[SCSI] mpt2sas: Added sysfs support for trace buffer

Added support so the diag ring buffer can be pulled via sysfs
Added three new shost attributes: host_trace_buffer,
host_trace_buffer_enable, and host_trace_buffer_size.  The
host_trace_buffer_enable attribute is used to either post or release
the trace buffers.   The host_trace_buffer_size attribute contains
the size of the trace buffer. The host_trace_buffer atttribute contains
a maximum 4KB window of the buffer. In order to read the entire host buffer,
you will need to write the offset to  host_trace_buffer prior to reading
it. release the host buffer, then write the entire host buffer contents to
a file.
In addition to this enhancement, we moved the automatic posting of host buffers
at driver load time to be called prior to port_enable, instead of after.
That way discovery is available in the host buffer.

Signed-off-by: Kashyap Desai <kashyap.desai@lsi.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.c b/drivers/scsi/mpt2sas/mpt2sas_base.c
index 88befc7..93c0623 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.c
@@ -3529,8 +3529,12 @@ _base_make_ioc_operational(struct MPT2SAS_ADAPTER *ioc, int sleep_flag)
 	if (sleep_flag == CAN_SLEEP)
 		_base_static_config_pages(ioc);
 
-	if (ioc->wait_for_port_enable_to_complete && disable_discovery > 0)
-		return r;
+	if (ioc->wait_for_port_enable_to_complete) {
+		if (diag_buffer_enable != 0)
+			mpt2sas_enable_diag_buffer(ioc, diag_buffer_enable);
+		if (disable_discovery > 0)
+			return r;
+	}
 
 	r = _base_send_port_enable(ioc, sleep_flag);
 	if (r)
@@ -3679,8 +3683,6 @@ mpt2sas_base_attach(struct MPT2SAS_ADAPTER *ioc)
 		goto out_free_resources;
 
 	mpt2sas_base_start_watchdog(ioc);
-	if (diag_buffer_enable != 0)
-		mpt2sas_enable_diag_buffer(ioc, diag_buffer_enable);
 	return 0;
 
  out_free_resources: