To date, CXL flash devices do not support a single command abort operation.
Instead, the SISLite specification provides a context reset operation to
cleanup all pending commands for a given context.
When a context reset is successful, it is guaranteed that the AFU has
aborted all currently pending I/O. This sequence is less invasive than a
device or host reset and can be executed to support scsi command abort
requests. Add eh_abort_handler callback support to process command timeouts
and abort requests.
Signed-off-by: Uma Krishnan <ukri...@linux.vnet.ibm.com>
---
drivers/scsi/cxlflash/main.c | 61 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 61 insertions(+)
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 0a3de42..ceb247b 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -228,6 +228,10 @@ static void flush_pending_cmds(struct hwq *hwq)
* @hwq: Hardware queue owning the context to be reset.
* @reset_reg: MMIO register to perform reset.
*
+ * When the reset is successful, the SISLite specification guarantees that
+ * the AFU has aborted all currently pending I/O. Accordingly, these commands
+ * must be flushed.
+ *
* Return: 0 on success, -errno on failure
*/
static int context_reset(struct hwq *hwq, __be64 __iomem *reset_reg)
@@ -237,9 +241,12 @@ static int context_reset(struct hwq *hwq, __be64 __iomem
*reset_reg)
int rc = -ETIMEDOUT;
int nretry = 0;
u64 val = 0x1;
+ ulong lock_flags;
dev_dbg(dev, "%s: hwq=%p\n", __func__, hwq);
+ spin_lock_irqsave(&hwq->hsq_slock, lock_flags);
+
writeq_be(val, reset_reg);
do {
val = readq_be(reset_reg);
@@ -252,6 +259,11 @@ static int context_reset(struct hwq *hwq, __be64 __iomem
*reset_reg)
udelay(1 << nretry);
} while (nretry++ < MC_ROOM_RETRY_CNT);
+ if (!rc)
+ flush_pending_cmds(hwq);
+
+ spin_unlock_irqrestore(&hwq->hsq_slock, lock_flags);
+
dev_dbg(dev, "%s: returning rc=%d, val=%016llx nretry=%d\n",
__func__, rc, val, nretry);
return rc;
@@ -2256,6 +2268,54 @@ int cxlflash_afu_sync(struct afu *afu, ctx_hndl_t
ctx_hndl_u,
}
/**
+ * cxlflash_eh_abort_handler() - abort a SCSI command
+ * @scp: SCSI command to abort.
+ *
+ * CXL Flash devices do not support a single command abort. Reset the context
+ * as per SISLite specification. Flush any pending commands in the hardware
+ * queue before the reset.
+ *
+ * Return: SUCCESS/FAILED as defined in scsi/scsi.h
+ */
+static int cxlflash_eh_abort_handler(struct scsi_cmnd *scp)
+{
+ int rc = FAILED;
+ struct Scsi_Host *host = scp->device->host;
+ struct cxlflash_cfg *cfg = shost_priv(host);
+ struct afu_cmd *cmd = sc_to_afuc(scp);
+ struct device *dev = &cfg->dev->dev;
+ struct afu *afu = cfg->afu;
+ struct hwq *hwq = get_hwq(afu, cmd->hwq_index);
+
+ dev_dbg(dev, "%s: (scp=%p) %d/%d/%d/%llu "
+ "cdb=(%08x-%08x-%08x-%08x)\n", __func__, scp, host->host_no,
+ scp->device->channel, scp->device->id, scp->device->lun,
+ get_unaligned_be32(&((u32 *)scp->cmnd)[0]),
+ get_unaligned_be32(&((u32 *)scp->cmnd)[1]),
+ get_unaligned_be32(&((u32 *)scp->cmnd)[2]),
+ get_unaligned_be32(&((u32 *)scp->cmnd)[3]));
+
+ /* When the state is not normal, another reset/reload is in progress.
+ * Return failed and the mid-layer will invoke host reset handler.
+ */
+ if (cfg->state != STATE_NORMAL) {
+ dev_dbg(dev, "%s: Invalid state for abort, state=%d\n",
+ __func__, cfg->state);
+ goto out;
+ }
+
+ rc = afu->context_reset(hwq);
+ if (unlikely(rc))
+ goto out;
+
+ rc = SUCCESS;
+
+out:
+ dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);
+ return rc;
+}
+
+/**
* cxlflash_eh_device_reset_handler() - reset a single LUN
* @scp: SCSI command to send.
*
@@ -2969,6 +3029,7 @@ static struct scsi_host_template driver_template = {
.ioctl = cxlflash_ioctl,
.proc_name = CXLFLASH_NAME,
.queuecommand = cxlflash_queuecommand,
+ .eh_abort_handler = cxlflash_eh_abort_handler,
.eh_device_reset_handler = cxlflash_eh_device_reset_handler,
.eh_host_reset_handler = cxlflash_eh_host_reset_handler,
.change_queue_depth = cxlflash_change_queue_depth,
--
2.1.0
