Patchwork [2/3] scsi: Add 'hba_private' to SCSIRequest

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Submitter Hannes Reinecke
Date July 1, 2011, 3:35 p.m.
Message ID <1309534555-22178-3-git-send-email-hare@suse.de>
Download mbox | patch
Permalink /patch/102927/
State New
Headers show

Comments

Hannes Reinecke - July 1, 2011, 3:35 p.m.
'tag' is just an abstraction to identify the command
from the driver. So we should make that explicit by
replacing 'tag' with a driver-defined pointer 'hba_private'.
This saves the lookup for driver handling several commands
in parallel.
'tag' is still being kept for tracing purposes.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 hw/esp.c          |    2 +-
 hw/lsi53c895a.c   |   22 ++++++++--------------
 hw/scsi-bus.c     |    9 ++++++---
 hw/scsi-disk.c    |    4 ++--
 hw/scsi-generic.c |    5 +++--
 hw/scsi.h         |   10 +++++++---
 hw/spapr_vscsi.c  |   29 +++++++++--------------------
 hw/usb-msd.c      |    9 +--------
 8 files changed, 37 insertions(+), 53 deletions(-)
Paolo Bonzini - July 1, 2011, 3:57 p.m.
On 07/01/2011 05:35 PM, Hannes Reinecke wrote:
> 'tag' is just an abstraction to identify the command
> from the driver. So we should make that explicit by
> replacing 'tag' with a driver-defined pointer 'hba_private'.
> This saves the lookup for driver handling several commands
> in parallel.
> 'tag' is still being kept for tracing purposes.
>
> Signed-off-by: Hannes Reinecke<hare@suse.de>
> ---
>   hw/esp.c          |    2 +-
>   hw/lsi53c895a.c   |   22 ++++++++--------------
>   hw/scsi-bus.c     |    9 ++++++---
>   hw/scsi-disk.c    |    4 ++--
>   hw/scsi-generic.c |    5 +++--
>   hw/scsi.h         |   10 +++++++---
>   hw/spapr_vscsi.c  |   29 +++++++++--------------------
>   hw/usb-msd.c      |    9 +--------
>   8 files changed, 37 insertions(+), 53 deletions(-)
>
> diff --git a/hw/esp.c b/hw/esp.c
> index 6d3f5d2..aa87197 100644
> --- a/hw/esp.c
> +++ b/hw/esp.c
> @@ -244,7 +244,7 @@ static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
>
>       DPRINTF("do_busid_cmd: busid 0x%x\n", busid);
>       lun = busid&  7;
> -    s->current_req = scsi_req_new(s->current_dev, 0, lun);
> +    s->current_req = scsi_req_new(s->current_dev, 0, lun, NULL);
>       datalen = scsi_req_enqueue(s->current_req, buf);
>       s->ti_size = datalen;
>       if (datalen != 0) {
> diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
> index 940b43a..69eec1d 100644
> --- a/hw/lsi53c895a.c
> +++ b/hw/lsi53c895a.c
> @@ -661,7 +661,7 @@ static lsi_request *lsi_find_by_tag(LSIState *s, uint32_t tag)
>   static void lsi_request_cancelled(SCSIRequest *req)
>   {
>       LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
> -    lsi_request *p;
> +    lsi_request *p = req->hba_private;
>
>       if (s->current&&  req == s->current->req) {
>           scsi_req_unref(req);
> @@ -670,7 +670,6 @@ static void lsi_request_cancelled(SCSIRequest *req)
>           return;
>       }
>
> -    p = lsi_find_by_tag(s, req->tag);
>       if (p) {
>           QTAILQ_REMOVE(&s->queue, p, next);
>           scsi_req_unref(req);
> @@ -680,18 +679,12 @@ static void lsi_request_cancelled(SCSIRequest *req)
>
>   /* Record that data is available for a queued command.  Returns zero if
>      the device was reselected, nonzero if the IO is deferred.  */
> -static int lsi_queue_tag(LSIState *s, uint32_t tag, uint32_t len)
> +static int lsi_queue_req(LSIState *s, SCSIRequest *req, uint32_t len)
>   {
> -    lsi_request *p;
> -
> -    p = lsi_find_by_tag(s, tag);
> -    if (!p) {
> -        BADF("IO with unknown tag %d\n", tag);
> -        return 1;
> -    }
> +    lsi_request *p = req->hba_private;
>
>       if (p->pending) {
> -        BADF("Multiple IO pending for tag %d\n", tag);
> +        BADF("Multiple IO pending for request %p\n", p);
>       }
>       p->pending = len;
>       /* Reselect if waiting for it, or if reselection triggers an IRQ
> @@ -743,9 +736,9 @@ static void lsi_transfer_data(SCSIRequest *req, uint32_t len)
>       LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
>       int out;
>
> -    if (s->waiting == 1 || !s->current || req->tag != s->current->tag ||
> +    if (s->waiting == 1 || !s->current || req->hba_private != s->current ||
>           (lsi_irq_on_rsl(s)&&  !(s->scntl1&  LSI_SCNTL1_CON))) {
> -        if (lsi_queue_tag(s, req->tag, len)) {
> +        if (lsi_queue_req(s, req, len)) {
>               return;
>           }
>       }
> @@ -789,7 +782,8 @@ static void lsi_do_command(LSIState *s)
>       assert(s->current == NULL);
