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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: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Acked-by: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
zero-colors
Uma Krishnan 2017-06-21 21:15:06 -05:00 committed by Martin K. Petersen
parent a1ea04b3eb
commit 7c4c41f172
1 changed files with 61 additions and 0 deletions
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61
drivers/scsi/cxlflash/main.c
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@ -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,