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SubjectRE: [RFC/RFT PATCH] scsi: pm8001: Expose HW queues for pm80xx hw
Date
Hi John,

AFAIK, there is no such restrictions. Any queue can be used for internal/external commands.

Regards,
Viswas G

> -----Original Message-----
> From: John Garry <john.garry@huawei.com>
> Sent: Monday, February 1, 2021 4:53 PM
> To: Viswas G - I30667 <Viswas.G@microchip.com>; jejb@linux.ibm.com;
> martin.petersen@oracle.com; akshatzen@google.com; Ruksar Devadi -
> I52327 <Ruksar.devadi@microchip.com>; radha@google.com;
> bjashnani@google.com; vishakhavc@google.com;
> jinpu.wang@cloud.ionos.com; Ashokkumar N - X53535
> <Ashokkumar.N@microchip.com>
> Cc: linux-scsi@vger.kernel.org; linux-kernel@vger.kernel.org; hare@suse.de;
> kashyap.desai@broadcom.com; ming.lei@redhat.com
> Subject: Re: [RFC/RFT PATCH] scsi: pm8001: Expose HW queues for pm80xx
> hw
>
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the
> content is safe
>
> On 31/01/2021 07:19, Viswas.G@microchip.com wrote:
> > Thanks Johns.
> >
> > We could see a kernel crash while testing this patch.
>
> Thanks for testing.
>
> >
> > [ 246.724632] scsi host10: pm80xx
> > [ 248.005258] sas: Enter sas_scsi_recover_host busy: 0 failed: 0 [
> > 248.168973] BUG: kernel NULL pointer dereference, address:
> > 0000000000000110 [ 248.175926] #PF: supervisor read access in kernel
> > mode [ 248.181065] #PF: error_code(0x0000) - not-present page [
> > 248.186196] PGD 0 P4D 0 [ 248.188736] Oops: 0000 [#1] SMP PTI
> > [ 248.192230] CPU: 10 PID: 77 Comm: kworker/u26:2 Kdump: loaded
> Tainted: G S OE 5.11.0-rc3 #2
> > [ 248.201614] Hardware name: Supermicro Super Server/X10DRi-LN4+,
> > BIOS 3.1 06/08/2018 [ 248.209258] Workqueue: events_unbound
> > async_run_entry_fn [ 248.214571] RIP:
> > 0010:pm80xx_chip_sata_req+0x7f/0x5e0 [pm80xx] [ 248.220413] Code: c1
> > 7c c1 e9 03 4d 8b ac 24 80 01 00 00 48 c7 44 24 14 00 00 00 00 89 04
> > 24 31 c0 48 c7 84 24 88 00 00 00 00 00 00 00 f3 48 ab <48> 8b ba 10 01
> > 00 00 e8 35 35 c6 ef c1 e8 10 89 44 24 04 0f b6 43 [ 248.239157] RSP:
> > 0018:ffffb98d834979f0 EFLAGS: 00010046 [ 248.244384] RAX:
> > 0000000000000000 RBX: ffff9523c321c000 RCX: 0000000000000000 [
> > 248.251516] RDX: 0000000000000000 RSI: ffff952450720048 RDI:
> > ffffb98d83497a80 [ 248.258641] RBP: ffff9523c7420000 R08:
> > 0000000000000100 R09: 0000000000000001 [ 248.265764] R10:
> > 0000000000000001 R11: ffff9523c9e40000 R12: ffff9523ca1c3600 [
> > 248.272887] R13: ffff9523c9e40000 R14: ffffb98d83497a04 R15:
> ffff952450720048 [ 248.280013] FS: 0000000000000000(0000)
> GS:ffff9527afd00000(0000) knlGS:0000000000000000 [ 248.288090] CS: 0010
> DS: 0000 ES: 0000 CR0: 0000000080050033 [ 248.293826] CR2:
> 0000000000000110 CR3: 000000029ac10001 CR4: 00000000001706e0 [
> 248.300952] Call Trace:
>
> I think that the problem here is that ata_queued_cmd->scmd is NULL for the
> ata internal command.
