Re: [PATCH 4/18] block copy: initial XCOPY offload support

From: Douglas Gilbert
Date: Wed Oct 22 2014 - 12:12:37 EST

See below ...

On 14-10-22 03:26 PM, Mikulas Patocka wrote:
This is Martin Petersen's xcopy patch
(https://git.kernel.org/cgit/linux/kernel/git/mkp/linux.git/commit/?h=xcopy&id=0bdeed274e16b3038a851552188512071974eea8)
with some bug fixes, ported to the current kernel.

This patch makes it possible to use the SCSI XCOPY command.

We create a bio that has REQ_COPY flag in bi_rw and a bi_copy structure
that defines the source device. The target device is defined in the
bi_bdev and bi_iter.bi_sector.

There is a new BLKCOPY ioctl that makes it possible to use XCOPY from
userspace. The ioctl argument is a pointer to an array of four uint64_t
values.

The first value is a source byte offset, the second value is a destination
byte offset, the third value is byte length. The forth value is written by
the kernel and it represents the number of bytes that the kernel actually
copied.

Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>

---
Documentation/ABI/testing/sysfs-block | 9 +
block/bio.c | 2
block/blk-core.c | 5
block/blk-lib.c | 95 ++++++++++++
block/blk-merge.c | 7
block/blk-settings.c | 13 +
block/blk-sysfs.c | 10 +
block/compat_ioctl.c | 1
block/ioctl.c | 49 ++++++
drivers/scsi/scsi.c | 57 +++++++
drivers/scsi/sd.c | 269 +++++++++++++++++++++++++++++++++-
drivers/scsi/sd.h | 4
include/linux/bio.h | 9 -
include/linux/blk_types.h | 15 +
include/linux/blkdev.h | 15 +
include/scsi/scsi_device.h | 3
include/uapi/linux/fs.h | 1
17 files changed, 551 insertions(+), 13 deletions(-)

Index: linux-3.18-rc1/Documentation/ABI/testing/sysfs-block
===================================================================
--- linux-3.18-rc1.orig/Documentation/ABI/testing/sysfs-block 2014-10-21 01:04:13.000000000 +0200
+++ linux-3.18-rc1/Documentation/ABI/testing/sysfs-block 2014-10-21 01:04:22.000000000 +0200
@@ -228,3 +228,12 @@ Description:
write_same_max_bytes is 0, write same is not supported
by the device.

+
+What: /sys/block/<disk>/queue/copy_max_bytes
+Date: January 2014
+Contact: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
+Description:
+ Devices that support copy offloading will set this value
+ to indicate the maximum buffer size in bytes that can be
+ copied in one operation. If the copy_max_bytes is 0 the
+ device does not support copy offload.
Index: linux-3.18-rc1/block/blk-core.c
===================================================================
--- linux-3.18-rc1.orig/block/blk-core.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/blk-core.c 2014-10-21 01:04:22.000000000 +0200
@@ -1828,6 +1828,11 @@ generic_make_request_checks(struct bio *
goto end_io;
}

