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path: root/drivers/scsi/libfc/fc_exch.c
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Diffstat (limited to 'drivers/scsi/libfc/fc_exch.c')
-rw-r--r--drivers/scsi/libfc/fc_exch.c37
1 files changed, 26 insertions, 11 deletions
diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index cc320a91b7b7..f5c3c1d09651 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -2127,6 +2127,24 @@ cleanup:
* @arg: The argument to be passed to the response handler
* @timer_msec: The timeout period for the exchange
*
+ * The exchange response handler is set in this routine to resp()
+ * function pointer. It can be called in two scenarios: if a timeout
+ * occurs or if a response frame is received for the exchange. The
+ * fc_frame pointer in response handler will also indicate timeout
+ * as error using IS_ERR related macros.
+ *
+ * The exchange destructor handler is also set in this routine.
+ * The destructor handler is invoked by EM layer when exchange
+ * is about to free, this can be used by caller to free its
+ * resources along with exchange free.
+ *
+ * The arg is passed back to resp and destructor handler.
+ *
+ * The timeout value (in msec) for an exchange is set if non zero
+ * timer_msec argument is specified. The timer is canceled when
+ * it fires or when the exchange is done. The exchange timeout handler
+ * is registered by EM layer.
+ *
* The frame pointer with some of the header's fields must be
* filled before calling this routine, those fields are:
*
@@ -2137,14 +2155,13 @@ cleanup:
* - frame control
* - parameter or relative offset
*/
-static struct fc_seq *fc_exch_seq_send(struct fc_lport *lport,
- struct fc_frame *fp,
- void (*resp)(struct fc_seq *,
- struct fc_frame *fp,
- void *arg),
- void (*destructor)(struct fc_seq *,
- void *),
- void *arg, u32 timer_msec)
+struct fc_seq *fc_exch_seq_send(struct fc_lport *lport,
+ struct fc_frame *fp,
+ void (*resp)(struct fc_seq *,
+ struct fc_frame *fp,
+ void *arg),
+ void (*destructor)(struct fc_seq *, void *),
+ void *arg, u32 timer_msec)
{
struct fc_exch *ep;
struct fc_seq *sp = NULL;
@@ -2197,6 +2214,7 @@ err:
fc_exch_delete(ep);
return NULL;
}
+EXPORT_SYMBOL(fc_exch_seq_send);
/**
* fc_exch_rrq() - Send an ELS RRQ (Reinstate Recovery Qualifier) command
@@ -2630,9 +2648,6 @@ int fc_exch_init(struct fc_lport *lport)
if (!lport->tt.seq_set_resp)
lport->tt.seq_set_resp = fc_seq_set_resp;
- if (!lport->tt.exch_seq_send)
- lport->tt.exch_seq_send = fc_exch_seq_send;
-
if (!lport->tt.seq_send)
lport->tt.seq_send = fc_seq_send;