>
> Please try this fix:
>
> ---->8-----
>
> @@ -4451,7 +4451,7 @@ static int pm80xx_chip_sata_req(struct
> pm8001_hba_info *pm8001_ha,
> struct scsi_cmnd *scmd = qc->scsicmd;
> u32 tag = ccb->ccb_tag;
> int ret;
> - u32 q_index, blk_tag;
> + u32 q_index = 0, blk_tag;
> struct sata_start_req sata_cmd;
> u32 hdr_tag, ncg_tag = 0;
> u64 phys_addr, start_addr, end_addr; @@ -4463,8 +4463,10 @@ static
> int pm80xx_chip_sata_req(struct pm8001_hba_info *pm8001_ha,
> u32 opc = OPC_INB_SATA_HOST_OPSTART;
> memset(&sata_cmd, 0, sizeof(sata_cmd));
>
> - blk_tag = blk_mq_unique_tag(scmd->request);
> - q_index = blk_mq_unique_tag_to_hwq(blk_tag);
> + if (scmd) {
> + blk_tag = blk_mq_unique_tag(scmd->request);
> + q_index = blk_mq_unique_tag_to_hwq(blk_tag);
> + }
> circularQ = &pm8001_ha->inbnd_q_tbl[q_index];
>
> ----8<-----
>
> You may need similar for other dispatch paths also - like smp - but I don't
> think that you will.
>
> BTW, do you know if there is actually a limitation on the HW that queue
> #0 is used for all "internal" IO (mpi), like phy control operation? Jack?
>
> Thanks,
> John
>
>
> > [ 248.303402] pm8001_task_exec.isra.9+0x2a4/0x460 [pm80xx] [
> > 248.308805] sas_ata_qc_issue+0x187/0x220 [libsas] [ 248.313607]
> > ata_qc_issue+0x107/0x1e0 [libata] [ 248.318069]
> > ata_exec_internal_sg+0x2c8/0x580 [libata] [ 248.323217]
> > ata_exec_internal+0x5f/0x90 [libata] [ 248.327931]
> > ata_dev_read_id+0x306/0x480 [libata] [ 248.332647]
> > ata_eh_recover+0x7ea/0x12a0 [libata] [ 248.337369] ?
> > vprintk_emit+0x114/0x220 [ 248.341208] ? sas_ata_sched_eh+0x60/0x60
> > [libsas] [ 248.346002] ? sas_ata_prereset+0x50/0x50 [libsas] [
> > 248.350795] ? printk+0x58/0x6f [ 248.353941] ?
> > sas_ata_sched_eh+0x60/0x60 [libsas] [ 248.358733] ?
> > sas_ata_prereset+0x50/0x50 [libsas] [ 248.363525]
> > ata_do_eh+0x40/0xb0 [libata] [ 248.367556]
> > ata_scsi_port_error_handler+0x354/0x770 [libata] [ 248.373318]
> > async_sas_ata_eh+0x44/0x7b [libsas] [ 248.377938]
> > async_run_entry_fn+0x39/0x160 [ 248.382040]
> > process_one_work+0x1cb/0x360 [ 248.386050]
> worker_thread+0x30/0x370
> > [ 248.389706] ? processe_work+0x360/0x360 [ 248.393884]
> > kthread+0x116/0x130 [ 248.397116] ? kthread_park+0x80/0x80 [
> > 248.400773] ret_from_fork+0x22/0x30 [ 248.404355] Modules linked in:
> > pm80xx(OE) libsas scsi_transport_sas xt_CHECKSUM xt_MASQUERADE
> > xt_conntrack ipt_REJECT nf_reject_ipv4 nft_compat nft_counter
> nft_chain_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 nf_tables
> nfnetlink tun bridge stp llc rfkill sunrpc vfat fat intel_rapl_msr
> intel_rapl_common sb_edac x86_pkg_temp_thermal intel_powerclamp
> coretemp kvm_intel kvm irqbypass joydev crct10dif_pclmul crc32_pclmul
> ghash_clmulni_intel ipmi_ssif iTCO_wdt iTCO_vendor_support mei_me rapl
> i2c_i801 intel_cstate mei acpi_ipmi lpc_ich intel_uncore pcspkr ipmi_si
> i2c_smbus ipmi_devintf ipmi_msghandler acpi_power_meter acpi_pad
> ioatdma ip_tables xfs libcrc32c sr_mod sd_mod cdrom t10_pi sg ast
> drm_vram_helper drm_kms_helper syscopyarea igb sysfillrect sysimgblt
> fb_sys_fops drm_ttm_helper ttm ahci libahci dca drm crc32c_intel libata
