+++ /dev/null
-From: Robert Love <robert.w.love@intel.com>
-Subject: libfc: Ensure correct device_put/get usage (round 2)
-References:
-
-Reference counting was barely used and where used
-it was incorrect. This patch creates a few simple
-policies.
-
-When the rport->dev [e.g. struct device] is initialized
-it starts with a refcnt of 1. Whenever we're using the
-rport we will increment the count. When we logoff we
-should decrement the count to 0 and the 'release'
-function will be called. The FC transport provides the
-release function for real rports and libfc provides it
-for rogue rports. When we switch from a rogue to real
-rport we'll decrement the refcnt on the rogue rport
-and increment it for the real rport, after we've created
-it.
-
-Any externally initiated action on an rport (login,
-logoff) will not require the caller to increment and
-decrement the refcnt.
-
-For rport_login(), the rport will have just been created
-and therefore no other thread would be able to access
-this object.
-
-For rport_logoff(), the rport will have been removed
-from the list of rports and therefore no other thread
-would be able to lookup() this rport.
-
-This patch removes the get_device() from the rport_lookup
-function. These are the places where it is called and why
-we don't need a reference.
-
-fc_disc_recv_rscn_req() - called for single port RSCNs
- the disc mutex is held and
- ensures that no other thread
- will find this rport.
-
-fc_disc_new_target() - Same. The rport cannot be looked up
- so no other thread can free the rport.
- This code looks buggy though, we
- shouldn't be calling rport_login() on
- a 'real' rport, which we could do.
-
-fc_disc_single() - Same. disc mutex protects the list.
-
-fc_lport_recv_req() - Similar, but this time the lport lock
- ensures that no incoming requests are
- processed until the current request
- for an rport has returned.
-
-When the rport layer needs to send a request it will
-increment the count so that the EM can be confident that
-the rport is present when making the callback. If
-fc_remote_port_delete() is called before the response
-callback, which is often the case for LOGO commands, the
-refcnt will still have a value of 1 becuase we grabbed the
-lock before the ctels_send() is called. The exchange would
-have been removed and so the callback will be called with
-an error code. After processing the error code we'll
-decrement the refcnt for the last time and the rport will
-be free'd.
-
-Since point-to-point mode is not working this patch
-does not consider point-to-point.
-
-Signed-off-by: Robert Love <robert.w.love@intel.com>
-Acked-by: Bernhard Walle <bwalle@suse.de>
----
-
- drivers/scsi/libfc/fc_disc.c | 5 +----
- drivers/scsi/libfc/fc_lport.c | 5 ++---
- drivers/scsi/libfc/fc_rport.c | 21 ++++++++++++++-------
- 3 files changed, 17 insertions(+), 14 deletions(-)
-
-
---- a/drivers/scsi/libfc/fc_disc.c
-+++ b/drivers/scsi/libfc/fc_disc.c
-@@ -81,7 +81,6 @@ struct fc_rport *fc_disc_lookup_rport(co
- if (rport->port_id == port_id) {
- disc_found = 1;
- found = rport;
-- get_device(&found->dev);
- break;
- }
- }
-@@ -767,10 +766,8 @@ static void fc_disc_single(struct fc_dis
- goto out;
-
- rport = lport->tt.rport_lookup(lport, dp->ids.port_id);
-- if (rport) {
-+ if (rport)
- fc_disc_del_target(disc, rport);
-- put_device(&rport->dev); /* hold from lookup */
-- }
-
- new_rport = fc_rport_rogue_create(dp);
- if (new_rport) {
---- a/drivers/scsi/libfc/fc_lport.c
-+++ b/drivers/scsi/libfc/fc_lport.c
-@@ -908,10 +908,9 @@ static void fc_lport_recv_req(struct fc_
- d_id = ntoh24(fh->fh_d_id);
-
- rport = lport->tt.rport_lookup(lport, s_id);
-- if (rport) {
-+ if (rport)
- lport->tt.rport_recv_req(sp, fp, rport);
-- put_device(&rport->dev); /* hold from lookup */
-- } else {
-+ else {
- rjt_data.fp = NULL;
- rjt_data.reason = ELS_RJT_UNAB;
- rjt_data.explan = ELS_EXPL_NONE;
---- a/drivers/scsi/libfc/fc_rport.c
-+++ b/drivers/scsi/libfc/fc_rport.c
-@@ -111,16 +111,11 @@ struct fc_rport *fc_rport_rogue_create(s
- rport->roles = dp->ids.roles;
- rport->maxframe_size = FC_MIN_MAX_PAYLOAD;
- /*
-- * init the device, so other code can manipulate the rport as if
-- * it came from the fc class. We also do an extra get because
-- * libfc will free this rport instead of relying on the normal
-- * refcounting.