>       s->current = qemu_mallocz(sizeof(lsi_request));
>       s->current->tag = s->select_tag;
> -    s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun);
> +    s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun,
> +                                   s->current);
>
>       n = scsi_req_enqueue(s->current->req, buf);
>       if (n) {
> diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
> index ad6a730..8b1a412 100644
> --- a/hw/scsi-bus.c
> +++ b/hw/scsi-bus.c
> @@ -131,7 +131,8 @@ int scsi_bus_legacy_handle_cmdline(SCSIBus *bus)
>       return res;
>   }
>
> -SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t lun)
> +SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag,
> +                            uint32_t lun, void *hba_private)
>   {
>       SCSIRequest *req;
>
> @@ -141,14 +142,16 @@ SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t l
>       req->dev = d;
>       req->tag = tag;
>       req->lun = lun;
> +    req->hba_private = hba_private;
>       req->status = -1;
>       trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
>       return req;
>   }
>
> -SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun)
> +SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun,
> +                          void *hba_private)
>   {
> -    return d->info->alloc_req(d, tag, lun);
> +    return d->info->alloc_req(d, tag, lun, hba_private);
>   }
>
>   uint8_t *scsi_req_get_buf(SCSIRequest *req)
> diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
> index a8c7372..c2a99fe 100644
> --- a/hw/scsi-disk.c
> +++ b/hw/scsi-disk.c
> @@ -81,13 +81,13 @@ static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type);
>   static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf);
>
>   static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag,
> -        uint32_t lun)
> +                                     uint32_t lun, void *hba_private)
>   {
>       SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
>       SCSIRequest *req;
>       SCSIDiskReq *r;
>
> -    req = scsi_req_alloc(sizeof(SCSIDiskReq),&s->qdev, tag, lun);
> +    req = scsi_req_alloc(sizeof(SCSIDiskReq),&s->qdev, tag, lun, hba_private);
>       r = DO_UPCAST(SCSIDiskReq, req, req);
>       r->iov.iov_base = qemu_blockalign(s->bs, SCSI_DMA_BUF_SIZE);
>       return req;
> diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
> index 8e59c7e..90345a7 100644
> --- a/hw/scsi-generic.c
> +++ b/hw/scsi-generic.c
> @@ -96,11 +96,12 @@ static int scsi_get_sense(SCSIRequest *req, uint8_t *outbuf, int len)
>       return size;
>   }
>
> -static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun)
> +static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun,
> +                                     void *hba_private)
>   {
>       SCSIRequest *req;
>
> -    req = scsi_req_alloc(sizeof(SCSIGenericReq), d, tag, lun);
> +    req = scsi_req_alloc(sizeof(SCSIGenericReq), d, tag, lun, hba_private);
>       return req;
>   }
>
> diff --git a/hw/scsi.h b/hw/scsi.h
> index c1dca35..6b15bbc 100644
> --- a/hw/scsi.h
> +++ b/hw/scsi.h
> @@ -43,6 +43,7 @@ struct SCSIRequest {
>       } cmd;
>       BlockDriverAIOCB  *aiocb;
>       bool enqueued;
> +    void *hba_private;
>       QTAILQ_ENTRY(SCSIRequest) next;
>   };
>
> @@ -67,7 +68,8 @@ struct SCSIDeviceInfo {
>       DeviceInfo qdev;
>       scsi_qdev_initfn init;
>       void (*destroy)(SCSIDevice *s);
> -    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun);
> +    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun,
> +                              void *hba_private);
>       void (*free_req)(SCSIRequest *req);
>       int32_t (*send_command)(SCSIRequest *req, uint8_t *buf);
>       void (*read_data)(SCSIRequest *req);
> @@ -138,8 +140,10 @@ extern const struct SCSISense sense_code_LUN_FAILURE;
>   int scsi_build_sense(SCSISense sense, uint8_t *buf, int len, int fixed);
>   int scsi_sense_valid(SCSISense sense);
>
> -SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t lun);
> -SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun);
> +SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag,
> +                            uint32_t lun, void *hba_private);
> +SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun,
> +                          void *hba_private);
>   int32_t scsi_req_enqueue(SCSIRequest *req, uint8_t *buf);
>   void scsi_req_free(SCSIRequest *req);
>   SCSIRequest *scsi_req_ref(SCSIRequest *req);
> diff --git a/hw/spapr_vscsi.c b/hw/spapr_vscsi.c
> index 1c901ef..9e1cb2e 100644
> --- a/hw/spapr_vscsi.c
> +++ b/hw/spapr_vscsi.c
