[SCSI] mpt2sas: Support for greater than 2TB capacity WarpDrive

The driver is modified to allow access to the greater than 2TB WarpDrive
and properly handle direct-io mapping for WarpDrive volumes greater than 2TB.

Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>

2 files changed, 74 insertions, 43 deletions

diff --git a/drivers/scsi/mpt2sas/mpt2sas_base.h b/drivers/scsi/mpt2sas/mpt2sas_base.h
index b3b03bb8ab50..88ead5ed2afc 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_base.h
+++ b/drivers/scsi/mpt2sas/mpt2sas_base.h
@@ -374,6 +374,7 @@ struct _sas_device {
  * @percent_complete: resync percent complete
  * @direct_io_enabled: Whether direct io to PDs are allowed or not
  * @stripe_exponent: X where 2powX is the stripe sz in blocks
+ * @block_exponent: X where 2powX is the block sz in bytes
  * @max_lba: Maximum number of LBA in the volume
  * @stripe_sz: Stripe Size of the volume
  * @device_info: Device info of the volume member disk
@@ -395,6 +396,7 @@ struct _raid_device {
         u8      percent_complete;
         u8      direct_io_enabled;
         u8      stripe_exponent;
+        u8      block_exponent;
         u64     max_lba;
         u32     stripe_sz;
         u32     device_info;
diff --git a/drivers/scsi/mpt2sas/mpt2sas_scsih.c b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
index a9efc4551086..ba8171fe17ef 100644
--- a/drivers/scsi/mpt2sas/mpt2sas_scsih.c
+++ b/drivers/scsi/mpt2sas/mpt2sas_scsih.c
@@ -1780,11 +1780,9 @@ _scsih_init_warpdrive_properties(struct MPT2SAS_ADAPTER *ioc,
         Mpi2ConfigReply_t mpi_reply;
         u16 sz;
         u8 num_pds, count;
-        u64 mb = 1024 * 1024;
-        u64 tb_2 = 2 * mb * mb;
-        u64 capacity;
-        u32 stripe_sz;
-        u8 i, stripe_exp;
+        unsigned long stripe_sz, block_sz;
+        u8 stripe_exp, block_exp;
+        u64 dev_max_lba;
 
         if (!ioc->is_warpdrive)
                 return;
@@ -1848,51 +1846,57 @@ _scsih_init_warpdrive_properties(struct MPT2SAS_ADAPTER *ioc,
                             vol_pg0->PhysDisk[count].PhysDiskNum);
                         goto out_error;
                 }
+                /* Disable direct I/O if member drive lba exceeds 4 bytes */
+                dev_max_lba = le64_to_cpu(pd_pg0.DeviceMaxLBA);
+                if (dev_max_lba >> 32) {
+                        printk(MPT2SAS_INFO_FMT "WarpDrive : Direct IO is "
+                            "disabled for the drive with handle(0x%04x) member"
+                            "handle (0x%04x) unsupported max lba 0x%016llx\n",
+                            ioc->name, raid_device->handle,
+                            le16_to_cpu(pd_pg0.DevHandle),
+                            (unsigned long long)dev_max_lba);
+                        goto out_error;
+                }
+
                 raid_device->pd_handle[count] = le16_to_cpu(pd_pg0.DevHandle);
         }
 
         /*
          * Assumption for WD: Direct I/O is not supported if the volume is
-         * not RAID0, if the stripe size is not 64KB, if the block size is
-         * not 512 and if the volume size is >2TB
+         * not RAID0
          */
-        if (raid_device->volume_type != MPI2_RAID_VOL_TYPE_RAID0 ||
-            le16_to_cpu(vol_pg0->BlockSize) != 512) {
+        if (raid_device->volume_type != MPI2_RAID_VOL_TYPE_RAID0) {
                 printk(MPT2SAS_INFO_FMT "WarpDrive : Direct IO is disabled "
                     "for the drive with handle(0x%04x): type=%d, "
                     "s_sz=%uK, blk_size=%u\n", ioc->name,
                     raid_device->handle, raid_device->volume_type,
-                    le32_to_cpu(vol_pg0->StripeSize)/2,
+                    (le32_to_cpu(vol_pg0->StripeSize) *
+                    le16_to_cpu(vol_pg0->BlockSize)) / 1024,
                     le16_to_cpu(vol_pg0->BlockSize));
                 goto out_error;
         }
 