+ if (bio->bi_rw & REQ_COPY && !bdev_copy_offload(bio->bi_bdev)) {
+ err = -EOPNOTSUPP;
+ goto end_io;
+ }
+
/*
* Various block parts want %current->io_context and lazy ioc
* allocation ends up trading a lot of pain for a small amount of
Index: linux-3.18-rc1/block/blk-lib.c
===================================================================
--- linux-3.18-rc1.orig/block/blk-lib.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/blk-lib.c 2014-10-21 01:04:22.000000000 +0200
@@ -304,3 +304,98 @@ int blkdev_issue_zeroout(struct block_de
return __blkdev_issue_zeroout(bdev, sector, nr_sects, gfp_mask);
}
EXPORT_SYMBOL(blkdev_issue_zeroout);
+
+/**
+ * blkdev_issue_copy - queue a copy same operation
+ * @src_bdev: source blockdev
+ * @src_sector: source sector
+ * @dst_bdev: destination blockdev
+ * @dst_sector: destination sector
+ * @nr_sects: number of sectors to copy
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ * Copy a block range from source device to target device.
+ */
+int blkdev_issue_copy(struct block_device *src_bdev, sector_t src_sector,
+ struct block_device *dst_bdev, sector_t dst_sector,
+ unsigned int nr_sects, gfp_t gfp_mask)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *sq = bdev_get_queue(src_bdev);
+ struct request_queue *dq = bdev_get_queue(dst_bdev);
+ unsigned int max_copy_sectors;
+ struct bio_batch bb;
+ int ret = 0;
+
+ if (!sq || !dq)
+ return -ENXIO;
+
+ max_copy_sectors = min(sq->limits.max_copy_sectors,
+ dq->limits.max_copy_sectors);
+
+ if (max_copy_sectors == 0)
+ return -EOPNOTSUPP;
+
+ if (src_sector + nr_sects < src_sector ||
+ dst_sector + nr_sects < dst_sector)
+ return -EINVAL;
+
+ /* Do not support overlapping copies */
+ if (src_bdev == dst_bdev &&
+ abs64((u64)dst_sector - (u64)src_sector) < nr_sects)
+ return -EOPNOTSUPP;
+
+ atomic_set(&bb.done, 1);
+ bb.error = 0;
+ bb.wait = &wait;
+
+ while (nr_sects) {
+ struct bio *bio;
+ struct bio_copy *bc;
+ unsigned int chunk;
+
+ bc = kmalloc(sizeof(struct bio_copy), gfp_mask);
+ if (!bc) {
+ ret = -ENOMEM;
+ break;
+ }
+
+ bio = bio_alloc(gfp_mask, 1);
+ if (!bio) {
+ kfree(bc);
+ ret = -ENOMEM;
+ break;
+ }
+
+ chunk = min(nr_sects, max_copy_sectors);
+
+ bio->bi_iter.bi_sector = dst_sector;
+ bio->bi_iter.bi_size = chunk << 9;
+ bio->bi_end_io = bio_batch_end_io;
+ bio->bi_bdev = dst_bdev;
+ bio->bi_private = &bb;
+ bio->bi_copy = bc;
+
+ bc->bic_bdev = src_bdev;
+ bc->bic_sector = src_sector;
+
+ atomic_inc(&bb.done);
+ submit_bio(REQ_WRITE | REQ_COPY, bio);
+
+ src_sector += chunk;
+ dst_sector += chunk;
+ nr_sects -= chunk;
+ }
+
+ /* Wait for bios in-flight */
+ if (!atomic_dec_and_test(&bb.done))
+ wait_for_completion_io(&wait);
+
+ if (likely(!ret))
+ ret = bb.error;
+
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_copy);
+
Index: linux-3.18-rc1/block/blk-merge.c
===================================================================
--- linux-3.18-rc1.orig/block/blk-merge.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/blk-merge.c 2014-10-21 01:04:22.000000000 +0200
@@ -26,10 +26,7 @@ static unsigned int __blk_recalc_rq_segm
* This should probably be returning 0, but blk_add_request_payload()
* (Christoph!!!!)
*/
- if (bio->bi_rw & REQ_DISCARD)
- return 1;
-
- if (bio->bi_rw & REQ_WRITE_SAME)
+ if (bio->bi_rw & (REQ_DISCARD | REQ_WRITE_SAME | REQ_COPY))
return 1;

fbio = bio;
@@ -205,7 +202,7 @@ static int __blk_bios_map_sg(struct requ
nsegs = 0;
cluster = blk_queue_cluster(q);

- if (bio->bi_rw & REQ_DISCARD) {
+ if (bio->bi_rw & (REQ_DISCARD | REQ_COPY)) {
/*
* This is a hack - drivers should be neither modifying the
* biovec, nor relying on bi_vcnt - but because of
Index: linux-3.18-rc1/block/blk-settings.c
===================================================================
--- linux-3.18-rc1.orig/block/blk-settings.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/blk-settings.c 2014-10-21 01:04:22.000000000 +0200
@@ -115,6 +115,7 @@ void blk_set_default_limits(struct queue
lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
lim->chunk_sectors = 0;
lim->max_write_same_sectors = 0;
+ lim->max_copy_sectors = 0;
lim->max_discard_sectors = 0;
lim->discard_granularity = 0;
lim->discard_alignment = 0;
@@ -322,6 +323,18 @@ void blk_queue_max_write_same_sectors(st
EXPORT_SYMBOL(blk_queue_max_write_same_sectors);

/**
+ * blk_queue_max_copy_sectors - set max sectors for a single copy operation
+ * @q: the request queue for the device
+ * @max_copy_sectors: maximum number of sectors per copy operation
+ **/
+void blk_queue_max_copy_sectors(struct request_queue *q,
+ unsigned int max_copy_sectors)
+{
+ q->limits.max_copy_sectors = max_copy_sectors;
+}
+EXPORT_SYMBOL(blk_queue_max_copy_sectors);
+
+/**
* blk_queue_max_segments - set max hw segments for a request for this queue
* @q: the request queue for the device
* @max_segments: max number of segments
Index: linux-3.18-rc1/block/blk-sysfs.c
===================================================================
--- linux-3.18-rc1.orig/block/blk-sysfs.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/blk-sysfs.c 2014-10-21 01:04:22.000000000 +0200
@@ -166,6 +166,11 @@ static ssize_t queue_write_same_max_show
(unsigned long long)q->limits.max_write_same_sectors << 9);
}

+static ssize_t queue_copy_max_show(struct request_queue *q, char *page)
+{
+ return sprintf(page, "%llu\n",
+ (unsigned long long)q->limits.max_copy_sectors << 9);
+}

static ssize_t
queue_max_sectors_store(struct request_queue *q, const char *page, size_t count)
@@ -379,6 +384,10 @@ static struct queue_sysfs_entry queue_wr
.show = queue_write_same_max_show,
};