> i2c_algo_bit wmi dm_mirror dm_region_hash dm_log dm_mod fuse [
> 248.483431] CR2: 0000000000000110
> > [ 0.000000] Linux version 5.11.0-rc3 (root@localhost.localdomain) (gcc
> (GCC) 8.3.1 20191121 (Red Hat 8.3.1-5), GNU ld version 2.30-79.el8) #2 SMP
> Mon Jan 25 23:56:12 IST 2021
> > [ 0.000000] Command line: elfcorehr=0x45000000
> BOOT_IMAGE=(hd14,gpt2)/vmlinuz-5.11.0-rc3 ro
> resume=/dev/mapper/rhel-swap rhgb console=ttyS1,115200 loglevel=7
> irqpoll nr_cpus=1 reset_devices cgroup_disable=memory mce=off numa=off
> udev.children-max=2 panic=10 rootflags=nofail acpi_no_memhotplug
> transparent_hugepage=never nokaslr novmcoredd hest_disable
> disable_cpu_apicid=0
> >
> >
> >> -----Original Message-----
> >> From: John Garry <john.garry@huawei.com>
> >> Sent: Tuesday, January 5, 2021 4:47 PM
> >> To: jejb@linux.ibm.com; martin.petersen@oracle.com;
> >> akshatzen@google.com; Viswas G - I30667 <Viswas.G@microchip.com>;
> >> Ruksar Devadi - I52327 <Ruksar.devadi@microchip.com>;
> >> radha@google.com; bjashnani@google.com; vishakhavc@google.com;
> >> jinpu.wang@cloud.ionos.com; Ashokkumar N - X53535
> >> <Ashokkumar.N@microchip.com>
> >> Cc: linux-scsi@vger.kernel.org; linux-kernel@vger.kernel.org;
> >> hare@suse.de; kashyap.desai@broadcom.com; ming.lei@redhat.com;
> John
> >> Garry <john.garry@huawei.com>
> >> Subject: [RFC/RFT PATCH] scsi: pm8001: Expose HW queues for pm80xx
> hw
> >>
> >> EXTERNAL EMAIL: Do not click links or open attachments unless you
> >> know the content is safe
> >>
> >> In commit 05c6c029a44d ("scsi: pm80xx: Increase number of supported
> >> queues"), support for 80xx chip was improved by enabling multiple HW
> >> queues.
> >>
> >> In this, like other SCSI MQ HBA drivers, the HW queues were not
> >> exposed to upper layer, and instead the driver managed the queues
> internally.
> >>
> >> However, this management duplicates blk-mq code. In addition, the HW
> >> queue management is sub-optimal for a system where the number of
> CPUs
> >> exceeds the HW queues - this is because queues are selected in a
> >> round- robin fashion, when it would be better to make adjacent CPUs
> >> submit on the same queue. And finally, the affinity of the completion
> >> queue interrupts is not set to mirror the cpu<->HQ queue mapping, which
> is suboptimal.
> >>
> >> As such, for when MSIX is supported, expose HW queues to upper layer.
> >> Flag PCI_IRQ_AFFINITY is set for allocating the MSIX vectors to
> >> automatically assign affinity for the completion queue interrupts.
> >>
> >> Signed-off-by: John Garry <john.garry@huawei.com>
> >>
> >> ---
> >> I sent as an RFC/RFT as I have no HW to test. In addition, since HW
> >> queue
> >> #0 is used always for internal commands (like in send_task_abort()),
> >> if all CPUs associated with HW queue #0 are offlined, the interrupt
> >> for that queue will be shutdown, and no CPUs would be available to
> >> service any internal commands completion. To solve that, we need [0]
> >> merged first and switch over to use the new API. But we can still test
> performance in the meantime.
> >>
> >> I assume someone else is making the change to use the request tag for
> >> IO tag management.
