Re: Change in reported values of some block integrity sysfs attributes

[Anuj Gupta]

On Fri, Feb 21, 2025 at 04:07:55PM +0530, Anuj gupta wrote:
> > I don't see any change in what's reported with block/for-next in a
> > regular SCSI HBA/disk setup. Will have to look at whether there is a
> > stacking issue wrt. multipathing.
> 
> Hi Martin, Christoph,
> 
> It seems this change in behaviour is not limited to SCSI only. As Nikhil
> mentioned an earlier commit
> [9f4aa46f2a74 ("block: invert the BLK_INTEGRITY_{GENERATE,VERIFY} flags")]
> causes this change in behaviour. On my setup with a NVMe drive not formatted
> with PI, I see that:
> 
> Without this commit:
> Value reported by read_verify and write_generate sysfs entries is 0.
> 
> With this commit:
> Value reported by read_verify and write_generate sysfs entries is 1.
> 
> Diving a bit deeper, both these flags got inverted due to this commit.
> But during init (in nvme_init_integrity) these values get initialized to 0,
> inturn setting the sysfs entries to 1. In order to fix this, the driver has to
> initialize both these flags to 1 in nvme_init_integrity if PI is not 
> supported.
> That way, the value in sysfs for these entries would become 0 again. Tried 
> this
> approach in my setup, and I am able to see the right values now. Then 
> something
> like this would also need to be done for SCSI too.

This is the patch that I used:

diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c
index 818d4e49aab5..6cd9f57131cc 100644
--- a/drivers/nvme/host/core.c
+++ b/drivers/nvme/host/core.c
@@ -1799,6 +1799,7 @@ static bool nvme_init_integrity(struct nvme_ns_head *head,
 
        memset(bi, 0, sizeof(*bi));
 
+       bi->flags |= BLK_INTEGRITY_NOGENERATE | BLK_INTEGRITY_NOVERIFY;
        if (!head->ms)
                return true;
 
@@ -1817,11 +1818,15 @@ static bool nvme_init_integrity(struct nvme_ns_head 
*head,
                        bi->csum_type = BLK_INTEGRITY_CSUM_CRC;
                        bi->tag_size = sizeof(u16) + sizeof(u32);
                        bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
+                       bi->flags &= ~(BLK_INTEGRITY_NOGENERATE |
+                                      BLK_INTEGRITY_NOVERIFY);
                        break;
                case NVME_NVM_NS_64B_GUARD:
                        bi->csum_type = BLK_INTEGRITY_CSUM_CRC64;
                        bi->tag_size = sizeof(u16) + 6;
                        bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE;
+                       bi->flags &= ~(BLK_INTEGRITY_NOGENERATE |
+                                      BLK_INTEGRITY_NOVERIFY);
                        break;
                default:
                        break;
@@ -1835,12 +1840,16 @@ static bool nvme_init_integrity(struct nvme_ns_head 
*head,
                        bi->tag_size = sizeof(u16);
                        bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE |
                                     BLK_INTEGRITY_REF_TAG;
+                       bi->flags &= ~(BLK_INTEGRITY_NOGENERATE |
+                                      BLK_INTEGRITY_NOVERIFY);
                        break;
                case NVME_NVM_NS_64B_GUARD:
                        bi->csum_type = BLK_INTEGRITY_CSUM_CRC64;
                        bi->tag_size = sizeof(u16);
                        bi->flags |= BLK_INTEGRITY_DEVICE_CAPABLE |
                                     BLK_INTEGRITY_REF_TAG;
+                       bi->flags &= ~(BLK_INTEGRITY_NOGENERATE |
+                                      BLK_INTEGRITY_NOVERIFY);
                        break;
                default:
                        break;