Re: [PATCH v4] aacraid: reply queue mapping to CPUs based of IRQ affinity

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On 11/23/23 13:01, John Garry wrote:
On 20/05/2023 00:08, Sagar Biradar wrote:
Fix the IO hang that arises because of MSIx vector not
having a mapped online CPU upon receiving completion.

The SCSI cmds take the blk_mq route, which is setup during the init.
The reserved cmds fetch the vector_no from mq_map after the init
is complete and before the init, they use 0 - as per the norm.

Reviewed-by: Gilbert Wu <gilbert.wu@xxxxxxxxxxxxx>
Signed-off-by: Sagar Biradar <Sagar.Biradar@xxxxxxxxxxxxx>

This the patch which seems to be causing the issue in https://bugzilla.kernel.org/show_bug.cgi?id=217599

I will comment here since I got no response there...

---
  drivers/scsi/aacraid/aacraid.h  |  1 +
  drivers/scsi/aacraid/comminit.c |  1 -
  drivers/scsi/aacraid/commsup.c  |  6 +++++-
  drivers/scsi/aacraid/linit.c    | 14 ++++++++++++++
  drivers/scsi/aacraid/src.c      | 25 +++++++++++++++++++++++--
  5 files changed, 43 insertions(+), 4 deletions(-)

diff --git a/drivers/scsi/aacraid/aacraid.h b/drivers/scsi/aacraid/aacraid.h
index 5e115e8b2ba4..7c6efde75da6 100644
--- a/drivers/scsi/aacraid/aacraid.h
+++ b/drivers/scsi/aacraid/aacraid.h
@@ -1678,6 +1678,7 @@ struct aac_dev
      u32            handle_pci_error;
      bool            init_reset;
      u8            soft_reset_support;
+    u8            use_map_queue;
  };
  #define aac_adapter_interrupt(dev) \
diff --git a/drivers/scsi/aacraid/comminit.c b/drivers/scsi/aacraid/comminit.c
index bd99c5492b7d..a5483e7e283a 100644
--- a/drivers/scsi/aacraid/comminit.c
+++ b/drivers/scsi/aacraid/comminit.c
@@ -657,4 +657,3 @@ struct aac_dev *aac_init_adapter(struct aac_dev *dev)
      return dev;
  }
-
diff --git a/drivers/scsi/aacraid/commsup.c b/drivers/scsi/aacraid/commsup.c
index deb32c9f4b3e..3f062e4013ab 100644
--- a/drivers/scsi/aacraid/commsup.c
+++ b/drivers/scsi/aacraid/commsup.c
@@ -223,8 +223,12 @@ int aac_fib_setup(struct aac_dev * dev)
  struct fib *aac_fib_alloc_tag(struct aac_dev *dev, struct scsi_cmnd *scmd)
  {
      struct fib *fibptr;
+    u32 blk_tag;
+    int i;
-    fibptr = &dev->fibs[scsi_cmd_to_rq(scmd)->tag];
+    blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
+    i = blk_mq_unique_tag_to_tag(blk_tag);
+    fibptr = &dev->fibs[i];
      /*
       *    Null out fields that depend on being zero at the start of
       *    each I/O
diff --git a/drivers/scsi/aacraid/linit.c b/drivers/scsi/aacraid/linit.c
index 5ba5c18b77b4..9caf8c314ce1 100644
--- a/drivers/scsi/aacraid/linit.c
+++ b/drivers/scsi/aacraid/linit.c
@@ -19,6 +19,7 @@
  #include <linux/compat.h>
  #include <linux/blkdev.h>
+#include <linux/blk-mq-pci.h>
  #include <linux/completion.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
@@ -505,6 +506,15 @@ static int aac_slave_configure(struct scsi_device *sdev)
      return 0;
  }
+static void aac_map_queues(struct Scsi_Host *shost)
+{
+    struct aac_dev *aac = (struct aac_dev *)shost->hostdata;
+
+    blk_mq_pci_map_queues(&shost->tag_set.map[HCTX_TYPE_DEFAULT],
+                aac->pdev, 0);
+    aac->use_map_queue = true;
+}
+
  /**
   *    aac_change_queue_depth        -    alter queue depths
   *    @sdev:    SCSI device we are considering
@@ -1489,6 +1499,7 @@ static struct scsi_host_template aac_driver_template = {
      .bios_param            = aac_biosparm,
      .shost_groups            = aac_host_groups,
      .slave_configure        = aac_slave_configure,
+    .map_queues            = aac_map_queues,
      .change_queue_depth        = aac_change_queue_depth,
      .sdev_groups            = aac_dev_groups,
      .eh_abort_handler        = aac_eh_abort,
@@ -1776,6 +1787,8 @@ static int aac_probe_one(struct pci_dev *pdev, const struct pci_device_id *id)
      shost->max_lun = AAC_MAX_LUN;
      pci_set_drvdata(pdev, shost);
+    shost->nr_hw_queues = aac->max_msix;
+    shost->host_tagset = 1;
      error = scsi_add_host(shost, &pdev->dev);
      if (error)
@@ -1908,6 +1921,7 @@ static void aac_remove_one(struct pci_dev *pdev)
      struct aac_dev *aac = (struct aac_dev *)shost->hostdata;
      aac_cancel_rescan_worker(aac);
+    aac->use_map_queue = false;
      scsi_remove_host(shost);
      __aac_shutdown(aac);
diff --git a/drivers/scsi/aacraid/src.c b/drivers/scsi/aacraid/src.c
index 11ef58204e96..61949f374188 100644
--- a/drivers/scsi/aacraid/src.c
+++ b/drivers/scsi/aacraid/src.c
@@ -493,6 +493,10 @@ static int aac_src_deliver_message(struct fib *fib)
  #endif
      u16 vector_no;
+    struct scsi_cmnd *scmd;
+    u32 blk_tag;
+    struct Scsi_Host *shost = dev->scsi_host_ptr;
+    struct blk_mq_queue_map *qmap;
      atomic_inc(&q->numpending);
@@ -505,8 +509,25 @@ static int aac_src_deliver_message(struct fib *fib)
          if ((dev->comm_interface == AAC_COMM_MESSAGE_TYPE3)
              && dev->sa_firmware)
              vector_no = aac_get_vector(dev);
-        else
-            vector_no = fib->vector_no;
+        else {
+            if (!fib->vector_no || !fib->callback_data) {
+                if (shost && dev->use_map_queue) {
+                    qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT];
+                    vector_no = qmap->mq_map[raw_smp_processor_id()];
+                }
+                /*
+                 *    We hardcode the vector_no for
+                 *    reserved commands as a valid shost is
+                 *    absent during the init
+                 */
+                else
+                    vector_no = 0;
+            } else {
+                scmd = (struct scsi_cmnd *)fib->callback_data;
+                blk_tag = blk_mq_unique_tag(scsi_cmd_to_rq(scmd));
+                vector_no = blk_mq_unique_tag_to_hwq(blk_tag);



