[SCSI] sd: Identify DIF protection type and application tag ownership

If a disk is formatted with protection information (Inquiry bit
PROTECT=1) it is required to support Read Capacity(16).  Force use of
the 16-bit command in this case and extract the P_TYPE field which
indicates whether the disk is formatted using DIF Type 1, 2 or 3.

The ATO (App Tag Own) bit in the Control Mode Page indicates whether
the storage device or the initiator own the contents of the
DIF application tag.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

2 files changed, 141 insertions, 4 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 99dddcae7851..56b9501d12f3 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -233,6 +233,24 @@ sd_show_allow_restart(struct device *dev, struct device_attribute *attr,
         return snprintf(buf, 40, "%d\n", sdkp->device->allow_restart);
 }
 
+static ssize_t
+sd_show_protection_type(struct device *dev, struct device_attribute *attr,
+                        char *buf)
+{
+        struct scsi_disk *sdkp = to_scsi_disk(dev);
+
+        return snprintf(buf, 20, "%u\n", sdkp->protection_type);
+}
+
+static ssize_t
+sd_show_app_tag_own(struct device *dev, struct device_attribute *attr,
+                    char *buf)
+{
+        struct scsi_disk *sdkp = to_scsi_disk(dev);
+
+        return snprintf(buf, 20, "%u\n", sdkp->ATO);
+}
+
 static struct device_attribute sd_disk_attrs[] = {
         __ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
                sd_store_cache_type),
@@ -241,6 +259,8 @@ static struct device_attribute sd_disk_attrs[] = {
                sd_store_allow_restart),
         __ATTR(manage_start_stop, S_IRUGO|S_IWUSR, sd_show_manage_start_stop,
                sd_store_manage_start_stop),
+        __ATTR(protection_type, S_IRUGO, sd_show_protection_type, NULL),
+        __ATTR(app_tag_own, S_IRUGO, sd_show_app_tag_own, NULL),
         __ATTR_NULL,
 };
 
@@ -1164,6 +1184,49 @@ sd_spinup_disk(struct scsi_disk *sdkp)
         }
 }
 
+
+/*
+ * Determine whether disk supports Data Integrity Field.
+ */
+void sd_read_protection_type(struct scsi_disk *sdkp, unsigned char *buffer)
+{
+        struct scsi_device *sdp = sdkp->device;
+        u8 type;
+
+        if (scsi_device_protection(sdp) == 0 || (buffer[12] & 1) == 0)
+                type = 0;
+        else
+                type = ((buffer[12] >> 1) & 7) + 1; /* P_TYPE 0 = Type 1 */
+
+        switch (type) {
+        case SD_DIF_TYPE0_PROTECTION:
+                sdkp->protection_type = 0;
+                break;
+
+        case SD_DIF_TYPE1_PROTECTION:
+        case SD_DIF_TYPE3_PROTECTION:
+                sdkp->protection_type = type;
+                break;
+
+        case SD_DIF_TYPE2_PROTECTION:
+                sd_printk(KERN_ERR, sdkp, "formatted with DIF Type 2 "  \
+                          "protection which is currently unsupported. " \
+                          "Disabling disk!\n");
+                goto disable;
+
+        default:
+                sd_printk(KERN_ERR, sdkp, "formatted with unknown "     \
+                          "protection type %d. Disabling disk!\n", type);
+                goto disable;
+        }
+
+        return;
+
+disable:
+        sdkp->protection_type = 0;
+        sdkp->capacity = 0;
+}
+
 /*
  * read disk capacity
  */
@@ -1173,7 +1236,8 @@ sd_read_capacity(struct scsi_disk *sdkp, unsigned char *buffer)
         unsigned char cmd[16];
         int the_result, retries;
         int sector_size = 0;
-        int longrc = 0;
+        /* Force READ CAPACITY(16) when PROTECT=1 */
+        int longrc = scsi_device_protection(sdkp->device) ? 1 : 0;
         struct scsi_sense_hdr sshdr;
         int sense_valid = 0;
         struct scsi_device *sdp = sdkp->device;
@@ -1185,8 +1249,8 @@ repeat:
                         memset((void *) cmd, 0, 16);
                         cmd[0] = SERVICE_ACTION_IN;
                         cmd[1] = SAI_READ_CAPACITY_16;
-                        cmd[13] = 12;
-                        memset((void *) buffer, 0, 12);
+                        cmd[13] = 13;
+                        memset((void *) buffer, 0, 13);
                 } else {
                         cmd[0] = READ_CAPACITY;
                         memset((void *) &cmd[1], 0, 9);
@@ -1194,7 +1258,7 @@ repeat:
                 }
                 