+static struct queue_sysfs_entry queue_copy_max_entry = {
+ .attr = {.name = "copy_max_bytes", .mode = S_IRUGO },
+ .show = queue_copy_max_show,
+};
static struct queue_sysfs_entry queue_nonrot_entry = {
.attr = {.name = "rotational", .mode = S_IRUGO | S_IWUSR },
.show = queue_show_nonrot,
@@ -427,6 +436,7 @@ static struct attribute *default_attrs[]
&queue_discard_max_entry.attr,
&queue_discard_zeroes_data_entry.attr,
&queue_write_same_max_entry.attr,
+ &queue_copy_max_entry.attr,
&queue_nonrot_entry.attr,
&queue_nomerges_entry.attr,
&queue_rq_affinity_entry.attr,
Index: linux-3.18-rc1/block/ioctl.c
===================================================================
--- linux-3.18-rc1.orig/block/ioctl.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/ioctl.c 2014-10-21 01:04:22.000000000 +0200
@@ -201,6 +201,31 @@ static int blk_ioctl_zeroout(struct bloc
return blkdev_issue_zeroout(bdev, start, len, GFP_KERNEL);
}

+static int blk_ioctl_copy(struct block_device *bdev, uint64_t src_offset,
+ uint64_t dst_offset, uint64_t len)
+{
+ if (src_offset & 511)
+ return -EINVAL;
+ if (dst_offset & 511)
+ return -EINVAL;
+ if (len & 511)
+ return -EINVAL;
+ src_offset >>= 9;
+ dst_offset >>= 9;
+ len >>= 9;
+
+ if (unlikely(src_offset + len < src_offset) ||
+ unlikely(src_offset + len > (i_size_read(bdev->bd_inode) >> 9)))
+ return -EINVAL;
+
+ if (unlikely(dst_offset + len < dst_offset) ||
+ unlikely(dst_offset + len > (i_size_read(bdev->bd_inode) >> 9)))
+ return -EINVAL;
+
+ return blkdev_issue_copy(bdev, src_offset, bdev, dst_offset, len,
+ GFP_KERNEL);
+}
+
static int put_ushort(unsigned long arg, unsigned short val)
{
return put_user(val, (unsigned short __user *)arg);
@@ -329,6 +354,30 @@ int blkdev_ioctl(struct block_device *bd
return blk_ioctl_zeroout(bdev, range[0], range[1]);
}

+ case BLKCOPY: {
+ uint64_t range[4];
+
+ range[3] = 0;
+
+ if (copy_to_user((void __user *)(arg + 24), &range[3], 8))
+ return -EFAULT;
+
+ if (!(mode & FMODE_WRITE))
+ return -EBADF;
+
+ if (copy_from_user(range, (void __user *)arg, 24))
+ return -EFAULT;
+
+ ret = blk_ioctl_copy(bdev, range[0], range[1], range[2]);
+ if (!ret) {
+ range[3] = range[2];
+ if (copy_to_user((void __user *)(arg + 24), &range[3], 8))
+ return -EFAULT;
+ }
+
+ return ret;
+ }
+
case HDIO_GETGEO: {
struct hd_geometry geo;

Index: linux-3.18-rc1/drivers/scsi/scsi.c
===================================================================
--- linux-3.18-rc1.orig/drivers/scsi/scsi.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/drivers/scsi/scsi.c 2014-10-21 01:04:22.000000000 +0200
@@ -995,6 +995,62 @@ int scsi_get_vpd_page(struct scsi_device
EXPORT_SYMBOL_GPL(scsi_get_vpd_page);

/**
+ * scsi_lookup_naa - Lookup NAA descriptor in VPD page 0x83
+ * @sdev: The device to ask
+ *
+ * Copy offloading requires us to know the NAA descriptor for both
+ * source and target device. This descriptor is mandatory in the Device
+ * Identification VPD page. Locate this descriptor in the returned VPD
+ * data so we don't have to do lookups for every copy command.
+ */
+static void scsi_lookup_naa(struct scsi_device *sdev)
+{
+ unsigned char *buf = sdev->vpd_pg83;
+ unsigned int len = sdev->vpd_pg83_len;
+
+ if (buf[1] != 0x83 || get_unaligned_be16(&buf[2]) == 0) {
+ sdev_printk(KERN_ERR, sdev,
+ "%s: VPD page 0x83 contains no descriptors\n",
+ __func__);
+ return;
+ }
+
+ buf += 4;
+ len -= 4;
+
+ do {
+ unsigned int desig_len = buf[3] + 4;
+
+ /* Binary code set */
+ if ((buf[0] & 0xf) != 1)
+ goto skip;
+
+ /* Target association */
+ if ((buf[1] >> 4) & 0x3)
+ goto skip;
+
+ /* NAA designator */
+ if ((buf[1] & 0xf) != 0x3)
+ goto skip;
+
+ sdev->naa = buf;
+ sdev->naa_len = desig_len;
+
+ return;
+
+ skip:
+ buf += desig_len;
+ len -= desig_len;
+
+ } while (len > 0);
+
+ sdev_printk(KERN_ERR, sdev,
+ "%s: VPD page 0x83 NAA descriptor not found\n", __func__);
+
+ return;
+}
+
+/**
* scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
* @sdev: The device to ask
*
@@ -1078,6 +1134,7 @@ retry_pg83:
}
sdev->vpd_pg83_len = result;
sdev->vpd_pg83 = vpd_buf;
+ scsi_lookup_naa(sdev);
}
}

