linux/drivers/scsi/libfc/fc_disc.c
Joe Eykholt 2ab7e1ecb8 [SCSI] libfc: send GPN_ID in reaction to single-port RSCNs.
When an RSCN indicates changes to individual remote ports,
don't blindly log them out and then back in.  Instead, determine
whether they're still in the directory, by doing GPN_ID.

If that is successful, call login, which will send ADISC and reverify,
otherwise, call logoff.  Perhaps we should just delete the rport,
not send LOGO, but it seems safer.

Also, fix a possible issue where if a mix of records in the RSCN
cause us to queue disc_ports for disc_single and then we decide
to do full rediscovery, we leak memory for those disc_ports queued.

So, go through the list of disc_ports even if doing full discovery.
Free the disc_ports in any case.  If any of the disc_single() calls
return error, do a full discovery.

The ability to fill in GPN_ID requests was added to fc_ct_fill().
For this, it needs the FC_ID to be passed in as an arg.
The did parameter for fc_elsct_send() is used for that, since the
actual D_DID will always be 0xfffffc for all CT requests so far.

Signed-off-by: Joe Eykholt <jeykholt@cisco.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2009-09-10 12:08:03 -05:00

739 lines
20 KiB
C

/*
* Copyright(c) 2007 - 2008 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
* Maintained at www.Open-FCoE.org
*/
/*
* Target Discovery
*
* This block discovers all FC-4 remote ports, including FCP initiators. It
* also handles RSCN events and re-discovery if necessary.
*/
/*
* DISC LOCKING
*
* The disc mutex is can be locked when acquiring rport locks, but may not
* be held when acquiring the lport lock. Refer to fc_lport.c for more
* details.
*/
#include <linux/timer.h>
#include <linux/err.h>
#include <asm/unaligned.h>
#include <scsi/fc/fc_gs.h>
#include <scsi/libfc.h>
#define FC_DISC_RETRY_LIMIT 3 /* max retries */
#define FC_DISC_RETRY_DELAY 500UL /* (msecs) delay */
static void fc_disc_gpn_ft_req(struct fc_disc *);
static void fc_disc_gpn_ft_resp(struct fc_seq *, struct fc_frame *, void *);
static void fc_disc_done(struct fc_disc *, enum fc_disc_event);
static void fc_disc_timeout(struct work_struct *);
static int fc_disc_single(struct fc_lport *, struct fc_disc_port *);
static void fc_disc_restart(struct fc_disc *);
/**
* fc_disc_stop_rports() - delete all the remote ports associated with the lport
* @disc: The discovery job to stop rports on
*
* Locking Note: This function expects that the lport mutex is locked before
* calling it.
*/
void fc_disc_stop_rports(struct fc_disc *disc)
{
struct fc_lport *lport;
struct fc_rport_priv *rdata, *next;
lport = disc->lport;
mutex_lock(&disc->disc_mutex);
list_for_each_entry_safe(rdata, next, &disc->rports, peers)
lport->tt.rport_logoff(rdata);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_recv_rscn_req() - Handle Registered State Change Notification (RSCN)
* @sp: Current sequence of the RSCN exchange
* @fp: RSCN Frame
* @lport: Fibre Channel host port instance
*
* Locking Note: This function expects that the disc_mutex is locked
* before it is called.
