Commit c2c292f4 authored by Uma Krishnan's avatar Uma Krishnan Committed by Martin K. Petersen
Browse files

scsi: cxlflash: Handle AFU sync failures 



AFU sync operations are not currently evaluated for failure. This is
acceptable for paths where there is not a dependency on the AFU being
consistent with the host. Examples include link reset events and LUN
cleanup operations. On paths where there is a dependency, such as a LUN
open, a sync failure should be acted upon.

In the event of AFU sync failures, either log or cleanup as appropriate for
operations that are dependent on a successful sync completion.

Update documentation to reflect behavior in the event of an AFU sync
failure.

Signed-off-by: default avatarUma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: default avatarMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 0b09e711

Documentation/powerpc/cxlflash.txt

+12 −0
Original line number Diff line number Diff line
@@ -257,6 +257,12 @@ DK_CXLFLASH_VLUN_RESIZE 
    operating in the virtual mode and used to program a LUN translation

    table that the AFU references when provided with a resource handle.



    This ioctl can return -EAGAIN if an AFU sync operation takes too long.

    In addition to returning a failure to user, cxlflash will also schedule

    an asynchronous AFU reset. Should the user choose to retry the operation,

    it is expected to succeed. If this ioctl fails with -EAGAIN, the user

    can either retry the operation or treat it as a failure.



DK_CXLFLASH_RELEASE

-------------------

    This ioctl is responsible for releasing a previously obtained
@@ -309,6 +315,12 @@ DK_CXLFLASH_VLUN_CLONE 
    clone. This is to avoid a stale entry in the file descriptor table of the

    child process.



    This ioctl can return -EAGAIN if an AFU sync operation takes too long.

    In addition to returning a failure to user, cxlflash will also schedule

    an asynchronous AFU reset. Should the user choose to retry the operation,

    it is expected to succeed. If this ioctl fails with -EAGAIN, the user

    can either retry the operation or treat it as a failure.



DK_CXLFLASH_VERIFY

------------------

    This ioctl is used to detect various changes such as the capacity of

drivers/scsi/cxlflash/superpipe.c

+31 −3
Original line number Diff line number Diff line
@@ -56,6 +56,19 @@ static void marshal_det_to_rele(struct dk_cxlflash_detach *detach, 
	release->context_id = detach->context_id;

}



/**

 * marshal_udir_to_rele() - translate udirect to release structure

 * @udirect:	Source structure from which to translate/copy.

 * @release:	Destination structure for the translate/copy.

 */

static void marshal_udir_to_rele(struct dk_cxlflash_udirect *udirect,

				 struct dk_cxlflash_release *release)

{

	release->hdr = udirect->hdr;

	release->context_id = udirect->context_id;

	release->rsrc_handle = udirect->rsrc_handle;

}



/**

 * cxlflash_free_errpage() - frees resources associated with global error page

 */
@@ -622,6 +635,7 @@ int _cxlflash_disk_release(struct scsi_device *sdev, 
	res_hndl_t rhndl = release->rsrc_handle;



	int rc = 0;

	int rcr = 0;

	u64 ctxid = DECODE_CTXID(release->context_id),

	    rctxid = release->context_id;
@@ -686,8 +700,12 @@ int _cxlflash_disk_release(struct scsi_device *sdev, 
		rhte_f1->dw = 0;

		dma_wmb(); /* Make RHT entry bottom-half clearing visible */



		if (!ctxi->err_recovery_active)

			cxlflash_afu_sync(afu, ctxid, rhndl, AFU_HW_SYNC);

		if (!ctxi->err_recovery_active) {

			rcr = cxlflash_afu_sync(afu, ctxid, rhndl, AFU_HW_SYNC);

			if (unlikely(rcr))

				dev_dbg(dev, "%s: AFU sync failed rc=%d\n",

					__func__, rcr);

		}

		break;

	default:

		WARN(1, "Unsupported LUN mode!");
@@ -1929,6 +1947,7 @@ static int cxlflash_disk_direct_open(struct scsi_device *sdev, void *arg) 
	struct afu *afu = cfg->afu;

	struct llun_info *lli = sdev->hostdata;

	struct glun_info *gli = lli->parent;

	struct dk_cxlflash_release rel = { { 0 }, 0 };



	struct dk_cxlflash_udirect *pphys = (struct dk_cxlflash_udirect *)arg;
@@ -1970,13 +1989,18 @@ static int cxlflash_disk_direct_open(struct scsi_device *sdev, void *arg) 
	rsrc_handle = (rhte - ctxi->rht_start);



	rht_format1(rhte, lli->lun_id[sdev->channel], ctxi->rht_perms, port);

	cxlflash_afu_sync(afu, ctxid, rsrc_handle, AFU_LW_SYNC);



	last_lba = gli->max_lba;

	pphys->hdr.return_flags = 0;

	pphys->last_lba = last_lba;

	pphys->rsrc_handle = rsrc_handle;



	rc = cxlflash_afu_sync(afu, ctxid, rsrc_handle, AFU_LW_SYNC);

	if (unlikely(rc)) {

		dev_dbg(dev, "%s: AFU sync failed rc=%d\n", __func__, rc);

		goto err2;

	}



out:

	if (likely(ctxi))

		put_context(ctxi);
@@ -1984,6 +2008,10 @@ out: 
		__func__, rsrc_handle, rc, last_lba);

	return rc;



err2:

	marshal_udir_to_rele(pphys, &rel);

	_cxlflash_disk_release(sdev, ctxi, &rel);

	goto out;

err1:

	cxlflash_lun_detach(gli);

	goto out;

drivers/scsi/cxlflash/vlun.c

+64 −24
Original line number Diff line number Diff line
@@ -594,7 +594,9 @@ static int grow_lxt(struct afu *afu, 
	rhte->lxt_cnt = my_new_size;

	dma_wmb(); /* Make RHT entry's LXT table size update visible */



	cxlflash_afu_sync(afu, ctxid, rhndl, AFU_LW_SYNC);

	rc = cxlflash_afu_sync(afu, ctxid, rhndl, AFU_LW_SYNC);

	if (unlikely(rc))

		rc = -EAGAIN;



	/* free old lxt if reallocated */

	if (lxt != lxt_old)
@@ -673,8 +675,11 @@ static int shrink_lxt(struct afu *afu, 
	rhte->lxt_start = lxt;

	dma_wmb(); /* Make RHT entry's LXT table update visible */



	if (needs_sync)

		cxlflash_afu_sync(afu, ctxid, rhndl, AFU_HW_SYNC);

	if (needs_sync) {

		rc = cxlflash_afu_sync(afu, ctxid, rhndl, AFU_HW_SYNC);

		if (unlikely(rc))

			rc = -EAGAIN;

	}



	if (needs_ws) {

		/*
@@ -792,6 +797,21 @@ int _cxlflash_vlun_resize(struct scsi_device *sdev, 
		rc = grow_lxt(afu, sdev, ctxid, rhndl, rhte, &new_size);

	else if (new_size < rhte->lxt_cnt)

		rc = shrink_lxt(afu, sdev, rhndl, rhte, ctxi, &new_size);

	else {

		/*

		 * Rare case where there is already sufficient space, just

		 * need to perform a translation sync with the AFU. This

		 * scenario likely follows a previous sync failure during

		 * a resize operation. Accordingly, perform the heavyweight

		 * form of translation sync as it is unknown which type of

		 * resize failed previously.

		 */

		rc = cxlflash_afu_sync(afu, ctxid, rhndl, AFU_HW_SYNC);

		if (unlikely(rc)) {

			rc = -EAGAIN;

			goto out;

		}

	}



	resize->hdr.return_flags = 0;

	resize->last_lba = (new_size * MC_CHUNK_SIZE * gli->blk_len);
@@ -1084,10 +1104,13 @@ static int clone_lxt(struct afu *afu, 
{

	struct cxlflash_cfg *cfg = afu->parent;

	struct device *dev = &cfg->dev->dev;

	struct sisl_lxt_entry *lxt;

	struct sisl_lxt_entry *lxt = NULL;

	bool locked = false;

	u32 ngrps;

	u64 aun;		/* chunk# allocated by block allocator */

	int i, j;

	int j;

	int i = 0;

	int rc = 0;



	ngrps = LXT_NUM_GROUPS(rhte_src->lxt_cnt);
@@ -1095,33 +1118,29 @@ static int clone_lxt(struct afu *afu, 
		/* allocate new LXTs for clone */

		lxt = kzalloc((sizeof(*lxt) * LXT_GROUP_SIZE * ngrps),

				GFP_KERNEL);

		if (unlikely(!lxt))

			return -ENOMEM;

		if (unlikely(!lxt)) {

			rc = -ENOMEM;

			goto out;

		}



		/* copy over */

		memcpy(lxt, rhte_src->lxt_start,

		       (sizeof(*lxt) * rhte_src->lxt_cnt));



		/* clone the LBAs in block allocator via ref_cnt */

		/* clone the LBAs in block allocator via ref_cnt, note that the

		 * block allocator mutex must be held until it is established

		 * that this routine will complete without the need for a

		 * cleanup.

		 */

		mutex_lock(&blka->mutex);

		locked = true;

		for (i = 0; i < rhte_src->lxt_cnt; i++) {

			aun = (lxt[i].rlba_base >> MC_CHUNK_SHIFT);

			if (ba_clone(&blka->ba_lun, aun) == -1ULL) {

				/* free the clones already made */

				for (j = 0; j < i; j++) {

					aun = (lxt[j].rlba_base >>

					       MC_CHUNK_SHIFT);

					ba_free(&blka->ba_lun, aun);

				}



				mutex_unlock(&blka->mutex);

				kfree(lxt);

				return -EIO;

				rc = -EIO;

				goto err;

			}

		}

		mutex_unlock(&blka->mutex);

	} else {

		lxt = NULL;

	}



	/*
@@ -1136,10 +1155,31 @@ static int clone_lxt(struct afu *afu, 
	rhte->lxt_cnt = rhte_src->lxt_cnt;

	dma_wmb(); /* Make RHT entry's LXT table size update visible */



	cxlflash_afu_sync(afu, ctxid, rhndl, AFU_LW_SYNC);

	rc = cxlflash_afu_sync(afu, ctxid, rhndl, AFU_LW_SYNC);

	if (unlikely(rc)) {

		rc = -EAGAIN;

		goto err2;

	}



	dev_dbg(dev, "%s: returning\n", __func__);

	return 0;

out:

	if (locked)

		mutex_unlock(&blka->mutex);

	dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);

	return rc;

err2:

	/* Reset the RHTE */

	rhte->lxt_cnt = 0;

	dma_wmb();

	rhte->lxt_start = NULL;

	dma_wmb();

err:

	/* free the clones already made */

	for (j = 0; j < i; j++) {

		aun = (lxt[j].rlba_base >> MC_CHUNK_SHIFT);

		ba_free(&blka->ba_lun, aun);

	}

	kfree(lxt);

	goto out;

}



/**

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