remove 2TB limit in sd

modern storage boxes support >2TB arrays, but READ CAPACITY
may return 2TB only (with 512 bytes blocksize). According to
SBC, target may return 0xffffffff as device size in order to
notify initiator that device size can't fit into 32 bits and
that initiator should use Long READ CAPACITY with 64bits LBA
field. Following patch implements this logic.

drivers/scsi/sd.c

@@ -172,7 +172,7 @@ static inline struct scsi_disk *scsi_disk(struct gendisk *disk)
  **/
 static int sd_init_command(struct scsi_cmnd * SCpnt)
 {
-	int this_count, timeout;
+	unsigned int this_count, timeout;
 	struct gendisk *disk;
 	sector_t block;
 	struct scsi_device *sdp = SCpnt->device;
@@ -298,8 +298,23 @@ static int sd_init_command(struct scsi_cmnd * SCpnt)
 		"writing" : "reading", this_count, SCpnt->request->nr_sectors));
 
 	SCpnt->cmnd[1] = 0;
-
-	if (((this_count > 0xff) || (block > 0x1fffff)) || SCpnt->device->ten) {
+	
+	if (block > 0xffffffff) {
+		SCpnt->cmnd[0] += READ_16 - READ_6;
+		SCpnt->cmnd[2] = (unsigned char) (block >> 56) & 0xff;
+		SCpnt->cmnd[3] = (unsigned char) (block >> 48) & 0xff;
+		SCpnt->cmnd[4] = (unsigned char) (block >> 40) & 0xff;
+		SCpnt->cmnd[5] = (unsigned char) (block >> 32) & 0xff;
+		SCpnt->cmnd[6] = (unsigned char) (block >> 24) & 0xff;
+		SCpnt->cmnd[7] = (unsigned char) (block >> 16) & 0xff;
+		SCpnt->cmnd[8] = (unsigned char) (block >> 8) & 0xff;
+		SCpnt->cmnd[9] = (unsigned char) block & 0xff;
+		SCpnt->cmnd[10] = (unsigned char) (this_count >> 24) & 0xff;
+		SCpnt->cmnd[11] = (unsigned char) (this_count >> 16) & 0xff;
+		SCpnt->cmnd[12] = (unsigned char) (this_count >> 8) & 0xff;
+		SCpnt->cmnd[13] = (unsigned char) this_count & 0xff;
+		SCpnt->cmnd[14] = SCpnt->cmnd[15] = 0;
+	} else if (((this_count > 0xff) || (block > 0x1fffff)) || SCpnt->device->ten) {
 		if (this_count > 0xffff)
 			this_count = 0xffff;
 
@@ -904,24 +919,34 @@ sd_read_cache_type(struct scsi_disk *sdkp, char *diskname,
 static void
 sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
 		 struct scsi_request *SRpnt, unsigned char *buffer) {
-	unsigned char cmd[10];
+	unsigned char cmd[16];
 	struct scsi_device *sdp = sdkp->device;
 	int the_result, retries;
-	int sector_size;
+	int sector_size = 0;
+	int longrc = 0;
 
+repeat:
 	retries = 3;
 	do {
-		cmd[0] = READ_CAPACITY;
-		memset((void *) &cmd[1], 0, 9);
-		memset((void *) buffer, 0, 8);
-
+		if (longrc) {
+			memset((void *) cmd, 0, 16);
+			cmd[0] = SERVICE_ACTION_IN;
+			cmd[1] = 0x10; /* READ CAPACITY (16) */
+			cmd[13] = 12;
+			memset((void *) buffer, 0, 12);
+		} else {
+			cmd[0] = READ_CAPACITY;
+			memset((void *) &cmd[1], 0, 9);
+			memset((void *) buffer, 0, 8);
+		}
+		
 		SRpnt->sr_cmd_len = 0;
 		SRpnt->sr_sense_buffer[0] = 0;
 		SRpnt->sr_sense_buffer[2] = 0;
 		SRpnt->sr_data_direction = SCSI_DATA_READ;
 
 		scsi_wait_req(SRpnt, (void *) cmd, (void *) buffer,
-			      8, SD_TIMEOUT, SD_MAX_RETRIES);
+			      longrc ? 12 : 8, SD_TIMEOUT, SD_MAX_RETRIES);
 
 		if (media_not_present(sdkp, SRpnt))
 			return;
@@ -931,7 +956,7 @@ sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
 