*/
static void fc_disc_recv_rscn_req(struct fc_seq *sp, struct fc_frame *fp,
struct fc_disc *disc)
{
struct fc_lport *lport;
struct fc_els_rscn *rp;
struct fc_els_rscn_page *pp;
struct fc_seq_els_data rjt_data;
unsigned int len;
int redisc = 0;
enum fc_els_rscn_ev_qual ev_qual;
enum fc_els_rscn_addr_fmt fmt;
LIST_HEAD(disc_ports);
struct fc_disc_port *dp, *next;
lport = disc->lport;
FC_DISC_DBG(disc, "Received an RSCN event\n");
/* make sure the frame contains an RSCN message */
rp = fc_frame_payload_get(fp, sizeof(*rp));
if (!rp)
goto reject;
/* make sure the page length is as expected (4 bytes) */
if (rp->rscn_page_len != sizeof(*pp))
goto reject;
/* get the RSCN payload length */
len = ntohs(rp->rscn_plen);
if (len < sizeof(*rp))
goto reject;
/* make sure the frame contains the expected payload */
rp = fc_frame_payload_get(fp, len);
if (!rp)
goto reject;
/* payload must be a multiple of the RSCN page size */
len -= sizeof(*rp);
if (len % sizeof(*pp))
goto reject;
for (pp = (void *)(rp + 1); len > 0; len -= sizeof(*pp), pp++) {
ev_qual = pp->rscn_page_flags >> ELS_RSCN_EV_QUAL_BIT;
ev_qual &= ELS_RSCN_EV_QUAL_MASK;
fmt = pp->rscn_page_flags >> ELS_RSCN_ADDR_FMT_BIT;
fmt &= ELS_RSCN_ADDR_FMT_MASK;
/*
* if we get an address format other than port
* (area, domain, fabric), then do a full discovery
*/
switch (fmt) {
case ELS_ADDR_FMT_PORT:
FC_DISC_DBG(disc, "Port address format for port "
"(%6x)\n", ntoh24(pp->rscn_fid));
dp = kzalloc(sizeof(*dp), GFP_KERNEL);
if (!dp) {
redisc = 1;
break;
}
dp->lp = lport;
dp->port_id = ntoh24(pp->rscn_fid);
list_add_tail(&dp->peers, &disc_ports);
break;
case ELS_ADDR_FMT_AREA:
case ELS_ADDR_FMT_DOM:
case ELS_ADDR_FMT_FAB:
default:
FC_DISC_DBG(disc, "Address format is (%d)\n", fmt);
redisc = 1;
break;
}
}
lport->tt.seq_els_rsp_send(sp, ELS_LS_ACC, NULL);
/*
* If not doing a complete rediscovery, do GPN_ID on
* the individual ports mentioned in the list.
* If any of these get an error, do a full rediscovery.
* In any case, go through the list and free the entries.
*/
list_for_each_entry_safe(dp, next, &disc_ports, peers) {
list_del(&dp->peers);
if (!redisc)
redisc = fc_disc_single(lport, dp);
kfree(dp);
}
if (redisc) {
FC_DISC_DBG(disc, "RSCN received: rediscovering\n");
fc_disc_restart(disc);
} else {
FC_DISC_DBG(disc, "RSCN received: not rediscovering. "
"redisc %d state %d in_prog %d\n",
redisc, lport->state, disc->pending);
}
fc_frame_free(fp);
return;
reject:
FC_DISC_DBG(disc, "Received a bad RSCN frame\n");
rjt_data.fp = NULL;
rjt_data.reason = ELS_RJT_LOGIC;
rjt_data.explan = ELS_EXPL_NONE;
lport->tt.seq_els_rsp_send(sp, ELS_LS_RJT, &rjt_data);
fc_frame_free(fp);
}
/**
* fc_disc_recv_req() - Handle incoming requests
* @sp: Current sequence of the request exchange
* @fp: The frame
* @lport: The FC local port
*
* Locking Note: This function is called from the EM and will lock
* the disc_mutex before calling the handler for the
* request.
*/
static void fc_disc_recv_req(struct fc_seq *sp, struct fc_frame *fp,
struct fc_lport *lport)
{
u8 op;
struct fc_disc *disc = &lport->disc;
op = fc_frame_payload_op(fp);
switch (op) {
case ELS_RSCN:
mutex_lock(&disc->disc_mutex);
fc_disc_recv_rscn_req(sp, fp, disc);
mutex_unlock(&disc->disc_mutex);
break;
default:
FC_DISC_DBG(disc, "Received an unsupported request, "
"the opcode is (%x)\n", op);
break;
}
}
/**
* fc_disc_restart() - Restart discovery
* @lport: FC discovery context
*
* Locking Note: This function expects that the disc mutex
* is already locked.
