Commit 5fbb96c8 authored by Matthew R. Ochs's avatar Matthew R. Ochs Committed by Martin K. Petersen
Browse files

scsi: cxlflash: Use cmd_size for private commands 



Instead of using a private pool of AFU commands, use cmd_size to prime
the private pool of SCSI commands such that they are allocated with a
size large enough to contain an aligned AFU command. Use scsi_cmd_priv()
to derive the aligned/zeroed private command on queuecommand and TMF
paths. Remove cmd_checkout() as it is no longer required. The remaining
AFU private command infrastructure will be removed in a cleanup commit.

Signed-off-by: default avatarMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Acked-by: default avatarUma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 350bb478

drivers/scsi/cxlflash/common.h

+14 −0
Original line number Diff line number Diff line
@@ -19,6 +19,7 @@ 
#include <linux/rwsem.h>

#include <linux/types.h>

#include <scsi/scsi.h>

#include <scsi/scsi_cmnd.h>

#include <scsi/scsi_device.h>



extern const struct file_operations cxlflash_cxl_fops;
@@ -146,6 +147,19 @@ struct afu_cmd { 
	 */

} __aligned(cache_line_size());



static inline struct afu_cmd *sc_to_afuc(struct scsi_cmnd *sc)

{

	return PTR_ALIGN(scsi_cmd_priv(sc), __alignof__(struct afu_cmd));

}



static inline struct afu_cmd *sc_to_afucz(struct scsi_cmnd *sc)

{

	struct afu_cmd *afuc = sc_to_afuc(sc);



	memset(afuc, 0, sizeof(*afuc));

	return afuc;

}



struct afu {

	/* Stuff requiring alignment go first. */

drivers/scsi/cxlflash/main.c

+11 −54
Original line number Diff line number Diff line
@@ -34,38 +34,6 @@ MODULE_AUTHOR("Manoj N. Kumar <manoj@linux.vnet.ibm.com>"); 
MODULE_AUTHOR("Matthew R. Ochs <mrochs@linux.vnet.ibm.com>");

MODULE_LICENSE("GPL");



/**

 * cmd_checkout() - checks out an AFU command

 * @afu:	AFU to checkout from.

 *

 * Commands are checked out in a round-robin fashion. Note that since

 * the command pool is larger than the hardware queue, the majority of

 * times we will only loop once or twice before getting a command. The

 * CDB within the command is initialized (zeroed) prior to returning.

 *

 * Return: The checked out command or NULL when command pool is empty.

 */

static struct afu_cmd *cmd_checkout(struct afu *afu)

{

	int k, dec = CXLFLASH_NUM_CMDS;

	struct afu_cmd *cmd;



	while (dec--) {

		k = (afu->cmd_couts++ & (CXLFLASH_NUM_CMDS - 1));



		cmd = &afu->cmd[k];



		if (!atomic_dec_if_positive(&cmd->free)) {

			pr_devel("%s: returning found index=%d cmd=%p\n",

				 __func__, cmd->slot, cmd);

			memset(cmd->rcb.cdb, 0, sizeof(cmd->rcb.cdb));

			return cmd;

		}

	}



	return NULL;

}



/**

 * cmd_checkin() - checks in an AFU command

 * @cmd:	AFU command to checkin.
@@ -232,7 +200,6 @@ static void cmd_complete(struct afu_cmd *cmd) 
			scp->result = (DID_OK << 16);



		cmd_is_tmf = cmd->cmd_tmf;

		cmd_checkin(cmd); /* Don't use cmd after here */



		pr_debug_ratelimited("%s: calling scsi_done scp=%p result=%X "

				     "ioasc=%d\n", __func__, scp, scp->result,
@@ -365,7 +332,7 @@ static void wait_resp(struct afu *afu, struct afu_cmd *cmd) 
 */

static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd)

{

	struct afu_cmd *cmd;

	struct afu_cmd *cmd = sc_to_afucz(scp);



	u32 port_sel = scp->device->channel + 1;

	short lflag = 0;
@@ -376,13 +343,6 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) 
	int rc = 0;

	ulong to;



	cmd = cmd_checkout(afu);

	if (unlikely(!cmd)) {

		dev_err(dev, "%s: could not get a free command\n", __func__);

		rc = SCSI_MLQUEUE_HOST_BUSY;

		goto out;

