-to-controllers-which-do-not-support-it.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sumit Saxena <[email protected]>
Date: Fri, 8 Jul 2016 03:30:16 -0700
Subject: megaraid_sas: Do not fire MR_DCMD_PD_LIST_QUERY to controllers which do not support it

From: Sumit Saxena <[email protected]>

commit d9083160c2f6ee456ea867ea2279c1fc6124e56f upstream.

There was an issue reported by Lucz Geza on Dell Perc 6i. As per issue reported, megaraid_sas driver goes into an infinite error reporting loop as soon as there is a change in the status of one of the arrays (degrade, resync online etc ). Below are the error logs reported continuously-

Jun 25 08:49:30 ns8 kernel: [  757.757017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.778017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.799017] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.820018] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115
Jun 25 08:49:30 ns8 kernel: [  757.841018] megaraid_sas 0000:02:00.0: DCMD failed/not supported by firmware: megasas_get_pd_list 4115

This issue is very much specific to controllers which do not support DCMD- MR_DCMD_PD_LIST_QUERY. In case of any hotplugging/rescanning of drives, AEN thread will be scheduled by driver and fire DCMD- MR_DCMD_PD_LIST_QUERY and if this DCMD is failed then driver will fail this event processing and will not go ahead for further events. This will cause infinite loop of same event getting retried infinitely and causing above mentioned logs.

Fix for this problem is: not to fire DCMD MR_DCMD_PD_LIST_QUERY for controllers which do not support it and send DCMD SUCCESS status to AEN function so that it can go ahead with other event processing.

---
 drivers/scsi/megaraid/megaraid_sas_base.c |    6 ++++++
 1 file changed, 6 insertions(+)

@@ -4079,6 +4079,12 @@ megasas_get_pd_list(struct megasas_insta
 	struct MR_PD_ADDRESS *pd_addr;
 	dma_addr_t ci_h = 0;
 
+	if (instance->pd_list_not_supported) {
+		dev_info(&instance->pdev->dev, "MR_DCMD_PD_LIST_QUERY "
+		"not supported by firmware\n");
+		return ret;
+	}
+
 	cmd = megasas_get_cmd(instance);
 
 	if (!cmd) {

Patches currently in stable-queue which might be from [email protected] are

queue-4.7/megaraid_sas-do-not-fire-mr_dcmd_pd_list_query-to-controllers-which-do-not-support-it.patch