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