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scsi: sd: add concurrent positioning ranges support

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Add the sd_read_cpr() function to the sd scsi disk driver to discover
if a device has multiple concurrent positioning ranges (i.e. multiple
actuators on an HDD). The existence of VPD page B9h indicates if a
device has multiple concurrent positioning ranges. The page content
describes each range supported by the device.

sd_read_cpr() is called from sd_revalidate_disk() and uses the block
layer functions disk_alloc_independent_access_ranges() and
disk_set_independent_access_ranges() to represent the set of actuators
of the device as independent access ranges.

The format of the Concurrent Positioning Ranges VPD page B9h is defined
in section 6.6.6 of SBC-5.

Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Link: https://lore.kernel.org/r/20211027022223.183838-3-damien.lemoal@wdc.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Damien Le Moal 2021-10-27 11:22:20 +09:00 committed by Jens Axboe
parent a2247f19ee
commit e815d36548
2 changed files with 82 additions and 0 deletions
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81
drivers/scsi/sd.c
View File

@ -3088,6 +3088,86 @@ static void sd_read_security(struct scsi_disk *sdkp, unsigned char *buffer)
sdkp->security = 1;
}
static inline sector_t sd64_to_sectors(struct scsi_disk *sdkp, u8 *buf)
{
return logical_to_sectors(sdkp->device, get_unaligned_be64(buf));
}
/**
* sd_read_cpr - Query concurrent positioning ranges
* @sdkp: disk to query
*/
static void sd_read_cpr(struct scsi_disk *sdkp)
{
struct blk_independent_access_ranges *iars = NULL;
unsigned char *buffer = NULL;
unsigned int nr_cpr = 0;
int i, vpd_len, buf_len = SD_BUF_SIZE;
u8 *desc;
/*
* We need to have the capacity set first for the block layer to be
* able to check the ranges.
*/
if (sdkp->first_scan)
return;
if (!sdkp->capacity)
goto out;
/*
* Concurrent Positioning Ranges VPD: there can be at most 256 ranges,
* leading to a maximum page size of 64 + 256*32 bytes.
*/
buf_len = 64 + 256*32;
buffer = kmalloc(buf_len, GFP_KERNEL);
if (!buffer || scsi_get_vpd_page(sdkp->device, 0xb9, buffer, buf_len))
goto out;
/* We must have at least a 64B header and one 32B range descriptor */
vpd_len = get_unaligned_be16(&buffer[2]) + 3;
if (vpd_len > buf_len || vpd_len < 64 + 32 || (vpd_len & 31)) {
sd_printk(KERN_ERR, sdkp,
"Invalid Concurrent Positioning Ranges VPD page\n");
goto out;
}
nr_cpr = (vpd_len - 64) / 32;
if (nr_cpr == 1) {
nr_cpr = 0;
goto out;
}
iars = disk_alloc_independent_access_ranges(sdkp->disk, nr_cpr);
if (!iars) {
nr_cpr = 0;
goto out;
}
desc = &buffer[64];
for (i = 0; i < nr_cpr; i++, desc += 32) {
if (desc[0] != i) {
sd_printk(KERN_ERR, sdkp,
"Invalid Concurrent Positioning Range number\n");
nr_cpr = 0;
break;
}
iars->ia_range[i].sector = sd64_to_sectors(sdkp, desc + 8);
iars->ia_range[i].nr_sectors = sd64_to_sectors(sdkp, desc + 16);
}
out:
disk_set_independent_access_ranges(sdkp->disk, iars);
if (nr_cpr && sdkp->nr_actuators != nr_cpr) {
sd_printk(KERN_NOTICE, sdkp,
"%u concurrent positioning ranges\n", nr_cpr);
sdkp->nr_actuators = nr_cpr;
}
kfree(buffer);
}
/*
* Determine the device's preferred I/O size for reads and writes
* unless the reported value is unreasonably small, large, not a
@ -3203,6 +3283,7 @@ static int sd_revalidate_disk(struct gendisk *disk)
sd_read_app_tag_own(sdkp, buffer);
sd_read_write_same(sdkp, buffer);
sd_read_security(sdkp, buffer);
sd_read_cpr(sdkp);
}
/*

1
drivers/scsi/sd.h
View File

@ -106,6 +106,7 @@ struct scsi_disk {
u8 protection_type;/* Data Integrity Field */
u8 provisioning_mode;
u8 zeroing_mode;
u8 nr_actuators; /* Number of actuators */
unsigned ATO : 1; /* state of disk ATO bit */
unsigned cache_override : 1; /* temp override of WCE,RCD */
unsigned WCE : 1; /* state of disk WCE bit */