#include <linux/slab.h>
#include <linux/err.h>
#include <linux/export.h>
+#include <linux/log2.h>
#include <scsi/fc/fc_fc2.h>
fr_eof(fp) = FC_EOF_N;
}
- /*
- * Initialize remainig fh fields
- * from fc_fill_fc_hdr
- */
+ /* Initialize remaining fh fields from fc_fill_fc_hdr */
fh->fh_ox_id = htons(ep->oxid);
fh->fh_rx_id = htons(ep->rxid);
fh->fh_seq_id = ep->seq.id;
* fc_exch_timer_cancel() - cancel exch timer
* @ep: The exchange whose timer to be canceled
*/
-static inline void fc_exch_timer_cancel(struct fc_exch *ep)
+static inline void fc_exch_timer_cancel(struct fc_exch *ep)
{
if (cancel_delayed_work(&ep->timeout_work)) {
FC_EXCH_DBG(ep, "Exchange timer canceled\n");
FC_EXCH_DBG(ep, "Exchange timer armed : %d msecs\n", timer_msec);
- if (queue_delayed_work(fc_exch_workqueue, &ep->timeout_work,
- msecs_to_jiffies(timer_msec)))
- fc_exch_hold(ep); /* hold for timer */
+ fc_exch_hold(ep); /* hold for timer */
+ if (!queue_delayed_work(fc_exch_workqueue, &ep->timeout_work,
+ msecs_to_jiffies(timer_msec)))
+ fc_exch_release(ep);
}
/**
/**
* fc_exch_done_locked() - Complete an exchange with the exchange lock held
* @ep: The exchange that is complete
+ *
+ * Note: May sleep if invoked from outside a response handler.
*/
static int fc_exch_done_locked(struct fc_exch *ep)
{
* ep, and in that case we only clear the resp and set it as
* complete, so it can be reused by the timer to send the rrq.
*/
- ep->resp = NULL;
if (ep->state & FC_EX_DONE)
return rc;
ep->esb_stat |= ESB_ST_COMPLETE;
}
static int fc_seq_send_locked(struct fc_lport *lport, struct fc_seq *sp,
- struct fc_frame *fp)
+ struct fc_frame *fp)
{
struct fc_exch *ep;
struct fc_frame_header *fh = fc_frame_header_get(fp);
- int error;
+ int error = -ENXIO;
u32 f_ctl;
u8 fh_type = fh->fh_type;
ep = fc_seq_exch(sp);
+
+ if (ep->esb_stat & (ESB_ST_COMPLETE | ESB_ST_ABNORMAL)) {
+ fc_frame_free(fp);
+ goto out;
+ }
+
WARN_ON(!(ep->esb_stat & ESB_ST_SEQ_INIT));
f_ctl = ntoh24(fh->fh_f_ctl);
* @lport: The local port that the exchange will be sent on
* @sp: The sequence to be sent
* @fp: The frame to be sent on the exchange
+ *
+ * Note: The frame will be freed either by a direct call to fc_frame_free(fp)
+ * or indirectly by calling libfc_function_template.frame_send().
*/
static int fc_seq_send(struct fc_lport *lport, struct fc_seq *sp,
struct fc_frame *fp)
/*
* Set the response handler for the exchange associated with a sequence.
+ *
+ * Note: May sleep if invoked from outside a response handler.
*/
static void fc_seq_set_resp(struct fc_seq *sp,
void (*resp)(struct fc_seq *, struct fc_frame *,
void *arg)
{
struct fc_exch *ep = fc_seq_exch(sp);
+ DEFINE_WAIT(wait);
spin_lock_bh(&ep->ex_lock);
+ while (ep->resp_active && ep->resp_task != current) {
+ prepare_to_wait(&ep->resp_wq, &wait, TASK_UNINTERRUPTIBLE);
+ spin_unlock_bh(&ep->ex_lock);
+
+ schedule();
+
+ spin_lock_bh(&ep->ex_lock);
+ }
+ finish_wait(&ep->resp_wq, &wait);
ep->resp = resp;
ep->arg = arg;
spin_unlock_bh(&ep->ex_lock);
if (!sp)
return -ENOMEM;
- ep->esb_stat |= ESB_ST_SEQ_INIT | ESB_ST_ABNORMAL;
if (timer_msec)
fc_exch_timer_set_locked(ep, timer_msec);
- /*
- * If not logged into the fabric, don't send ABTS but leave
- * sequence active until next timeout.
- */
- if (!ep->sid)
- return 0;
-
- /*
- * Send an abort for the sequence that timed out.