> @@ -121,7 +121,7 @@ static struct vscsi_req *vscsi_get_req(VSCSIState *s)
>       return NULL;
>   }
>
> -static void vscsi_put_req(VSCSIState *s, vscsi_req *req)
> +static void vscsi_put_req(vscsi_req *req)
>   {
>       if (req->sreq != NULL) {
>           scsi_req_unref(req->sreq);
> @@ -130,15 +130,6 @@ static void vscsi_put_req(VSCSIState *s, vscsi_req *req)
>       req->active = 0;
>   }
>
> -static vscsi_req *vscsi_find_req(VSCSIState *s, SCSIRequest *req)
> -{
> -    uint32_t tag = req->tag;
> -    if (tag>= VSCSI_REQ_LIMIT || !s->reqs[tag].active) {
> -        return NULL;
> -    }
> -    return&s->reqs[tag];
> -}
> -
>   static void vscsi_decode_id_lun(uint64_t srp_lun, int *id, int *lun)
>   {
>       /* XXX Figure that one out properly ! This is crackpot */
> @@ -454,7 +445,7 @@ static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
>       if (n) {
>           req->senselen = n;
>           vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
> -        vscsi_put_req(s, req);
> +        vscsi_put_req(req);
>           return;
>       }
>
> @@ -483,7 +474,7 @@ static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
>   static void vscsi_transfer_data(SCSIRequest *sreq, uint32_t len)
>   {
>       VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
> -    vscsi_req *req = vscsi_find_req(s, sreq);
> +    vscsi_req *req = sreq->hba_private;
>       uint8_t *buf;
>       int rc = 0;
>
> @@ -530,8 +521,7 @@ static void vscsi_transfer_data(SCSIRequest *sreq, uint32_t len)
>   /* Callback to indicate that the SCSI layer has completed a transfer.  */
>   static void vscsi_command_complete(SCSIRequest *sreq, uint32_t status)
>   {
> -    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
> -    vscsi_req *req = vscsi_find_req(s, sreq);
> +    vscsi_req *req = sreq->hba_private;
>       int32_t res_in = 0, res_out = 0;
>
>       dprintf("VSCSI: SCSI cmd complete, r=0x%x tag=0x%x status=0x%x, req=%p\n",
> @@ -563,15 +553,14 @@ static void vscsi_command_complete(SCSIRequest *sreq, uint32_t status)
>           }
>       }
>       vscsi_send_rsp(s, req, 0, res_in, res_out);
> -    vscsi_put_req(s, req);
> +    vscsi_put_req(req);
>   }
>
>   static void vscsi_request_cancelled(SCSIRequest *sreq)
>   {
> -    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
> -    vscsi_req *req = vscsi_find_req(s, sreq);
> +    vscsi_req *req = sreq->hba_private;
>
> -    vscsi_put_req(s, req);
> +    vscsi_put_req(req);
>   }
>
>   static void vscsi_process_login(VSCSIState *s, vscsi_req *req)
> @@ -659,7 +648,7 @@ static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
>       }
>
>       req->lun = lun;
> -    req->sreq = scsi_req_new(sdev, req->qtag, lun);
> +    req->sreq = scsi_req_new(sdev, req->qtag, lun, req);
>       n = scsi_req_enqueue(req->sreq, srp->cmd.cdb);
>
>       dprintf("VSCSI: Queued command tag 0x%x CMD 0x%x ID %d LUN %d ret: %d\n",
> @@ -858,7 +847,7 @@ static void vscsi_got_payload(VSCSIState *s, vscsi_crq *crq)
>       }
>
>       if (done) {
> -        vscsi_put_req(s, req);
> +        vscsi_put_req(req);
>       }
>   }
>
> diff --git a/hw/usb-msd.c b/hw/usb-msd.c
> index 86582cc..bfea096 100644
> --- a/hw/usb-msd.c
> +++ b/hw/usb-msd.c
> @@ -216,10 +216,6 @@ static void usb_msd_transfer_data(SCSIRequest *req, uint32_t len)
>       MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
>       USBPacket *p = s->packet;
>
> -    if (req->tag != s->tag) {
> -        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", req->tag);
> -    }
> -
>       assert((s->mode == USB_MSDM_DATAOUT) == (req->cmd.mode == SCSI_XFER_TO_DEV));
>       s->scsi_len = len;
>       s->scsi_buf = scsi_req_get_buf(req);
> @@ -241,9 +237,6 @@ static void usb_msd_command_complete(SCSIRequest *req, uint32_t status)
>       MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
>       USBPacket *p = s->packet;
>
> -    if (req->tag != s->tag) {
> -        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", req->tag);
> -    }
>       DPRINTF("Command complete %d\n", status);
>       s->residue = s->data_len;
>       s->result = status != 0;
> @@ -387,7 +380,7 @@ static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
>                       s->tag, cbw.flags, cbw.cmd_len, s->data_len);
>               s->residue = 0;
>               s->scsi_len = 0;
> -            s->req = scsi_req_new(s->scsi_dev, s->tag, 0);
> +            s->req = scsi_req_new(s->scsi_dev, s->tag, 0, NULL);
>               scsi_req_enqueue(s->req, cbw.cmd);
>               /* ??? Should check that USB and SCSI data transfer
>                  directions match.  */