Index: linux-3.18-rc1/drivers/scsi/sd.c
===================================================================
--- linux-3.18-rc1.orig/drivers/scsi/sd.c 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/drivers/scsi/sd.c 2014-10-21 01:04:22.000000000 +0200
@@ -100,6 +100,7 @@ MODULE_ALIAS_SCSI_DEVICE(TYPE_RBC);

static void sd_config_discard(struct scsi_disk *, unsigned int);
static void sd_config_write_same(struct scsi_disk *);
+static void sd_config_copy(struct scsi_disk *);
static int sd_revalidate_disk(struct gendisk *);
static void sd_unlock_native_capacity(struct gendisk *disk);
static int sd_probe(struct device *);
@@ -477,6 +478,48 @@ max_write_same_blocks_store(struct devic
}
static DEVICE_ATTR_RW(max_write_same_blocks);

+static ssize_t
+max_copy_blocks_show(struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ struct scsi_disk *sdkp = to_scsi_disk(dev);
+
+ return snprintf(buf, 20, "%u\n", sdkp->max_copy_blocks);
+}
+
+static ssize_t
+max_copy_blocks_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct scsi_disk *sdkp = to_scsi_disk(dev);
+ struct scsi_device *sdp = sdkp->device;
+ unsigned long max;
+ int err;
+
+ if (!capable(CAP_SYS_ADMIN))
+ return -EACCES;
+
+ if (sdp->type != TYPE_DISK)
+ return -EINVAL;
+
+ err = kstrtoul(buf, 10, &max);
+
+ if (err)
+ return err;
+
+ if (max == 0)
+ sdp->no_copy = 1;
+ else if (max <= SD_MAX_COPY_BLOCKS) {
+ sdp->no_copy = 0;
+ sdkp->max_copy_blocks = max;
+ }
+
+ sd_config_copy(sdkp);
+
+ return count;
+}
+static DEVICE_ATTR_RW(max_copy_blocks);
+
static struct attribute *sd_disk_attrs[] = {
&dev_attr_cache_type.attr,
&dev_attr_FUA.attr,
@@ -488,6 +531,7 @@ static struct attribute *sd_disk_attrs[]
&dev_attr_thin_provisioning.attr,
&dev_attr_provisioning_mode.attr,
&dev_attr_max_write_same_blocks.attr,
+ &dev_attr_max_copy_blocks.attr,
&dev_attr_max_medium_access_timeouts.attr,
NULL,
};
@@ -883,6 +927,116 @@ static int sd_setup_write_same_cmnd(stru
return ret;
}

