From e55f87531c2c1eb071a296df7eb67f83d5f0b5df Mon Sep 17 00:00:00 2001 From: Christof Schmitt Date: Thu, 18 Nov 2010 14:53:18 +0100 Subject: [PATCH] [SCSI] zfcp: Issue FCP command without holding SCSI host_lock Interrupting the connection to the FCP channel while I/O requests are being issued can lead to this deadlock. scsi_dispatch_cmd already holds the host_lock while the recovery trigger tries to acquire the host_lock again when iterating through the scsi_devices. INFO: lockdep is turned off. BUG: spinlock lockup on CPU#1, blast/9660, 0000000078f38878 CPU: 1 Not tainted 2.6.35.7SWEN2 #2 Process blast (pid: 9660, task: 0000000071f75940, ksp: 0000000074393ac0) 0000000074393640 00000000743935c0 0000000000000002 0000000000000000 0000000074393660 00000000743935d8 00000000743935d8 00000000005590c2 0000000000000000 0000000078f38878 0000000026ede800 0000000078f38878 000000000000000d 040000000000000c 0000000074393628 0000000000000000 0000000000000000 0000000000100b2a 00000000743935c0 0000000074393600 Call Trace: ([<0000000000100a32>] show_trace+0xee/0x144) [<00000000003be202>] do_raw_spin_lock+0x112/0x178 [<000000000055d408>] _raw_spin_lock_irqsave+0x90/0xb0 [<00000000003f1514>] __scsi_iterate_devices+0x38/0xbc [<00000000004849b0>] zfcp_erp_clear_adapter_status+0xd0/0x16c [<000000000048587a>] zfcp_erp_adapter_reopen+0x3a/0xb4 [<0000000000489812>] zfcp_fsf_req_send+0x166/0x180 [<000000000048c8d6>] zfcp_fsf_fcp_cmnd+0x272/0x408 [<000000000048f864>] zfcp_scsi_queuecommand+0x11c/0x1e0 [<00000000003f1f2a>] scsi_dispatch_cmd+0x1d6/0x324 [<00000000003f9910>] scsi_request_fn+0x42c/0x56c [<00000000003828ae>] __blk_run_queue+0x86/0x140 [<000000000037f742>] elv_insert+0x11a/0x208 [<000000000038104c>] blk_insert_cloned_request+0x84/0xe4 [<000003c0032b7c64>] dm_dispatch_request+0x6c/0x94 [dm_mod] [<000003c0032b7d5c>] map_request+0xd0/0x100 [dm_mod] [<000003c0032b9a78>] dm_request_fn+0xec/0x1bc [dm_mod] [<0000000000382c0e>] generic_unplug_device+0x5a/0x6c [<000003c0032b7f98>] dm_unplug_all+0x74/0x9c [dm_mod] [<00000000001d1272>] sync_page+0x76/0x9c [<00000000001d12ba>] sync_page_killable+0x22/0x60 [<000000000055a768>] __wait_on_bit_lock+0xc0/0x124 [<00000000001d1140>] __lock_page_killable+0x78/0x84 [<00000000001d351c>] generic_file_aio_read+0x5a4/0x7e8 [<0000000000228ec0>] do_sync_read+0xc8/0x12c [<0000000000229edc>] vfs_read+0xac/0x1ac [<000000000022a0d8>] SyS_read+0x58/0xa8 [<00000000001146de>] sysc_noemu+0x10/0x16 [<00000200000493c4>] 0x200000493c4 INFO: lockdep is turned off. Call zfcp_fsf_fcp_cmnd without the host_lock and disable the interrupts when acquiring the req_q_lock. According to the patch description in "[PATCH] Eliminate error handler overload of the SCSI serial number", the serial_number is not used, so simply drop the queuecommand wrapper function and run zfcp_scsi_queuecommand without holding the host_lock. Reviewed-by: Swen Schillig Signed-off-by: Christof Schmitt Signed-off-by: James Bottomley --- drivers/s390/scsi/zfcp_fsf.c | 5 +++-- drivers/s390/scsi/zfcp_scsi.c | 7 ++----- 2 files changed, 5 insertions(+), 7 deletions(-) diff --git a/drivers/s390/scsi/zfcp_fsf.c b/drivers/s390/scsi/zfcp_fsf.c index f75707a8de2b..2eb7dd56ab80 100644 --- a/drivers/s390/scsi/zfcp_fsf.c +++ b/drivers/s390/scsi/zfcp_fsf.c @@ -2170,12 +2170,13 @@ int zfcp_fsf_fcp_cmnd(struct scsi_cmnd *scsi_cmnd) struct zfcp_adapter *adapter = zfcp_sdev->port->adapter; struct zfcp_qdio *qdio = adapter->qdio; struct fsf_qtcb_bottom_io *io; + unsigned long flags; if (unlikely(!(atomic_read(&zfcp_sdev->status) & ZFCP_STATUS_COMMON_UNBLOCKED))) return -EBUSY; - spin_lock(&qdio->req_q_lock); + spin_lock_irqsave(&qdio->req_q_lock, flags); if (atomic_read(&qdio->req_q_free) <= 0) { atomic_inc(&qdio->req_q_full); goto out; @@ -2239,7 +2240,7 @@ failed_scsi_cmnd: zfcp_fsf_req_free(req); scsi_cmnd->host_scribble = NULL; out: - spin_unlock(&qdio->req_q_lock); + spin_unlock_irqrestore(&qdio->req_q_lock, flags); return retval; } diff --git a/drivers/s390/scsi/zfcp_scsi.c b/drivers/s390/scsi/zfcp_scsi.c index 6bd2dbc4c316..63529ed801eb 100644 --- a/drivers/s390/scsi/zfcp_scsi.c +++ b/drivers/s390/scsi/zfcp_scsi.c @@ -76,8 +76,8 @@ static void zfcp_scsi_command_fail(struct scsi_cmnd *scpnt, int result) scpnt->scsi_done(scpnt); } -static int zfcp_scsi_queuecommand_lck(struct scsi_cmnd *scpnt, - void (*done) (struct scsi_cmnd *)) +static +int zfcp_scsi_queuecommand(struct Scsi_Host *shost, struct scsi_cmnd *scpnt) { struct zfcp_scsi_dev *zfcp_sdev = sdev_to_zfcp(scpnt->device); struct zfcp_adapter *adapter = zfcp_sdev->port->adapter; @@ -87,7 +87,6 @@ static int zfcp_scsi_queuecommand_lck(struct scsi_cmnd *scpnt, /* reset the status for this request */ scpnt->result = 0; scpnt->host_scribble = NULL; - scpnt->scsi_done = done; scsi_result = fc_remote_port_chkready(rport); if (unlikely(scsi_result)) { @@ -127,8 +126,6 @@ static int zfcp_scsi_queuecommand_lck(struct scsi_cmnd *scpnt, return ret; } -static DEF_SCSI_QCMD(zfcp_scsi_queuecommand) - static int zfcp_scsi_slave_alloc(struct scsi_device *sdev) { struct fc_rport *rport = starget_to_rport(scsi_target(sdev)); -- 2.20.1