| Message ID | 1464008051-6429-6-git-send-email-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 05/23/2016 06:54 AM, Paolo Bonzini wrote: > scsi-block will be able to do FUA just by passing the request through > to the LUN (which is also more efficient); there is no need to emulate > it like we do for scsi-disk. > > Add a new method to distinguish this. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > hw/scsi/scsi-disk.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > @@ -239,7 +241,7 @@ static void scsi_write_do_fua(SCSIDiskReq *r) > goto done; > } > > - if (scsi_is_cmd_fua(&r->req.cmd)) { > + if (r->need_fua_emulation) { BDRV_REQ_FUA is defined for writes,... > block_acct_start(blk_get_stats(s->qdev.conf.blk), &r->acct, 0, > BLOCK_ACCT_FLUSH); > r->req.aiocb = blk_aio_flush(s->qdev.conf.blk, scsi_aio_complete, r); > @@ -416,7 +418,7 @@ static void scsi_read_data(SCSIRequest *req) > > first = !r->started; > r->started = true; > - if (first && scsi_is_cmd_fua(&r->req.cmd)) { > + if (first && r->need_fua_emulation) { ...but while FUA semantics are definitely defined in SCSI for reads, I don't know if we've properly wired them up in our block layer for that purpose. In particular, while bdrv_driver_pwritev() definitely has a flush fallback if .supported_write_flags lacks BDRV_REQ_FUA, bdrv_driver_preadv() does not currently look at flags. The idea makes sense, but I don't know if it is incomplete without first making sure FUA works on reads throughout the block layer.
On Mon, 05/23 14:54, Paolo Bonzini wrote: > scsi-block will be able to do FUA just by passing the request through > to the LUN (which is also more efficient); there is no need to emulate > it like we do for scsi-disk. Even for scsi-disk, shall we just use the block layer FUA fallback already by passing BDRV_REQ_FUA in blk_aio_pwritev and simply the code in this series? > > Add a new method to distinguish this. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > hw/scsi/scsi-disk.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c > index 4b5db59..f9870e9 100644 > --- a/hw/scsi/scsi-disk.c > +++ b/hw/scsi/scsi-disk.c > @@ -69,6 +69,7 @@ typedef struct SCSIDiskClass { > SCSIDeviceClass parent_class; > DMAIOFunc *dma_readv; > DMAIOFunc *dma_writev; > + bool (*need_fua_emulation)(SCSICommand *cmd); > } SCSIDiskClass; > > typedef struct SCSIDiskReq { > @@ -78,6 +79,7 @@ typedef struct SCSIDiskReq { > uint32_t sector_count; > uint32_t buflen; > bool started; > + bool need_fua_emulation; > struct iovec iov; > QEMUIOVector qiov; > BlockAcctCookie acct; > @@ -239,7 +241,7 @@ static void scsi_write_do_fua(SCSIDiskReq *r) > goto done; > } > > - if (scsi_is_cmd_fua(&r->req.cmd)) { > + if (r->need_fua_emulation) { Should this evaluate a call to r->need_fua_emulation() instead of the function pointer itself? > block_acct_start(blk_get_stats(s->qdev.conf.blk), &r->acct, 0, > BLOCK_ACCT_FLUSH); > r->req.aiocb = blk_aio_flush(s->qdev.conf.blk, scsi_aio_complete, r); > @@ -416,7 +418,7 @@ static void scsi_read_data(SCSIRequest *req) > > first = !r->started; > r->started = true; > - if (first && scsi_is_cmd_fua(&r->req.cmd)) { > + if (first && r->need_fua_emulation) { > block_acct_start(blk_get_stats(s->qdev.conf.blk), &r->acct, 0, > BLOCK_ACCT_FLUSH); > r->req.aiocb = blk_aio_flush(s->qdev.conf.blk, scsi_do_read_cb, r); > @@ -2157,6 +2159,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf) > { > SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req); > SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev); > + SCSIDiskClass *sdc = (SCSIDiskClass *) object_get_class(OBJECT(s)); > uint32_t len; > uint8_t command; > > @@ -2215,6 +2218,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf) > scsi_check_condition(r, SENSE_CODE(LBA_OUT_OF_RANGE)); > return 0; > } > + r->need_fua_emulation = sdc->need_fua_emulation(&r->req.cmd); > if (r->sector_count == 0) { > scsi_req_complete(&r->req, GOOD); > } > @@ -2704,6 +2708,7 @@ static void scsi_disk_base_class_initfn(ObjectClass *klass, void *data) > dc->reset = scsi_disk_reset; > sdc->dma_readv = scsi_dma_readv; > sdc->dma_writev = scsi_dma_writev; > + sdc->need_fua_emulation = scsi_is_cmd_fua; > } > > static const TypeInfo scsi_disk_base_info = { > -- > 2.5.5 > > >
On 24/05/2016 05:04, Fam Zheng wrote: > On Mon, 05/23 14:54, Paolo Bonzini wrote: > > scsi-block will be able to do FUA just by passing the request through > > to the LUN (which is also more efficient); there is no need to emulate > > it like we do for scsi-disk. > > Even for scsi-disk, shall we just use the block layer FUA fallback already by > passing BDRV_REQ_FUA in blk_aio_pwritev and simply the code in this series? That's a good idea but it should be done separately, I think. Thanks, Paolo
diff --git a/hw/scsi/scsi-disk.c b/hw/scsi/scsi-disk.c index 4b5db59..f9870e9 100644 --- a/hw/scsi/scsi-disk.c +++ b/hw/scsi/scsi-disk.c @@ -69,6 +69,7 @@ typedef struct SCSIDiskClass { SCSIDeviceClass parent_class; DMAIOFunc *dma_readv; DMAIOFunc *dma_writev; + bool (*need_fua_emulation)(SCSICommand *cmd); } SCSIDiskClass; typedef struct SCSIDiskReq { @@ -78,6 +79,7 @@ typedef struct SCSIDiskReq { uint32_t sector_count; uint32_t buflen; bool started; + bool need_fua_emulation; struct iovec iov; QEMUIOVector qiov; BlockAcctCookie acct; @@ -239,7 +241,7 @@ static void scsi_write_do_fua(SCSIDiskReq *r) goto done; } - if (scsi_is_cmd_fua(&r->req.cmd)) { + if (r->need_fua_emulation) { block_acct_start(blk_get_stats(s->qdev.conf.blk), &r->acct, 0, BLOCK_ACCT_FLUSH); r->req.aiocb = blk_aio_flush(s->qdev.conf.blk, scsi_aio_complete, r); @@ -416,7 +418,7 @@ static void scsi_read_data(SCSIRequest *req) first = !r->started; r->started = true; - if (first && scsi_is_cmd_fua(&r->req.cmd)) { + if (first && r->need_fua_emulation) { block_acct_start(blk_get_stats(s->qdev.conf.blk), &r->acct, 0, BLOCK_ACCT_FLUSH); r->req.aiocb = blk_aio_flush(s->qdev.conf.blk, scsi_do_read_cb, r); @@ -2157,6 +2159,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf) { SCSIDiskReq *r = DO_UPCAST(SCSIDiskReq, req, req); SCSIDiskState *s = DO_UPCAST(SCSIDiskState, qdev, req->dev); + SCSIDiskClass *sdc = (SCSIDiskClass *) object_get_class(OBJECT(s)); uint32_t len; uint8_t command; @@ -2215,6 +2218,7 @@ static int32_t scsi_disk_dma_command(SCSIRequest *req, uint8_t *buf) scsi_check_condition(r, SENSE_CODE(LBA_OUT_OF_RANGE)); return 0; } + r->need_fua_emulation = sdc->need_fua_emulation(&r->req.cmd); if (r->sector_count == 0) { scsi_req_complete(&r->req, GOOD); } @@ -2704,6 +2708,7 @@ static void scsi_disk_base_class_initfn(ObjectClass *klass, void *data) dc->reset = scsi_disk_reset; sdc->dma_readv = scsi_dma_readv; sdc->dma_writev = scsi_dma_writev; + sdc->need_fua_emulation = scsi_is_cmd_fua; } static const TypeInfo scsi_disk_base_info = {
scsi-block will be able to do FUA just by passing the request through to the LUN (which is also more efficient); there is no need to emulate it like we do for scsi-disk. Add a new method to distinguish this. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- hw/scsi/scsi-disk.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)