+static void sd_config_copy(struct scsi_disk *sdkp)
+{
+ struct request_queue *q = sdkp->disk->queue;
+ unsigned int logical_block_size = sdkp->device->sector_size;
+
+ if (sdkp->device->no_copy)
+ sdkp->max_copy_blocks = 0;
+
+ /* Segment descriptor 0x02 has a 64k block limit */
+ sdkp->max_copy_blocks = min(sdkp->max_copy_blocks,
+ (u32)SD_MAX_CSD2_BLOCKS);
+
+ blk_queue_max_copy_sectors(q, sdkp->max_copy_blocks *
+ (logical_block_size >> 9));
+}
+
+static int sd_setup_copy_cmnd(struct scsi_cmnd *cmd)
+{
+ struct request *rq = cmd->request;
+ struct scsi_device *src_sdp, *dst_sdp;
+ struct gendisk *src_disk;
+ struct request_queue *src_queue, *dst_queue;
+ sector_t src_lba, dst_lba;
+ unsigned int nr_blocks, buf_len, nr_bytes = blk_rq_bytes(rq);
+ int ret;
+ struct bio *bio = rq->bio;
+ struct page *page;
+ unsigned char *buf;
+
+ if (!bio->bi_copy)
+ return BLKPREP_KILL;
+
+ dst_sdp = scsi_disk(rq->rq_disk)->device;
+ dst_queue = rq->rq_disk->queue;
+ src_disk = bio->bi_copy->bic_bdev->bd_disk;
+ src_queue = src_disk->queue;
+ if (!src_queue ||
+ src_queue->make_request_fn != blk_queue_bio ||
+ src_queue->request_fn != dst_queue->request_fn ||
+ *(struct scsi_driver **)rq->rq_disk->private_data !=
+ *(struct scsi_driver **)src_disk->private_data)
+ return BLKPREP_KILL;
+ src_sdp = scsi_disk(src_disk)->device;
+
+ if (src_sdp->no_copy || dst_sdp->no_copy)
+ return BLKPREP_KILL;
+
+ if (src_sdp->sector_size != dst_sdp->sector_size)
+ return BLKPREP_KILL;
+
+ dst_lba = blk_rq_pos(rq) >> (ilog2(dst_sdp->sector_size) - 9);
+ src_lba = bio->bi_copy->bic_sector >> (ilog2(src_sdp->sector_size) - 9);
+ nr_blocks = blk_rq_sectors(rq) >> (ilog2(dst_sdp->sector_size) - 9);
+
+ page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
+ if (!page)
+ return BLKPREP_DEFER;
+
+ buf = page_address(page);
+
+ /* Extended Copy (LID1) Parameter List (16 bytes) */
+ buf[0] = 0; /* LID */
+ buf[1] = 3 << 3; /* LID usage 11b */
+ put_unaligned_be16(32 + 32, &buf[2]); /* 32 bytes per E4 desc. */
+ put_unaligned_be32(28, &buf[8]); /* 28 bytes per B2B desc. */
+ buf += 16;
+
+ /* Source CSCD (32 bytes) */
+ buf[0] = 0xe4; /* Identification desc. */
+ memcpy(&buf[4], src_sdp->naa, src_sdp->naa_len);
+ buf += 32;
+
+ /* Destination CSCD (32 bytes) */
+ buf[0] = 0xe4; /* Identification desc. */
+ memcpy(&buf[4], dst_sdp->naa, dst_sdp->naa_len);
+ buf += 32;
+
+ /* Segment descriptor (28 bytes) */
+ buf[0] = 0x02; /* Block to block desc. */
+ put_unaligned_be16(0x18, &buf[2]); /* Descriptor length */
+ put_unaligned_be16(0, &buf[4]); /* Source is desc. 0 */
+ put_unaligned_be16(1, &buf[6]); /* Dest. is desc. 1 */
+ put_unaligned_be16(nr_blocks, &buf[10]);
+ put_unaligned_be64(src_lba, &buf[12]);
+ put_unaligned_be64(dst_lba, &buf[20]);
+
+ /* CDB */
+ cmd->cmd_len = 16;
+ memset(cmd->cmnd, 0, cmd->cmd_len);
+ cmd->cmnd[0] = EXTENDED_COPY;
+ cmd->cmnd[1] = 0; /* LID1 */
+ buf_len = 16 + 32 + 32 + 28;
+ put_unaligned_be32(buf_len, &cmd->cmnd[10]);
+ rq->timeout = SD_COPY_TIMEOUT;
+
+ rq->completion_data = page;
+ blk_add_request_payload(rq, page, buf_len);
+
+ cmd->transfersize = buf_len;
+ cmd->allowed = 0; /* don't retry */
+
+ rq->__data_len = buf_len;
+ ret = scsi_init_io(cmd, GFP_ATOMIC);
+ rq->__data_len = nr_bytes;
+
+ if (ret != BLKPREP_OK)
+ __free_page(page);
+ return ret;
+}
+
static int sd_setup_flush_cmnd(struct scsi_cmnd *cmd)
{
struct request *rq = cmd->request;
@@ -1145,6 +1299,8 @@ static int sd_init_command(struct scsi_c
return sd_setup_discard_cmnd(cmd);
else if (rq->cmd_flags & REQ_WRITE_SAME)
return sd_setup_write_same_cmnd(cmd);
+ else if (rq->cmd_flags & REQ_COPY)
+ return sd_setup_copy_cmnd(cmd);
else if (rq->cmd_flags & REQ_FLUSH)
return sd_setup_flush_cmnd(cmd);
else
@@ -1155,7 +1311,7 @@ static void sd_uninit_command(struct scs
{
struct request *rq = SCpnt->request;

- if (rq->cmd_flags & REQ_DISCARD)
+ if (rq->cmd_flags & (REQ_DISCARD | REQ_COPY))
__free_page(rq->completion_data);

if (SCpnt->cmnd != rq->cmd) {
@@ -1698,7 +1854,8 @@ static int sd_done(struct scsi_cmnd *SCp
unsigned char op = SCpnt->cmnd[0];
unsigned char unmap = SCpnt->cmnd[1] & 8;

- if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME) {
+ if (req->cmd_flags & REQ_DISCARD || req->cmd_flags & REQ_WRITE_SAME ||
+ req->cmd_flags & REQ_COPY) {
if (!result) {
good_bytes = blk_rq_bytes(req);
scsi_set_resid(SCpnt, 0);
@@ -1757,6 +1914,14 @@ static int sd_done(struct scsi_cmnd *SCp
/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
switch (op) {
+ case EXTENDED_COPY:
+ sdkp->device->no_copy = 1;
+ sd_config_copy(sdkp);
+
+ good_bytes = 0;
+ req->__data_len = blk_rq_bytes(req);
+ req->cmd_flags |= REQ_QUIET;
+ break;

Perhaps you are checking somewhere else ... EXTENDED_COPY
opcode (0x83) has had service actions since SPC-4 rev 34
(February 2012). By the time SPC-4 becomes standardized
this command will most likely be called EXTENDED COPY(LID1)
and will be opcode=0x83, service_action=0.

To change the level of confusion, opcode 0x83 itself has
been renamed "Third-party Copy OUT". Not sure why T10 went
for mixed capitalization here when most other opcode names
are in upper case, perhaps to stress that it was an opcode
shared by several commands.

So please add a further check for ((cmd[1] & 0x1f) == 0)
unless that has been done elsewhere. With that in place
a COPY OPERATION ABORT [opcode=0x83, service_action=0x1c]
issued from my ddptctl utility won't trigger this code.

There is a T10 proposal to drop EXTENDED COPY(LID1) in
SPC-5 in favour of EXTENDED COPY(LID4) [opcode=0x83,
service_action=0x1] which can be considered as a
superset of the former. Something to think about for
the future; perhaps a comment.