> >>
> >> [0] https://lore.kernel.org/linux-scsi/47ba045e-a490-198b-1744-
> >> 529f97192d3b@suse.de/
> >>
> >> diff --git a/drivers/scsi/pm8001/pm8001_init.c
> >> b/drivers/scsi/pm8001/pm8001_init.c
> >> index ee2de177d0d0..73479803a23e 100644
> >> --- a/drivers/scsi/pm8001/pm8001_init.c
> >> +++ b/drivers/scsi/pm8001/pm8001_init.c
> >> @@ -81,6 +81,15 @@ LIST_HEAD(hba_list);
> >>
> >> struct workqueue_struct *pm8001_wq;
> >>
> >> +static int pm8001_map_queues(struct Scsi_Host *shost) {
> >> + struct sas_ha_struct *sha = SHOST_TO_SAS_HA(shost);
> >> + struct pm8001_hba_info *pm8001_ha = sha->lldd_ha;
> >> + struct blk_mq_queue_map *qmap =
> >> +&shost->tag_set.map[HCTX_TYPE_DEFAULT];
> >> +
> >> + return blk_mq_pci_map_queues(qmap, pm8001_ha->pdev, 0); }
> >> +
> >> /*
> >> * The main structure which LLDD must register for scsi core.
> >> */
> >> @@ -106,6 +115,7 @@ static struct scsi_host_template pm8001_sht = {
> >> #ifdef CONFIG_COMPAT
> >> .compat_ioctl = sas_ioctl,
> >> #endif
> >> + .map_queues = pm8001_map_queues,
> >> .shost_attrs = pm8001_host_attrs,
> >> .track_queue_depth = 1,
> >> };
> >> @@ -923,9 +933,8 @@ static int pm8001_configure_phy_settings(struct
> >> pm8001_hba_info *pm8001_ha) static u32 pm8001_setup_msix(struct
> >> pm8001_hba_info *pm8001_ha) {
> >> u32 number_of_intr;
> >> - int rc, cpu_online_count;
> >> + int rc;
> >> unsigned int allocated_irq_vectors;
> >> -
> >> /* SPCv controllers supports 64 msi-x */
> >> if (pm8001_ha->chip_id == chip_8001) {
> >> number_of_intr = 1;
> >> @@ -933,16 +942,15 @@ static u32 pm8001_setup_msix(struct
> >> pm8001_hba_info *pm8001_ha)
> >> number_of_intr = PM8001_MAX_MSIX_VEC;
> >> }
> >>
> >> - cpu_online_count = num_online_cpus();
> >> - number_of_intr = min_t(int, cpu_online_count, number_of_intr);
> >> - rc = pci_alloc_irq_vectors(pm8001_ha->pdev, number_of_intr,
> >> - number_of_intr, PCI_IRQ_MSIX);
> >> + /* Use default affinity descriptor, which spreads *all* vectors */
> >> + rc = pci_alloc_irq_vectors(pm8001_ha->pdev, 1,
> >> + number_of_intr, PCI_IRQ_MSIX |
> >> + PCI_IRQ_AFFINITY);
> >> allocated_irq_vectors = rc;
> >> if (rc < 0)
> >> return rc;
> >>
> >> /* Assigns the number of interrupts */
> >> - number_of_intr = min_t(int, allocated_irq_vectors, number_of_intr);
> >> + number_of_intr = allocated_irq_vectors;
> >> pm8001_ha->number_of_intr = number_of_intr;
> >>
> >> /* Maximum queue number updating in HBA structure */ @@
> >> -1113,6
> >> +1121,16 @@ static int pm8001_pci_probe(struct pci_dev *pdev,
> >> if (rc)
> >> goto err_out_enable;
> >>
> >> + if (pm8001_ha->number_of_intr > 1) {
> >> + shost->nr_hw_queues = pm8001_ha->number_of_intr;
> >> + /*
> >> + * For now, ensure we're not sent too many commands by
> setting
> >> + * host_tagset. This is also required if we start using request
> >> + * tag.