-        capacity = (u64) le16_to_cpu(vol_pg0->BlockSize) *
-            (le64_to_cpu(vol_pg0->MaxLBA) + 1);
-
-        if (capacity > tb_2) {
+        stripe_sz = le32_to_cpu(vol_pg0->StripeSize);
+        stripe_exp = find_first_bit(&stripe_sz, 32);
+        if (stripe_exp == 32) {
                 printk(MPT2SAS_INFO_FMT "WarpDrive : Direct IO is disabled "
-                "for the drive with handle(0x%04x) since drive sz > 2TB\n",
-                ioc->name, raid_device->handle);
+                "for the drive with handle(0x%04x) invalid stripe sz %uK\n",
+                    ioc->name, raid_device->handle,
+                    (le32_to_cpu(vol_pg0->StripeSize) *
+                    le16_to_cpu(vol_pg0->BlockSize)) / 1024);
                 goto out_error;
         }
-
-        stripe_sz = le32_to_cpu(vol_pg0->StripeSize);
-        stripe_exp = 0;
-        for (i = 0; i < 32; i++) {
-                if (stripe_sz & 1)
-                        break;
-                stripe_exp++;
-                stripe_sz >>= 1;
-        }
-        if (i == 32) {
+        raid_device->stripe_exponent = stripe_exp;
+        block_sz = le16_to_cpu(vol_pg0->BlockSize);
+        block_exp = find_first_bit(&block_sz, 16);
+        if (block_exp == 16) {
                 printk(MPT2SAS_INFO_FMT "WarpDrive : Direct IO is disabled "
-                    "for the drive with handle(0x%04x) invalid stripe sz %uK\n",
+                    "for the drive with handle(0x%04x) invalid block sz %u\n",
                     ioc->name, raid_device->handle,
-                    le32_to_cpu(vol_pg0->StripeSize)/2);
+                    le16_to_cpu(vol_pg0->BlockSize));
                 goto out_error;
         }
-        raid_device->stripe_exponent = stripe_exp;
+        raid_device->block_exponent = block_exp;
         raid_device->direct_io_enabled = 1;
 
         printk(MPT2SAS_INFO_FMT "WarpDrive : Direct IO is Enabled for the drive"
@@ -3808,8 +3812,9 @@ _scsih_setup_direct_io(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
 {
         u32 v_lba, p_lba, stripe_off, stripe_unit, column, io_size;
         u32 stripe_sz, stripe_exp;
-        u8 num_pds, *cdb_ptr, *tmp_ptr, *lba_ptr1, *lba_ptr2;
+        u8 num_pds, *cdb_ptr, i;
         u8 cdb0 = scmd->cmnd[0];
+        u64 v_llba;
 
         /*
          * Try Direct I/O to RAID memeber disks
@@ -3820,15 +3825,11 @@ _scsih_setup_direct_io(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
 
                 if ((cdb0 < READ_16) || !(cdb_ptr[2] | cdb_ptr[3] | cdb_ptr[4]
                         | cdb_ptr[5])) {
-                        io_size = scsi_bufflen(scmd) >> 9;
+                        io_size = scsi_bufflen(scmd) >>
+                            raid_device->block_exponent;
+                        i = (cdb0 < READ_16) ? 2 : 6;
                         /* get virtual lba */
-                        lba_ptr1 = lba_ptr2 = (cdb0 < READ_16) ? &cdb_ptr[2] :
-                            &cdb_ptr[6];
-                        tmp_ptr = (u8 *)&v_lba + 3;
-                        *tmp_ptr-- = *lba_ptr1++;
-                        *tmp_ptr-- = *lba_ptr1++;
-                        *tmp_ptr-- = *lba_ptr1++;
-                        *tmp_ptr = *lba_ptr1;
+                        v_lba = be32_to_cpu(*(__be32 *)(&cdb_ptr[i]));
 
                         if (((u64)v_lba + (u64)io_size - 1) <=
                             (u32)raid_device->max_lba) {
@@ -3847,11 +3848,39 @@ _scsih_setup_direct_io(struct MPT2SAS_ADAPTER *ioc, struct scsi_cmnd *scmd,
                                         mpi_request->DevHandle =
                                                 cpu_to_le16(raid_device->
                                                     pd_handle[column]);
-                                        tmp_ptr = (u8 *)&p_lba + 3;
-                                        *lba_ptr2++ = *tmp_ptr--;
-                                        *lba_ptr2++ = *tmp_ptr--;
-                                        *lba_ptr2++ = *tmp_ptr--;
-                                        *lba_ptr2 = *tmp_ptr;
+                                        (*(__be32 *)(&cdb_ptr[i])) =
+                                                cpu_to_be32(p_lba);
+                                        /*
+                                        * WD: To indicate this I/O is directI/O
+                                        */
+                                        _scsih_scsi_direct_io_set(ioc, smid, 1);
+                                }
+                        }
+                } else {
+                        io_size = scsi_bufflen(scmd) >>
+                            raid_device->block_exponent;
+                        /* get virtual lba */
+                        v_llba = be64_to_cpu(*(__be64 *)(&cdb_ptr[2]));
+
+                        if ((v_llba + (u64)io_size - 1) <=
+                            raid_device->max_lba) {
+                                stripe_sz = raid_device->stripe_sz;
+                                stripe_exp = raid_device->stripe_exponent;
+                                stripe_off = (u32) (v_llba & (stripe_sz - 1));
+
+                                /* Check whether IO falls within a stripe */
+                                if ((stripe_off + io_size) <= stripe_sz) {
+                                        num_pds = raid_device->num_pds;
+                                        p_lba = (u32)(v_llba >> stripe_exp);
+                                        stripe_unit = p_lba / num_pds;
+                                        column = p_lba % num_pds;
+                                        p_lba = (stripe_unit << stripe_exp) +
+                                            stripe_off;
+                                        mpi_request->DevHandle =
+                                                cpu_to_le16(raid_device->
+                                                    pd_handle[column]);
+                                        (*(__be64 *)(&cdb_ptr[2])) =
+                                            cpu_to_be64((u64)p_lba);
                                         /*
                                         * WD: To indicate this I/O is directI/O
                                         */