[15/17] nvmet: Add metadata support for block devices

Commit Message

Max Gurtovoy March 27, 2020, 5:15 p.m. UTC

From: Israel Rukshin <[e-mail]>

Create a block IO request for the metadata from the protection SG list.

Signed-off-by: Israel Rukshin <[e-mail]>
Signed-off-by: Max Gurtovoy <[e-mail]>
---
 drivers/nvme/target/io-cmd-bdev.c | 87 ++++++++++++++++++++++++++++++++++++++-
 1 file changed, 85 insertions(+), 2 deletions(-)

Comments

Christoph Hellwig April 21, 2020, 3:33 p.m. UTC | #1

On Fri, Mar 27, 2020 at 08:15:43PM +0300, Max Gurtovoy wrote:
> -	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
> +	if (!nvmet_check_transfer_len(req,
> +				      nvmet_rw_data_len(req) + req->md_len))

Shouldn't we also calculate the actual metadata length on the fly here?

>  	blk_start_plug(&plug);
> +	if (req->use_md)

Can't we use a non-NULL req->md_sg or non-null req->md_sg_cnt as a
metadata supported indicator and remove the use_md flag?  Maybe wrap
them in a helper function that also checks for blk integrity support
using IS_ENABLED and we can skip the stubs as well.

Max Gurtovoy April 23, 2020, 5:25 p.m. UTC | #2

On 4/21/2020 6:33 PM, Christoph Hellwig wrote:
> On Fri, Mar 27, 2020 at 08:15:43PM +0300, Max Gurtovoy wrote:
>> -	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
>> +	if (!nvmet_check_transfer_len(req,
>> +				      nvmet_rw_data_len(req) + req->md_len))
> Shouldn't we also calculate the actual metadata length on the fly here?

we calculate it during nvmet_init_req.


>
>>   	blk_start_plug(&plug);
>> +	if (req->use_md)
> Can't we use a non-NULL req->md_sg or non-null req->md_sg_cnt as a
> metadata supported indicator and remove the use_md flag?  Maybe wrap
> them in a helper function that also checks for blk integrity support
> using IS_ENABLED and we can skip the stubs as well.

I'll replace it with:

static inline bool nvmet_req_has_pi(struct nvmet_req *req)
{
         return req->sq->ctrl->pi_support && nvmet_ns_has_pi(req->ns);
}


>

Christoph Hellwig April 24, 2020, 7:54 a.m. UTC | #3

On Thu, Apr 23, 2020 at 08:25:24PM +0300, Max Gurtovoy wrote:
>
> On 4/21/2020 6:33 PM, Christoph Hellwig wrote:
>> On Fri, Mar 27, 2020 at 08:15:43PM +0300, Max Gurtovoy wrote:
>>> -	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
>>> +	if (!nvmet_check_transfer_len(req,
>>> +				      nvmet_rw_data_len(req) + req->md_len))
>> Shouldn't we also calculate the actual metadata length on the fly here?
>
> we calculate it during nvmet_init_req.

Indeed.  

>
>>
>>>   	blk_start_plug(&plug);
>>> +	if (req->use_md)
>> Can't we use a non-NULL req->md_sg or non-null req->md_sg_cnt as a
>> metadata supported indicator and remove the use_md flag?  Maybe wrap
>> them in a helper function that also checks for blk integrity support
>> using IS_ENABLED and we can skip the stubs as well.
>
> I'll replace it with:
>
> static inline bool nvmet_req_has_pi(struct nvmet_req *req)
> {
>         return req->sq->ctrl->pi_support && nvmet_ns_has_pi(req->ns);
> }

Actually I think you can simply check for a non-0 md_len, as we always
set them at the same time.

