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authorMartin K. Petersen <martin.petersen@oracle.com>2008-07-17 04:28:35 -0400
committerJames Bottomley <James.Bottomley@HansenPartnership.com>2008-07-26 15:14:56 -0400
commitaf55ff675a8461da6a632320710b050af4366e0c (patch)
tree2d85ec327340f11f79cedb7d962d232c31819a8c /drivers/scsi/sd_dif.c
parente0597d70012c82e16ee152270a55d89d8bf66693 (diff)
[SCSI] sd: Support for SCSI disk (SBC) Data Integrity Field
Support for controllers and disks that implement DIF protection information: - During command preparation the RDPROTECT/WRPROTECT must be set correctly if the target has DIF enabled. - READ(6) and WRITE(6) are not supported when DIF is on. - The controller must be told how to handle the I/O via the protection operation field in scsi_cmnd. - Refactor the I/O completion code that extracts failed LBA from the returned sense data and handle DIF failures correctly. - sd_dif.c implements the functions required to prepare and complete requests with protection information attached. Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com> Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Diffstat (limited to 'drivers/scsi/sd_dif.c')
-rw-r--r--drivers/scsi/sd_dif.c538
1 files changed, 538 insertions, 0 deletions
diff --git a/drivers/scsi/sd_dif.c b/drivers/scsi/sd_dif.c
new file mode 100644
index 00000000000..4d17f3d35aa
--- /dev/null
+++ b/drivers/scsi/sd_dif.c
@@ -0,0 +1,538 @@
+/*
+ * 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/crc-t10dif.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 <net/checksum.h>
+
+#include "sd.h"
+
+typedef __u16 (csum_fn) (void *, unsigned int);
+
+static __u16 sd_dif_crc_fn(void *data, unsigned int len)
+{
+ return cpu_to_be16(crc_t10dif(data, len));
+}
+
+static __u16 sd_dif_ip_fn(void *data, unsigned int len)
+{
+ return ip_compute_csum(data, len);
+}
+
+/*
+ * Type 1 and Type 2 protection use the same format: 16 bit guard tag,
+ * 16 bit app tag, 32 bit reference tag.
+ */
+static void sd_dif_type1_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+ void *buf = bix->data_buf;
+ struct sd_dif_tuple *sdt = bix->prot_buf;
+ sector_t sector = bix->sector;
+ unsigned int i;
+
+ for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+ sdt->guard_tag = fn(buf, bix->sector_size);
+ sdt->ref_tag = cpu_to_be32(sector & 0xffffffff);
+ sdt->app_tag = 0;
+
+ buf += bix->sector_size;
+ sector++;
+ }
+}
+
+static void sd_dif_type1_generate_crc(struct blk_integrity_exchg *bix)
+{
+ sd_dif_type1_generate(bix, sd_dif_crc_fn);
+}
+
+static void sd_dif_type1_generate_ip(struct blk_integrity_exchg *bix)
+{
+ sd_dif_type1_generate(bix, sd_dif_ip_fn);
+}
+
+static int sd_dif_type1_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+ void *buf = bix->data_buf;
+ struct sd_dif_tuple *sdt = bix->prot_buf;
+ sector_t sector = bix->sector;
+ unsigned int i;
+ __u16 csum;
+
+ for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+ /* Unwritten sectors */
+ if (sdt->app_tag == 0xffff)
+ return 0;
+
+ /* Bad ref tag received from disk */
+ if (sdt->ref_tag == 0xffffffff) {
+ printk(KERN_ERR
+ "%s: bad phys ref tag on sector %lu\n",
+ bix->disk_name, (unsigned long)sector);
+ return -EIO;
+ }
+
+ if (be32_to_cpu(sdt->ref_tag) != (sector & 0xffffffff)) {