And to push my own barrow here, have you considered
token based copies based on POPULATE TOKEN and WRITE
USING TOKEN? If not I can continue to use FreeBSD and
FreeNAS as they have implemented them (plus the LID4
equivalent of what its being presented here).

and ....

case UNMAP:
sd_config_discard(sdkp, SD_LBP_DISABLE);
break;
@@ -2745,6 +2910,105 @@ static void sd_read_write_same(struct sc
sdkp->ws10 = 1;
}

+static void sd_read_copy_operations(struct scsi_disk *sdkp,
+ unsigned char *buffer)
+{
+ struct scsi_device *sdev = sdkp->device;
+ struct scsi_sense_hdr sshdr;
+ unsigned char cdb[16];
+ unsigned int result, len, i;
+ bool b2b_desc = false, id_desc = false;
+
+ if (sdev->naa_len == 0)
+ return;
+
+ /* Verify that the device has 3PC set in INQUIRY response */
+ if (sdev->inquiry_len < 6 || (sdev->inquiry[5] & (1 << 3)) == 0)
+ return;
+
+ /* Receive Copy Operation Parameters */
+ memset(cdb, 0, 16);
+ cdb[0] = RECEIVE_COPY_RESULTS;

This is now the "Third-party Copy IN" opcode [0x84]. In this
case RECEIVE_COPY_RESULTS is deceptive as this is _not_ the
command being built.

+ cdb[1] = 0x3;

with service action 0x3 which is the RECEIVE COPY OPERATION
PARAMETERS command. Opcode 0x84 has had service actions for
a lot longer than opcode 0x83, but the original naming lingers
on.

The code is correct, the naming could be clearer.

Doug Gilbert

+ put_unaligned_be32(SD_BUF_SIZE, &cdb[10]);
+
+ memset(buffer, 0, SD_BUF_SIZE);
+ result = scsi_execute_req(sdev, cdb, DMA_FROM_DEVICE,
+ buffer, SD_BUF_SIZE, &sshdr,
+ SD_TIMEOUT, SD_MAX_RETRIES, NULL);
+
+ if (!scsi_status_is_good(result)) {
+ sd_printk(KERN_ERR, sdkp,
+ "%s: Receive Copy Operating Parameters failed\n",
+ __func__);
+ return;
+ }
+
+ /* The RCOP response is a minimum of 44 bytes long. First 4
+ * bytes contain the length of the remaining buffer, i.e. 40+
+ * bytes. Trailing the defined fields is a list of supported
+ * descriptors. We need at least 2 descriptors to drive the
+ * target, hence 42.
+ */
+ len = get_unaligned_be32(&buffer[0]);
+ if (len < 42) {
+ sd_printk(KERN_ERR, sdkp, "%s: result too short (%u)\n",
+ __func__, len);
+ return;
+ }
+
+ if ((buffer[4] & 1) == 0) {
+ sd_printk(KERN_ERR, sdkp, "%s: does not support SNLID\n",
+ __func__);
+ return;
+ }
+
+ if (get_unaligned_be16(&buffer[8]) < 2) {
+ sd_printk(KERN_ERR, sdkp,
+ "%s: Need 2 or more CSCD descriptors\n", __func__);
+ return;
+ }
+
+ if (get_unaligned_be16(&buffer[10]) < 1) {
+ sd_printk(KERN_ERR, sdkp,
+ "%s: Need 1 or more segment descriptor\n", __func__);
+ return;
+ }
+
+ if (len - 40 != buffer[43]) {
+ sd_printk(KERN_ERR, sdkp,
+ "%s: Buffer len and descriptor count mismatch " \
+ "(%u vs. %u)\n", __func__, len - 40, buffer[43]);
+ return;
+ }
+
+ for (i = 44 ; i < len + 4 ; i++) {
+ if (buffer[i] == 0x02)
+ b2b_desc = true;
+
+ if (buffer[i] == 0xe4)
+ id_desc = true;
+ }
+
+ if (!b2b_desc) {
+ sd_printk(KERN_ERR, sdkp,
+ "%s: No block 2 block descriptor (0x02)\n",
+ __func__);
+ return;
+ }
+
+ if (!id_desc) {
+ sd_printk(KERN_ERR, sdkp,
+ "%s: No identification descriptor (0xE4)\n",
+ __func__);
+ return;
+ }
+
+ sdkp->max_copy_blocks = get_unaligned_be32(&buffer[16])
+ >> ilog2(sdev->sector_size);
+ sd_config_copy(sdkp);
+}
+
static int sd_try_extended_inquiry(struct scsi_device *sdp)
{
/* Attempt VPD inquiry if the device blacklist explicitly calls
@@ -2810,6 +3074,7 @@ static int sd_revalidate_disk(struct gen
sd_read_cache_type(sdkp, buffer);
sd_read_app_tag_own(sdkp, buffer);
sd_read_write_same(sdkp, buffer);
+ sd_read_copy_operations(sdkp, buffer);
}

sdkp->first_scan = 0;
Index: linux-3.18-rc1/drivers/scsi/sd.h
===================================================================
--- linux-3.18-rc1.orig/drivers/scsi/sd.h 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/drivers/scsi/sd.h 2014-10-21 01:04:22.000000000 +0200
@@ -19,6 +19,7 @@
*/
#define SD_FLUSH_TIMEOUT_MULTIPLIER 2
#define SD_WRITE_SAME_TIMEOUT (120 * HZ)
+#define SD_COPY_TIMEOUT (120 * HZ)

