From: mdr@sgi.com Date: Mon, 1 May 2006 18:07:04 +0000 (-0500) Subject: [SCSI] mptfc: race between mptfc_register_dev and mptfc_target_alloc X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6dd727da92290193d0f74fa39f3ad53f423524db;p=linux-beck.git [SCSI] mptfc: race between mptfc_register_dev and mptfc_target_alloc A race condition exists in mptfc between the thread registering a device with the fc transport and the scan work generated by the transport. This race existed prior to the application of the mptfc bug fix patch. mptfc_register_dev() calls fc_remote_port_add() with the FC_RPORT_ROLE_TARGET bit set in the rport ids passed to the function. Having this bit set causes fc_remote_port_add() to schedule a scan of the device. This scan can execute before mptfc_register_dev() can fill in the dd_data in the rport structure. When this happens, mptfc_target_alloc() will fail because dd_data is null. Attached is a patch which fixes the problem. The patch changes the rport ids passed to fc_remote_port_add() to not have the TARGET bit set. This prevents the scan from being scheduled. After mptfc_register_dev() fills in the rport dd_data field, fc_remote_port_rolechg() is called, changing the role of the rport to TARGET. Thus, the scan is scheduled after dd_data is filled in which prevents the failure in mptfc_target_alloc(). Signed-off-by: Michael Reed Signed-off-by: Eric Moore Signed-off-by: James Bottomley --- diff --git a/drivers/message/fusion/mptfc.c b/drivers/message/fusion/mptfc.c index e1fb5a166366..856487741ef4 100644 --- a/drivers/message/fusion/mptfc.c +++ b/drivers/message/fusion/mptfc.c @@ -341,9 +341,6 @@ mptfc_generate_rport_ids(FCDevicePage0_t *pg0, struct fc_rport_identifiers *rid) rid->port_name = ((u64)pg0->WWPN.High) << 32 | (u64)pg0->WWPN.Low; rid->port_id = pg0->PortIdentifier; rid->roles = FC_RPORT_ROLE_UNKNOWN; - rid->roles |= FC_RPORT_ROLE_FCP_TARGET; - if (pg0->Protocol & MPI_FC_DEVICE_PAGE0_PROT_FCP_INITIATOR) - rid->roles |= FC_RPORT_ROLE_FCP_INITIATOR; return 0; } @@ -357,10 +354,15 @@ mptfc_register_dev(MPT_ADAPTER *ioc, int channel, FCDevicePage0_t *pg0) int new_ri = 1; u64 pn, nn; VirtTarget *vtarget; + u32 roles = FC_RPORT_ROLE_UNKNOWN; if (mptfc_generate_rport_ids(pg0, &rport_ids) < 0) return; + roles |= FC_RPORT_ROLE_FCP_TARGET; + if (pg0->Protocol & MPI_FC_DEVICE_PAGE0_PROT_FCP_INITIATOR) + roles |= FC_RPORT_ROLE_FCP_INITIATOR; + /* scan list looking for a match */ list_for_each_entry(ri, &ioc->fc_rports, list) { pn = (u64)ri->pg0.WWPN.High << 32 | (u64)ri->pg0.WWPN.Low; @@ -400,8 +402,9 @@ mptfc_register_dev(MPT_ADAPTER *ioc, int channel, FCDevicePage0_t *pg0) vtarget->bus_id = pg0->CurrentBus; } } - /* once dd_data is filled in, commands will issue to hardware */ *((struct mptfc_rport_info **)rport->dd_data) = ri; + /* scan will be scheduled once rport becomes a target */ + fc_remote_port_rolechg(rport,roles); pn = (u64)ri->pg0.WWPN.High << 32 | (u64)ri->pg0.WWPN.Low; nn = (u64)ri->pg0.WWNN.High << 32 | (u64)ri->pg0.WWNN.Low;