Re: [PATCH v9 6/9] nvmet: add copy command support for bdev and file ns
From: Nitesh Shetty
Date: Tue Apr 25 2023 - 04:41:35 EST
On Tue, Apr 25, 2023 at 06:36:51AM +0000, Chaitanya Kulkarni wrote:
> On 4/11/23 01:10, Anuj Gupta wrote:
> > From: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
> >
> > Add support for handling target command on target.
>
> what is target command ?
>
> command that you have added is :nvme_cmd_copy
>
acked. It was supposed to be nvme_cmd_copy.
> > For bdev-ns we call into blkdev_issue_copy, which the block layer
> > completes by a offloaded copy request to backend bdev or by emulating the
> > request.
> >
> > For file-ns we call vfs_copy_file_range to service our request.
> >
> > Currently target always shows copy capability by setting
> > NVME_CTRL_ONCS_COPY in controller ONCS.
>
> there is nothing mentioned about target/loop.c in commit log ?
>
acked, will add the description for loop device.
> > Signed-off-by: Nitesh Shetty <nj.shetty@xxxxxxxxxxx>
> > Signed-off-by: Anuj Gupta <anuj20.g@xxxxxxxxxxx>
> > ---
> > drivers/nvme/target/admin-cmd.c | 9 +++--
> > drivers/nvme/target/io-cmd-bdev.c | 58 +++++++++++++++++++++++++++++++
> > drivers/nvme/target/io-cmd-file.c | 52 +++++++++++++++++++++++++++
> > drivers/nvme/target/loop.c | 6 ++++
> > drivers/nvme/target/nvmet.h | 1 +
> > 5 files changed, 124 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/nvme/target/admin-cmd.c b/drivers/nvme/target/admin-cmd.c
> > index 80099df37314..978786ec6a9e 100644
> > --- a/drivers/nvme/target/admin-cmd.c
> > +++ b/drivers/nvme/target/admin-cmd.c
> > @@ -433,8 +433,7 @@ static void nvmet_execute_identify_ctrl(struct nvmet_req *req)
> > id->nn = cpu_to_le32(NVMET_MAX_NAMESPACES);
> > id->mnan = cpu_to_le32(NVMET_MAX_NAMESPACES);
> > id->oncs = cpu_to_le16(NVME_CTRL_ONCS_DSM |
> > - NVME_CTRL_ONCS_WRITE_ZEROES);
> > -
> > + NVME_CTRL_ONCS_WRITE_ZEROES | NVME_CTRL_ONCS_COPY);
> > /* XXX: don't report vwc if the underlying device is write through */
> > id->vwc = NVME_CTRL_VWC_PRESENT;
> >
> > @@ -536,6 +535,12 @@ static void nvmet_execute_identify_ns(struct nvmet_req *req)
> >
> > if (req->ns->bdev)
> > nvmet_bdev_set_limits(req->ns->bdev, id);
> > + else {
> > + id->msrc = (u8)to0based(BIO_MAX_VECS - 1);
> > + id->mssrl = cpu_to_le16(BIO_MAX_VECS <<
> > + (PAGE_SHIFT - SECTOR_SHIFT));
> > + id->mcl = cpu_to_le32(le16_to_cpu(id->mssrl));
> > + }
> >
> > /*
> > * We just provide a single LBA format that matches what the
> > diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
> > index c2d6cea0236b..0af273097aa4 100644
> > --- a/drivers/nvme/target/io-cmd-bdev.c
> > +++ b/drivers/nvme/target/io-cmd-bdev.c
> > @@ -46,6 +46,19 @@ void nvmet_bdev_set_limits(struct block_device *bdev, struct nvme_id_ns *id)
> > id->npda = id->npdg;
> > /* NOWS = Namespace Optimal Write Size */
> > id->nows = to0based(bdev_io_opt(bdev) / bdev_logical_block_size(bdev));
> > +
> > + /*Copy limits*/
>
> above comment doesn't make any sense ...
>
acked, will remove it next version.