+ printk(KERN_ERR
+ "%s: ref tag error on sector %lu (rcvd %u)\n",
+ bix->disk_name, (unsigned long)sector,
+ be32_to_cpu(sdt->ref_tag));
+ return -EIO;
+ }
+
+ csum = fn(buf, bix->sector_size);
+
+ if (sdt->guard_tag != csum) {
+ printk(KERN_ERR "%s: guard tag error on sector %lu " \
+ "(rcvd %04x, data %04x)\n", bix->disk_name,
+ (unsigned long)sector,
+ be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
+ return -EIO;
+ }
+
+ buf += bix->sector_size;
+ sector++;
+ }
+
+ return 0;
+}
+
+static int sd_dif_type1_verify_crc(struct blk_integrity_exchg *bix)
+{
+ return sd_dif_type1_verify(bix, sd_dif_crc_fn);
+}
+
+static int sd_dif_type1_verify_ip(struct blk_integrity_exchg *bix)
+{
+ return sd_dif_type1_verify(bix, sd_dif_ip_fn);
+}
+
+/*
+ * Functions for interleaving and deinterleaving application tags
+ */
+static void sd_dif_type1_set_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+ struct sd_dif_tuple *sdt = prot;
+ char *tag = tag_buf;
+ unsigned int i, j;
+
+ for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
+ sdt->app_tag = tag[j] << 8 | tag[j+1];
+ BUG_ON(sdt->app_tag == 0xffff);
+ }
+}
+
+static void sd_dif_type1_get_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+ struct sd_dif_tuple *sdt = prot;
+ char *tag = tag_buf;
+ unsigned int i, j;
+
+ for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
+ tag[j] = (sdt->app_tag & 0xff00) >> 8;
+ tag[j+1] = sdt->app_tag & 0xff;
+ }
+}
+
+static struct blk_integrity dif_type1_integrity_crc = {
+ .name = "T10-DIF-TYPE1-CRC",
+ .generate_fn = sd_dif_type1_generate_crc,
+ .verify_fn = sd_dif_type1_verify_crc,
+ .get_tag_fn = sd_dif_type1_get_tag,
+ .set_tag_fn = sd_dif_type1_set_tag,
+ .tuple_size = sizeof(struct sd_dif_tuple),
+ .tag_size = 0,
+};
+
+static struct blk_integrity dif_type1_integrity_ip = {
+ .name = "T10-DIF-TYPE1-IP",
+ .generate_fn = sd_dif_type1_generate_ip,
+ .verify_fn = sd_dif_type1_verify_ip,
+ .get_tag_fn = sd_dif_type1_get_tag,
+ .set_tag_fn = sd_dif_type1_set_tag,
+ .tuple_size = sizeof(struct sd_dif_tuple),
+ .tag_size = 0,
+};
+
+
+/*
+ * Type 3 protection has a 16-bit guard tag and 16 + 32 bits of opaque
+ * tag space.
+ */
+static void sd_dif_type3_generate(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+ void *buf = bix->data_buf;
+ struct sd_dif_tuple *sdt = bix->prot_buf;
+ unsigned int i;
+
+ for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+ sdt->guard_tag = fn(buf, bix->sector_size);
+ sdt->ref_tag = 0;
+ sdt->app_tag = 0;
+
+ buf += bix->sector_size;
+ }
+}
+
+static void sd_dif_type3_generate_crc(struct blk_integrity_exchg *bix)
+{
+ sd_dif_type3_generate(bix, sd_dif_crc_fn);
+}
+
+static void sd_dif_type3_generate_ip(struct blk_integrity_exchg *bix)
+{
+ sd_dif_type3_generate(bix, sd_dif_ip_fn);
+}
+
+static int sd_dif_type3_verify(struct blk_integrity_exchg *bix, csum_fn *fn)
+{
+ void *buf = bix->data_buf;
+ struct sd_dif_tuple *sdt = bix->prot_buf;
+ sector_t sector = bix->sector;
+ unsigned int i;
+ __u16 csum;
+
+ for (i = 0 ; i < bix->data_size ; i += bix->sector_size, sdt++) {
+ /* Unwritten sectors */
+ if (sdt->app_tag == 0xffff && sdt->ref_tag == 0xffffffff)
+ return 0;
+
+ csum = fn(buf, bix->sector_size);
+
+ if (sdt->guard_tag != csum) {
+ printk(KERN_ERR "%s: guard tag error on sector %lu " \