*/
static void fc_disc_restart(struct fc_disc *disc)
{
if (!disc->disc_callback)
return;
FC_DISC_DBG(disc, "Restarting discovery\n");
disc->requested = 1;
if (disc->pending)
return;
/*
* Advance disc_id. This is an arbitrary non-zero number that will
* match the value in the fc_rport_priv after discovery for all
* freshly-discovered remote ports. Avoid wrapping to zero.
*/
disc->disc_id = (disc->disc_id + 2) | 1;
disc->retry_count = 0;
fc_disc_gpn_ft_req(disc);
}
/**
* fc_disc_start() - Fibre Channel Target discovery
* @lport: FC local port
* @disc_callback: function to be called when discovery is complete
*/
static void fc_disc_start(void (*disc_callback)(struct fc_lport *,
enum fc_disc_event),
struct fc_lport *lport)
{
struct fc_disc *disc = &lport->disc;
/*
* At this point we may have a new disc job or an existing
* one. Either way, let's lock when we make changes to it
* and send the GPN_FT request.
*/
mutex_lock(&disc->disc_mutex);
disc->disc_callback = disc_callback;
fc_disc_restart(disc);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_done() - Discovery has been completed
* @disc: FC discovery context
* @event: discovery completion status
*
* Locking Note: This function expects that the disc mutex is locked before
* it is called. The discovery callback is then made with the lock released,
* and the lock is re-taken before returning from this function
*/
static void fc_disc_done(struct fc_disc *disc, enum fc_disc_event event)
{
struct fc_lport *lport = disc->lport;
struct fc_rport_priv *rdata;
FC_DISC_DBG(disc, "Discovery complete\n");
disc->pending = 0;
if (disc->requested) {
fc_disc_restart(disc);
return;
}
/*
* Go through all remote ports. If they were found in the latest
* discovery, reverify or log them in. Otherwise, log them out.
* Skip ports which were never discovered. These are the dNS port
* and ports which were created by PLOGI.
*/
list_for_each_entry(rdata, &disc->rports, peers) {
if (!rdata->disc_id)
continue;
if (rdata->disc_id == disc->disc_id)
lport->tt.rport_login(rdata);
else
lport->tt.rport_logoff(rdata);
}
mutex_unlock(&disc->disc_mutex);
disc->disc_callback(lport, event);
mutex_lock(&disc->disc_mutex);
}
/**
* fc_disc_error() - Handle error on dNS request
* @disc: FC discovery context
* @fp: The frame pointer
*/
static void fc_disc_error(struct fc_disc *disc, struct fc_frame *fp)
{
struct fc_lport *lport = disc->lport;
unsigned long delay = 0;
FC_DISC_DBG(disc, "Error %ld, retries %d/%d\n",
PTR_ERR(fp), disc->retry_count,
FC_DISC_RETRY_LIMIT);
if (!fp || PTR_ERR(fp) == -FC_EX_TIMEOUT) {
/*
* Memory allocation failure, or the exchange timed out,
* retry after delay.
*/
if (disc->retry_count < FC_DISC_RETRY_LIMIT) {
/* go ahead and retry */
if (!fp)
delay = msecs_to_jiffies(FC_DISC_RETRY_DELAY);
else {
delay = msecs_to_jiffies(lport->e_d_tov);
/* timeout faster first time */
if (!disc->retry_count)
delay /= 4;
}
disc->retry_count++;
schedule_delayed_work(&disc->disc_work, delay);
} else
fc_disc_done(disc, DISC_EV_FAILED);
}
}
/**
* fc_disc_gpn_ft_req() - Send Get Port Names by FC-4 type (GPN_FT) request
* @lport: FC discovery context
*
* Locking Note: This function expects that the disc_mutex is locked
* before it is called.
*/
static void fc_disc_gpn_ft_req(struct fc_disc *disc)
{
struct fc_frame *fp;
struct fc_lport *lport = disc->lport;
WARN_ON(!fc_lport_test_ready(lport));
disc->pending = 1;
disc->requested = 0;
disc->buf_len = 0;
disc->seq_count = 0;
fp = fc_frame_alloc(lport,
sizeof(struct fc_ct_hdr) +
sizeof(struct fc_ns_gid_ft));
if (!fp)
goto err;
if (lport->tt.elsct_send(lport, 0, fp,
FC_NS_GPN_FT,
fc_disc_gpn_ft_resp,
disc, lport->e_d_tov))
return;
err:
fc_disc_error(disc, fp);
}
/**
* fc_disc_gpn_ft_parse() - Parse the body of the dNS GPN_FT response.