> > + if (bdev_max_copy_sectors(bdev)) {
> > + id->msrc = id->msrc;
> > + id->mssrl = cpu_to_le16((bdev_max_copy_sectors(bdev) <<
> > + SECTOR_SHIFT) / bdev_logical_block_size(bdev));
> > + id->mcl = cpu_to_le32(id->mssrl);
> > + } else {
> > + id->msrc = (u8)to0based(BIO_MAX_VECS - 1);
> > + id->mssrl = cpu_to_le16((BIO_MAX_VECS << PAGE_SHIFT) /
> > + bdev_logical_block_size(bdev));
> > + id->mcl = cpu_to_le32(id->mssrl);
> > + }
> > }
> >
> > void nvmet_bdev_ns_disable(struct nvmet_ns *ns)
> > @@ -184,6 +197,19 @@ static void nvmet_bio_done(struct bio *bio)
> > nvmet_req_bio_put(req, bio);
> > }
> >
> > +static void nvmet_bdev_copy_end_io(void *private, int comp_len)
> > +{
> > + struct nvmet_req *req = (struct nvmet_req *)private;
> > +
> > + if (comp_len == req->copy_len) {
> > + req->cqe->result.u32 = cpu_to_le32(1);
> > + nvmet_req_complete(req, errno_to_nvme_status(req, 0));
> > + } else {
> > + req->cqe->result.u32 = cpu_to_le32(0);
> > + nvmet_req_complete(req, blk_to_nvme_status(req, BLK_STS_IOERR));
> > + }
> > +}
> > +
>
> please reduce calls for nvmet_req_complete().
>
> +static void nvmet_bdev_copy_end_io(void *private, int comp_len)
> +{
> + struct nvmet_req *req = (struct nvmet_req *)private;
> + u16 status;
> +
> + if (comp_len == req->copy_len) {
> + req->cqe->result.u32 = cpu_to_le32(1);
> + status = errno_to_nvme_status(req, 0));
> + } else {
> + req->cqe->result.u32 = cpu_to_le32(0);
> + status = blk_to_nvme_status(req, BLK_STS_IOERR));
> + }
> + nvmet_req_complete(req, status);
> +}
> +
>
makes sense, will modify this snippet.
> > #ifdef CONFIG_BLK_DEV_INTEGRITY
> > static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
> > struct sg_mapping_iter *miter)
> > @@ -450,6 +476,34 @@ static void nvmet_bdev_execute_write_zeroes(struct nvmet_req *req)
> > }
> > }
> >
> > +/* At present we handle only one range entry */
>
> please add explanation why ...
>
Because we aligned copy offload similar to copy_file_range in out recent
revisions, discarding multi range support.
Sure we will update comments to reflect the same.
> > +static void nvmet_bdev_execute_copy(struct nvmet_req *req)
> > +{
> > + struct nvme_copy_range range;
> > + struct nvme_command *cmnd = req->cmd;
>
> don't use cmnd, cmd is used everywhere and matches req->cmd,
> applies to everywhere in this patch...
>
acked
> > + int ret;
>
> wrong return type is should be u16 since nvmet_copy_from_sgl()
> returns u16 if I remember correctly.
>
> > +
> > +
>
acked
> no extra white line between declaration and body of functions
>
acked
> > + ret = nvmet_copy_from_sgl(req, 0, &range, sizeof(range));
> > + if (ret)
> > + goto out;
> > +
> > + ret = blkdev_issue_copy(req->ns->bdev,
> > + le64_to_cpu(cmnd->copy.sdlba) << req->ns->blksize_shift,
> > + req->ns->bdev,
> > + le64_to_cpu(range.slba) << req->ns->blksize_shift,
> > + (le16_to_cpu(range.nlb) + 1) << req->ns->blksize_shift,
> > + nvmet_bdev_copy_end_io, (void *)req, GFP_KERNEL);
> > + if (ret) {
> > + req->cqe->result.u32 = cpu_to_le32(0);
> > + nvmet_req_complete(req, blk_to_nvme_status(req, BLK_STS_IOERR));
> > + }
> > +
> > + return;
> > +out:
> > + nvmet_req_complete(req, errno_to_nvme_status(req, ret));
> > +}
> > +
>
> again one call to nvmet_req_complete() can do the same job.
> consider following totally untested :-
> /* TODO: add detailed comment here why you support one range ? */
> static void nvmet_bdev_execute_copy(struct nvmet_req *req)
> {
> u32 blkshift = req->ns->blksize_shift;
> struct nvme_command *cmnd = req->cmd;
> struct nvme_copy_range range;
> u16 status;
>
> status = nvmet_copy_from_sgl(req, 0, &range, sizeof(range));
> if (status) {
> goto out;
> }
>
> ret = blkdev_issue_copy(req->ns->bdev,
> le64_to_cpu(cmnd->copy.sdlba) << blkshift,
> req->ns->bdev,
> le64_to_cpu(range.slba) << blksize_shift,
> (le16_to_cpu(range.nlb) + 1) <<
> blksize_shift,
> nvmet_bdev_copy_end_io, (void *)req,
> GFP_KERNEL);
> if (ret) {
> req->cqe->result.u32 = cpu_to_le32(0);
> status = blk_to_nvme_status(req, BLK_STS_IOERR);
> out:
> nvmet_req_complete(req, status);
> }
> }
>
acked, thanks for sharing the snippet
> > u16 nvmet_bdev_parse_io_cmd(struct nvmet_req *req)
> > {
> > switch (req->cmd->common.opcode) {
> > @@ -468,6 +522,10 @@ u16 nvmet_bdev_parse_io_cmd(struct nvmet_req *req)
> > case nvme_cmd_write_zeroes:
> > req->execute = nvmet_bdev_execute_write_zeroes;
> > return 0;
> > + case nvme_cmd_copy:
> > + req->execute = nvmet_bdev_execute_copy;
> > + return 0;
> > +
> > default:
> > return nvmet_report_invalid_opcode(req);
> > }
> > diff --git a/drivers/nvme/target/io-cmd-file.c b/drivers/nvme/target/io-cmd-file.c
> > index 2d068439b129..69f198ecec77 100644
> > --- a/drivers/nvme/target/io-cmd-file.c
> > +++ b/drivers/nvme/target/io-cmd-file.c
> > @@ -322,6 +322,49 @@ static void nvmet_file_dsm_work(struct work_struct *w)
> > }
> > }
> >
> > +static void nvmet_file_copy_work(struct work_struct *w)
> > +{
> > + struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
> > + int nr_range;
> > + loff_t pos;
> > + struct nvme_command *cmnd = req->cmd;
> > + int ret = 0, len = 0, src, id;
>
> reverse tree style for declaration ...
