3 files changed, 92 insertions, 18 deletions

diff --git a/arch/s390/include/asm/dasd.h b/arch/s390/include/asm/dasd.h
index 218bce81ec70..b604a9186f8e 100644
--- a/arch/s390/include/asm/dasd.h
+++ b/arch/s390/include/asm/dasd.h
@@ -217,6 +217,25 @@ typedef struct dasd_symmio_parms {
         int rssd_result_len;
 } __attribute__ ((packed)) dasd_symmio_parms_t;
 
+/*
+ * Data returned by Sense Path Group ID (SNID)
+ */
+struct dasd_snid_data {
+        struct {
+                __u8 group:2;
+                __u8 reserve:2;
+                __u8 mode:1;
+                __u8 res:3;
+        } __attribute__ ((packed)) path_state;
+        __u8 pgid[11];
+} __attribute__ ((packed));
+
+struct dasd_snid_ioctl_data {
+        struct dasd_snid_data data;
+        __u8 path_mask;
+} __attribute__ ((packed));
+
+
 /********************************************************************************
  * SECTION: Definition of IOCTLs
  *
@@ -261,25 +280,10 @@ typedef struct dasd_symmio_parms {
 /* Set Attributes (cache operations) */
 #define BIODASDSATTR   _IOW(DASD_IOCTL_LETTER,2,attrib_data_t) 
 
+/* Get Sense Path Group ID (SNID) data */
+#define BIODASDSNID    _IOWR(DASD_IOCTL_LETTER, 1, struct dasd_snid_ioctl_data)
+
 #define BIODASDSYMMIO  _IOWR(DASD_IOCTL_LETTER, 240, dasd_symmio_parms_t)
 
 #endif                          /* DASD_H */
 
-/*
- * Overrides for Emacs so that we follow Linus's tabbing style.
- * Emacs will notice this stuff at the end of the file and automatically
- * adjust the settings for this buffer only.  This must remain at the end
- * of the file.
- * ---------------------------------------------------------------------------
- * Local variables:
- * c-indent-level: 4 
- * c-brace-imaginary-offset: 0
- * c-brace-offset: -4
- * c-argdecl-indent: 4
- * c-label-offset: -4
- * c-continued-statement-offset: 4
- * c-continued-brace-offset: 0
- * indent-tabs-mode: nil
- * tab-width: 8
- * End:
- */
diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index 50cf96389d2c..bf61274af3bb 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -2802,6 +2802,73 @@ dasd_eckd_steal_lock(struct dasd_device *device)
 }
 
 /*
+ * SNID - Sense Path Group ID
+ * This ioctl may be used in situations where I/O is stalled due to
+ * a reserve, so if the normal dasd_smalloc_request fails, we use the
+ * preallocated dasd_reserve_req.
+ */
+static int dasd_eckd_snid(struct dasd_device *device,
+                          void __user *argp)
+{
+        struct dasd_ccw_req *cqr;
+        int rc;
+        struct ccw1 *ccw;
+        int useglobal;
+        struct dasd_snid_ioctl_data usrparm;
+
+        if (!capable(CAP_SYS_ADMIN))
+                return -EACCES;
+
+        if (copy_from_user(&usrparm, argp, sizeof(usrparm)))
+                return -EFAULT;
+
+        useglobal = 0;
+        cqr = dasd_smalloc_request(DASD_ECKD_MAGIC, 1,
+                                   sizeof(struct dasd_snid_data), device);
+        if (IS_ERR(cqr)) {
+                mutex_lock(&dasd_reserve_mutex);
+                useglobal = 1;
+                cqr = &dasd_reserve_req->cqr;
+                memset(cqr, 0, sizeof(*cqr));
+                memset(&dasd_reserve_req->ccw, 0,
+                       sizeof(dasd_reserve_req->ccw));
+                cqr->cpaddr = &dasd_reserve_req->ccw;
+                cqr->data = &dasd_reserve_req->data;
+                cqr->magic = DASD_ECKD_MAGIC;
+        }
+        ccw = cqr->cpaddr;
+        ccw->cmd_code = DASD_ECKD_CCW_SNID;
+        ccw->flags |= CCW_FLAG_SLI;
+        ccw->count = 12;
+        ccw->cda = (__u32)(addr_t) cqr->data;
+        cqr->startdev = device;
+        cqr->memdev = device;
+        clear_bit(DASD_CQR_FLAGS_USE_ERP, &cqr->flags);
+        set_bit(DASD_CQR_FLAGS_FAILFAST, &cqr->flags);
+        cqr->retries = 5;
+        cqr->expires = 10 * HZ;
+        cqr->buildclk = get_clock();
+        cqr->status = DASD_CQR_FILLED;
+        cqr->lpm = usrparm.path_mask;
+
+        rc = dasd_sleep_on_immediatly(cqr);
+        /* verify that I/O processing didn't modify the path mask */
+        if (!rc && usrparm.path_mask && (cqr->lpm != usrparm.path_mask))
+                rc = -EIO;
+        if (!rc) {
+                usrparm.data = *((struct dasd_snid_data *)cqr->data);
+                if (copy_to_user(argp, &usrparm, sizeof(usrparm)))
+                        rc = -EFAULT;
+        }
+
+        if (useglobal)
+                mutex_unlock(&dasd_reserve_mutex);
+        else
+                dasd_sfree_request(cqr, cqr->memdev);
+        return rc;
+}
+
+/*
  * Read performance statistics
  */
 static int
@@ -3036,6 +3103,8 @@ dasd_eckd_ioctl(struct dasd_block *block, unsigned int cmd, void __user *argp)
                 return dasd_eckd_reserve(device);
         case BIODASDSLCK:
                 return dasd_eckd_steal_lock(device);
+        case BIODASDSNID:
+                return dasd_eckd_snid(device, argp);
         case BIODASDSYMMIO:
                 return dasd_symm_io(device, argp);
         default:
diff --git a/drivers/s390/block/dasd_eckd.h b/drivers/s390/block/dasd_eckd.h
index 0eb49655a6cd..12097c24f2f5 100644
--- a/drivers/s390/block/dasd_eckd.h
+++ b/drivers/s390/block/dasd_eckd.h
@@ -27,6 +27,7 @@
 #define DASD_ECKD_CCW_WRITE_CKD          0x1d
 #define DASD_ECKD_CCW_READ_CKD           0x1e
 #define DASD_ECKD_CCW_PSF                0x27
+#define DASD_ECKD_CCW_SNID               0x34
 #define DASD_ECKD_CCW_RSSD               0x3e
 #define DASD_ECKD_CCW_LOCATE_RECORD      0x47
 #define DASD_ECKD_CCW_SNSS               0x54