s390/dasd: channel path aware error recovery

With this feature, the DASD device driver more robustly handles DASDs
that are attached via multiple channel paths and are subject to
constant Interface-Control-Checks (IFCCs) and Channel-Control-Checks
(CCCs) or loss of High-Performance-FICON (HPF) functionality on one or
more of these paths.

If a channel path does not work correctly, it is removed from normal
operation as long as other channel paths are available. All extended
error recovery states can be queried and reset via user space
interfaces.

Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com>
Reviewed-by: Sebastian Ott <sebott@linux.vnet.ibm.com>
Reviewed-by: Jan Hoeppner <hoeppner@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 68 insertions, 0 deletions

diff --git a/drivers/s390/block/dasd_int.h b/drivers/s390/block/dasd_int.h
index d75f996884d9..24be210c10e5 100644
--- a/drivers/s390/block/dasd_int.h
+++ b/drivers/s390/block/dasd_int.h
@@ -378,6 +378,10 @@ struct dasd_discipline {
 	int (*check_attention)(struct dasd_device *, __u8);
 	int (*host_access_count)(struct dasd_device *);
 	int (*hosts_print)(struct dasd_device *, struct seq_file *);
+	void (*handle_hpf_error)(struct dasd_device *, struct irb *);
+	void (*disable_hpf)(struct dasd_device *);
+	int (*hpf_enabled)(struct dasd_device *);
+	void (*reset_path)(struct dasd_device *, __u8);
 };
 
 extern struct dasd_discipline *dasd_diag_discipline_pointer;
@@ -407,11 +411,19 @@ extern struct dasd_discipline *dasd_diag_discipline_pointer;
 #define DASD_PATH_MISCABLED    5
 #define DASD_PATH_NOHPF        6
 #define DASD_PATH_CUIR	       7
+#define DASD_PATH_IFCC	       8
 
+#define DASD_THRHLD_MAX		4294967295U
+#define DASD_INTERVAL_MAX	4294967295U
 
 struct dasd_path {
 	unsigned long flags;
+	u8 cssid;
+	u8 ssid;
+	u8 chpid;
 	struct dasd_conf_data *conf_data;
+	atomic_t error_count;
+	unsigned long long errorclk;
 };
 
 
@@ -491,6 +503,7 @@ struct dasd_device {
 	struct work_struct reload_device;
 	struct work_struct kick_validate;
 	struct work_struct suc_work;
+	struct work_struct requeue_requests;
 	struct timer_list timer;
 
 	debug_info_t *debug_area;
@@ -506,6 +519,9 @@ struct dasd_device {
 
 	unsigned long blk_timeout;
 
+	unsigned long path_thrhld;
+	unsigned long path_interval;
+
 	struct dentry *debugfs_dentry;
 	struct dentry *hosts_dentry;
 	struct dasd_profile profile;
@@ -715,6 +731,7 @@ void dasd_set_target_state(struct dasd_device *, int);
 void dasd_kick_device(struct dasd_device *);
 void dasd_restore_device(struct dasd_device *);
 void dasd_reload_device(struct dasd_device *);
+void dasd_schedule_requeue(struct dasd_device *);
 
 void dasd_add_request_head(struct dasd_ccw_req *);
 void dasd_add_request_tail(struct dasd_ccw_req *);
@@ -941,6 +958,21 @@ static inline void dasd_path_clear_cuir(struct dasd_device *device, int chp)
 	__clear_bit(DASD_PATH_CUIR, &device->path[chp].flags);
 }
 
+static inline void dasd_path_ifcc(struct dasd_device *device, int chp)
+{
+	set_bit(DASD_PATH_IFCC, &device->path[chp].flags);
+}
+
+static inline int dasd_path_is_ifcc(struct dasd_device *device, int chp)
+{
+	return test_bit(DASD_PATH_IFCC, &device->path[chp].flags);
+}
+
+static inline void dasd_path_clear_ifcc(struct dasd_device *device, int chp)
+{
+	clear_bit(DASD_PATH_IFCC, &device->path[chp].flags);
+}
+
 static inline void dasd_path_clear_nohpf(struct dasd_device *device, int chp)
 {
 	__clear_bit(DASD_PATH_NOHPF, &device->path[chp].flags);
@@ -1032,6 +1064,17 @@ static inline __u8 dasd_path_get_cuirpm(struct dasd_device *device)
 	return cuirpm;
 }
 
+static inline __u8 dasd_path_get_ifccpm(struct dasd_device *device)
+{
+	int chp;
+	__u8 ifccpm = 0x00;
+
+	for (chp = 0; chp < 8; chp++)
+		if (dasd_path_is_ifcc(device, chp))
+			ifccpm |= 0x80 >> chp;
+	return ifccpm;
+}
+
 static inline __u8 dasd_path_get_hpfpm(struct dasd_device *device)
 {
 	int chp;
@@ -1056,6 +1099,20 @@ static inline void dasd_path_add_tbvpm(struct dasd_device *device, __u8 pm)
 			dasd_path_verify(device, chp);
 }
 
+static inline __u8 dasd_path_get_notoperpm(struct dasd_device *device)
+{
+	int chp;
+	__u8 nopm = 0x00;
+
+	for (chp = 0; chp < 8; chp++)
+		if (dasd_path_is_nohpf(device, chp) ||
+		    dasd_path_is_ifcc(device, chp) ||
+		    dasd_path_is_cuir(device, chp) ||
+		    dasd_path_is_miscabled(device, chp))
+			nopm |= 0x80 >> chp;
+	return nopm;
+}
+
 static inline void dasd_path_add_opm(struct dasd_device *device, __u8 pm)
 {
 	int chp;
@@ -1070,6 +1127,7 @@ static inline void dasd_path_add_opm(struct dasd_device *device, __u8 pm)
 			dasd_path_clear_nohpf(device, chp);
 			dasd_path_clear_cuir(device, chp);
 			dasd_path_clear_cable(device, chp);
+			dasd_path_clear_ifcc(device, chp);
 		}
 }
 
@@ -1091,6 +1149,15 @@ static inline void dasd_path_add_cuirpm(struct dasd_device *device, __u8 pm)
 			dasd_path_cuir(device, chp);
 }
 
+static inline void dasd_path_add_ifccpm(struct dasd_device *device, __u8 pm)
+{
+	int chp;
+
+	for (chp = 0; chp < 8; chp++)
+		if (pm & (0x80 >> chp))
+			dasd_path_ifcc(device, chp);
+}
+
 static inline void dasd_path_add_nppm(struct dasd_device *device, __u8 pm)
 {
 	int chp;
@@ -1148,6 +1215,7 @@ static inline void dasd_path_set_opm(struct dasd_device *device, __u8 pm)
 			dasd_path_clear_nohpf(device, chp);
 			dasd_path_clear_cuir(device, chp);
 			dasd_path_clear_cable(device, chp);
+			dasd_path_clear_ifcc(device, chp);
 		}
 	}
 }