> >> + */
> >> + shost->host_tagset = 1;
> >> + }
> >> +
> >> rc = scsi_add_host(shost, &pdev->dev);
> >> if (rc)
> >> goto err_out_ha_free; diff --git
> >> a/drivers/scsi/pm8001/pm8001_sas.h
> >> b/drivers/scsi/pm8001/pm8001_sas.h
> >> index f2c8cbad3853..74bc6fed693e 100644
> >> --- a/drivers/scsi/pm8001/pm8001_sas.h
> >> +++ b/drivers/scsi/pm8001/pm8001_sas.h
> >> @@ -55,6 +55,8 @@
> >> #include <scsi/scsi_tcq.h>
> >> #include <scsi/sas_ata.h>
> >> #include <linux/atomic.h>
> >> +#include <linux/blk-mq.h>
> >> +#include <linux/blk-mq-pci.h>
> >> #include "pm8001_defs.h"
> >>
> >> #define DRV_NAME "pm80xx"
> >> diff --git a/drivers/scsi/pm8001/pm80xx_hwi.c
> >> b/drivers/scsi/pm8001/pm80xx_hwi.c
> >> index 6772b0924dac..31d65ce91e7d 100644
> >> --- a/drivers/scsi/pm8001/pm80xx_hwi.c
> >> +++ b/drivers/scsi/pm8001/pm80xx_hwi.c
> >> @@ -4299,12 +4299,13 @@ static int pm80xx_chip_ssp_io_req(struct
> >> pm8001_hba_info *pm8001_ha,
> >> struct domain_device *dev = task->dev;
> >> struct pm8001_device *pm8001_dev = dev->lldd_dev;
> >> struct ssp_ini_io_start_req ssp_cmd;
> >> + struct scsi_cmnd *scmd = task->uldd_task;
> >> u32 tag = ccb->ccb_tag;
> >> int ret;
> >> u64 phys_addr, start_addr, end_addr;
> >> u32 end_addr_high, end_addr_low;
> >> struct inbound_queue_table *circularQ;
> >> - u32 q_index, cpu_id;
> >> + u32 blk_tag, q_index;
> >> u32 opc = OPC_INB_SSPINIIOSTART;
> >> memset(&ssp_cmd, 0, sizeof(ssp_cmd));
> >> memcpy(ssp_cmd.ssp_iu.lun, task->ssp_task.LUN, 8); @@
> >> -4323,8
> >> +4324,8 @@ static int pm80xx_chip_ssp_io_req(struct pm8001_hba_info
> >> *pm8001_ha,
> >> ssp_cmd.ssp_iu.efb_prio_attr |= (task->ssp_task.task_attr & 7);
> >> memcpy(ssp_cmd.ssp_iu.cdb, task->ssp_task.cmd->cmnd,
> >> task->ssp_task.cmd->cmd_len);
> >> - cpu_id = smp_processor_id();
> >> - q_index = (u32) (cpu_id) % (pm8001_ha->max_q_num);
> >> + blk_tag = blk_mq_unique_tag(scmd->request);
> >> + q_index = blk_mq_unique_tag_to_hwq(blk_tag);
> >> circularQ = &pm8001_ha->inbnd_q_tbl[q_index];
> >>
> >> /* Check if encryption is set */ @@ -4446,9 +4447,11 @@
> >> static int pm80xx_chip_sata_req(struct pm8001_hba_info *pm8001_ha,
> >> struct sas_task *task = ccb->task;
> >> struct domain_device *dev = task->dev;
> >> struct pm8001_device *pm8001_ha_dev = dev->lldd_dev;
> >> + struct ata_queued_cmd *qc = task->uldd_task;
> >> + struct scsi_cmnd *scmd = qc->scsicmd;
> >> u32 tag = ccb->ccb_tag;
> >> int ret;
> >> - u32 q_index, cpu_id;
> >> + u32 q_index, blk_tag;
> >> struct sata_start_req sata_cmd;
> >> u32 hdr_tag, ncg_tag = 0;
> >> u64 phys_addr, start_addr, end_addr; @@ -4459,8 +4462,9 @@
> >> static int pm80xx_chip_sata_req(struct pm8001_hba_info *pm8001_ha,
> >> unsigned long flags;
> >> u32 opc = OPC_INB_SATA_HOST_OPSTART;
> >> memset(&sata_cmd, 0, sizeof(sata_cmd));
> >> - cpu_id = smp_processor_id();
> >> - q_index = (u32) (cpu_id) % (pm8001_ha->max_q_num);
> >> +
> >> + blk_tag = blk_mq_unique_tag(scmd->request);
> >
> > Here the scsi command is NULL.
> >
> > if(scmd) {
> > blk_tag = blk_mq_unique_tag(scmd->request);
> > q_index = blk_mq_unique_tag_to_hwq(blk_tag);
> > } else {
> > q_index = 0;
> > }
> >
> > With this change, we have started our testing. We will update you the
> result soon.
> >
> >> + q_index = blk_mq_unique_tag_to_hwq(blk_tag);
> >> circularQ = &pm8001_ha->inbnd_q_tbl[q_index];
> >>
> >> if (task->data_dir == DMA_NONE) {
> >> --
> >> 2.26.2
> >
> > .
> >

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