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scsi: cxlflash: Use local mutex for AFU serialization

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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: Matthew R. Ochs <mrochs@linux.vnet.ibm.com>
Signed-off-by: Uma Krishnan <ukrishn@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Matthew R. Ochs 2018-05-11 14:05:37 -05:00 committed by Martin K. Petersen
parent 32a9ae415b
commit e63a8d886d
2 changed files with 4 additions and 3 deletions
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1
drivers/scsi/cxlflash/common.h
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@ -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 */

6
drivers/scsi/cxlflash/main.c
View file

@ -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;