	}



	/* When Task Management Function is active do not send another */

	spin_lock_irqsave(&cfg->tmf_slock, lock_flags);

	if (cfg->tmf_active)
@@ -394,6 +354,7 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) 
	spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);



	cmd->rcb.ctx_id = afu->ctx_hndl;

	cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;

	cmd->rcb.port_sel = port_sel;

	cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
@@ -402,8 +363,10 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) 
	cmd->rcb.req_flags = (SISL_REQ_FLAGS_PORT_LUN_ID |

			      SISL_REQ_FLAGS_SUP_UNDERRUN | lflag);



	/* Stash the scp in the reserved field, for reuse during interrupt */

	/* Stash the scp in the command, for reuse during interrupt */

	cmd->rcb.scp = scp;

	cmd->parent = afu;

	spin_lock_init(&cmd->slock);



	/* Copy the CDB from the cmd passed in */

	memcpy(cmd->rcb.cdb, &tmfcmd, sizeof(tmfcmd));
@@ -411,7 +374,6 @@ static int send_tmf(struct afu *afu, struct scsi_cmnd *scp, u64 tmfcmd) 
	/* Send the command */

	rc = send_cmd(afu, cmd);

	if (unlikely(rc)) {

		cmd_checkin(cmd);

		spin_lock_irqsave(&cfg->tmf_slock, lock_flags);

		cfg->tmf_active = false;

		spin_unlock_irqrestore(&cfg->tmf_slock, lock_flags);
@@ -467,7 +429,7 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) 
	struct cxlflash_cfg *cfg = (struct cxlflash_cfg *)host->hostdata;

	struct afu *afu = cfg->afu;

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

	struct afu_cmd *cmd;

	struct afu_cmd *cmd = sc_to_afucz(scp);

	u32 port_sel = scp->device->channel + 1;

	int nseg, i, ncount;

	struct scatterlist *sg;
@@ -512,17 +474,11 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) 
		break;

	}



	cmd = cmd_checkout(afu);

	if (unlikely(!cmd)) {

		dev_err(dev, "%s: could not get a free command\n", __func__);

		rc = SCSI_MLQUEUE_HOST_BUSY;

		goto out;

	}



	kref_get(&cfg->afu->mapcount);

	kref_got = 1;



	cmd->rcb.ctx_id = afu->ctx_hndl;

	cmd->rcb.msi = SISL_MSI_RRQ_UPDATED;

	cmd->rcb.port_sel = port_sel;

	cmd->rcb.lun_id = lun_to_lunid(scp->device->lun);
@@ -536,6 +492,8 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) 


	/* Stash the scp in the reserved field, for reuse during interrupt */

	cmd->rcb.scp = scp;

	cmd->parent = afu;

	spin_lock_init(&cmd->slock);



	nseg = scsi_dma_map(scp);

	if (unlikely(nseg < 0)) {
@@ -556,10 +514,8 @@ static int cxlflash_queuecommand(struct Scsi_Host *host, struct scsi_cmnd *scp) 


	/* Send the command */

	rc = send_cmd(afu, cmd);

	if (unlikely(rc)) {

		cmd_checkin(cmd);

	if (unlikely(rc))

		scsi_dma_unmap(scp);

	}



out:

	if (kref_got)
@@ -2314,6 +2270,7 @@ static struct scsi_host_template driver_template = { 
	.change_queue_depth = cxlflash_change_queue_depth,

	.cmd_per_lun = CXLFLASH_MAX_CMDS_PER_LUN,

	.can_queue = CXLFLASH_MAX_CMDS,

	.cmd_size = sizeof(struct afu_cmd) + __alignof__(struct afu_cmd) - 1,

	.this_id = -1,

	.sg_tablesize = 1,	/* No scatter gather support */

	.max_sectors = CXLFLASH_MAX_SECTORS,

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