[PATCH v2 07/14] cxlflash: Use cmd_size for private commands
Uma Krishnan
ukrishn at linux.vnet.ibm.com
Tue Nov 29 11:42:19 AEDT 2016
From: "Matthew R. Ochs" <mrochs at linux.vnet.ibm.com>
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: Matthew R. Ochs <mrochs at linux.vnet.ibm.com>
---
drivers/scsi/cxlflash/common.h | 14 +++++++++
drivers/scsi/cxlflash/main.c | 65 +++++++-----------------------------------
2 files changed, 25 insertions(+), 54 deletions(-)
diff --git a/drivers/scsi/cxlflash/common.h b/drivers/scsi/cxlflash/common.h
index 4525514..539908f 100644
--- a/drivers/scsi/cxlflash/common.h
+++ b/drivers/scsi/cxlflash/common.h
@@ -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. */
diff --git a/drivers/scsi/cxlflash/main.c b/drivers/scsi/cxlflash/main.c
index 0f13b4d..43140ce 100644
--- a/drivers/scsi/cxlflash/main.c
+++ b/drivers/scsi/cxlflash/main.c
@@ -35,38 +35,6 @@ MODULE_AUTHOR("Matthew R. Ochs <mrochs at 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,
--
2.1.0
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