Acked-by: Paolo Bonzini <pbonzini@redhat.com>

Have a nice weekend.

Paolo

Patch

diff --git a/hw/esp.c b/hw/esp.c
index 6d3f5d2..aa87197 100644
--- a/hw/esp.c
+++ b/hw/esp.c
@@ -244,7 +244,7 @@  static void do_busid_cmd(ESPState *s, uint8_t *buf, uint8_t busid)
 
     DPRINTF("do_busid_cmd: busid 0x%x\n", busid);
     lun = busid & 7;
-    s->current_req = scsi_req_new(s->current_dev, 0, lun);
+    s->current_req = scsi_req_new(s->current_dev, 0, lun, NULL);
     datalen = scsi_req_enqueue(s->current_req, buf);
     s->ti_size = datalen;
     if (datalen != 0) {
diff --git a/hw/lsi53c895a.c b/hw/lsi53c895a.c
index 940b43a..69eec1d 100644
--- a/hw/lsi53c895a.c
+++ b/hw/lsi53c895a.c
@@ -661,7 +661,7 @@  static lsi_request *lsi_find_by_tag(LSIState *s, uint32_t tag)
 static void lsi_request_cancelled(SCSIRequest *req)
 {
     LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
-    lsi_request *p;
+    lsi_request *p = req->hba_private;
 
     if (s->current && req == s->current->req) {
         scsi_req_unref(req);
@@ -670,7 +670,6 @@  static void lsi_request_cancelled(SCSIRequest *req)
         return;
     }
 
