[PATCH v2 12/16] scsi: sd: Support reading atomic write properties from block limits VPD

John Garry
2023-12-12T11:10:04Z

Also update block layer request queue sysfs properties.

See sbc4r22 section 6.6.4 - Block limits VPD page.

Signed-off-by: John Garry <john.g.garry@oracle.com>
---
drivers/scsi/sd.c | 69 ++++++++++++++++++++++++++++++++++++++++++++++-
drivers/scsi/sd.h | 8 ++++++
2 files changed, 76 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index 542a4bbb21bc..fa857a08341f 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -916,6 +916,65 @@ static blk_status_t sd_setup_unmap_cmnd(struct scsi_cmnd *cmd)
return scsi_alloc_sgtables(cmd);
}

+static void sd_config_atomic(struct scsi_disk *sdkp)
+{
+ unsigned int logical_block_size = sdkp->device->sector_size,
+ physical_block_size_sectors, max_atomic, unit_min, unit_max;
+ struct request_queue *q = sdkp->disk->queue;
+
+ if ((!sdkp->max_atomic && !sdkp->max_atomic_with_boundary) ||
+ sdkp->protection_type == T10_PI_TYPE2_PROTECTION)
+ return;
+
+ physical_block_size_sectors = sdkp->physical_block_size /
+ sdkp->device->sector_size;
+
+ unit_min = rounddown_pow_of_two(sdkp->atomic_granularity ?
+ sdkp->atomic_granularity :
+ physical_block_size_sectors);
+
+ /*
+ * Only use atomic boundary when we have the odd scenario of
+ * sdkp->max_atomic == 0, which the spec does permit.
+ */
+ if (sdkp->max_atomic) {
+ max_atomic = sdkp->max_atomic;
+ unit_max = rounddown_pow_of_two(sdkp->max_atomic);
+ sdkp->use_atomic_write_boundary = 0;
+ } else {
+ max_atomic = sdkp->max_atomic_with_boundary;
+ unit_max = rounddown_pow_of_two(sdkp->max_atomic_boundary);
+ sdkp->use_atomic_write_boundary = 1;
+ }
+
+ /*
+ * Ensure compliance with granularity and alignment. For now, keep it
+ * simple and just don't support atomic writes for values mismatched
+ * with max_{boundary}atomic, physical block size, and
+ * atomic_granularity itself.
+ *
+ * We're really being distrustful by checking unit_max also...
+ */
+ if (sdkp->atomic_granularity > 1) {
+ if (unit_min > 1 && unit_min % sdkp->atomic_granularity)
+ return;
+ if (unit_max > 1 && unit_max % sdkp->atomic_granularity)
+ return;
+ }
+
+ if (sdkp->atomic_alignment > 1) {
+ if (unit_min > 1 && unit_min % sdkp->atomic_alignment)
+ return;
+ if (unit_max > 1 && unit_max % sdkp->atomic_alignment)
+ return;
+ }
+
+ blk_queue_atomic_write_max_bytes(q, max_atomic * logical_block_size);
+ blk_queue_atomic_write_unit_min_sectors(q, unit_min);
+ blk_queue_atomic_write_unit_max_sectors(q, unit_max);
+ blk_queue_atomic_write_boundary_bytes(q, 0);
+}
+
static blk_status_t sd_setup_write_same16_cmnd(struct scsi_cmnd *cmd,
bool unmap)
{
@@ -3071,7 +3130,7 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
sdkp->max_ws_blocks = (u32)get_unaligned_be64(&vpd->data[36]);

if (!sdkp->lbpme)
- goto out;
+ goto read_atomics;

lba_count = get_unaligned_be32(&vpd->data[20]);
desc_count = get_unaligned_be32(&vpd->data[24]);
@@ -3102,6 +3161,14 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
else
sd_config_discard(sdkp, SD_LBP_DISABLE);
}
+read_atomics:
+ sdkp->max_atomic = get_unaligned_be32(&vpd->data[44]);
+ sdkp->atomic_alignment = get_unaligned_be32(&vpd->data[48]);
+ sdkp->atomic_granularity = get_unaligned_be32(&vpd->data[52]);
+ sdkp->max_atomic_with_boundary = get_unaligned_be32(&vpd->data[56]);
+ sdkp->max_atomic_boundary = get_unaligned_be32(&vpd->data[60]);
+
+ sd_config_atomic(sdkp);
}

out:
diff --git a/drivers/scsi/sd.h b/drivers/scsi/sd.h
index 409dda5350d1..990188a56b51 100644
--- a/drivers/scsi/sd.h
+++ b/drivers/scsi/sd.h
@@ -121,6 +121,13 @@ struct scsi_disk {
u32 max_unmap_blocks;
u32 unmap_granularity;
u32 unmap_alignment;
+
+ u32 max_atomic;
+ u32 atomic_alignment;
+ u32 atomic_granularity;
+ u32 max_atomic_with_boundary;
+ u32 max_atomic_boundary;
+
u32 index;
unsigned int physical_block_size;
unsigned int max_medium_access_timeouts;
@@ -151,6 +158,7 @@ struct scsi_disk {
unsigned urswrz : 1;
unsigned security : 1;
unsigned ignore_medium_access_errors : 1;
+ unsigned use_atomic_write_boundary : 1;
};
#define to_scsi_disk(obj) container_of(obj, struct scsi_disk, disk_dev)

--
2.35.3