Patch

diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 2e9e309..018acd7 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -164,6 +164,61 @@  static void nvmet_bio_done(struct bio *bio)
 		bio_put(bio);
 }
 
+#ifdef CONFIG_BLK_DEV_INTEGRITY
+static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
+				struct sg_mapping_iter *miter)
+{
+	struct blk_integrity *bi;
+	struct bio_integrity_payload *bip;
+	struct block_device *bdev = req->ns->bdev;
+	int rc;
+	size_t resid, len;
+
+	bi = bdev_get_integrity(bdev);
+	if (unlikely(!bi)) {
+		pr_err("Unable to locate bio_integrity\n");
+		return -ENODEV;
+	}
+
+	bip = bio_integrity_alloc(bio, GFP_NOIO,
+			min_t(unsigned int, req->md_sg_cnt, BIO_MAX_PAGES));
+	if (IS_ERR(bip)) {
+		pr_err("Unable to allocate bio_integrity_payload\n");
+		return PTR_ERR(bip);
+	}
+
+	bip->bip_iter.bi_size = bio_integrity_bytes(bi, bio_sectors(bio));
+	/* virtual start sector must be in integrity interval units */
+	bip_set_seed(bip, bio->bi_iter.bi_sector >>
+		     (bi->interval_exp - SECTOR_SHIFT));
+
+	resid = bip->bip_iter.bi_size;
+	while (resid > 0 && sg_miter_next(miter)) {
+		len = min_t(size_t, miter->length, resid);
+		rc = bio_integrity_add_page(bio, miter->page, len,
+					    offset_in_page(miter->addr));
+		if (unlikely(rc != len)) {
+			pr_err("bio_integrity_add_page() failed; %d\n", rc);
+			sg_miter_stop(miter);
+			return -ENOMEM;
+		}
+
+		resid -= len;
+		if (len < miter->length)
+			miter->consumed -= miter->length - len;
+	}
+	sg_miter_stop(miter);
+
+	return 0;
+}
+#else
+static int nvmet_bdev_alloc_bip(struct nvmet_req *req, struct bio *bio,
+				struct sg_mapping_iter *miter)
+{
+	return 0;
+}
+#endif /* CONFIG_BLK_DEV_INTEGRITY */
+
 static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 {
 	int sg_cnt = req->sg_cnt;
@@ -171,9 +226,11 @@  static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 	struct scatterlist *sg;
 	struct blk_plug plug;
 	sector_t sector;
-	int op, i;
+	int op, i, rc;
+	struct sg_mapping_iter prot_miter;
 
-	if (!nvmet_check_transfer_len(req, nvmet_rw_data_len(req)))
+	if (!nvmet_check_transfer_len(req,
+				      nvmet_rw_data_len(req) + req->md_len))
 		return;
 
 	if (!req->sg_cnt) {
@@ -208,11 +265,25 @@  static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 	bio->bi_opf = op;
 
 	blk_start_plug(&plug);
+	if (req->use_md)
+		sg_miter_start(&prot_miter, req->md_sg, req->md_sg_cnt,
+			       op == REQ_OP_READ ? SG_MITER_FROM_SG :
+						   SG_MITER_TO_SG);
+
 	for_each_sg(req->sg, sg, req->sg_cnt, i) {
 		while (bio_add_page(bio, sg_page(sg), sg->length, sg->offset)
 				!= sg->length) {
 			struct bio *prev = bio;
 
+			if (req->use_md) {
+				rc = nvmet_bdev_alloc_bip(req, bio,
+							  &prot_miter);
+				if (unlikely(rc)) {
+					bio_io_error(bio);
+					return;
+				}
+			}
+
 			bio = bio_alloc(GFP_KERNEL, min(sg_cnt, BIO_MAX_PAGES));
 			bio_set_dev(bio, req->ns->bdev);
 			bio->bi_iter.bi_sector = sector;
@@ -226,6 +297,14 @@  static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 		sg_cnt--;
 	}
 
+	if (req->use_md) {
+		rc = nvmet_bdev_alloc_bip(req, bio, &prot_miter);
+		if (unlikely(rc)) {
+			bio_io_error(bio);
+			return;
+		}
+	}
+
 	submit_bio(bio);
 	blk_finish_plug(&plug);
 }
@@ -353,6 +432,10 @@  u16 nvmet_bdev_parse_io_cmd(struct nvmet_req *req)
 	case nvme_cmd_read:
 	case nvme_cmd_write:
 		req->execute = nvmet_bdev_execute_rw;
+		if (req->sq->ctrl->pi_support && nvmet_ns_has_pi(req->ns)) {
+			req->use_md = true;
+			req->md_len = nvmet_rw_md_len(req);
+		}
 		return 0;
 	case nvme_cmd_flush:
 		req->execute = nvmet_bdev_execute_flush;