| Message ID | 20210316193905.1673600-1-jollys@google.com |
|---|---|
| State | New |
| Headers | show |
| Series | scsi: libsas: Reset num_scatter if libata mark qc as NODATA | expand |
在 2021/3/17 3:39, Jolly Shah 写道: > When the cache_type for the scsi device is changed, the scsi layer > issues a MODE_SELECT command. The caching mode details are communicated > via a request buffer associated with the scsi command with data > direction set as DMA_TO_DEVICE (scsi_mode_select). When this command > reaches the libata layer, as a part of generic initial setup, libata > layer sets up the scatterlist for the command using the scsi command > (ata_scsi_qc_new). This command is then translated by the libata layer > into ATA_CMD_SET_FEATURES (ata_scsi_mode_select_xlat). The libata layer > treats this as a non data command (ata_mselect_caching), since it only > needs an ata taskfile to pass the caching on/off information to the > device. It does not need the scatterlist that has been setup, so it does > not perform dma_map_sg on the scatterlist (ata_qc_issue). Unfortunately, > when this command reaches the libsas layer(sas_ata_qc_issue), libsas > layer sees it as a non data command with a scatterlist. It cannot > extract the correct dma length, since the scatterlist has not been > mapped with dma_map_sg for a DMA operation. When this partially > constructed SAS task reaches pm80xx LLDD, it results in below warning. > > "pm80xx_chip_sata_req 6058: The sg list address > start_addr=0x0000000000000000 data_len=0x0end_addr_high=0xffffffff > end_addr_low=0xffffffff has crossed 4G boundary" > > This patch assigns appropriate value to num_sectors for ata non data > commands. > > Signed-off-by: Jolly Shah <jollys@google.com> > --- > drivers/scsi/libsas/sas_ata.c | 6 ++++-- > 1 file changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c > index 024e5a550759..94ec08cebbaa 100644 > --- a/drivers/scsi/libsas/sas_ata.c > +++ b/drivers/scsi/libsas/sas_ata.c > @@ -209,10 +209,12 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) > task->num_scatter = si; > } > > - if (qc->tf.protocol == ATA_PROT_NODATA) > + if (qc->tf.protocol == ATA_PROT_NODATA) { > task->data_dir = DMA_NONE; > - else > + task->num_scatter = 0; > + } else { > task->data_dir = qc->dma_dir; > + } > task->scatter = qc->sg; > task->ata_task.retry_count = 1; > task->task_state_flags = SAS_TASK_STATE_PENDING; > Thanks for the patch. Except the warning, any functional errors? The code looks good to me, Reviewed-by: Jason Yan <yanaijie@huawei.com>
Hi Jason, Thanks for the review. On Tue, Mar 16, 2021 at 6:50 PM Jason Yan <yanaijie@huawei.com> wrote: > > > 在 2021/3/17 3:39, Jolly Shah 写道: > > When the cache_type for the scsi device is changed, the scsi layer > > issues a MODE_SELECT command. The caching mode details are communicated > > via a request buffer associated with the scsi command with data > > direction set as DMA_TO_DEVICE (scsi_mode_select). When this command > > reaches the libata layer, as a part of generic initial setup, libata > > layer sets up the scatterlist for the command using the scsi command > > (ata_scsi_qc_new). This command is then translated by the libata layer > > into ATA_CMD_SET_FEATURES (ata_scsi_mode_select_xlat). The libata layer > > treats this as a non data command (ata_mselect_caching), since it only > > needs an ata taskfile to pass the caching on/off information to the > > device. It does not need the scatterlist that has been setup, so it does > > not perform dma_map_sg on the scatterlist (ata_qc_issue). Unfortunately, > > when this command reaches the libsas layer(sas_ata_qc_issue), libsas > > layer sees it as a non data command with a scatterlist. It cannot > > extract the correct dma length, since the scatterlist has not been > > mapped with dma_map_sg for a DMA operation. When this partially > > constructed SAS task reaches pm80xx LLDD, it results in below warning. > > > > "pm80xx_chip_sata_req 6058: The sg list address > > start_addr=0x0000000000000000 data_len=0x0end_addr_high=0xffffffff > > end_addr_low=0xffffffff has crossed 4G boundary" > > > > This patch assigns appropriate value to num_sectors for ata non data > > commands. > > > > Signed-off-by: Jolly Shah <jollys@google.com> > > --- > > drivers/scsi/libsas/sas_ata.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c > > index 024e5a550759..94ec08cebbaa 100644 > > --- a/drivers/scsi/libsas/sas_ata.c > > +++ b/drivers/scsi/libsas/sas_ata.c > > @@ -209,10 +209,12 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) > > task->num_scatter = si; > > } > > > > - if (qc->tf.protocol == ATA_PROT_NODATA) > > + if (qc->tf.protocol == ATA_PROT_NODATA) { > > task->data_dir = DMA_NONE; > > - else > > + task->num_scatter = 0; > > + } else { > > task->data_dir = qc->dma_dir; > > + } > > task->scatter = qc->sg; > > task->ata_task.retry_count = 1; > > task->task_state_flags = SAS_TASK_STATE_PENDING; > > > > Thanks for the patch. Except the warning, any functional errors? > No functional errors observed. Thanks, Jolly Shah > The code looks good to me, > > Reviewed-by: Jason Yan <yanaijie@huawei.com>
