From 423f7cf467045eab616f97309aed87a54b5e351d Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 30 Jan 2007 12:07:27 -0800 Subject: [PATCH] [SCSI] libsas: Don't BUG when connecting two expanders via wide port libsas: Don't BUG when connecting two expanders via wide port When a device is connected to an expander, the discovery process goes through sas_ex_discover_dev to figure out what's attached to the phy. If it is the case that the phy being discovered happens to be the second phy of a wide link to an expander, that discover_dev function will incorrectly call sas_ex_discover_expander, which creates another sas_port and tries to attach the other sas_phys to the new port, thus triggering a BUG. The correct thing to do is to check the other ex_phys of the expander to see if there's a sas_port for this sas_phy, and attach the sas_phy to the existing sas_port. This is easily triggered if one enables the phys of a wide port between expanders one by one. This second version of the patch fixes a small regression in the case where all the phys show up at once and we accidentally try to attach to a port that hasn't been created yet. Signed-off-by: Darrick J. Wong Signed-off-by: James Bottomley --- drivers/scsi/libsas/sas_expander.c | 30 ++++++++++++++++++++++++++++++ 1 file changed, 30 insertions(+) diff --git a/drivers/scsi/libsas/sas_expander.c b/drivers/scsi/libsas/sas_expander.c index d9b9a008d36d..dc70c180e115 100644 --- a/drivers/scsi/libsas/sas_expander.c +++ b/drivers/scsi/libsas/sas_expander.c @@ -678,6 +678,29 @@ static struct domain_device *sas_ex_discover_end_dev( return NULL; } +/* See if this phy is part of a wide port */ +static int sas_ex_join_wide_port(struct domain_device *parent, int phy_id) +{ + struct ex_phy *phy = &parent->ex_dev.ex_phy[phy_id]; + int i; + + for (i = 0; i < parent->ex_dev.num_phys; i++) { + struct ex_phy *ephy = &parent->ex_dev.ex_phy[i]; + + if (ephy == phy) + continue; + + if (!memcmp(phy->attached_sas_addr, ephy->attached_sas_addr, + SAS_ADDR_SIZE) && ephy->port) { + sas_port_add_phy(ephy->port, phy->phy); + phy->phy_state = PHY_DEVICE_DISCOVERED; + return 0; + } + } + + return -ENODEV; +} + static struct domain_device *sas_ex_discover_expander( struct domain_device *parent, int phy_id) { @@ -810,6 +833,13 @@ static int sas_ex_discover_dev(struct domain_device *dev, int phy_id) return res; } + res = sas_ex_join_wide_port(dev, phy_id); + if (!res) { + SAS_DPRINTK("Attaching ex phy%d to wide port %016llx\n", + phy_id, SAS_ADDR(ex_phy->attached_sas_addr)); + return res; + } + switch (ex_phy->attached_dev_type) { case SAS_END_DEV: child = sas_ex_discover_end_dev(dev, phy_id);