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usb-gadget/tcm: Conversion to percpu_ida tag pre-allocation
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This patch converts usb-gadget target to use percpu_ida tag
pre-allocation for struct usbg_cmd descriptor, in order to
avoid fast-path struct usbg_cmd memory allocations.

Note by default this is currently hardcoded to 128.

Tested-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
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Nicholas Bellinger committed Mar 11, 2016
1 parent 5f27eda commit 71e7ae8
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Showing 2 changed files with 60 additions and 39 deletions.
97 changes: 58 additions & 39 deletions drivers/usb/gadget/function/f_tcm.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1073,39 +1073,66 @@ static void usbg_cmd_work(struct work_struct *work)
usbg_cleanup_cmd(cmd);
}

static struct usbg_cmd *usbg_get_cmd(struct f_uas *fu,
struct tcm_usbg_nexus *tv_nexus, u32 scsi_tag)
{
struct se_session *se_sess = tv_nexus->tvn_se_sess;
struct usbg_cmd *cmd;
int tag;

tag = percpu_ida_alloc(&se_sess->sess_tag_pool, GFP_ATOMIC);
if (tag < 0)
return ERR_PTR(-ENOMEM);

cmd = &((struct usbg_cmd *)se_sess->sess_cmd_map)[tag];
memset(cmd, 0, sizeof(*cmd));
cmd->se_cmd.map_tag = tag;
cmd->se_cmd.tag = cmd->tag = scsi_tag;
cmd->fu = fu;

return cmd;
}

static void usbg_release_cmd(struct se_cmd *);

static int usbg_submit_command(struct f_uas *fu,
void *cmdbuf, unsigned int len)
{
struct command_iu *cmd_iu = cmdbuf;
struct usbg_cmd *cmd;
struct usbg_tpg *tpg;
struct tcm_usbg_nexus *tv_nexus;
struct usbg_tpg *tpg = fu->tpg;
struct tcm_usbg_nexus *tv_nexus = tpg->tpg_nexus;
u32 cmd_len;
u16 scsi_tag;

if (cmd_iu->iu_id != IU_ID_COMMAND) {
pr_err("Unsupported type %d\n", cmd_iu->iu_id);
return -EINVAL;
}

cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
if (!cmd)
return -ENOMEM;
tv_nexus = tpg->tpg_nexus;
if (!tv_nexus) {
pr_err("Missing nexus, ignoring command\n");
return -EINVAL;
}

cmd->fu = fu;
cmd_len = (cmd_iu->len & ~0x3) + 16;
if (cmd_len > USBG_MAX_CMD)
return -EINVAL;

scsi_tag = be16_to_cpup(&cmd_iu->tag);
cmd = usbg_get_cmd(fu, tv_nexus, scsi_tag);
if (IS_ERR(cmd)) {
pr_err("usbg_get_cmd failed\n");
return -ENOMEM;
}

/* XXX until I figure out why I can't free in on complete */
kref_init(&cmd->ref);
kref_get(&cmd->ref);

tpg = fu->tpg;
cmd_len = (cmd_iu->len & ~0x3) + 16;
if (cmd_len > USBG_MAX_CMD)
goto err;

memcpy(cmd->cmd_buf, cmd_iu->cdb, cmd_len);

cmd->tag = be16_to_cpup(&cmd_iu->tag);
cmd->se_cmd.tag = cmd->tag;
if (fu->flags & USBG_USE_STREAMS) {
if (cmd->tag > UASP_SS_EP_COMP_NUM_STREAMS)
goto err;
Expand All @@ -1117,12 +1144,6 @@ static int usbg_submit_command(struct f_uas *fu,
cmd->stream = &fu->stream[0];
}

tv_nexus = tpg->tpg_nexus;
if (!tv_nexus) {
pr_err("Missing nexus, ignoring command\n");
goto err;
}