/*
* Number of allowed retries
@@ -48,6 +49,8 @@ enum {
SD_MAX_XFER_BLOCKS = 0xffffffff,
SD_MAX_WS10_BLOCKS = 0xffff,
SD_MAX_WS16_BLOCKS = 0x7fffff,
+ SD_MAX_CSD2_BLOCKS = 0xffff,
+ SD_MAX_COPY_BLOCKS = 0xffffffff,
};

enum {
@@ -69,6 +72,7 @@ struct scsi_disk {
u32 max_xfer_blocks;
u32 max_ws_blocks;
u32 max_unmap_blocks;
+ u32 max_copy_blocks;
u32 unmap_granularity;
u32 unmap_alignment;
u32 index;
Index: linux-3.18-rc1/include/linux/bio.h
===================================================================
--- linux-3.18-rc1.orig/include/linux/bio.h 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/include/linux/bio.h 2014-10-21 01:04:22.000000000 +0200
@@ -106,7 +106,7 @@ static inline bool bio_has_data(struct b
{
if (bio &&
bio->bi_iter.bi_size &&
- !(bio->bi_rw & REQ_DISCARD))
+ !(bio->bi_rw & (REQ_DISCARD | REQ_COPY)))
return true;

return false;
@@ -260,8 +260,8 @@ static inline unsigned bio_segments(stru
struct bvec_iter iter;

/*
- * We special case discard/write same, because they interpret bi_size
- * differently:
+ * We special case discard/write same/copy, because they
+ * interpret bi_size differently:
*/

if (bio->bi_rw & REQ_DISCARD)
@@ -270,6 +270,9 @@ static inline unsigned bio_segments(stru
if (bio->bi_rw & REQ_WRITE_SAME)
return 1;

+ if (bio->bi_rw & REQ_COPY)
+ return 1;
+
bio_for_each_segment(bv, bio, iter)
segs++;

Index: linux-3.18-rc1/include/linux/blk_types.h
===================================================================
--- linux-3.18-rc1.orig/include/linux/blk_types.h 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/include/linux/blk_types.h 2014-10-21 01:04:30.000000000 +0200
@@ -39,6 +39,11 @@ struct bvec_iter {
current bvec */
};

+struct bio_copy {
+ struct block_device *bic_bdev;
+ sector_t bic_sector;
+};
+
/*
* main unit of I/O for the block layer and lower layers (ie drivers and
* stacking drivers)
@@ -83,6 +88,7 @@ struct bio {
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif
};
+ struct bio_copy *bi_copy; /* TODO, use bi_integrity */

unsigned short bi_vcnt; /* how many bio_vec's */

@@ -160,6 +166,7 @@ enum rq_flag_bits {
__REQ_DISCARD, /* request to discard sectors */
__REQ_SECURE, /* secure discard (used with __REQ_DISCARD) */
__REQ_WRITE_SAME, /* write same block many times */
+ __REQ_COPY, /* copy block range */

__REQ_NOIDLE, /* don't anticipate more IO after this one */
__REQ_INTEGRITY, /* I/O includes block integrity payload */
@@ -202,6 +209,7 @@ enum rq_flag_bits {
#define REQ_PRIO (1ULL << __REQ_PRIO)
#define REQ_DISCARD (1ULL << __REQ_DISCARD)
#define REQ_WRITE_SAME (1ULL << __REQ_WRITE_SAME)
+#define REQ_COPY (1ULL << __REQ_COPY)
#define REQ_NOIDLE (1ULL << __REQ_NOIDLE)
#define REQ_INTEGRITY (1ULL << __REQ_INTEGRITY)

@@ -210,14 +218,15 @@ enum rq_flag_bits {
#define REQ_COMMON_MASK \
(REQ_WRITE | REQ_FAILFAST_MASK | REQ_SYNC | REQ_META | REQ_PRIO | \
REQ_DISCARD | REQ_WRITE_SAME | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | \
- REQ_SECURE | REQ_INTEGRITY)
+ REQ_SECURE | REQ_INTEGRITY | REQ_COPY)
#define REQ_CLONE_MASK REQ_COMMON_MASK

-#define BIO_NO_ADVANCE_ITER_MASK (REQ_DISCARD|REQ_WRITE_SAME)
+#define BIO_NO_ADVANCE_ITER_MASK (REQ_DISCARD|REQ_WRITE_SAME|REQ_COPY)

/* This mask is used for both bio and request merge checking */
#define REQ_NOMERGE_FLAGS \
- (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
+ (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | \
+ REQ_COPY)

