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Commit f3db032f authored by nagalakshmi.nandigama@lsi.com's avatar nagalakshmi.nandigama@lsi.com Committed by James Bottomley
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[SCSI] mpt2sas: Fix for dead lock occurring between host_lock and sas_device_lock 



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: default avatarNagalakshmi Nandigama <nagalakshmi.nandigama@lsi.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent f881cead

drivers/scsi/mpt2sas/mpt2sas_scsih.c

+10 −5
Original line number Diff line number Diff line
@@ -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);