Example device, JMicron JMS567 UAS SATA bridge:
[tom@localhost ~]$ sudo sg_readcap -16 /dev/sdc
Read Capacity results:
Protection: prot_en=0, p_type=0, p_i_exponent=0
Logical block provisioning: lbpme=0, lbprz=0
Last logical block address=468862127 (0x1bf244af), Number of
logical blocks=468862128
Logical block length=512 bytes
Logical blocks per physical block exponent=3 [so physical block
length=4096 bytes]
Lowest aligned logical block address=0
Hence:
Device size: 240057409536 bytes, 228936.6 MiB, 240.06 GB
[tom@localhost ~]$ sudo sg_vpd -a /dev/sdc
Supported VPD pages VPD page:
Supported VPD pages [sv]
Unit serial number [sn]
Device identification [di]
Block limits (SBC) [bl]
Logical block provisioning (SBC) [lbpv]
Unit serial number VPD page:
Unit serial number: 1504380500000432
Device Identification VPD page:
Addressed logical unit:
designator type: NAA, code set: Binary
0x3015043805000004
designator type: T10 vendor identification, code set: ASCII
vendor id: JMicron
vendor specific: Generic 1504380500000432
Block limits VPD page (SBC):
Write same non-zero (WSNZ): 0
Maximum compare and write length: 0 blocks
Optimal transfer length granularity: 8 blocks
Maximum transfer length: 65535 blocks
Optimal transfer length: 65535 blocks
Maximum prefetch length: 65535 blocks
Maximum unmap LBA count: 65472
Maximum unmap block descriptor count: 1
Optimal unmap granularity: 1
Unmap granularity alignment valid: 0
Unmap granularity alignment: 0
Maximum write same length: 0x0 blocks
Maximum atomic transfer length: 0
Atomic alignment: 0
Atomic transfer length granularity: 0
Maximum atomic transfer length with atomic boundary: 0
Maximum atomic boundary size: 0
Logical block provisioning VPD page (SBC):
Unmap command supported (LBPU): 1
Write same (16) with unmap bit supported (LBWS): 0
Write same (10) with unmap bit supported (LBWS10): 0
Logical block provisioning read zeros (LBPRZ): 0
Anchored LBAs supported (ANC_SUP): 0
Threshold exponent: 1
Descriptor present (DP): 0
Minimum percentage: 0
Provisioning type: 0
Threshold percentage: 0
On 9 March 2016 at 11:26, <tom.ty89@xxxxxxxxx> wrote:
> From: Tom Yan <tom.ty89@xxxxxxxxx>
>
> Some devices have details of their support on unmapping on the
> Block Limits and/or Logical Block Provisioning VPDs while they
> do not set the LBPME bit to 1. Though this is required by the
> SCSI standards, the VPDs are giving even more concrete details
> about the support, so they should be used even when the bit
> is set to 0.
>
> Signed-off-by: Tom Yan <tom.ty89@xxxxxxxxx>
>
> diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
> index d749da7..a0d7c73 100644
> --- a/drivers/scsi/sd.c
> +++ b/drivers/scsi/sd.c
> @@ -2670,9 +2670,6 @@ static void sd_read_block_limits(struct scsi_disk *sdkp)
>
> sdkp->max_ws_blocks = (u32)get_unaligned_be64(&buffer[36]);
>
> - if (!sdkp->lbpme)
> - goto out;
> -
> lba_count = get_unaligned_be32(&buffer[20]);
> desc_count = get_unaligned_be32(&buffer[24]);
>
> @@ -2747,9 +2744,6 @@ static void sd_read_block_provisioning(struct scsi_disk *sdkp)
> unsigned char *buffer;
> const int vpd_len = 8;
>
> - if (sdkp->lbpme == 0)
> - return;
> -
> buffer = kmalloc(vpd_len, GFP_KERNEL);
>
> if (!buffer || scsi_get_vpd_page(sdkp->device, 0xb2, buffer, vpd_len))
> --
> 2.7.2
>
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