-    p = lsi_find_by_tag(s, req->tag);
     if (p) {
         QTAILQ_REMOVE(&s->queue, p, next);
         scsi_req_unref(req);
@@ -680,18 +679,12 @@  static void lsi_request_cancelled(SCSIRequest *req)
 
 /* Record that data is available for a queued command.  Returns zero if
    the device was reselected, nonzero if the IO is deferred.  */
-static int lsi_queue_tag(LSIState *s, uint32_t tag, uint32_t len)
+static int lsi_queue_req(LSIState *s, SCSIRequest *req, uint32_t len)
 {
-    lsi_request *p;
-
-    p = lsi_find_by_tag(s, tag);
-    if (!p) {
-        BADF("IO with unknown tag %d\n", tag);
-        return 1;
-    }
+    lsi_request *p = req->hba_private;
 
     if (p->pending) {
-        BADF("Multiple IO pending for tag %d\n", tag);
+        BADF("Multiple IO pending for request %p\n", p);
     }
     p->pending = len;
     /* Reselect if waiting for it, or if reselection triggers an IRQ
@@ -743,9 +736,9 @@  static void lsi_transfer_data(SCSIRequest *req, uint32_t len)
     LSIState *s = DO_UPCAST(LSIState, dev.qdev, req->bus->qbus.parent);
     int out;
 
-    if (s->waiting == 1 || !s->current || req->tag != s->current->tag ||
+    if (s->waiting == 1 || !s->current || req->hba_private != s->current ||
         (lsi_irq_on_rsl(s) && !(s->scntl1 & LSI_SCNTL1_CON))) {
-        if (lsi_queue_tag(s, req->tag, len)) {
+        if (lsi_queue_req(s, req, len)) {
             return;
         }
     }
@@ -789,7 +782,8 @@  static void lsi_do_command(LSIState *s)
     assert(s->current == NULL);
     s->current = qemu_mallocz(sizeof(lsi_request));
     s->current->tag = s->select_tag;
-    s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun);
+    s->current->req = scsi_req_new(dev, s->current->tag, s->current_lun,
+                                   s->current);
 
     n = scsi_req_enqueue(s->current->req, buf);
     if (n) {
diff --git a/hw/scsi-bus.c b/hw/scsi-bus.c
index ad6a730..8b1a412 100644
--- a/hw/scsi-bus.c
+++ b/hw/scsi-bus.c
@@ -131,7 +131,8 @@  int scsi_bus_legacy_handle_cmdline(SCSIBus *bus)
     return res;
 }
 
-SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t lun)
+SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag,
+                            uint32_t lun, void *hba_private)
 {
     SCSIRequest *req;
 
@@ -141,14 +142,16 @@  SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t l
     req->dev = d;
     req->tag = tag;
     req->lun = lun;
+    req->hba_private = hba_private;
     req->status = -1;
     trace_scsi_req_alloc(req->dev->id, req->lun, req->tag);
     return req;
 }
 
-SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun)
+SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun,
+                          void *hba_private)
 {
-    return d->info->alloc_req(d, tag, lun);
+    return d->info->alloc_req(d, tag, lun, hba_private);
 }
 
 uint8_t *scsi_req_get_buf(SCSIRequest *req)
diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
index a8c7372..c2a99fe 100644
--- a/hw/scsi-disk.c
+++ b/hw/scsi-disk.c
@@ -81,13 +81,13 @@  static int scsi_handle_rw_error(SCSIDiskReq *r, int error, int type);
 static int scsi_disk_emulate_command(SCSIDiskReq *r, uint8_t *outbuf);
 
 static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag,
-        uint32_t lun)
+                                     uint32_t lun, void *hba_private)
 {
     SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, d);
     SCSIRequest *req;
     SCSIDiskReq *r;
 
-    req = scsi_req_alloc(sizeof(SCSIDiskReq), &s->qdev, tag, lun);
+    req = scsi_req_alloc(sizeof(SCSIDiskReq), &s->qdev, tag, lun, hba_private);
     r = DO_UPCAST(SCSIDiskReq, req, req);
     r->iov.iov_base = qemu_blockalign(s->bs, SCSI_DMA_BUF_SIZE);
     return req;
diff --git a/hw/scsi-generic.c b/hw/scsi-generic.c
index 8e59c7e..90345a7 100644
--- a/hw/scsi-generic.c
+++ b/hw/scsi-generic.c
@@ -96,11 +96,12 @@  static int scsi_get_sense(SCSIRequest *req, uint8_t *outbuf, int len)
     return size;
 }
 