>
acked
> > +
> > + nr_range = cmnd->copy.nr_range + 1;
> > + pos = le64_to_cpu(req->cmd->copy.sdlba) << req->ns->blksize_shift;
>
> you have a cmd variable above and you are still using req->cmd ?
> why create a variable on stack then ? u don't need that variable
> anyways...
>
acked
> > + if (unlikely(pos + req->transfer_len > req->ns->size)) {
> > + nvmet_req_complete(req, errno_to_nvme_status(req, -ENOSPC));
> > + return;
> > + }
> > +
> > + for (id = 0 ; id < nr_range; id++) {
> > + struct nvme_copy_range range;
> > +
> > + ret = nvmet_copy_from_sgl(req, id * sizeof(range), &range,
> > + sizeof(range));
> > + if (ret)
> > + goto out;
> > +
> > + len = (le16_to_cpu(range.nlb) + 1) << (req->ns->blksize_shift);
> > + src = (le64_to_cpu(range.slba) << (req->ns->blksize_shift));
> > + ret = vfs_copy_file_range(req->ns->file, src, req->ns->file,
> > + pos, len, 0);
>
> 5th paramaeter to vfs_copy_file_range() is size_t you have used int
> for len ? also
> vfs_copy_file_range() returns ssize_t you are catching it in int ?
>
acked, will change it to ssize_t.
> > +out:
> > + if (ret != len) {
> > + pos += ret;
> > + req->cqe->result.u32 = cpu_to_le32(id);
> > + nvmet_req_complete(req, ret < 0 ?
> > + errno_to_nvme_status(req, ret) :
> > + errno_to_nvme_status(req, -EIO));
>
> again plz don't add multiple nvmet_req_complete() calls
>
acked
> > + return;
> > +
> > + } else
> > + pos += len;
> > + }
> > +
> > + nvmet_req_complete(req, 0);
> > +
> > +}
>
> wrt above comments consider following totally untested :-
>
> static void nvmet_file_copy_work(struct work_struct *w)
> {
> struct nvmet_req *req = container_of(w, struct nvmet_req, f.work);
> int nr_range = req->cmd->copy.nr_range + 1;
> u16 status = 0;
> int src, id;
> ssize_t ret;
> size_t len;
> loff_t pos;
>
> pos = le64_to_cpu(req->cmd->copy.sdlba) << req->ns->blksize_shift;
> if (unlikely(pos + req->transfer_len > req->ns->size)) {
> nvmet_req_complete(req, errno_to_nvme_status(req,
> -ENOSPC));
> return;
> }
>
> for (id = 0 ; id < nr_range; id++) {
> struct nvme_copy_range range;
>
> status = nvmet_copy_from_sgl(req, id * sizeof(range),
> &range,
> sizeof(range));
> if (status)
> goto out;
>
> src = (le64_to_cpu(range.slba) <<
> (req->ns->blksize_shift));
> len = (le16_to_cpu(range.nlb) + 1) <<
> (req->ns->blksize_shift);
>
> ret = vfs_copy_file_range(req->ns->file, src,
> req->ns->file,
> pos, len, 0);
>
> if (ret != len) {
> req->cqe->result.u32 = cpu_to_le32(id);
> if (ret < 0)
> status = errno_to_nvme_status(req, ret);
> else
> status = errno_to_nvme_status(req, -EIO);
> goto out;
> }
> pos += ret;
> }
> out:
> nvmet_req_complete(req, status);
> }
>
>
Thanks for snippet will update this in next version.
--
Nitesh Shetty