                 the_result = scsi_execute_req(sdp, cmd, DMA_FROM_DEVICE,
-                                              buffer, longrc ? 12 : 8, &sshdr,
+                                              buffer, longrc ? 13 : 8, &sshdr,
                                               SD_TIMEOUT, SD_MAX_RETRIES);
 
                 if (media_not_present(sdkp, &sshdr))
@@ -1269,6 +1333,8 @@ repeat:
                         
                 sector_size = (buffer[8] << 24) |
                         (buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
+
+                sd_read_protection_type(sdkp, buffer);
         }       
 
         /* Some devices return the total number of sectors, not the
@@ -1530,6 +1596,52 @@ defaults:
         sdkp->DPOFUA = 0;
 }
 
+/*
+ * The ATO bit indicates whether the DIF application tag is available
+ * for use by the operating system.
+ */
+void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
+{
+        int res, offset;
+        struct scsi_device *sdp = sdkp->device;
+        struct scsi_mode_data data;
+        struct scsi_sense_hdr sshdr;
+
+        if (sdp->type != TYPE_DISK)
+                return;
+
+        if (sdkp->protection_type == 0)
+                return;
+
+        res = scsi_mode_sense(sdp, 1, 0x0a, buffer, 36, SD_TIMEOUT,
+                              SD_MAX_RETRIES, &data, &sshdr);
+
+        if (!scsi_status_is_good(res) || !data.header_length ||
+            data.length < 6) {
+                sd_printk(KERN_WARNING, sdkp,
+                          "getting Control mode page failed, assume no ATO\n");
+
+                if (scsi_sense_valid(&sshdr))
+                        sd_print_sense_hdr(sdkp, &sshdr);
+
+                return;
+        }
+
+        offset = data.header_length + data.block_descriptor_length;
+
+        if ((buffer[offset] & 0x3f) != 0x0a) {
+                sd_printk(KERN_ERR, sdkp, "ATO Got wrong page\n");
+                return;
+        }
+
+        if ((buffer[offset + 5] & 0x80) == 0)
+                return;
+
+        sdkp->ATO = 1;
+
+        return;
+}
+
 /**
  *      sd_revalidate_disk - called the first time a new disk is seen,
  *      performs disk spin up, read_capacity, etc.
@@ -1566,6 +1678,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
         sdkp->write_prot = 0;
         sdkp->WCE = 0;
         sdkp->RCD = 0;
+        sdkp->ATO = 0;
 
         sd_spinup_disk(sdkp);
 
@@ -1577,6 +1690,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
                 sd_read_capacity(sdkp, buffer);
                 sd_read_write_protect_flag(sdkp, buffer);
                 sd_read_cache_type(sdkp, buffer);
+                sd_read_app_tag_own(sdkp, buffer);
         }
 
         /*
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 03a3d45cfa42..86b18d4170fe 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -41,7 +41,9 @@ struct scsi_disk {
         u32             index;
         u8              media_present;
         u8              write_prot;
+        u8              protection_type;/* Data Integrity Field */
         unsigned        previous_state : 1;
+        unsigned        ATO : 1;        /* state of disk ATO bit */
         unsigned        WCE : 1;        /* state of disk WCE bit */
         unsigned        RCD : 1;        /* state of disk RCD bit, unused */
         unsigned        DPOFUA : 1;     /* state of disk DPOFUA bit */
@@ -59,4 +61,25 @@ static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
                     (sdsk)->disk->disk_name, ##a) :                     \
         sdev_printk(prefix, (sdsk)->device, fmt, ##a)
 
+/*
+ * A DIF-capable target device can be formatted with different
+ * protection schemes.  Currently 0 through 3 are defined:
+ *
+ * Type 0 is regular (unprotected) I/O
+ *
+ * Type 1 defines the contents of the guard and reference tags
+ *
+ * Type 2 defines the contents of the guard and reference tags and
+ * uses 32-byte commands to seed the latter
+ *
+ * Type 3 defines the contents of the guard tag only
+ */
+
+enum sd_dif_target_protection_types {
+        SD_DIF_TYPE0_PROTECTION = 0x0,
+        SD_DIF_TYPE1_PROTECTION = 0x1,
+        SD_DIF_TYPE2_PROTECTION = 0x2,
+        SD_DIF_TYPE3_PROTECTION = 0x3,
+};
+
 #endif /* _SCSI_DISK_H */