Hi John, Thanks for the review. On Wed, Mar 17, 2021 at 4:44 AM John Garry <john.garry@huawei.com> wrote: > > On 16/03/2021 19:39, Jolly Shah wrote: > > When the cache_type for the scsi device is changed, the scsi layer > > issues a MODE_SELECT command. The caching mode details are communicated > > via a request buffer associated with the scsi command with data > > direction set as DMA_TO_DEVICE (scsi_mode_select). When this command > > reaches the libata layer, as a part of generic initial setup, libata > > layer sets up the scatterlist for the command using the scsi command > > (ata_scsi_qc_new). This command is then translated by the libata layer > > into ATA_CMD_SET_FEATURES (ata_scsi_mode_select_xlat). The libata layer > > treats this as a non data command (ata_mselect_caching), since it only > > needs an ata taskfile to pass the caching on/off information to the > > device. It does not need the scatterlist that has been setup, so it does > > not perform dma_map_sg on the scatterlist (ata_qc_issue). > > So if we don't perform the dma_map_sg() on the sgl at this point, then > it seems to me that we should not perform for_each_sg() on it either, > right? That is still what happens in sas_ata_qc_issue() in this case. > Yes that's right. To avoid that, I can add elseif block for ATA_PROT_NODATA before for_each_sg() is performed. Currently there's existing code block for ATA_PROT_NODATA after for_each_sg() is performed, reused that to reset num_scatter. Please suggest. > > Unfortunately, > > when this command reaches the libsas layer(sas_ata_qc_issue), libsas > > layer sees it as a non data command with a scatterlist. It cannot > > extract the correct dma length, since the scatterlist has not been > > mapped with dma_map_sg for a DMA operation. When this partially > > constructed SAS task reaches pm80xx LLDD, it results in below warning. > > > > "pm80xx_chip_sata_req 6058: The sg list address > > start_addr=0x0000000000000000 data_len=0x0end_addr_high=0xffffffff > > end_addr_low=0xffffffff has crossed 4G boundary" > > > > This patch assigns appropriate value to num_sectors for ata non data > > commands. > > > > Signed-off-by: Jolly Shah <jollys@google.com> > > --- > > drivers/scsi/libsas/sas_ata.c | 6 ++++-- > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c > > index 024e5a550759..94ec08cebbaa 100644 > > --- a/drivers/scsi/libsas/sas_ata.c > > +++ b/drivers/scsi/libsas/sas_ata.c > > @@ -209,10 +209,12 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) > > task->num_scatter = si; > > } > > > > - if (qc->tf.protocol == ATA_PROT_NODATA) > > + if (qc->tf.protocol == ATA_PROT_NODATA) { > > task->data_dir = DMA_NONE; > > - else > > + task->num_scatter = 0; > > task->num_scatter has already been set in this function. Best not set it > twice. > Sure. Please suggest if I should update patch to above suggested approach. That will avoid setting num_scatter twice. Thanks, Jolly Shah > Thanks, > John > > > + } else { > > task->data_dir = qc->dma_dir; > > + } > > task->scatter = qc->sg; > > task->ata_task.retry_count = 1; > > task->task_state_flags = SAS_TASK_STATE_PENDING; > > >
On 18/03/2021 00:24, Jolly Shah wrote: > Hi John, > > Thanks for the review. > > > On Wed, Mar 17, 2021 at 4:44 AM John Garry <john.garry@huawei.com> wrote: >> >> On 16/03/2021 19:39, Jolly Shah wrote: >>> When the cache_type for the scsi device is changed, the scsi layer >>> issues a MODE_SELECT command. The caching mode details are communicated >>> via a request buffer associated with the scsi command with data >>> direction set as DMA_TO_DEVICE (scsi_mode_select). When this command >>> reaches the libata layer, as a part of generic initial setup, libata >>> layer sets up the scatterlist for the command using the scsi command >>> (ata_scsi_qc_new). This command is then translated by