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authorChristof Schmitt <christof.schmitt@de.ibm.com>2010-09-08 14:39:57 +0200
committerJames Bottomley <James.Bottomley@suse.de>2010-09-16 22:54:19 -0400
commit44a24cb3731495336d77f3a955a7004997270dfd (patch)
tree3fdf2df31c2f528e6bd01c99a942ae2de2b9d39a /drivers/s390/scsi/zfcp_qdio.c
parentf8210e34887e1feb977a9b6b8caa086855af40c9 (diff)
[SCSI] zfcp: Change spin_lock_bh to spin_lock_irq to fix lockdep warning
With the change to use the data on the SCSI device, iterating through all LUNs/scsi_devices takes the SCSI host_lock. This triggers warnings from the lock dependency checker: ========================================================= [ INFO: possible irq lock inversion dependency detected ] 2.6.34.1 #97 --------------------------------------------------------- chchp/3224 just changed the state of lock: (&(shost->host_lock)->rlock){-.-...}, at: [<00000000003a73f4>] __scsi_iterate_devices+0x38/0xbc but this lock took another, HARDIRQ-unsafe lock in the past: (&(&qdio->req_q_lock)->rlock){+.-...} and interrupts could create inverse lock ordering between them. other info that might help us debug this: [ 24.972394] 2 locks held by chchp/3224: #0: (&(sch->lock)->rlock){-.-...}, at: [<0000000000401efa>] do_IRQ+0xb2/0x1e4 #1: (&adapter->port_list_lock){.-....}, at: [<0000000000490302>] zfcp_erp_modify_adapter_status+0x9e/0x16c [...] ========================================================= [ INFO: possible irq lock inversion dependency detected ] 2.6.34.1 #98 --------------------------------------------------------- chchp/3235 just changed the state of lock: (&(shost->host_lock)->rlock){-.-...}, at: [<00000000003a73f4>] __scsi_iterate_devices+0x38/0xbc but this lock took another, HARDIRQ-unsafe lock in the past: (&(&qdio->stat_lock)->rlock){+.-...} and interrupts could create inverse lock ordering between them. other info that might help us debug this: 2 locks held by chchp/3235: #0: (&(sch->lock)->rlock){-.-...}, at: [<0000000000401efa>] do_IRQ+0xb2/0x1e4 #1: (&adapter->port_list_lock){.-.-..}, at: [<00000000004902f6>] zfcp_erp_modify_adapter_status+0x9e/0x16c [...] To stop this warning, change the request queue lock to disable irqs, not only softirq. The changes are required only outside of the critical "send fcp command" path. Reviewed-by: Swen Schillig <swen@vnet.ibm.com> Signed-off-by: Christof Schmitt <christof.schmitt@de.ibm.com> Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Diffstat (limited to 'drivers/s390/scsi/zfcp_qdio.c')
-rw-r--r--drivers/s390/scsi/zfcp_qdio.c18
1 files changed, 10 insertions, 8 deletions
diff --git a/drivers/s390/scsi/zfcp_qdio.c b/drivers/s390/scsi/zfcp_qdio.c
index b2635759721c..60e6e5714eb9 100644
--- a/drivers/s390/scsi/zfcp_qdio.c
+++ b/drivers/s390/scsi/zfcp_qdio.c
@@ -60,13 +60,11 @@ static inline void zfcp_qdio_account(struct zfcp_qdio *qdio)
unsigned long long now, span;
int used;
- spin_lock(&qdio->stat_lock);
now = get_clock_monotonic();
span = (now - qdio->req_q_time) >> 12;
used = QDIO_MAX_BUFFERS_PER_Q - atomic_read(&qdio->req_q_free);
qdio->req_q_util += used * span;
qdio->req_q_time = now;
- spin_unlock(&qdio->stat_lock);
}
static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
@@ -84,7 +82,9 @@ static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
/* cleanup all SBALs being program-owned now */
zfcp_qdio_zero_sbals(qdio->req_q, idx, count);
+ spin_lock_irq(&qdio->stat_lock);
zfcp_qdio_account(qdio);
+ spin_unlock_irq(&qdio->stat_lock);
atomic_add(count, &qdio->req_q_free);
wake_up(&qdio->req_q_wq);
}
@@ -201,11 +201,11 @@ int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
static int zfcp_qdio_sbal_check(struct zfcp_qdio *qdio)
{
- spin_lock_bh(&qdio->req_q_lock);
+ spin_lock_irq(&qdio->req_q_lock);
if (atomic_read(&qdio->req_q_free) ||
!(atomic_read(&qdio->adapter->status) & ZFCP_STATUS_ADAPTER_QDIOUP))
return 1;
- spin_unlock_bh(&qdio->req_q_lock);
+ spin_unlock_irq(&qdio->req_q_lock);
return 0;
}
@@ -223,7 +223,7 @@ int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
{
long ret;
- spin_unlock_bh(&qdio->req_q_lock);
+ spin_unlock_irq(&qdio->req_q_lock);
ret = wait_event_interruptible_timeout(qdio->req_q_wq,
zfcp_qdio_sbal_check(qdio), 5 * HZ);
@@ -239,7 +239,7 @@ int zfcp_qdio_sbal_get(struct zfcp_qdio *qdio)
zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdsbg_1", NULL);
}
- spin_lock_bh(&qdio->req_q_lock);
+ spin_lock_irq(&qdio->req_q_lock);
return -EIO;
}
@@ -254,7 +254,9 @@ int zfcp_qdio_send(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
int retval;
u8 sbal_number = q_req->sbal_number;
+ spin_lock(&qdio->stat_lock);
zfcp_qdio_account(qdio);
+ spin_unlock(&qdio->stat_lock);
retval = do_QDIO(qdio->adapter->ccw_device, QDIO_FLAG_SYNC_OUTPUT, 0,
q_req->sbal_first, sbal_number);
@@ -328,9 +330,9 @@ void zfcp_qdio_close(struct zfcp_qdio *qdio)
return;
/* clear QDIOUP flag, thus do_QDIO is not called during qdio_shutdown */
- spin_lock_bh(&qdio->req_q_lock);
+ spin_lock_irq(&qdio->req_q_lock);
atomic_clear_mask(ZFCP_STATUS_ADAPTER_QDIOUP, &adapter->status);
- spin_unlock_bh(&qdio->req_q_lock);
+ spin_unlock_irq(&qdio->req_q_lock);
wake_up(&qdio->req_q_wq);