- */
- fp = fc_frame_alloc(ep->lp, 0);
- if (fp) {
- fc_fill_fc_hdr(fp, FC_RCTL_BA_ABTS, ep->did, ep->sid,
- FC_TYPE_BLS, FC_FC_END_SEQ | FC_FC_SEQ_INIT, 0);
- error = fc_seq_send_locked(ep->lp, sp, fp);
- } else
- error = -ENOBUFS;
+ if (ep->sid) {
+ /*
+ * Send an abort for the sequence that timed out.
+ */
+ fp = fc_frame_alloc(ep->lp, 0);
+ if (fp) {
+ ep->esb_stat |= ESB_ST_SEQ_INIT;
+ fc_fill_fc_hdr(fp, FC_RCTL_BA_ABTS, ep->did, ep->sid,
+ FC_TYPE_BLS, FC_FC_END_SEQ |
+ FC_FC_SEQ_INIT, 0);
+ error = fc_seq_send_locked(ep->lp, sp, fp);
+ } else {
+ error = -ENOBUFS;
+ }
+ } else {
+ /*
+ * If not logged into the fabric, don't send ABTS but leave
+ * sequence active until next timeout.
+ */
+ error = 0;
+ }
+ ep->esb_stat |= ESB_ST_ABNORMAL;
return error;
}
return error;
}
+/**
+ * fc_invoke_resp() - invoke ep->resp()
+ *
+ * Notes:
+ * It is assumed that after initialization finished (this means the
+ * first unlock of ex_lock after fc_exch_alloc()) ep->resp and ep->arg are
+ * modified only via fc_seq_set_resp(). This guarantees that none of these
+ * two variables changes if ep->resp_active > 0.
+ *
+ * If an fc_seq_set_resp() call is busy modifying ep->resp and ep->arg when
+ * this function is invoked, the first spin_lock_bh() call in this function
+ * will wait until fc_seq_set_resp() has finished modifying these variables.
+ *
+ * Since fc_exch_done() invokes fc_seq_set_resp() it is guaranteed that that
+ * ep->resp() won't be invoked after fc_exch_done() has returned.
+ *
+ * The response handler itself may invoke fc_exch_done(), which will clear the
+ * ep->resp pointer.
+ *
+ * Return value:
+ * Returns true if and only if ep->resp has been invoked.
+ */
+static bool fc_invoke_resp(struct fc_exch *ep, struct fc_seq *sp,
+ struct fc_frame *fp)
+{
+ void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
+ void *arg;
+ bool res = false;
+
+ spin_lock_bh(&ep->ex_lock);
+ ep->resp_active++;
+ if (ep->resp_task != current)
+ ep->resp_task = !ep->resp_task ? current : NULL;
+ resp = ep->resp;
+ arg = ep->arg;
+ spin_unlock_bh(&ep->ex_lock);
+
+ if (resp) {
+ resp(sp, fp, arg);
+ res = true;
+ } else if (!IS_ERR(fp)) {
+ fc_frame_free(fp);
+ }
+
+ spin_lock_bh(&ep->ex_lock);
+ if (--ep->resp_active == 0)
+ ep->resp_task = NULL;
+ spin_unlock_bh(&ep->ex_lock);
+
+ if (ep->resp_active == 0)
+ wake_up(&ep->resp_wq);
+
+ return res;
+}
+
/**
* fc_exch_timeout() - Handle exchange timer expiration
* @work: The work_struct identifying the exchange that timed out
struct fc_exch *ep = container_of(work, struct fc_exch,
timeout_work.work);
struct fc_seq *sp = &ep->seq;
- void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
- void *arg;
u32 e_stat;
int rc = 1;
fc_exch_rrq(ep);
goto done;
} else {
- resp = ep->resp;
- arg = ep->arg;
- ep->resp = NULL;
if (e_stat & ESB_ST_ABNORMAL)
rc = fc_exch_done_locked(ep);
spin_unlock_bh(&ep->ex_lock);
if (!rc)
fc_exch_delete(ep);
- if (resp)
- resp(sp, ERR_PTR(-FC_EX_TIMEOUT), arg);
+ fc_invoke_resp(ep, sp, ERR_PTR(-FC_EX_TIMEOUT));
+ fc_seq_set_resp(sp, NULL, ep->arg);
fc_seq_exch_abort(sp, 2 * ep->r_a_tov);
goto done;
}
ep->f_ctl = FC_FC_FIRST_SEQ; /* next seq is first seq */
ep->rxid = FC_XID_UNKNOWN;
ep->class = mp->class;
+ ep->resp_active = 0;
+ init_waitqueue_head(&ep->resp_wq);
INIT_DELAYED_WORK(&ep->timeout_work, fc_exch_timeout);
out:
return ep;
pool = per_cpu_ptr(mp->pool, xid & fc_cpu_mask);
spin_lock_bh(&pool->lock);
ep = fc_exch_ptr_get(pool, (xid - mp->min_xid) >> fc_cpu_order);
- if (ep && ep->xid == xid)
+ if (ep) {
+ WARN_ON(ep->xid != xid);
fc_exch_hold(ep);
+ }
spin_unlock_bh(&pool->lock);
}
return ep;
* fc_exch_done() - Indicate that an exchange/sequence tuple is complete and
* the memory allocated for the related objects may be freed.