the libata layer >>> into ATA_CMD_SET_FEATURES (ata_scsi_mode_select_xlat). The libata layer >>> treats this as a non data command (ata_mselect_caching), since it only >>> needs an ata taskfile to pass the caching on/off information to the >>> device. It does not need the scatterlist that has been setup, so it does >>> not perform dma_map_sg on the scatterlist (ata_qc_issue). >> >> So if we don't perform the dma_map_sg() on the sgl at this point, then >> it seems to me that we should not perform for_each_sg() on it either, >> right? That is still what happens in sas_ata_qc_issue() in this case. >> Hi Jolly Shah, > > Yes that's right. To avoid that, I can add elseif block for > ATA_PROT_NODATA before for_each_sg() is performed. Currently there's > existing code block for ATA_PROT_NODATA after for_each_sg() is > performed, > reused that to reset num_scatter. Please suggest. > How about just combine the 2x if-else statements into 1x if-elif-else statement, like: if (ata_is_atapi(qc->tf.protocol)) { memcpy(task->ata_task.atapi_packet, qc->cdb, qc->dev->cdb_len); task->total_xfer_len = qc->nbytes; task->num_scatter = qc->n_elem; task->data_dir = qc->dma_dir; } else if (qc->tf.protocol == ATA_PROT_NODATA) { task->data_dir = DMA_NONE; } else { for_each_sg(qc->sg, sg, qc->n_elem, si) xfer += sg_dma_len(sg); task->total_xfer_len = xfer; task->num_scatter = si; task->data_dir = qc->dma_dir; } >>> Unfortunately, >>> when this command reaches the libsas layer(sas_ata_qc_issue), libsas >>> layer sees it as a non data command with a scatterlist. It cannot >>> extract the correct dma length, since the scatterlist has not been >>> mapped with dma_map_sg for a DMA operation. When this partially >>> constructed SAS task reaches pm80xx LLDD, it results in below warning. >>> >>> "pm80xx_chip_sata_req 6058: The sg list address >>> start_addr=0x0000000000000000 data_len=0x0end_addr_high=0xffffffff >>> end_addr_low=0xffffffff has crossed 4G boundary" >>> >>> This patch assigns appropriate value to num_sectors for ata non data >>> commands. >>> >>> Signed-off-by: Jolly Shah <jollys@google.com> >>> --- >>> drivers/scsi/libsas/sas_ata.c | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c >>> index 024e5a550759..94ec08cebbaa 100644 >>> --- a/drivers/scsi/libsas/sas_ata.c >>> +++ b/drivers/scsi/libsas/sas_ata.c >>> @@ -209,10 +209,12 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) >>> task->num_scatter = si; >>> } >>> >>> - if (qc->tf.protocol == ATA_PROT_NODATA) >>> + if (qc->tf.protocol == ATA_PROT_NODATA) { >>> task->data_dir = DMA_NONE; >>> - else >>> + task->num_scatter = 0; >> >> task->num_scatter has already been set in this function. Best not set it >> twice. >> > > Sure. Please suggest if I should update patch to above suggested > approach. That will avoid setting num_scatter twice. > Thanks, John BTW, could we add a fixes tag?
Hi John, On Thu, Mar 18, 2021 at 9:19 AM John Garry <john.garry@huawei.com> wrote: > > On 18/03/2021 00:24, Jolly Shah wrote: > > Hi John, > > > > Thanks for the review. > > > > > > On Wed, Mar 17, 2021 at 4:44 AM John Garry <john.garry@huawei.com> wrote: > >> > >> On 16/03/2021 19:39, Jolly Shah wrote: > >>> When the cache_type for the scsi device is changed, the scsi layer > >>> issues a MODE_SELECT command. The caching mode details are communicated > >>> via a request buffer associated with the scsi command with data > >>> direction set as DMA_TO_DEVICE (scsi_mode_select). When this command > >>> reaches the libata layer, as a part of generic initial setup, libata > >>> layer sets up the scatterlist for the command using the scsi command > >>> (ata_scsi_qc_new). This command is then translated by the libata layer > >>> into ATA_CMD_SET_FEATURES (ata_scsi_mode_select_xlat). The libata layer > >>> treats this as a non data command (ata_mselect_caching), since it only > >>> needs an ata taskfile to pass the caching on/off information to the > >>> device. It does not need the scatterlist that has been setup, so it does > >>> not perform dma_map_sg on the scatterlist (ata_qc_issue). > >> > >> So if we don't perform the dma_map_sg() on the sgl at this point, then > >> it seems to me that we should not perform for_each_sg() on it either, > >> right? That is still what happens in sas_ata_qc_issue() in this case. > >> > > Hi Jolly Shah, > > > > > Yes that's right. To avoid that, I can add elseif block for > > ATA_PROT_NODATA before for_each_sg() is performed. Currently there's > > existing