 	} while (the_result && retries);
 
-	if (the_result) {
+	if (the_result && !longrc) {
 		printk(KERN_NOTICE "%s : READ CAPACITY failed.\n"
 		       "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
 		       diskname, diskname,
@@ -957,16 +982,51 @@ sd_read_capacity(struct scsi_disk *sdkp, char *diskname,
 		sdkp->capacity = 0x200000; /* 1 GB - random */
 
 		return;
-	}
-
-	sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
-			      (buffer[1] << 16) |
-			      (buffer[2] << 8) |
-			      buffer[3]);
-
-	sector_size = (buffer[4] << 24) |
-		(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
+	} else if (the_result && longrc) {
+		/* READ CAPACITY(16) has been failed */
+		printk(KERN_NOTICE "%s : READ CAPACITY(16) failed.\n"
+		       "%s : status=%x, message=%02x, host=%d, driver=%02x \n",
+		       diskname, diskname,
+		       status_byte(the_result),
+		       msg_byte(the_result),
+		       host_byte(the_result),
+		       driver_byte(the_result));
+		printk(KERN_NOTICE "%s : use 0xffffffff as device size\n",
+		       diskname);
+		
+		sdkp->capacity = 1 + (sector_t) 0xffffffff;		
+		goto got_data;
+	}	
+	
+	if (!longrc) {
+		sector_size = (buffer[4] << 24) |
+			(buffer[5] << 16) | (buffer[6] << 8) | buffer[7];
+		if (buffer[0] == 0xff && buffer[1] == 0xff &&
+			buffer[2] == 0xff && buffer[3] == 0xff) {
+			printk(KERN_NOTICE "%s : very big device. try to use"
+				" READ CAPACITY(16).\n", diskname);
+			longrc = 1;
+			goto repeat;
+		}
+		sdkp->capacity = 1 + (((sector_t)buffer[0] << 24) |
+			(buffer[1] << 16) |
+			(buffer[2] << 8) |
+			buffer[3]);			
+	} else {
+		sdkp->capacity = 1 + (((sector_t)buffer[0] << 56) |
+			((sector_t)buffer[1] << 48) |
+			((sector_t)buffer[2] << 40) |
+			((sector_t)buffer[3] << 32) |
+			((sector_t)buffer[4] << 24) |
+			((sector_t)buffer[5] << 16) |
+			((sector_t)buffer[6] << 8)  |
+			(sector_t)buffer[7]);
+			
+		sector_size = (buffer[8] << 24) |
+			(buffer[9] << 16) | (buffer[10] << 8) | buffer[11];
+	}	
 
+got_data:
 	if (sector_size == 0) {
 		sector_size = 512;
 		printk(KERN_NOTICE "%s : sector size 0 reported, "
@@ -1139,10 +1199,10 @@ sd_init_onedisk(struct scsi_disk * sdkp, struct gendisk *disk)
 
 	if (sdkp->media_present)
 		sd_read_capacity(sdkp, disk->disk_name, SRpnt, buffer);
-
+	
 	if (sdp->removable && sdkp->media_present)
 		sd_read_write_protect_flag(sdkp, disk->disk_name, SRpnt, buffer);
-
+		
 	SRpnt->sr_device->ten = 1;
 	SRpnt->sr_device->remap = 1;
 

include/scsi/scsi.h

@@ -96,6 +96,10 @@ extern const unsigned char scsi_command_size[8];
 #define READ_ELEMENT_STATUS   0xb8
 #define SEND_VOLUME_TAG       0xb6
 #define WRITE_LONG_2          0xea
+#define READ_16               0x88
+#define WRITE_16              0x8a
+#define SERVICE_ACTION_IN     0x9e
+
 
 /*
  *  Status codes