* @lport: Fibre Channel host port instance
* @buf: GPN_FT response buffer
* @len: size of response buffer
*
* Goes through the list of IDs and names resulting from a request.
*/
static int fc_disc_gpn_ft_parse(struct fc_disc *disc, void *buf, size_t len)
{
struct fc_lport *lport;
struct fc_gpn_ft_resp *np;
char *bp;
size_t plen;
size_t tlen;
int error = 0;
struct fc_rport_identifiers ids;
struct fc_rport_priv *rdata;
lport = disc->lport;
disc->seq_count++;
/*
* Handle partial name record left over from previous call.
*/
bp = buf;
plen = len;
np = (struct fc_gpn_ft_resp *)bp;
tlen = disc->buf_len;
disc->buf_len = 0;
if (tlen) {
WARN_ON(tlen >= sizeof(*np));
plen = sizeof(*np) - tlen;
WARN_ON(plen <= 0);
WARN_ON(plen >= sizeof(*np));
if (plen > len)
plen = len;
np = &disc->partial_buf;
memcpy((char *)np + tlen, bp, plen);
/*
* Set bp so that the loop below will advance it to the
* first valid full name element.
*/
bp -= tlen;
len += tlen;
plen += tlen;
disc->buf_len = (unsigned char) plen;
if (plen == sizeof(*np))
disc->buf_len = 0;
}
/*
* Handle full name records, including the one filled from above.
* Normally, np == bp and plen == len, but from the partial case above,
* bp, len describe the overall buffer, and np, plen describe the
* partial buffer, which if would usually be full now.
* After the first time through the loop, things return to "normal".
*/
while (plen >= sizeof(*np)) {
ids.port_id = ntoh24(np->fp_fid);
ids.port_name = ntohll(np->fp_wwpn);
if (ids.port_id != fc_host_port_id(lport->host) &&
ids.port_name != lport->wwpn) {
rdata = lport->tt.rport_create(lport, ids.port_id);
if (rdata) {
rdata->ids.port_name = ids.port_name;
rdata->disc_id = disc->disc_id;
} else {
printk(KERN_WARNING "libfc: Failed to allocate "
"memory for the newly discovered port "
"(%6x)\n", ids.port_id);
error = -ENOMEM;
}
}
if (np->fp_flags & FC_NS_FID_LAST) {
fc_disc_done(disc, DISC_EV_SUCCESS);
len = 0;
break;
}
len -= sizeof(*np);
bp += sizeof(*np);
np = (struct fc_gpn_ft_resp *)bp;
plen = len;
}
/*
* Save any partial record at the end of the buffer for next time.
*/
if (error == 0 && len > 0 && len < sizeof(*np)) {
if (np != &disc->partial_buf) {
FC_DISC_DBG(disc, "Partial buffer remains "
"for discovery\n");
memcpy(&disc->partial_buf, np, len);
}
disc->buf_len = (unsigned char) len;
}
return error;
}
/**
* fc_disc_timeout() - Retry handler for the disc component
* @work: Structure holding disc obj that needs retry discovery
*
* Handle retry of memory allocation for remote ports.
