From: Roman Bolshakov <r.bolshakov@yadro.com>
Date: Fri, 12 Nov 2021 17:54:46 +0300
Subject: scsi: qla2xxx: Format log strings only if needed
Patch-mainline: v5.16-rc5
Git-commit: 69002c8ce914ef0ae22a6ea14b43bb30b9a9a6a8
References: git-fixes

Commit 598a90f2002c ("scsi: qla2xxx: add ring buffer for tracing debug
logs") introduced unconditional log string formatting to ql_dbg() even if
ql_dbg_log event is disabled. It harms performance because some strings are
formatted in fastpath and/or interrupt context.

Link: https://lore.kernel.org/r/20211112145446.51210-1-r.bolshakov@yadro.com
Fixes: 598a90f2002c ("scsi: qla2xxx: add ring buffer for tracing debug logs")
Cc: Rajan Shanmugavelu <rajan.shanmugavelu@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Daniel Wagner <dwagner@suse.de>
---
 drivers/scsi/qla2xxx/qla_dbg.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/scsi/qla2xxx/qla_dbg.c
+++ b/drivers/scsi/qla2xxx/qla_dbg.c
@@ -2492,6 +2492,9 @@ ql_dbg(uint level, scsi_qla_host_t *vha,
 	struct va_format vaf;
 	char pbuf[64];
 
+	if (!ql_mask_match(level) && !trace_ql_dbg_log_enabled())
+		return;
+
 	va_start(va, fmt);
 
 	vaf.fmt = fmt;