* @sp: The sequence that has completed
+ *
+ * Note: May sleep if invoked from outside a response handler.
*/
static void fc_exch_done(struct fc_seq *sp)
{
spin_lock_bh(&ep->ex_lock);
rc = fc_exch_done_locked(ep);
spin_unlock_bh(&ep->ex_lock);
+
+ fc_seq_set_resp(sp, NULL, ep->arg);
if (!rc)
fc_exch_delete(ep);
}
}
}
+ spin_lock_bh(&ep->ex_lock);
/*
* At this point, we have the exchange held.
* Find or create the sequence.
* sending RSP, hence write request on other
* end never finishes.
*/
- spin_lock_bh(&ep->ex_lock);
sp->ssb_stat |= SSB_ST_RESP;
sp->id = fh->fh_seq_id;
- spin_unlock_bh(&ep->ex_lock);
} else {
+ spin_unlock_bh(&ep->ex_lock);
+
/* sequence/exch should exist */
reject = FC_RJT_SEQ_ID;
goto rel;
if (f_ctl & FC_FC_SEQ_INIT)
ep->esb_stat |= ESB_ST_SEQ_INIT;
+ spin_unlock_bh(&ep->ex_lock);
fr_seq(fp) = sp;
out:
if (!ep)
goto reject;
+
+ fp = fc_frame_alloc(ep->lp, sizeof(*ap));
+ if (!fp)
+ goto free;
+
spin_lock_bh(&ep->ex_lock);
if (ep->esb_stat & ESB_ST_COMPLETE) {
spin_unlock_bh(&ep->ex_lock);
+
+ fc_frame_free(fp);
goto reject;
}
- if (!(ep->esb_stat & ESB_ST_REC_QUAL))
+ if (!(ep->esb_stat & ESB_ST_REC_QUAL)) {
+ ep->esb_stat |= ESB_ST_REC_QUAL;
fc_exch_hold(ep); /* hold for REC_QUAL */
- ep->esb_stat |= ESB_ST_ABNORMAL | ESB_ST_REC_QUAL;
- fc_exch_timer_set_locked(ep, ep->r_a_tov);
-
- fp = fc_frame_alloc(ep->lp, sizeof(*ap));
- if (!fp) {
- spin_unlock_bh(&ep->ex_lock);
- goto free;
}
+ fc_exch_timer_set_locked(ep, ep->r_a_tov);
fh = fc_frame_header_get(fp);
ap = fc_frame_payload_get(fp, sizeof(*ap));
memset(ap, 0, sizeof(*ap));
}
sp = fc_seq_start_next_locked(sp);
fc_seq_send_last(sp, fp, FC_RCTL_BA_ACC, FC_TYPE_BLS);
+ ep->esb_stat |= ESB_ST_ABNORMAL;
spin_unlock_bh(&ep->ex_lock);
+
+free:
fc_frame_free(rx_fp);
return;
reject:
fc_exch_send_ba_rjt(rx_fp, FC_BA_RJT_UNABLE, FC_BA_RJT_INV_XID);
-free:
- fc_frame_free(rx_fp);
+ goto free;
}
/**
* If new exch resp handler is valid then call that
* first.
*/
- if (ep->resp)
- ep->resp(sp, fp, ep->arg);
- else
+ if (!fc_invoke_resp(ep, sp, fp))
lport->tt.lport_recv(lport, fp);
fc_exch_release(ep); /* release from lookup */
} else {
struct fc_exch *ep;
enum fc_sof sof;
u32 f_ctl;
- void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
- void *ex_resp_arg;
int rc;
ep = fc_exch_find(mp, ntohs(fh->fh_ox_id));
f_ctl = ntoh24(fh->fh_f_ctl);
fr_seq(fp) = sp;
+
+ spin_lock_bh(&ep->ex_lock);
if (f_ctl & FC_FC_SEQ_INIT)
ep->esb_stat |= ESB_ST_SEQ_INIT;
+ spin_unlock_bh(&ep->ex_lock);
if (fc_sof_needs_ack(sof))
fc_seq_send_ack(sp, fp);
- resp = ep->resp;
- ex_resp_arg = ep->arg;
if (fh->fh_type != FC_TYPE_FCP && fr_eof(fp) == FC_EOF_T &&
(f_ctl & (FC_FC_LAST_SEQ | FC_FC_END_SEQ)) ==
(FC_FC_LAST_SEQ | FC_FC_END_SEQ)) {
spin_lock_bh(&ep->ex_lock);
- resp = ep->resp;
rc = fc_exch_done_locked(ep);
WARN_ON(fc_seq_exch(sp) != ep);
spin_unlock_bh(&ep->ex_lock);
* If new exch resp handler is valid then call that
* first.