*/
static void fc_disc_timeout(struct work_struct *work)
{
struct fc_disc *disc = container_of(work,
struct fc_disc,
disc_work.work);
mutex_lock(&disc->disc_mutex);
fc_disc_gpn_ft_req(disc);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_gpn_ft_resp() - Handle a response frame from Get Port Names (GPN_FT)
* @sp: Current sequence of GPN_FT exchange
* @fp: response frame
* @lp_arg: Fibre Channel host port instance
*
* Locking Note: This function is called without disc mutex held, and
* should do all its processing with the mutex held
*/
static void fc_disc_gpn_ft_resp(struct fc_seq *sp, struct fc_frame *fp,
void *disc_arg)
{
struct fc_disc *disc = disc_arg;
struct fc_ct_hdr *cp;
struct fc_frame_header *fh;
enum fc_disc_event event = DISC_EV_NONE;
unsigned int seq_cnt;
unsigned int len;
int error = 0;
mutex_lock(&disc->disc_mutex);
FC_DISC_DBG(disc, "Received a GPN_FT response\n");
if (IS_ERR(fp)) {
fc_disc_error(disc, fp);
mutex_unlock(&disc->disc_mutex);
return;
}
WARN_ON(!fc_frame_is_linear(fp)); /* buffer must be contiguous */
fh = fc_frame_header_get(fp);
len = fr_len(fp) - sizeof(*fh);
seq_cnt = ntohs(fh->fh_seq_cnt);
if (fr_sof(fp) == FC_SOF_I3 && seq_cnt == 0 && disc->seq_count == 0) {
cp = fc_frame_payload_get(fp, sizeof(*cp));
if (!cp) {
FC_DISC_DBG(disc, "GPN_FT response too short, len %d\n",
fr_len(fp));
event = DISC_EV_FAILED;
} else if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
/* Accepted, parse the response. */
len -= sizeof(*cp);
error = fc_disc_gpn_ft_parse(disc, cp + 1, len);
} else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
FC_DISC_DBG(disc, "GPN_FT rejected reason %x exp %x "
"(check zoning)\n", cp->ct_reason,
cp->ct_explan);
event = DISC_EV_FAILED;
if (cp->ct_reason == FC_FS_RJT_UNABL &&
cp->ct_explan == FC_FS_EXP_FTNR)
event = DISC_EV_SUCCESS;
} else {
FC_DISC_DBG(disc, "GPN_FT unexpected response code "
"%x\n", ntohs(cp->ct_cmd));
event = DISC_EV_FAILED;
}
} else if (fr_sof(fp) == FC_SOF_N3 && seq_cnt == disc->seq_count) {
error = fc_disc_gpn_ft_parse(disc, fh + 1, len);
} else {
FC_DISC_DBG(disc, "GPN_FT unexpected frame - out of sequence? "
"seq_cnt %x expected %x sof %x eof %x\n",
seq_cnt, disc->seq_count, fr_sof(fp), fr_eof(fp));
event = DISC_EV_FAILED;
}
if (error)
fc_disc_error(disc, fp);
else if (event != DISC_EV_NONE)
fc_disc_done(disc, event);
fc_frame_free(fp);
mutex_unlock(&disc->disc_mutex);
}
/**
* fc_disc_gpn_id_resp() - Handle a response frame from Get Port Names (GPN_ID)
* @sp: exchange sequence
* @fp: response frame
* @rdata_arg: remote port private data
*
* Locking Note: This function is called without disc mutex held.
*/
static void fc_disc_gpn_id_resp(struct fc_seq *sp, struct fc_frame *fp,
void *rdata_arg)
{
struct fc_rport_priv *rdata = rdata_arg;
struct fc_rport_priv *new_rdata;
struct fc_lport *lport;
struct fc_disc *disc;
struct fc_ct_hdr *cp;
struct fc_ns_gid_pn *pn;
u64 port_name;
lport = rdata->local_port;
disc = &lport->disc;
mutex_lock(&disc->disc_mutex);
if (PTR_ERR(fp) == -FC_EX_CLOSED)
goto out;
if (IS_ERR(fp))
goto redisc;
cp = fc_frame_payload_get(fp, sizeof(*cp));
if (!cp)
goto redisc;
if (ntohs(cp->ct_cmd) == FC_FS_ACC) {
if (fr_len(fp) < sizeof(struct fc_frame_header) +
sizeof(*cp) + sizeof(*pn))
goto redisc;
