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| author | Hannes Reinecke <hare@suse.de> | 2016-09-30 11:01:15 +0200 |
|---|---|---|
| committer | Martin K. Petersen <martin.petersen@oracle.com> | 2016-11-08 17:29:46 -0500 |
| commit | a407c593398c886db4fa1fc5c6fec55e61187a09 (patch) | |
| tree | 5428a0f043492514d1d3c0b6097a511f46967a29 /drivers/scsi/libfc/fc_lport.c | |
| parent | 4d2095cc42a2d8062590891f929d9d694cbd927f (diff) | |
| download | lwn-a407c593398c886db4fa1fc5c6fec55e61187a09.tar.gz lwn-a407c593398c886db4fa1fc5c6fec55e61187a09.zip | |
scsi: libfc: Fixup disc_mutex handling
The list of attached 'rdata' remote port structures is RCU
protected, so there is no need to take the 'disc_mutex' when
traversing it.
Rather we should be using rcu_read_lock() and kref_get_unless_zero()
to validate the entries.
We need, however, take the disc_mutex when deleting an entry;
otherwise we risk clashes with list_add.
Signed-off-by: Hannes Reinecke <hare@suse.com>
Acked-by: Johannes Thumshirn <jth@kernel.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Diffstat (limited to 'drivers/scsi/libfc/fc_lport.c')
| -rw-r--r-- | drivers/scsi/libfc/fc_lport.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/scsi/libfc/fc_lport.c b/drivers/scsi/libfc/fc_lport.c index 04ce7cfb6d1b..4e11c90c783c 100644 --- a/drivers/scsi/libfc/fc_lport.c +++ b/drivers/scsi/libfc/fc_lport.c @@ -237,16 +237,19 @@ static const char *fc_lport_state(struct fc_lport *lport) * @remote_fid: The FID of the ptp rport * @remote_wwpn: The WWPN of the ptp rport * @remote_wwnn: The WWNN of the ptp rport + * + * Locking Note: The lport lock is expected to be held before calling + * this routine. */ static void fc_lport_ptp_setup(struct fc_lport *lport, u32 remote_fid, u64 remote_wwpn, u64 remote_wwnn) { - mutex_lock(&lport->disc.disc_mutex); if (lport->ptp_rdata) { lport->tt.rport_logoff(lport->ptp_rdata); kref_put(&lport->ptp_rdata->kref, lport->tt.rport_destroy); } + mutex_lock(&lport->disc.disc_mutex); lport->ptp_rdata = lport->tt.rport_create(lport, remote_fid); kref_get(&lport->ptp_rdata->kref); lport->ptp_rdata->ids.port_name = remote_wwpn; @@ -1007,8 +1010,10 @@ EXPORT_SYMBOL(fc_lport_reset); */ static void fc_lport_reset_locked(struct fc_lport *lport) { - if (lport->dns_rdata) + if (lport->dns_rdata) { lport->tt.rport_logoff(lport->dns_rdata); + lport->dns_rdata = NULL; + } if (lport->ptp_rdata) { lport->tt.rport_logoff(lport->ptp_rdata); |