-- *
- * Note: all this libfc rogue rport code will be removed for
- * upstream so it fine that this is really ugly and hacky right now.
- */
- device_initialize(&rport->dev);
-- get_device(&rport->dev);
-+ rport->dev.release = fc_rport_rogue_destroy; // XXX: bwalle
-
- mutex_init(&rdata->rp_mutex);
- rdata->local_port = dp->lp;
-@@ -402,9 +397,9 @@ static void fc_rport_timeout(struct work
- case RPORT_ST_NONE:
- break;
- }
-- put_device(&rport->dev);
-
- mutex_unlock(&rdata->rp_mutex);
-+ put_device(&rport->dev);
- }
-
- /**
-@@ -531,6 +526,7 @@ out:
- fc_frame_free(fp);
- err:
- mutex_unlock(&rdata->rp_mutex);
-+ put_device(&rport->dev);
- }
-
- /**
-@@ -562,6 +558,8 @@ static void fc_rport_enter_plogi(struct
- if (!lport->tt.elsct_send(lport, rport, fp, ELS_PLOGI,
- fc_rport_plogi_resp, rport, lport->e_d_tov))
- fc_rport_error(rport, fp);
-+ else
-+ get_device(&rport->dev);
- }
-
- /**
-@@ -631,6 +629,7 @@ out:
- fc_frame_free(fp);
- err:
- mutex_unlock(&rdata->rp_mutex);
-+ put_device(&rport->dev);
- }
-
- /**
-@@ -679,6 +678,7 @@ out:
- fc_frame_free(fp);
- err:
- mutex_unlock(&rdata->rp_mutex);
-+ put_device(&rport->dev);
- }
-
- /**
-@@ -712,6 +712,8 @@ static void fc_rport_enter_prli(struct f
- if (!lport->tt.elsct_send(lport, rport, fp, ELS_PRLI,
- fc_rport_prli_resp, rport, lport->e_d_tov))
- fc_rport_error(rport, fp);
-+ else
-+ get_device(&rport->dev);
- }
-
- /**
-@@ -777,6 +779,7 @@ out:
- fc_frame_free(fp);
- err:
- mutex_unlock(&rdata->rp_mutex);
-+ put_device(&rport->dev);
- }
-
- /**
-@@ -806,6 +809,8 @@ static void fc_rport_enter_rtv(struct fc
- if (!lport->tt.elsct_send(lport, rport, fp, ELS_RTV,
- fc_rport_rtv_resp, rport, lport->e_d_tov))
- fc_rport_error(rport, fp);
-+ else
-+ get_device(&rport->dev);
- }
-
- /**
-@@ -835,6 +840,8 @@ static void fc_rport_enter_logo(struct f
- if (!lport->tt.elsct_send(lport, rport, fp, ELS_LOGO,
- fc_rport_logo_resp, rport, lport->e_d_tov))
- fc_rport_error(rport, fp);
-+ else
-+ get_device(&rport->dev);
- }
-
-
projects / people / teissler / ipfire-2.x.git / blobdiff