pn = (struct fc_ns_gid_pn *)(cp + 1);
port_name = get_unaligned_be64(&pn->fn_wwpn);
if (rdata->ids.port_name == -1)
rdata->ids.port_name = port_name;
else if (rdata->ids.port_name != port_name) {
FC_DISC_DBG(disc, "GPN_ID accepted. WWPN changed. "
"Port-id %x wwpn %llx\n",
rdata->ids.port_id, port_name);
lport->tt.rport_logoff(rdata);
new_rdata = lport->tt.rport_create(lport,
rdata->ids.port_id);
if (new_rdata) {
new_rdata->disc_id = disc->disc_id;
lport->tt.rport_login(new_rdata);
}
goto out;
}
rdata->disc_id = disc->disc_id;
lport->tt.rport_login(rdata);
} else if (ntohs(cp->ct_cmd) == FC_FS_RJT) {
FC_DISC_DBG(disc, "GPN_ID rejected reason %x exp %x\n",
cp->ct_reason, cp->ct_explan);
lport->tt.rport_logoff(rdata);
} else {
FC_DISC_DBG(disc, "GPN_ID unexpected response code %x\n",
ntohs(cp->ct_cmd));
redisc:
fc_disc_restart(disc);
}
out:
mutex_unlock(&disc->disc_mutex);
kref_put(&rdata->kref, lport->tt.rport_destroy);
}
/**
* fc_disc_gpn_id_req() - Send Get Port Names by ID (GPN_ID) request
* @lport: local port
* @rdata: remote port private data
*
* Locking Note: This function expects that the disc_mutex is locked
* before it is called.
* On failure, an error code is returned.
*/
static int fc_disc_gpn_id_req(struct fc_lport *lport,
struct fc_rport_priv *rdata)
{
struct fc_frame *fp;
fp = fc_frame_alloc(lport, sizeof(struct fc_ct_hdr) +
sizeof(struct fc_ns_fid));
if (!fp)
return -ENOMEM;
if (!lport->tt.elsct_send(lport, rdata->ids.port_id, fp, FC_NS_GPN_ID,
fc_disc_gpn_id_resp, rdata, lport->e_d_tov))
return -ENOMEM;
kref_get(&rdata->kref);
return 0;
}
/**
* fc_disc_single() - Discover the directory information for a single target
* @lport: local port
* @dp: The port to rediscover
*
* Locking Note: This function expects that the disc_mutex is locked
* before it is called.
*/
static int fc_disc_single(struct fc_lport *lport, struct fc_disc_port *dp)
{
struct fc_rport_priv *rdata;
rdata = lport->tt.rport_create(lport, dp->port_id);
if (!rdata)
return -ENOMEM;
rdata->disc_id = 0;
return fc_disc_gpn_id_req(lport, rdata);
}
/**
* fc_disc_stop() - Stop discovery for a given lport
* @lport: The lport that discovery should stop for
*/
void fc_disc_stop(struct fc_lport *lport)
{
struct fc_disc *disc = &lport->disc;
if (disc) {
cancel_delayed_work_sync(&disc->disc_work);
fc_disc_stop_rports(disc);
}
}
/**
* fc_disc_stop_final() - Stop discovery for a given lport
* @lport: The lport that discovery should stop for
*
* This function will block until discovery has been
* completely stopped and all rports have been deleted.
*/
void fc_disc_stop_final(struct fc_lport *lport)
{
fc_disc_stop(lport);
lport->tt.rport_flush_queue();
}
/**
* fc_disc_init() - Initialize the discovery block
* @lport: FC local port
*/
int fc_disc_init(struct fc_lport *lport)
{
struct fc_disc *disc;
if (!lport->tt.disc_start)
lport->tt.disc_start = fc_disc_start;
if (!lport->tt.disc_stop)
lport->tt.disc_stop = fc_disc_stop;
if (!lport->tt.disc_stop_final)
lport->tt.disc_stop_final = fc_disc_stop_final;
if (!lport->tt.disc_recv_req)
lport->tt.disc_recv_req = fc_disc_recv_req;
disc = &lport->disc;
INIT_DELAYED_WORK(&disc->disc_work, fc_disc_timeout);
mutex_init(&disc->disc_mutex);
INIT_LIST_HEAD(&disc->rports);
disc->lport = lport;
return 0;
}
EXPORT_SYMBOL(fc_disc_init);