[S390] dasd_eckd / Write format R0 is now allowed BB

Permission is now granted to the subsystem to format write R0 with:
* an ID = CCHHR, where CC = physical cylinder number,
  HH = physical head number, and R = 0
* a key length of zero
* a data length of eight
* a data field containing all zeros

Signed-off-by: Jean-Baptiste Joret <joret@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 19 insertions, 6 deletions

diff --git a/drivers/s390/block/dasd_eckd.c b/drivers/s390/block/dasd_eckd.c
index bdb87998f364..0eb5e5888c42 100644
--- a/drivers/s390/block/dasd_eckd.c
+++ b/drivers/s390/block/dasd_eckd.c
@@ -1265,6 +1265,8 @@ dasd_eckd_format_device(struct dasd_device * device,
         int rpt, cyl, head;
         int cplength, datasize;
         int i;
+        int intensity = 0;
+        int r0_perm;
 
         private = (struct dasd_eckd_private *) device->private;
         rpt = recs_per_track(&private->rdc_data, 0, fdata->blksize);
@@ -1296,9 +1298,17 @@ dasd_eckd_format_device(struct dasd_device * device,
          *   Bit 1: write home address, currently not supported
          *   Bit 2: invalidate tracks
          *   Bit 3: use OS/390 compatible disk layout (cdl)
+         *   Bit 4: do not allow storage subsystem to modify record zero
          * Only some bit combinations do make sense.
          */
-        switch (fdata->intensity) {
+        if (fdata->intensity & 0x10) {
+                r0_perm = 0;
+                intensity = fdata->intensity & ~0x10;
+        } else {
+                r0_perm = 1;
+                intensity = fdata->intensity;
+        }
+        switch (intensity) {
         case 0x00:      /* Normal format */
         case 0x08:      /* Normal format, use cdl. */
                 cplength = 2 + rpt;
@@ -1335,11 +1345,14 @@ dasd_eckd_format_device(struct dasd_device * device,
         data = fcp->data;
         ccw = fcp->cpaddr;
 
-        switch (fdata->intensity & ~0x08) {
+        switch (intensity & ~0x08) {
         case 0x00: /* Normal format. */
                 define_extent(ccw++, (struct DE_eckd_data *) data,
                               fdata->start_unit, fdata->start_unit,
                               DASD_ECKD_CCW_WRITE_CKD, device);
+                /* grant subsystem permission to format R0 */
+                if (r0_perm)
+                        ((struct DE_eckd_data *)data)->ga_extended |= 0x04;
                 data += sizeof(struct DE_eckd_data);
                 ccw[-1].flags |= CCW_FLAG_CC;
                 locate_record(ccw++, (struct LO_eckd_data *) data,
@@ -1373,7 +1386,7 @@ dasd_eckd_format_device(struct dasd_device * device,
                 data += sizeof(struct LO_eckd_data);
                 break;
         }
-        if (fdata->intensity & 0x01) {  /* write record zero */
+        if (intensity & 0x01) { /* write record zero */
                 ect = (struct eckd_count *) data;
                 data += sizeof(struct eckd_count);
                 ect->cyl = cyl;
@@ -1388,7 +1401,7 @@ dasd_eckd_format_device(struct dasd_device * device,
                 ccw->cda = (__u32)(addr_t) ect;
                 ccw++;
         }
-        if ((fdata->intensity & ~0x08) & 0x04) {        /* erase track */
+        if ((intensity & ~0x08) & 0x04) {       /* erase track */
                 ect = (struct eckd_count *) data;
                 data += sizeof(struct eckd_count);
                 ect->cyl = cyl;
@@ -1411,14 +1424,14 @@ dasd_eckd_format_device(struct dasd_device * device,
                         ect->kl = 0;
                         ect->dl = fdata->blksize;
                         /* Check for special tracks 0-1 when formatting CDL */
-                        if ((fdata->intensity & 0x08) &&
+                        if ((intensity & 0x08) &&
                             fdata->start_unit == 0) {
                                 if (i < 3) {
                                         ect->kl = 4;
                                         ect->dl = sizes_trk0[i] - 4;
                                 }
                         }
-                        if ((fdata->intensity & 0x08) &&
+                        if ((intensity & 0x08) &&
                             fdata->start_unit == 1) {
                                 ect->kl = 44;
                                 ect->dl = LABEL_SIZE - 44;