+ "(rcvd %04x, data %04x)\n", bix->disk_name,
+ (unsigned long)sector,
+ be16_to_cpu(sdt->guard_tag), be16_to_cpu(csum));
+ return -EIO;
+ }
+
+ buf += bix->sector_size;
+ sector++;
+ }
+
+ return 0;
+}
+
+static int sd_dif_type3_verify_crc(struct blk_integrity_exchg *bix)
+{
+ return sd_dif_type3_verify(bix, sd_dif_crc_fn);
+}
+
+static int sd_dif_type3_verify_ip(struct blk_integrity_exchg *bix)
+{
+ return sd_dif_type3_verify(bix, sd_dif_ip_fn);
+}
+
+static void sd_dif_type3_set_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+ struct sd_dif_tuple *sdt = prot;
+ char *tag = tag_buf;
+ unsigned int i, j;
+
+ for (i = 0, j = 0 ; i < sectors ; i++, j += 6, sdt++) {
+ sdt->app_tag = tag[j] << 8 | tag[j+1];
+ sdt->ref_tag = tag[j+2] << 24 | tag[j+3] << 16 |
+ tag[j+4] << 8 | tag[j+5];
+ }
+}
+
+static void sd_dif_type3_get_tag(void *prot, void *tag_buf, unsigned int sectors)
+{
+ struct sd_dif_tuple *sdt = prot;
+ char *tag = tag_buf;
+ unsigned int i, j;
+
+ for (i = 0, j = 0 ; i < sectors ; i++, j += 2, sdt++) {
+ tag[j] = (sdt->app_tag & 0xff00) >> 8;
+ tag[j+1] = sdt->app_tag & 0xff;
+ tag[j+2] = (sdt->ref_tag & 0xff000000) >> 24;
+ tag[j+3] = (sdt->ref_tag & 0xff0000) >> 16;
+ tag[j+4] = (sdt->ref_tag & 0xff00) >> 8;
+ tag[j+5] = sdt->ref_tag & 0xff;
+ BUG_ON(sdt->app_tag == 0xffff || sdt->ref_tag == 0xffffffff);
+ }
+}
+
+static struct blk_integrity dif_type3_integrity_crc = {
+ .name = "T10-DIF-TYPE3-CRC",
+ .generate_fn = sd_dif_type3_generate_crc,
+ .verify_fn = sd_dif_type3_verify_crc,
+ .get_tag_fn = sd_dif_type3_get_tag,
+ .set_tag_fn = sd_dif_type3_set_tag,
+ .tuple_size = sizeof(struct sd_dif_tuple),
+ .tag_size = 0,
+};
+
+static struct blk_integrity dif_type3_integrity_ip = {
+ .name = "T10-DIF-TYPE3-IP",
+ .generate_fn = sd_dif_type3_generate_ip,
+ .verify_fn = sd_dif_type3_verify_ip,
+ .get_tag_fn = sd_dif_type3_get_tag,
+ .set_tag_fn = sd_dif_type3_set_tag,
+ .tuple_size = sizeof(struct sd_dif_tuple),
+ .tag_size = 0,
+};
+
+/*
+ * 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;
+
+ /* If this HBA doesn't support DIX, resort to normal I/O or DIF */
+ if (scsi_host_dix_capable(sdp->host, type) == 0) {
+
+ if (type == SD_DIF_TYPE0_PROTECTION)
+ return;
+
+ if (scsi_host_dif_capable(sdp->host, type) == 0) {
+ sd_printk(KERN_INFO, sdkp, "Type %d protection " \
+ "unsupported by HBA. Disabling DIF.\n", type);
+ sdkp->protection_type = 0;
+ return;
+ }
+
+ sd_printk(KERN_INFO, sdkp, "Enabling DIF Type %d protection\n",
+ type);
+
+ 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, &dif_type3_integrity_ip);
+ else
+ blk_integrity_register(disk, &dif_type1_integrity_ip);
+ else
+ if (type == SD_DIF_TYPE3_PROTECTION)
+ blk_integrity_register(disk, &dif_type3_integrity_crc);
+ else
+ blk_integrity_register(disk, &dif_type1_integrity_crc);
+
+ sd_printk(KERN_INFO, sdkp,
+ "Enabling %s integrity protection\n", disk->integrity->name);
+
+ /* Signal to block layer that we support sector tagging */
+ if (type && sdkp->ATO) {
+ if (type == SD_DIF_TYPE3_PROTECTION)
+ disk->integrity->tag_size = sizeof(u16) + sizeof(u32);
+ else
+ disk->integrity->tag_size = sizeof(u16);
+
+ sd_printk(KERN_INFO, sdkp, "DIF application tag size %u\n",
+ disk->integrity->tag_size);
+ }
+}
+
+/*
+ * DIF DMA operation magic decoder ring.
