[SCSI] fnic: Fnic Trace Utility

Fnic Trace utility is a tracing functionality built directly into fnic driver
to trace events. The benefit that trace buffer brings to fnic driver is the
ability to see what it happening inside the fnic driver. It also provides the
capability to trace every IO event inside fnic driver to debug panics, hangs
and potentially IO corruption issues. This feature makes it easy to find
problems in fnic driver and it also helps in tracking down strange bugs in a
more manageable way. Trace buffer is shared across all fnic instances for
this implementation.

Signed-off-by: Hiral Patel <hiralpat@cisco.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/drivers/scsi/fnic/fnic_main.c b/drivers/scsi/fnic/fnic_main.c
index fcecbb7281a..d601ac543c5 100644
--- a/drivers/scsi/fnic/fnic_main.c
+++ b/drivers/scsi/fnic/fnic_main.c
@@ -68,6 +68,10 @@ unsigned int fnic_log_level;
 module_param(fnic_log_level, int, S_IRUGO|S_IWUSR);
 MODULE_PARM_DESC(fnic_log_level, "bit mask of fnic logging levels");
 
+unsigned int fnic_trace_max_pages = 16;
+module_param(fnic_trace_max_pages, uint, S_IRUGO|S_IWUSR);
+MODULE_PARM_DESC(fnic_trace_max_pages, "Total allocated memory pages "
+					"for fnic trace buffer");
 
 static struct libfc_function_template fnic_transport_template = {
 	.frame_send = fnic_send,
@@ -861,6 +865,14 @@ static int __init fnic_init_module(void)
 
 	printk(KERN_INFO PFX "%s, ver %s\n", DRV_DESCRIPTION, DRV_VERSION);
 
+	/* Allocate memory for trace buffer */
+	err = fnic_trace_buf_init();
+	if (err < 0) {
+		printk(KERN_ERR PFX "Trace buffer initialization Failed "
+				  "Fnic Tracing utility is disabled\n");
+		fnic_trace_free();
+	}
+
 	/* Create a cache for allocation of default size sgls */
 	len = sizeof(struct fnic_dflt_sgl_list);
 	fnic_sgl_cache[FNIC_SGL_CACHE_DFLT] = kmem_cache_create
@@ -931,6 +943,7 @@ err_create_fnic_ioreq_slab:
 err_create_fnic_sgl_slab_max:
 	kmem_cache_destroy(fnic_sgl_cache[FNIC_SGL_CACHE_DFLT]);
 err_create_fnic_sgl_slab_dflt:
+	fnic_trace_free();
 	return err;
 }
 
@@ -942,6 +955,7 @@ static void __exit fnic_cleanup_module(void)
 	kmem_cache_destroy(fnic_sgl_cache[FNIC_SGL_CACHE_DFLT]);
 	kmem_cache_destroy(fnic_io_req_cache);
 	fc_release_transport(fnic_fc_transport);
+	fnic_trace_free();
 }
 
 module_init(fnic_init_module);