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scsi: zfcp: Trace when request remove fails after qdio send fails

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When we fail to send a FSF request in 'zfcp_fsf_req_send()' when calling
'zfcp_qdio_send()' we try to remove the request object from our internal
hash table again to prevent keeping a stale memory reference. This removal
might still - very much theoretically - fail.

To store some evidence of when this happens add a new trace record for
this case; tag: 'fsrsrmf'.

We reuse the 'ZFCP_DBF_HBA_RES' trace ID for this, but mark all fields
other then the request ID with ~0, to make fairly obvious that these are
invalid values. This faking has to be done because we don't have a valid
request object at this point, and can not safely access any of the memory
of the old object - we just failed to find it in our hash table, so it
might be gone already.

Here is an example of a decoded trace record:

    Timestamp      : 2023-02-17-13:09:12:748140
    Area           : HBA
    Subarea        : 1
    Level          : -
    Exception      : 000003ff7ff500c2
    CPU ID         : 0011
    Caller         : 0x0
    Record ID      : 1
    Tag            : fsrsrmf
    Request ID     : 0x0000000080126ab6
    Request status : 0xffffffff
    FSF cmnd       : 0xffffffff
    FSF sequence no: 0xffffffff
    FSF issued     : 2042-09-18-01:53:47:370495
    FSF stat       : 0xffffffff
    FSF stat qual  : ffffffff ffffffff ffffffff ffffffff
    Prot stat      : 0xffffffff
    Prot stat qual : ffffffff ffffffff ffffffff ffffffff
    Port handle    : 0xffffffff
    LUN handle     : 0xffffffff

This provides at least some basic evidence that this event happened, and
what object was affected.

Link: https://lore.kernel.org/r/99b8246b2d71b63fa4f9c56333e2037502f7f5af.1677000450.git.bblock@linux.ibm.com
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Steffen Maier <maier@linux.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Benjamin Block 2023-02-21 18:56:00 +01:00 committed by Martin K. Petersen
parent 3ab0181015
commit 901b894af5
3 changed files with 52 additions and 4 deletions
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44
drivers/s390/scsi/zfcp_dbf.c
View File

@ -4,7 +4,7 @@
*
* Debug traces for zfcp.
*
* Copyright IBM Corp. 2002, 2020
* Copyright IBM Corp. 2002, 2023
*/
#define KMSG_COMPONENT "zfcp"
@ -145,6 +145,48 @@ void zfcp_dbf_hba_fsf_fces(char *tag, const struct zfcp_fsf_req *req, u64 wwpn,
spin_unlock_irqrestore(&dbf->hba_lock, flags);
}
/**
* zfcp_dbf_hba_fsf_reqid - trace only the tag and a request ID
* @tag: tag documenting the source
* @level: trace level
* @adapter: adapter instance the request ID belongs to
* @req_id: the request ID to trace
*/
void zfcp_dbf_hba_fsf_reqid(const char *const tag, const int level,
struct zfcp_adapter *const adapter,
const u64 req_id)
{
struct zfcp_dbf *const dbf = adapter->dbf;
struct zfcp_dbf_hba *const rec = &dbf->hba_buf;
struct zfcp_dbf_hba_res *const res = &rec->u.res;
unsigned long flags;
if (unlikely(!debug_level_enabled(dbf->hba, level)))
return;
spin_lock_irqsave(&dbf->hba_lock, flags);
memset(rec, 0, sizeof(*rec));
memcpy(rec->tag, tag, ZFCP_DBF_TAG_LEN);
rec->id = ZFCP_DBF_HBA_RES;
rec->fsf_req_id = req_id;
rec->fsf_req_status = ~0u;
rec->fsf_cmd = ~0u;
rec->fsf_seq_no = ~0u;
res->req_issued = ~0ull;
res->prot_status = ~0u;
memset(res->prot_status_qual, 0xff, sizeof(res->prot_status_qual));
res->fsf_status = ~0u;
memset(res->fsf_status_qual, 0xff, sizeof(res->fsf_status_qual));
res->port_handle = ~0u;
res->lun_handle = ~0u;
debug_event(dbf->hba, level, rec, sizeof(*rec));
spin_unlock_irqrestore(&dbf->hba_lock, flags);
}
/**
* zfcp_dbf_hba_fsf_uss - trace event for an unsolicited status buffer
* @tag: tag indicating which kind of unsolicited status has been received

5
drivers/s390/scsi/zfcp_ext.h
View File

@ -4,7 +4,7 @@
*
* External function declarations.
*
* Copyright IBM Corp. 2002, 2020
* Copyright IBM Corp. 2002, 2023
*/
#ifndef ZFCP_EXT_H
@ -46,6 +46,9 @@ extern void zfcp_dbf_hba_fsf_res(char *, int, struct zfcp_fsf_req *);
extern void zfcp_dbf_hba_fsf_fces(char *tag, const struct zfcp_fsf_req *req,
u64 wwpn, u32 fc_security_old,
u32 fc_security_new);
extern void zfcp_dbf_hba_fsf_reqid(const char *const tag, const int level,
struct zfcp_adapter *const adapter,
const u64 req_id);
extern void zfcp_dbf_hba_bit_err(char *, struct zfcp_fsf_req *);
extern void zfcp_dbf_hba_def_err(struct zfcp_adapter *, u64, u16, void **);
extern void zfcp_dbf_san_req(char *, struct zfcp_fsf_req *, u32);

7
drivers/s390/scsi/zfcp_fsf.c
View File

@ -4,7 +4,7 @@
*
* Implementation of FSF commands.
*
* Copyright IBM Corp. 2002, 2020
* Copyright IBM Corp. 2002, 2023
*/
#define KMSG_COMPONENT "zfcp"
@ -892,8 +892,11 @@ static int zfcp_fsf_req_send(struct zfcp_fsf_req *req)
req->issued = get_tod_clock();
if (zfcp_qdio_send(qdio, &req->qdio_req)) {
del_timer_sync(&req->timer);
/* lookup request again, list might have changed */
zfcp_reqlist_find_rm(adapter->req_list, req_id);
if (zfcp_reqlist_find_rm(adapter->req_list, req_id) == NULL)
zfcp_dbf_hba_fsf_reqid("fsrsrmf", 1, adapter, req_id);
zfcp_erp_adapter_reopen(adapter, 0, "fsrs__1");
return -EIO;
}