switch (cmd_iu->prio_attr & 0x7) {
case UAS_HEAD_TAG:
cmd->prio_attr = TCM_HEAD_TAG;
Expand All @@ -1148,7 +1169,7 @@ static int usbg_submit_command(struct f_uas *fu,

return 0;
err:
kfree(cmd);
usbg_release_cmd(&cmd->se_cmd);
return -EINVAL;
}

Expand Down Expand Up @@ -1190,7 +1211,7 @@ static int bot_submit_command(struct f_uas *fu,
{
struct bulk_cb_wrap *cbw = cmdbuf;
struct usbg_cmd *cmd;
struct usbg_tpg *tpg;
struct usbg_tpg *tpg = fu->tpg;
struct tcm_usbg_nexus *tv_nexus;
u32 cmd_len;

Expand All @@ -1207,28 +1228,25 @@ static int bot_submit_command(struct f_uas *fu,
if (cmd_len < 1 || cmd_len > 16)
return -EINVAL;

cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
if (!cmd)
return -ENOMEM;
tv_nexus = tpg->tpg_nexus;
if (!tv_nexus) {
pr_err("Missing nexus, ignoring command\n");
return -ENODEV;
}

cmd->fu = fu;
cmd = usbg_get_cmd(fu, tv_nexus, cbw->Tag);
if (IS_ERR(cmd)) {
pr_err("usbg_get_cmd failed\n");
return -ENOMEM;
}

/* XXX until I figure out why I can't free in on complete */
kref_init(&cmd->ref);
kref_get(&cmd->ref);

tpg = fu->tpg;

memcpy(cmd->cmd_buf, cbw->CDB, cmd_len);

cmd->bot_tag = cbw->Tag;

tv_nexus = tpg->tpg_nexus;
if (!tv_nexus) {
pr_err("Missing nexus, ignoring command\n");
goto err;
}

cmd->prio_attr = TCM_SIMPLE_TAG;
cmd->unpacked_lun = cbw->Lun;
cmd->is_read = cbw->Flags & US_BULK_FLAG_IN ? 1 : 0;
Expand All @@ -1239,9 +1257,6 @@ static int bot_submit_command(struct f_uas *fu,
queue_work(tpg->workqueue, &cmd->work);

return 0;
err:
kfree(cmd);
return -EINVAL;
}

/* Start fabric.c code */
Expand Down Expand Up @@ -1294,8 +1309,10 @@ static void usbg_release_cmd(struct se_cmd *se_cmd)
{
struct usbg_cmd *cmd = container_of(se_cmd, struct usbg_cmd,
se_cmd);
struct se_session *se_sess = se_cmd->se_sess;

kfree(cmd->data_buf);
kfree(cmd);
percpu_ida_free(&se_sess->sess_tag_pool, se_cmd->map_tag);
}

static int usbg_shutdown_session(struct se_session *se_sess)
Expand Down Expand Up @@ -1607,7 +1624,9 @@ static int tcm_usbg_make_nexus(struct usbg_tpg *tpg, char *name)
goto out_unlock;
}

tv_nexus->tvn_se_sess = target_alloc_session(&tpg->se_tpg, 0, 0,
tv_nexus->tvn_se_sess = target_alloc_session(&tpg->se_tpg,
USB_G_DEFAULT_SESSION_TAGS,
sizeof(struct usbg_cmd),
TARGET_PROT_NORMAL, name,
tv_nexus, usbg_alloc_sess_cb);
if (IS_ERR(tv_nexus->tvn_se_sess)) {
Expand Down
2 changes: 2 additions & 0 deletions drivers/usb/gadget/function/tcm.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,6 +23,8 @@ enum {
#define USB_G_ALT_INT_BBB 0
#define USB_G_ALT_INT_UAS 1

#define USB_G_DEFAULT_SESSION_TAGS 128

struct tcm_usbg_nexus {
struct se_session *tvn_se_sess;
};
Expand Down

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