Hannes' patch in the bugzilla was to revert to using hw queue #0 always for internal commands, and it didn't help.

Could there be any issue in using hw queue #0 for regular SCSI commands?

AFAICS, that's a significant change. Previously we would use fib->vector_no to decide the queue, which was in range (1, dev->max_msix).

BTW, is there any code which relies on a command being sent/received on the HW queue same as fib->vector_no?

Yeah, and that's the clincher.
The vector/MSIx interrupt to use for the completion is encoded in the command (cf drivers/scsi/aacraid/src.c:aac_src_deliver_message()):

fib->hw_fib_va)->reply_qid = vector_no;

_and_ the command index:

fib->hw_fib_va)->request_id += (vector_no << 16);

so if we miscalculate the vector number here the command completion
will lookup the wrong command, and we get this issue.

But maybe the fix is relatively simple; can you try this:

diff --git a/drivers/scsi/aacraid/src.c b/drivers/scsi/aacraid/src.c
index 61949f374188..698a206a2b43 100644
--- a/drivers/scsi/aacraid/src.c
+++ b/drivers/scsi/aacraid/src.c
@@ -510,7 +510,7 @@ static int aac_src_deliver_message(struct fib *fib)
                        && dev->sa_firmware)
                        vector_no = aac_get_vector(dev);
                else {
-                       if (!fib->vector_no || !fib->callback_data) {
+                       if (!fib->callback_data) {
                                if (shost && dev->use_map_queue) {
qmap = &shost->tag_set.map[HCTX_TYPE_DEFAULT]; vector_no = qmap->mq_map[raw_smp_processor_id()];

Hmm?

Cheers,

Hannes
--
Dr. Hannes Reinecke                Kernel Storage Architect
hare@xxxxxxx                              +49 911 74053 688
SUSE Software Solutions GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Ivo Totev, Andrew McDonald,
Werner Knoblich





[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux