[PATCH 05/17] cxlflash: Handle AFU sync failures
Uma Krishnan
ukrishn at linux.vnet.ibm.com
Thu Jun 22 12:14:30 AEST 2017
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: Uma Krishnan <ukrishn at linux.vnet.ibm.com>
---
Documentation/powerpc/cxlflash.txt | 12 ++++++
drivers/scsi/cxlflash/superpipe.c | 34 +++++++++++++--
drivers/scsi/cxlflash/vlun.c | 88 +++++++++++++++++++++++++++-----------
3 files changed, 107 insertions(+), 27 deletions(-)
diff --git a/Documentation/powerpc/cxlflash.txt b/Documentation/powerpc/cxlflash.txt
index 66b4496..f9036cb 100644
--- a/Documentation/powerpc/cxlflash.txt
+++ b/Documentation/powerpc/cxlflash.txt
@@ -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
diff --git a/drivers/scsi/cxlflash/superpipe.c b/drivers/scsi/cxlflash/superpipe.c
index fe9f17a..ad0f996 100644
--- a/drivers/scsi/cxlflash/superpipe.c
+++ b/drivers/scsi/cxlflash/superpipe.c
@@ -57,6 +57,19 @@ static void marshal_det_to_rele(struct dk_cxlflash_detach *detach,
}
/**
+ * 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
*/
void cxlflash_free_errpage(void)
@@ -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 @@ static int cxlflash_disk_direct_open(struct scsi_device *sdev, void *arg)
__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;
diff --git a/drivers/scsi/cxlflash/vlun.c b/drivers/scsi/cxlflash/vlun.c
index 90b5c19..0800bcb 100644
--- a/drivers/scsi/cxlflash/vlun.c
+++ b/drivers/scsi/cxlflash/vlun.c
@@ -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;
}
/**
--
2.1.0
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