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[SCSI] mpt2sas: Fix for dead lock occurring between host_lock and sas_device_lock

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Fix for dead lock occurring between host_lock and sas_device_lock.

The deadlock is between two spin locks, between the shost->host_lock
and driver ioc->sas_device_lock.

The fix is to rearrange the code in the  FW/Driver device removal
handshake so the ioc->sas_device_lock is not occurring when the
shost->host_lock is taken.

[jejb: zero initialise sas_address to fix spurious compiler warning]
Signed-off-by: Nagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
nagalakshmi.nandigama@lsi.com 2011-10-19 15:37:14 +05:30 committed by James Bottomley
parent f881ceadd4
commit f3db032f1a
1 changed files with 10 additions and 5 deletions
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15
drivers/scsi/mpt2sas/mpt2sas_scsih.c
View file

@ -3016,7 +3016,8 @@ _scsih_tm_tr_send(struct MPT2SAS_ADAPTER *ioc, u16 handle)
Mpi2SCSITaskManagementRequest_t *mpi_request;
u16 smid;
struct _sas_device *sas_device;
struct MPT2SAS_TARGET *sas_target_priv_data;
struct MPT2SAS_TARGET *sas_target_priv_data = NULL;
u64 sas_address = 0;
unsigned long flags;
struct _tr_list *delayed_tr;
u32 ioc_state;
@ -3049,13 +3050,17 @@ _scsih_tm_tr_send(struct MPT2SAS_ADAPTER *ioc, u16 handle)
sas_device->starget->hostdata) {
sas_target_priv_data = sas_device->starget->hostdata;
sas_target_priv_data->deleted = 1;
dewtprintk(ioc, printk(MPT2SAS_INFO_FMT
"setting delete flag: handle(0x%04x), "
"sas_addr(0x%016llx)\n", ioc->name, handle,
(unsigned long long) sas_device->sas_address));
sas_address = sas_device->sas_address;
}
spin_unlock_irqrestore(&ioc->sas_device_lock, flags);
if (sas_target_priv_data) {
dewtprintk(ioc, printk(MPT2SAS_INFO_FMT "setting delete flag: "
"handle(0x%04x), sas_addr(0x%016llx)\n", ioc->name, handle,
(unsigned long long)sas_address));
_scsih_ublock_io_device(ioc, handle);
}
smid = mpt2sas_base_get_smid_hpr(ioc, ioc->tm_tr_cb_idx);
if (!smid) {
delayed_tr = kzalloc(sizeof(*delayed_tr), GFP_ATOMIC);