2 files changed, 109 insertions, 0 deletions

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 9093c7261f33..255da53e5a01 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -264,6 +264,15 @@ sd_show_app_tag_own(struct device *dev, struct device_attribute *attr,
         return snprintf(buf, 20, "%u\n", sdkp->ATO);
 }
 
+static ssize_t
+sd_show_thin_provisioning(struct device *dev, struct device_attribute *attr,
+                          char *buf)
+{
+        struct scsi_disk *sdkp = to_scsi_disk(dev);
+
+        return snprintf(buf, 20, "%u\n", sdkp->thin_provisioning);
+}
+
 static struct device_attribute sd_disk_attrs[] = {
         __ATTR(cache_type, S_IRUGO|S_IWUSR, sd_show_cache_type,
                sd_store_cache_type),
@@ -274,6 +283,7 @@ static struct device_attribute sd_disk_attrs[] = {
                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(thin_provisioning, S_IRUGO, sd_show_thin_provisioning, NULL),
         __ATTR_NULL,
 };
 
@@ -399,6 +409,57 @@ static void sd_prot_op(struct scsi_cmnd *scmd, unsigned int dif)
 }
 
 /**
+ * sd_prepare_discard - unmap blocks on thinly provisioned device
+ * @rq: Request to prepare
+ *
+ * Will issue either UNMAP or WRITE SAME(16) depending on preference
+ * indicated by target device.
+ **/
+static int sd_prepare_discard(struct request *rq)
+{
+        struct scsi_disk *sdkp = scsi_disk(rq->rq_disk);
+        struct bio *bio = rq->bio;
+        sector_t sector = bio->bi_sector;
+        unsigned int num = bio_sectors(bio);
+
+        if (sdkp->device->sector_size == 4096) {
+                sector >>= 3;
+                num >>= 3;
+        }
+
+        rq->cmd_type = REQ_TYPE_BLOCK_PC;
+        rq->timeout = SD_TIMEOUT;
+
+        memset(rq->cmd, 0, rq->cmd_len);
+
+        if (sdkp->unmap) {
+                char *buf = kmap_atomic(bio_page(bio), KM_USER0);
+
+                rq->cmd[0] = UNMAP;
+                rq->cmd[8] = 24;
+                rq->cmd_len = 10;
+
+                /* Ensure that data length matches payload */
+                rq->__data_len = bio->bi_size = bio->bi_io_vec->bv_len = 24;
+
+                put_unaligned_be16(6 + 16, &buf[0]);
+                put_unaligned_be16(16, &buf[2]);
+                put_unaligned_be64(sector, &buf[8]);
+                put_unaligned_be32(num, &buf[16]);
+
+                kunmap_atomic(buf, KM_USER0);
+        } else {
+                rq->cmd[0] = WRITE_SAME_16;
+                rq->cmd[1] = 0x8; /* UNMAP */
+                put_unaligned_be64(sector, &rq->cmd[2]);
+                put_unaligned_be32(num, &rq->cmd[10]);
+                rq->cmd_len = 16;
+        }
+
+        return BLKPREP_OK;
+}
+
+/**
  *      sd_init_command - build a scsi (read or write) command from
  *      information in the request structure.
  *      @SCpnt: pointer to mid-level's per scsi command structure that
@@ -418,6 +479,13 @@ static int sd_prep_fn(struct request_queue *q, struct request *rq)
         int ret, host_dif;
         unsigned char protect;
 
+        /*
+         * Discard request come in as REQ_TYPE_FS but we turn them into
+         * block PC requests to make life easier.
+         */
+        if (blk_discard_rq(rq))
+                ret = sd_prepare_discard(rq);
+
         if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
                 ret = scsi_setup_blk_pc_cmnd(sdp, rq);
                 goto out;
@@ -1432,6 +1500,19 @@ static int read_capacity_16(struct scsi_disk *sdkp, struct scsi_device *sdp,
                 sd_printk(KERN_NOTICE, sdkp,
                           "physical block alignment offset: %u\n", alignment);
 
+        if (buffer[14] & 0x80) { /* TPE */
+                struct request_queue *q = sdp->request_queue;
+
+                sdkp->thin_provisioning = 1;
+                q->limits.discard_granularity = sdkp->hw_sector_size;
+                q->limits.max_discard_sectors = 0xffffffff;
+
+                if (buffer[14] & 0x40) /* TPRZ */
+                        q->limits.discard_zeroes_data = 1;
+
+                queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, q);
+        }
+
         sdkp->capacity = lba + 1;
         return sector_size;
 }
@@ -1863,6 +1944,7 @@ void sd_read_app_tag_own(struct scsi_disk *sdkp, unsigned char *buffer)
  */
 static void sd_read_block_limits(struct scsi_disk *sdkp)
 {
+        struct request_queue *q = sdkp->disk->queue;
         unsigned int sector_sz = sdkp->device->sector_size;
         char *buffer;
 
@@ -1877,6 +1959,31 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
         blk_queue_io_opt(sdkp->disk->queue,
                          get_unaligned_be32(&buffer[12]) * sector_sz);
 
+        /* Thin provisioning enabled and page length indicates TP support */
+        if (sdkp->thin_provisioning && buffer[3] == 0x3c) {
+                unsigned int lba_count, desc_count, granularity;
+
+                lba_count = get_unaligned_be32(&buffer[20]);
+                desc_count = get_unaligned_be32(&buffer[24]);
+
+                if (lba_count) {
+                        q->limits.max_discard_sectors =
+                                lba_count * sector_sz >> 9;
+
+                        if (desc_count)
+                                sdkp->unmap = 1;
+                }
+
+                granularity = get_unaligned_be32(&buffer[28]);
+
+                if (granularity)
+                        q->limits.discard_granularity = granularity * sector_sz;
+
+                if (buffer[32] & 0x80)
+                        q->limits.discard_alignment =
+                                get_unaligned_be32(&buffer[32]) & ~(1 << 31);
+        }
+
         kfree(buffer);
 }
 
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index e374804d26fb..43d3caf268ef 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -60,6 +60,8 @@ struct scsi_disk {
         unsigned        RCD : 1;        /* state of disk RCD bit, unused */
         unsigned        DPOFUA : 1;     /* state of disk DPOFUA bit */
         unsigned        first_scan : 1;
+        unsigned        thin_provisioning : 1;
+        unsigned        unmap : 1;
 };
 #define to_scsi_disk(obj) container_of(obj,struct scsi_disk,dev)