-static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun)
+static SCSIRequest *scsi_new_request(SCSIDevice *d, uint32_t tag, uint32_t lun,
+                                     void *hba_private)
 {
     SCSIRequest *req;
 
-    req = scsi_req_alloc(sizeof(SCSIGenericReq), d, tag, lun);
+    req = scsi_req_alloc(sizeof(SCSIGenericReq), d, tag, lun, hba_private);
     return req;
 }
 
diff --git a/hw/scsi.h b/hw/scsi.h
index c1dca35..6b15bbc 100644
--- a/hw/scsi.h
+++ b/hw/scsi.h
@@ -43,6 +43,7 @@  struct SCSIRequest {
     } cmd;
     BlockDriverAIOCB  *aiocb;
     bool enqueued;
+    void *hba_private;
     QTAILQ_ENTRY(SCSIRequest) next;
 };
 
@@ -67,7 +68,8 @@  struct SCSIDeviceInfo {
     DeviceInfo qdev;
     scsi_qdev_initfn init;
     void (*destroy)(SCSIDevice *s);
-    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun);
+    SCSIRequest *(*alloc_req)(SCSIDevice *s, uint32_t tag, uint32_t lun,
+                              void *hba_private);
     void (*free_req)(SCSIRequest *req);
     int32_t (*send_command)(SCSIRequest *req, uint8_t *buf);
     void (*read_data)(SCSIRequest *req);
@@ -138,8 +140,10 @@  extern const struct SCSISense sense_code_LUN_FAILURE;
 int scsi_build_sense(SCSISense sense, uint8_t *buf, int len, int fixed);
 int scsi_sense_valid(SCSISense sense);
 
-SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag, uint32_t lun);
-SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun);
+SCSIRequest *scsi_req_alloc(size_t size, SCSIDevice *d, uint32_t tag,
+                            uint32_t lun, void *hba_private);
+SCSIRequest *scsi_req_new(SCSIDevice *d, uint32_t tag, uint32_t lun,
+                          void *hba_private);
 int32_t scsi_req_enqueue(SCSIRequest *req, uint8_t *buf);
 void scsi_req_free(SCSIRequest *req);
 SCSIRequest *scsi_req_ref(SCSIRequest *req);
diff --git a/hw/spapr_vscsi.c b/hw/spapr_vscsi.c
index 1c901ef..9e1cb2e 100644
--- a/hw/spapr_vscsi.c
+++ b/hw/spapr_vscsi.c
@@ -121,7 +121,7 @@  static struct vscsi_req *vscsi_get_req(VSCSIState *s)
     return NULL;
 }
 
-static void vscsi_put_req(VSCSIState *s, vscsi_req *req)
+static void vscsi_put_req(vscsi_req *req)
 {
     if (req->sreq != NULL) {
         scsi_req_unref(req->sreq);
@@ -130,15 +130,6 @@  static void vscsi_put_req(VSCSIState *s, vscsi_req *req)
     req->active = 0;
 }
 
-static vscsi_req *vscsi_find_req(VSCSIState *s, SCSIRequest *req)
-{
-    uint32_t tag = req->tag;
-    if (tag >= VSCSI_REQ_LIMIT || !s->reqs[tag].active) {
-        return NULL;
-    }
-    return &s->reqs[tag];
-}
-
 static void vscsi_decode_id_lun(uint64_t srp_lun, int *id, int *lun)
 {
     /* XXX Figure that one out properly ! This is crackpot */
@@ -454,7 +445,7 @@  static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
     if (n) {
         req->senselen = n;
         vscsi_send_rsp(s, req, CHECK_CONDITION, 0, 0);
-        vscsi_put_req(s, req);
+        vscsi_put_req(req);
         return;
     }
 