+ */
+void sd_dif_op(struct scsi_cmnd *scmd, unsigned int dif, unsigned int dix)
+{
+ int csum_convert, prot_op;
+
+ prot_op = 0;
+
+ /* Convert checksum? */
+ if (scsi_host_get_guard(scmd->device->host) != SHOST_DIX_GUARD_CRC)
+ csum_convert = 1;
+ else
+ csum_convert = 0;
+
+ switch (scmd->cmnd[0]) {
+ case READ_10:
+ case READ_12:
+ case READ_16:
+ if (dif && dix)
+ if (csum_convert)
+ prot_op = SCSI_PROT_READ_CONVERT;
+ else
+ prot_op = SCSI_PROT_READ_PASS;
+ else if (dif && !dix)
+ prot_op = SCSI_PROT_READ_STRIP;
+ else if (!dif && dix)
+ prot_op = SCSI_PROT_READ_INSERT;
+
+ break;
+
+ case WRITE_10:
+ case WRITE_12:
+ case WRITE_16:
+ if (dif && dix)
+ if (csum_convert)
+ prot_op = SCSI_PROT_WRITE_CONVERT;
+ else
+ prot_op = SCSI_PROT_WRITE_PASS;
+ else if (dif && !dix)
+ prot_op = SCSI_PROT_WRITE_INSERT;
+ else if (!dif && dix)
+ prot_op = SCSI_PROT_WRITE_STRIP;
+
+ break;
+ }
+
+ scsi_set_prot_op(scmd, prot_op);
+ scsi_set_prot_type(scmd, dif);
+}
+
+/*
+ * 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.
+ */
+int sd_dif_prepare(struct request *rq, sector_t hw_sector, unsigned int sector_sz)
+{
+ const int tuple_sz = sizeof(struct sd_dif_tuple);
+ struct bio *bio;
+ struct scsi_disk *sdkp;
+ struct sd_dif_tuple *sdt;
+ unsigned int i, j;
+ u32 phys, virt;
+
+ /* Already remapped? */
+ if (rq->cmd_flags & REQ_INTEGRITY)
+ return 0;
+
+ sdkp = rq->bio->bi_bdev->bd_disk->private_data;
+
+ if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION)
+ return 0;
+
+ rq->cmd_flags |= REQ_INTEGRITY;
+ phys = hw_sector & 0xffffffff;
+
+ __rq_for_each_bio(bio, rq) {
+ struct bio_vec *iv;
+
+ virt = bio->bi_integrity->bip_sector & 0xffffffff;
+
+ bip_for_each_vec(iv, bio->bi_integrity, i) {
+ sdt = kmap_atomic(iv->bv_page, KM_USER0)
+ + iv->bv_offset;
+
+ for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
+
+ if (be32_to_cpu(sdt->ref_tag) != virt)
+ goto error;
+
+ sdt->ref_tag = cpu_to_be32(phys);
+ virt++;
+ phys++;
+ }
+
+ kunmap_atomic(sdt, KM_USER0);
+ }
+ }
+
+ return 0;
+
+error:
+ kunmap_atomic(sdt, KM_USER0);
+ sd_printk(KERN_ERR, sdkp, "%s: virt %u, phys %u, ref %u\n",
+ __func__, virt, phys, be32_to_cpu(sdt->ref_tag));
+
+ return -EIO;
+}
+
+/*
+ * 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 sd_dif_tuple);
+ struct scsi_disk *sdkp;
+ struct bio *bio;
+ struct sd_dif_tuple *sdt;
+ unsigned int i, j, sectors, sector_sz;
+ u32 phys, virt;
+
+ sdkp = scsi_disk(scmd->request->rq_disk);
+
+ if (sdkp->protection_type == SD_DIF_TYPE3_PROTECTION || good_bytes == 0)
+ return;
+
+ sector_sz = scmd->device->sector_size;
+ sectors = good_bytes / sector_sz;
+
+ phys = scmd->request->sector & 0xffffffff;
+ if (sector_sz == 4096)
+ phys >>= 3;
+
+ __rq_for_each_bio(bio, scmd->request) {
+ struct bio_vec *iv;
+
+ virt = bio->bi_integrity->bip_sector & 0xffffffff;
+
+ bip_for_each_vec(iv, bio->bi_integrity, i) {
+ sdt = kmap_atomic(iv->bv_page, KM_USER0)
+ + iv->bv_offset;
+
+ for (j = 0 ; j < iv->bv_len ; j += tuple_sz, sdt++) {
+
+ if (sectors == 0) {
+ kunmap_atomic(sdt, KM_USER0);
+ return;
+ }
+
+ if (be32_to_cpu(sdt->ref_tag) != phys &&
+ sdt->app_tag != 0xffff)
+ sdt->ref_tag = 0xffffffff; /* Bad ref */
+ else
+ sdt->ref_tag = cpu_to_be32(virt);
+
+ virt++;
+ phys++;
+ sectors--;
+ }
+
+ kunmap_atomic(sdt, KM_USER0);
+ }
+ }
+}
+