Commit 7c4c41f1 authored by Uma Krishnan's avatar Uma Krishnan Committed by Martin K. Petersen
Browse files

scsi: cxlflash: Add scsi command abort handler 



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: 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 a1ea04b3

drivers/scsi/cxlflash/main.c

+61 −0
Original line number Diff line number Diff line
@@ -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;
@@ -2255,6 +2267,54 @@ out: 
	return rc;

}



/**

 * 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,

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