Initial import

1 files changed, 205 insertions, 0 deletions

diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
new file mode 100644
index 000000000..5c06d292b
--- /dev/null
+++ b/drivers/scsi/sd_dif.c
@@ -0,0 +1,205 @@
+/*
+ * sd_dif.c - SCSI Data Integrity Field
+ *
+ * Copyright (C) 2007, 2008 Oracle Corporation
+ * Written by: Martin K. Petersen <martin.petersen@oracle.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License version
+ * 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139,
+ * USA.
+ *
+ */
+
+#include <linux/blkdev.h>
+#include <linux/t10-pi.h>
+
+#include <scsi/scsi.h>
+#include <scsi/scsi_cmnd.h>
+#include <scsi/scsi_dbg.h>
+#include <scsi/scsi_device.h>
+#include <scsi/scsi_driver.h>
+#include <scsi/scsi_eh.h>
+#include <scsi/scsi_host.h>
+#include <scsi/scsi_ioctl.h>
+#include <scsi/scsicam.h>
+
+#include "sd.h"
+
+/*
+ * Configure exchange of protection information between OS and HBA.
+ */
+void sd_dif_config_host(struct scsi_disk *sdkp)
+{
+	struct scsi_device *sdp = sdkp->device;
+	struct gendisk *disk = sdkp->disk;
+	u8 type = sdkp->protection_type;
+	int dif, dix;
+
+	dif = scsi_host_dif_capable(sdp->host, type);
+	dix = scsi_host_dix_capable(sdp->host, type);
+
+	if (!dix && scsi_host_dix_capable(sdp->host, 0)) {
+		dif = 0; dix = 1;
+	}
+
+	if (!dix)
+		return;
+
+	/* Enable DMA of protection information */
+	if (scsi_host_get_guard(sdkp->device->host) & SHOST_DIX_GUARD_IP) {
+		if (type == SD_DIF_TYPE3_PROTECTION)
+			blk_integrity_register(disk, &t10_pi_type3_ip);
+		else
+			blk_integrity_register(disk, &t10_pi_type1_ip);
+
+		disk->integrity->flags |= BLK_INTEGRITY_IP_CHECKSUM;
+	} else
+		if (type == SD_DIF_TYPE3_PROTECTION)
+			blk_integrity_register(disk, &t10_pi_type3_crc);
+		else
+			blk_integrity_register(disk, &t10_pi_type1_crc);
+
+	sd_printk(KERN_NOTICE, sdkp,
+		  "Enabling DIX %s protection\n", disk->integrity->name);
+
+	/* Signal to block layer that we support sector tagging */
+	if (dif && type) {
+
+		disk->integrity->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
+
+		if (!sdkp->ATO)
+			return;
+
+		if (type == SD_DIF_TYPE3_PROTECTION)
+			disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
+		else
+			disk->integrity->tag_size = sizeof(u16);
+
+		sd_printk(KERN_NOTICE, sdkp, "DIF application tag size %u\n",
+			  disk->integrity->tag_size);
+	}
+}
+
+/*
+ * The virtual start sector is the one that was originally submitted
+ * by the block layer.	Due to partitioning, MD/DM cloning, etc. the
+ * actual physical start sector is likely to be different.  Remap
+ * protection information to match the physical LBA.
+ *
+ * From a protocol perspective there's a slight difference between
+ * Type 1 and 2.  The latter uses 32-byte CDBs exclusively, and the
+ * reference tag is seeded in the CDB.  This gives us the potential to
+ * avoid virt->phys remapping during write.  However, at read time we
+ * don't know whether the virt sector is the same as when we wrote it
+ * (we could be reading from real disk as opposed to MD/DM device.  So
+ * we always remap Type 2 making it identical to Type 1.
+ *
+ * Type 3 does not have a reference tag so no remapping is required.
+ */
+void sd_dif_prepare(struct scsi_cmnd *scmd)
+{
+	const int tuple_sz = sizeof(struct t10_pi_tuple);
+	struct bio *bio;
+	struct scsi_disk *sdkp;
+	struct t10_pi_tuple *pi;
+	u32 phys, virt;
+
+	sdkp = scsi_disk(scmd->request->rq_disk);
+
+	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
+		return;
+
+	phys = scsi_prot_ref_tag(scmd);
+
+	__rq_for_each_bio(bio, scmd->request) {
+		struct bio_integrity_payload *bip = bio_integrity(bio);
+		struct bio_vec iv;
+		struct bvec_iter iter;
+		unsigned int j;
+
+		/* Already remapped? */
+		if (bip->bip_flags & BIP_MAPPED_INTEGRITY)
+			break;
+
+		virt = bip_get_seed(bip) & 0xffffffff;
+
+		bip_for_each_vec(iv, bip, iter) {
+			pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
+
+			for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
+
+				if (be32_to_cpu(pi->ref_tag) == virt)
+					pi->ref_tag = cpu_to_be32(phys);
+
+				virt++;
+				phys++;
+			}
+
+			kunmap_atomic(pi);
+		}
+
+		bip->bip_flags |= BIP_MAPPED_INTEGRITY;
+	}
+}
+
+/*
+ * Remap physical sector values in the reference tag to the virtual
+ * values expected by the block layer.
+ */
+void sd_dif_complete(struct scsi_cmnd *scmd, unsigned int good_bytes)
+{
+	const int tuple_sz = sizeof(struct t10_pi_tuple);
+	struct scsi_disk *sdkp;
+	struct bio *bio;
+	struct t10_pi_tuple *pi;
+	unsigned int j, intervals;
+	u32 phys, virt;
+
+	sdkp = scsi_disk(scmd->request->rq_disk);
+
+	if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
+		return;
+
+	intervals = good_bytes / scsi_prot_interval(scmd);
+	phys = scsi_prot_ref_tag(scmd);
+
+	__rq_for_each_bio(bio, scmd->request) {
+		struct bio_integrity_payload *bip = bio_integrity(bio);
+		struct bio_vec iv;
+		struct bvec_iter iter;
+
+		virt = bip_get_seed(bip) & 0xffffffff;
+
+		bip_for_each_vec(iv, bip, iter) {
+			pi = kmap_atomic(iv.bv_page) + iv.bv_offset;
+
+			for (j = 0; j < iv.bv_len; j += tuple_sz, pi++) {
+
+				if (intervals == 0) {
+					kunmap_atomic(pi);
+					return;
+				}
+
+				if (be32_to_cpu(pi->ref_tag) == phys)
+					pi->ref_tag = cpu_to_be32(virt);
+
+				virt++;
+				phys++;
+				intervals--;
+			}
+
+			kunmap_atomic(pi);
+		}
+	}
+}
+