#define REQ_RAHEAD (1ULL << __REQ_RAHEAD)
#define REQ_THROTTLED (1ULL << __REQ_THROTTLED)
Index: linux-3.18-rc1/include/linux/blkdev.h
===================================================================
--- linux-3.18-rc1.orig/include/linux/blkdev.h 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/include/linux/blkdev.h 2014-10-21 01:04:22.000000000 +0200
@@ -291,6 +291,7 @@ struct queue_limits {
unsigned int io_opt;
unsigned int max_discard_sectors;
unsigned int max_write_same_sectors;
+ unsigned int max_copy_sectors;
unsigned int discard_granularity;
unsigned int discard_alignment;

@@ -1009,6 +1010,8 @@ extern void blk_queue_max_discard_sector
unsigned int max_discard_sectors);
extern void blk_queue_max_write_same_sectors(struct request_queue *q,
unsigned int max_write_same_sectors);
+extern void blk_queue_max_copy_sectors(struct request_queue *q,
+ unsigned int max_copy_sectors);
extern void blk_queue_logical_block_size(struct request_queue *, unsigned short);
extern void blk_queue_physical_block_size(struct request_queue *, unsigned int);
extern void blk_queue_alignment_offset(struct request_queue *q,
@@ -1167,6 +1170,8 @@ extern int blkdev_issue_discard(struct b
sector_t nr_sects, gfp_t gfp_mask, unsigned long flags);
extern int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask, struct page *page);
+extern int blkdev_issue_copy(struct block_device *, sector_t,
+ struct block_device *, sector_t, unsigned int, gfp_t);
extern int blkdev_issue_zeroout(struct block_device *bdev, sector_t sector,
sector_t nr_sects, gfp_t gfp_mask);
static inline int sb_issue_discard(struct super_block *sb, sector_t block,
@@ -1365,6 +1370,16 @@ static inline unsigned int bdev_write_sa
return 0;
}

+static inline unsigned int bdev_copy_offload(struct block_device *bdev)
+{
+ struct request_queue *q = bdev_get_queue(bdev);
+
+ if (q)
+ return q->limits.max_copy_sectors;
+
+ return 0;
+}
+
static inline int queue_dma_alignment(struct request_queue *q)
{
return q ? q->dma_alignment : 511;
Index: linux-3.18-rc1/include/scsi/scsi_device.h
===================================================================
--- linux-3.18-rc1.orig/include/scsi/scsi_device.h 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/include/scsi/scsi_device.h 2014-10-21 01:04:22.000000000 +0200
@@ -119,6 +119,8 @@ struct scsi_device {
unsigned char *vpd_pg83;
int vpd_pg80_len;
unsigned char *vpd_pg80;
+ unsigned char naa_len;
+ unsigned char *naa;
unsigned char current_tag; /* current tag */
struct scsi_target *sdev_target; /* used only for single_lun */

@@ -150,6 +152,7 @@ struct scsi_device {
unsigned use_10_for_ms:1; /* first try 10-byte mode sense/select */
unsigned no_report_opcodes:1; /* no REPORT SUPPORTED OPERATION CODES */
unsigned no_write_same:1; /* no WRITE SAME command */
+ unsigned no_copy:1; /* no copy offload */
unsigned use_16_for_rw:1; /* Use read/write(16) over read/write(10) */
unsigned skip_ms_page_8:1; /* do not use MODE SENSE page 0x08 */
unsigned skip_ms_page_3f:1; /* do not use MODE SENSE page 0x3f */
Index: linux-3.18-rc1/include/uapi/linux/fs.h
===================================================================
--- linux-3.18-rc1.orig/include/uapi/linux/fs.h 2014-10-21 01:04:15.000000000 +0200
+++ linux-3.18-rc1/include/uapi/linux/fs.h 2014-10-21 01:04:22.000000000 +0200
@@ -149,6 +149,7 @@ struct inodes_stat_t {
#define BLKSECDISCARD _IO(0x12,125)
#define BLKROTATIONAL _IO(0x12,126)
#define BLKZEROOUT _IO(0x12,127)
+#define BLKCOPY _IO(0x12,128)

#define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
#define FIBMAP _IO(0x00,1) /* bmap access */
Index: linux-3.18-rc1/block/compat_ioctl.c
===================================================================
--- linux-3.18-rc1.orig/block/compat_ioctl.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/compat_ioctl.c 2014-10-21 01:04:22.000000000 +0200
@@ -697,6 +697,7 @@ long compat_blkdev_ioctl(struct file *fi
* but we call blkdev_ioctl, which gets the lock for us
*/
case BLKRRPART:
+ case BLKCOPY:
return blkdev_ioctl(bdev, mode, cmd,
(unsigned long)compat_ptr(arg));
case BLKBSZSET_32:
Index: linux-3.18-rc1/block/bio.c
===================================================================
--- linux-3.18-rc1.orig/block/bio.c 2014-10-21 01:04:14.000000000 +0200
+++ linux-3.18-rc1/block/bio.c 2014-10-21 01:04:22.000000000 +0200
@@ -239,6 +239,8 @@ static void __bio_free(struct bio *bio)
{
bio_disassociate_task(bio);

+ kfree(bio->bi_copy);
+
if (bio_integrity(bio))
bio_integrity_free(bio);
}

--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/