@@ -483,7 +474,7 @@  static void vscsi_send_request_sense(VSCSIState *s, vscsi_req *req)
 static void vscsi_transfer_data(SCSIRequest *sreq, uint32_t len)
 {
     VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
-    vscsi_req *req = vscsi_find_req(s, sreq);
+    vscsi_req *req = sreq->hba_private;
     uint8_t *buf;
     int rc = 0;
 
@@ -530,8 +521,7 @@  static void vscsi_transfer_data(SCSIRequest *sreq, uint32_t len)
 /* Callback to indicate that the SCSI layer has completed a transfer.  */
 static void vscsi_command_complete(SCSIRequest *sreq, uint32_t status)
 {
-    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
-    vscsi_req *req = vscsi_find_req(s, sreq);
+    vscsi_req *req = sreq->hba_private;
     int32_t res_in = 0, res_out = 0;
 
     dprintf("VSCSI: SCSI cmd complete, r=0x%x tag=0x%x status=0x%x, req=%p\n",
@@ -563,15 +553,14 @@  static void vscsi_command_complete(SCSIRequest *sreq, uint32_t status)
         }
     }
     vscsi_send_rsp(s, req, 0, res_in, res_out);
-    vscsi_put_req(s, req);
+    vscsi_put_req(req);
 }
 
 static void vscsi_request_cancelled(SCSIRequest *sreq)
 {
-    VSCSIState *s = DO_UPCAST(VSCSIState, vdev.qdev, sreq->bus->qbus.parent);
-    vscsi_req *req = vscsi_find_req(s, sreq);
+    vscsi_req *req = sreq->hba_private;
 
-    vscsi_put_req(s, req);
+    vscsi_put_req(req);
 }
 
 static void vscsi_process_login(VSCSIState *s, vscsi_req *req)
@@ -659,7 +648,7 @@  static int vscsi_queue_cmd(VSCSIState *s, vscsi_req *req)
     }
 
     req->lun = lun;
-    req->sreq = scsi_req_new(sdev, req->qtag, lun);
+    req->sreq = scsi_req_new(sdev, req->qtag, lun, req);
     n = scsi_req_enqueue(req->sreq, srp->cmd.cdb);
 
     dprintf("VSCSI: Queued command tag 0x%x CMD 0x%x ID %d LUN %d ret: %d\n",
@@ -858,7 +847,7 @@  static void vscsi_got_payload(VSCSIState *s, vscsi_crq *crq)
     }
 
     if (done) {
-        vscsi_put_req(s, req);
+        vscsi_put_req(req);
     }
 }
 
diff --git a/hw/usb-msd.c b/hw/usb-msd.c
index 86582cc..bfea096 100644
--- a/hw/usb-msd.c
+++ b/hw/usb-msd.c
@@ -216,10 +216,6 @@  static void usb_msd_transfer_data(SCSIRequest *req, uint32_t len)
     MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
     USBPacket *p = s->packet;
 
-    if (req->tag != s->tag) {
-        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", req->tag);
-    }
-
     assert((s->mode == USB_MSDM_DATAOUT) == (req->cmd.mode == SCSI_XFER_TO_DEV));
     s->scsi_len = len;
     s->scsi_buf = scsi_req_get_buf(req);
@@ -241,9 +237,6 @@  static void usb_msd_command_complete(SCSIRequest *req, uint32_t status)
     MSDState *s = DO_UPCAST(MSDState, dev.qdev, req->bus->qbus.parent);
     USBPacket *p = s->packet;
 
-    if (req->tag != s->tag) {
-        fprintf(stderr, "usb-msd: Unexpected SCSI Tag 0x%x\n", req->tag);
-    }
     DPRINTF("Command complete %d\n", status);
     s->residue = s->data_len;
     s->result = status != 0;
@@ -387,7 +380,7 @@  static int usb_msd_handle_data(USBDevice *dev, USBPacket *p)
                     s->tag, cbw.flags, cbw.cmd_len, s->data_len);
             s->residue = 0;
             s->scsi_len = 0;
-            s->req = scsi_req_new(s->scsi_dev, s->tag, 0);
+            s->req = scsi_req_new(s->scsi_dev, s->tag, 0, NULL);
             scsi_req_enqueue(s->req, cbw.cmd);
             /* ??? Should check that USB and SCSI data transfer
                directions match.  */