*/
- if (resp)
- resp(sp, fp, ex_resp_arg);
- else
- fc_frame_free(fp);
+ fc_invoke_resp(ep, sp, fp);
+
fc_exch_release(ep);
return;
rel:
*/
static void fc_exch_abts_resp(struct fc_exch *ep, struct fc_frame *fp)
{
- void (*resp)(struct fc_seq *, struct fc_frame *fp, void *arg);
- void *ex_resp_arg;
struct fc_frame_header *fh;
struct fc_ba_acc *ap;
struct fc_seq *sp;
fc_exch_rctl_name(fh->fh_r_ctl));
if (cancel_delayed_work_sync(&ep->timeout_work)) {
- FC_EXCH_DBG(ep, "Exchange timer canceled\n");
+ FC_EXCH_DBG(ep, "Exchange timer canceled due to ABTS response\n");
fc_exch_release(ep); /* release from pending timer hold */
}
break;
}
- resp = ep->resp;
- ex_resp_arg = ep->arg;
-
/* do we need to do some other checks here. Can we reuse more of
* fc_exch_recv_seq_resp
*/
ntoh24(fh->fh_f_ctl) & FC_FC_LAST_SEQ)
rc = fc_exch_done_locked(ep);
spin_unlock_bh(&ep->ex_lock);
+
+ fc_exch_hold(ep);
if (!rc)
fc_exch_delete(ep);
-
- if (resp)
- resp(sp, fp, ex_resp_arg);
- else
- fc_frame_free(fp);
-
+ fc_invoke_resp(ep, sp, fp);
if (has_rec)
fc_exch_timer_set(ep, ep->r_a_tov);
-
+ fc_exch_release(ep);
}
/**
break;
default:
if (ep)
- FC_EXCH_DBG(ep, "BLS rctl %x - %s received",
+ FC_EXCH_DBG(ep, "BLS rctl %x - %s received\n",
fh->fh_r_ctl,
fc_exch_rctl_name(fh->fh_r_ctl));
break;
/**
* fc_exch_reset() - Reset an exchange
* @ep: The exchange to be reset
+ *
+ * Note: May sleep if invoked from outside a response handler.
*/
static void fc_exch_reset(struct fc_exch *ep)
{
struct fc_seq *sp;
- void (*resp)(struct fc_seq *, struct fc_frame *, void *);
- void *arg;
int rc = 1;
spin_lock_bh(&ep->ex_lock);
fc_exch_abort_locked(ep, 0);
ep->state |= FC_EX_RST_CLEANUP;
fc_exch_timer_cancel(ep);
- resp = ep->resp;
- ep->resp = NULL;
if (ep->esb_stat & ESB_ST_REC_QUAL)
atomic_dec(&ep->ex_refcnt); /* drop hold for rec_qual */
ep->esb_stat &= ~ESB_ST_REC_QUAL;
- arg = ep->arg;
sp = &ep->seq;
rc = fc_exch_done_locked(ep);
spin_unlock_bh(&ep->ex_lock);
+
+ fc_exch_hold(ep);
+
if (!rc)
fc_exch_delete(ep);
- if (resp)
- resp(sp, ERR_PTR(-FC_EX_CLOSED), arg);
+ fc_invoke_resp(ep, sp, ERR_PTR(-FC_EX_CLOSED));
+ fc_seq_set_resp(sp, NULL, ep->arg);
+ fc_exch_release(ep);
}
/**
switch (op) {
case ELS_LS_RJT:
- FC_EXCH_DBG(aborted_ep, "LS_RJT for RRQ");
+ FC_EXCH_DBG(aborted_ep, "LS_RJT for RRQ\n");
/* fall through */
case ELS_LS_ACC:
goto cleanup;
default:
- FC_EXCH_DBG(aborted_ep, "unexpected response op %x "
- "for RRQ", op);
+ FC_EXCH_DBG(aborted_ep, "unexpected response op %x for RRQ\n",
+ op);
return;
}
* cpu on which exchange originated by simple bitwise
* AND operation between fc_cpu_mask and exchange id.
*/
- fc_cpu_mask = 1;
- fc_cpu_order = 0;
- while (fc_cpu_mask < nr_cpu_ids) {
- fc_cpu_mask <<= 1;
- fc_cpu_order++;
- }
- fc_cpu_mask--;
+ fc_cpu_order = ilog2(roundup_pow_of_two(nr_cpu_ids));
+ fc_cpu_mask = (1 << fc_cpu_order) - 1;
fc_exch_workqueue = create_singlethread_workqueue("fc_exch_workqueue");
if (!fc_exch_workqueue)
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