code block for ATA_PROT_NODATA after for_each_sg() is > > performed, > > reused that to reset num_scatter. Please suggest. > > > > How about just combine the 2x if-else statements into 1x if-elif-else > statement, like: > > > if (ata_is_atapi(qc->tf.protocol)) { > memcpy(task->ata_task.atapi_packet, qc->cdb, qc->dev->cdb_len); > task->total_xfer_len = qc->nbytes; > task->num_scatter = qc->n_elem; > task->data_dir = qc->dma_dir; > } else if (qc->tf.protocol == ATA_PROT_NODATA) { > task->data_dir = DMA_NONE; > } else { > for_each_sg(qc->sg, sg, qc->n_elem, si) > xfer += sg_dma_len(sg); > > task->total_xfer_len = xfer; > task->num_scatter = si; > task->data_dir = qc->dma_dir; > } > Updated in v2. > >>> Unfortunately, > >>> when this command reaches the libsas layer(sas_ata_qc_issue), libsas > >>> layer sees it as a non data command with a scatterlist. It cannot > >>> extract the correct dma length, since the scatterlist has not been > >>> mapped with dma_map_sg for a DMA operation. When this partially > >>> constructed SAS task reaches pm80xx LLDD, it results in below warning. > >>> > >>> "pm80xx_chip_sata_req 6058: The sg list address > >>> start_addr=0x0000000000000000 data_len=0x0end_addr_high=0xffffffff > >>> end_addr_low=0xffffffff has crossed 4G boundary" > >>> > >>> This patch assigns appropriate value to num_sectors for ata non data > >>> commands. > >>> > >>> Signed-off-by: Jolly Shah <jollys@google.com> > >>> --- > >>> drivers/scsi/libsas/sas_ata.c | 6 ++++-- > >>> 1 file changed, 4 insertions(+), 2 deletions(-) > >>> > >>> diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c > >>> index 024e5a550759..94ec08cebbaa 100644 > >>> --- a/drivers/scsi/libsas/sas_ata.c > >>> +++ b/drivers/scsi/libsas/sas_ata.c > >>> @@ -209,10 +209,12 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) > >>> task->num_scatter = si; > >>> } > >>> > >>> - if (qc->tf.protocol == ATA_PROT_NODATA) > >>> + if (qc->tf.protocol == ATA_PROT_NODATA) { > >>> task->data_dir = DMA_NONE; > >>> - else > >>> + task->num_scatter = 0; > >> > >> task->num_scatter has already been set in this function. Best not set it > >> twice. > >> > > > > Sure. Please suggest if I should update patch to above suggested > > approach. That will avoid setting num_scatter twice. > > > > Thanks, > John > > BTW, could we add a fixes tag? Added in v2. Thanks, Jolly
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c index 024e5a550759..94ec08cebbaa 100644 --- a/drivers/scsi/libsas/sas_ata.c +++ b/drivers/scsi/libsas/sas_ata.c @@ -209,10 +209,12 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) task->num_scatter = si; } - if (qc->tf.protocol == ATA_PROT_NODATA) + if (qc->tf.protocol == ATA_PROT_NODATA) { task->data_dir = DMA_NONE; - else + task->num_scatter = 0; + } else { task->data_dir = qc->dma_dir; + } task->scatter = qc->sg; task->ata_task.retry_count = 1; task->task_state_flags = SAS_TASK_STATE_PENDING;
When the cache_type for the scsi device is changed, the scsi layer issues a MODE_SELECT command. The caching mode details are communicated via a request buffer associated with the scsi command with data direction set as DMA_TO_DEVICE (scsi_mode_select). When this command reaches the libata layer, as a part of generic initial setup, libata layer sets up the scatterlist for the command using the scsi command (ata_scsi_qc_new). This command is then translated by the libata layer into ATA_CMD_SET_FEATURES (ata_scsi_mode_select_xlat). The libata layer treats this as a non data command (ata_mselect_caching), since it only needs an ata taskfile to pass the caching on/off information to the device. It does not need the scatterlist that has been setup, so it does not perform dma_map_sg on the scatterlist (ata_qc_issue). Unfortunately, when this command reaches the libsas layer(sas_ata_qc_issue), libsas layer sees it as a non data command with a scatterlist. It cannot extract the correct dma length, since the scatterlist has not been mapped with dma_map_sg for a DMA operation. When this partially constructed SAS task reaches pm80xx LLDD, it results in below warning. "pm80xx_chip_sata_req 6058: The sg list address start_addr=0x0000000000000000 data_len=0x0end_addr_high=0xffffffff end_addr_low=0xffffffff has crossed 4G boundary" This patch assigns appropriate value to num_sectors for ata non data commands. Signed-off-by: Jolly Shah <jollys@google.com> --- drivers/scsi/libsas/sas_ata.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)