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Commit e63a8d88 authored by Matthew R. Ochs's avatar Matthew R. Ochs Committed by Martin K. Petersen
Browse files

scsi: cxlflash: Use local mutex for AFU serialization 



AFUs can only process a single AFU command at a time. This is enforced with
a global mutex situated within the AFU send routine. As this mutex has a
global scope, it has the potential to unnecessarily block commands destined
for other AFUs.

Instead of using a global mutex, transition the mutex to be per-AFU. This
will allow commands to only be blocked by siblings of the same AFU.

Signed-off-by: default avatarMatthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: default avatarUma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin K. Petersen <martin.petersen@oracle.com>
parent 32a9ae41

drivers/scsi/cxlflash/common.h

+1 −0
Original line number Diff line number Diff line
@@ -240,6 +240,7 @@ struct afu { 
	struct cxlflash_afu_map __iomem *afu_map;	/* entire MMIO map */



	atomic_t cmds_active;	/* Number of currently active AFU commands */

	struct mutex sync_active;	/* Mutex to serialize AFU commands */

	u64 hb;

	u32 internal_lun;	/* User-desired LUN mode for this AFU */

drivers/scsi/cxlflash/main.c

+3 −3
Original line number Diff line number Diff line
@@ -2126,6 +2126,7 @@ static int init_afu(struct cxlflash_cfg *cfg) 


	cfg->ops->perst_reloads_same_image(cfg->afu_cookie, true);



	mutex_init(&afu->sync_active);

	afu->num_hwqs = afu->desired_hwqs;

	for (i = 0; i < afu->num_hwqs; i++) {

		rc = init_mc(cfg, i);
@@ -2309,7 +2310,6 @@ static int send_afu_cmd(struct afu *afu, struct sisl_ioarcb *rcb) 
	char *buf = NULL;

	int rc = 0;

	int nretry = 0;

	static DEFINE_MUTEX(sync_active);



	if (cfg->state != STATE_NORMAL) {

		dev_dbg(dev, "%s: Sync not required state=%u\n",
@@ -2317,7 +2317,7 @@ static int send_afu_cmd(struct afu *afu, struct sisl_ioarcb *rcb) 
		return 0;

	}



	mutex_lock(&sync_active);

	mutex_lock(&afu->sync_active);

	atomic_inc(&afu->cmds_active);

	buf = kmalloc(sizeof(*cmd) + __alignof__(*cmd) - 1, GFP_KERNEL);

	if (unlikely(!buf)) {
@@ -2372,7 +2372,7 @@ static int send_afu_cmd(struct afu *afu, struct sisl_ioarcb *rcb) 
		*rcb->ioasa = cmd->sa;

out:

	atomic_dec(&afu->cmds_active);

	mutex_unlock(&sync_active);

	mutex_unlock(&afu->sync_active);

	kfree(buf);

	dev_dbg(dev, "%s: returning rc=%d\n", __func__, rc);

	return rc;