In preparation for a generic report zones command buffer allocation to the block layer, introduce three new request queue limits describing the device zone descriptor size (zone_descriptor_size limit), the needed granularity of the report zones command buffer size (zones_report_granularity limit) and the maximum size of a report zone command (max_zones_report_size limit).
For scsi, set these values respectively to 64 bytes, SECTOR_SIZE and the maximum transfer size used for regular read/write commands limited by the maximum number of pages (segments) that the hardware can map. This removes the need for the "magic" limit implemented with the macro SD_ZBC_REPORT_MAX_ZONES. For the null_blk driver and dm targets, the default value of 0 is used for these limits, indicating that these zoned devices do not need a buffer for the execution of report zones. Signed-off-by: Damien Le Moal <[email protected]> --- block/blk-settings.c | 3 +++ drivers/scsi/sd_zbc.c | 48 +++++++++++++++++++++--------------------- include/linux/blkdev.h | 4 ++++ 3 files changed, 31 insertions(+), 24 deletions(-) diff --git a/block/blk-settings.c b/block/blk-settings.c index 5f6dcc7a47bd..674cfc428334 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -53,6 +53,9 @@ void blk_set_default_limits(struct queue_limits *lim) lim->discard_granularity = 0; lim->discard_alignment = 0; lim->discard_misaligned = 0; + lim->zone_descriptor_size = 0; + lim->zones_report_granularity = 0; + lim->max_zones_report_size = 0; lim->logical_block_size = lim->physical_block_size = lim->io_min = 512; lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT); lim->alignment_offset = 0; diff --git a/drivers/scsi/sd_zbc.c b/drivers/scsi/sd_zbc.c index fbec99db6124..8dc96f4ea920 100644 --- a/drivers/scsi/sd_zbc.c +++ b/drivers/scsi/sd_zbc.c @@ -104,11 +104,6 @@ static int sd_zbc_do_report_zones(struct scsi_disk *sdkp, unsigned char *buf, return 0; } -/* - * Maximum number of zones to get with one report zones command. - */ -#define SD_ZBC_REPORT_MAX_ZONES 8192U - /** * Allocate a buffer for report zones reply. * @sdkp: The target disk @@ -129,21 +124,8 @@ static void *sd_zbc_alloc_report_buffer(struct scsi_disk *sdkp, size_t bufsize; void *buf; - /* - * Report zone buffer size should be at most 64B times the number of - * zones requested plus the 64B reply header, but should be at least - * SECTOR_SIZE for ATA devices. - * Make sure that this size does not exceed the hardware capabilities. - * Furthermore, since the report zone command cannot be split, make - * sure that the allocated buffer can always be mapped by limiting the - * number of pages allocated to the HBA max segments limit. - */ - nr_zones = min(nr_zones, SD_ZBC_REPORT_MAX_ZONES); - bufsize = roundup((nr_zones + 1) * 64, 512); - bufsize = min_t(size_t, bufsize, - queue_max_hw_sectors(q) << SECTOR_SHIFT); - bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT); - + bufsize = min_t(size_t, roundup(nr_zones * 64, SECTOR_SIZE), + q->limits.max_zones_report_size); buf = vzalloc(bufsize); if (buf) *buflen = bufsize; @@ -398,6 +380,8 @@ static int sd_zbc_check_zones(struct scsi_disk *sdkp, unsigned char *buf, int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf) { struct gendisk *disk = sdkp->disk; + struct request_queue *q = disk->queue; + unsigned int max_zones_report_size; unsigned int nr_zones; u32 zone_blocks = 0; int ret; @@ -423,13 +407,29 @@ int sd_zbc_read_zones(struct scsi_disk *sdkp, unsigned char *buf) goto err; /* The drive satisfies the kernel restrictions: set it up */ - blk_queue_chunk_sectors(sdkp->disk->queue, + blk_queue_chunk_sectors(q, logical_to_sectors(sdkp->device, zone_blocks)); - blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, sdkp->disk->queue); - blk_queue_required_elevator_features(sdkp->disk->queue, - ELEVATOR_F_ZBD_SEQ_WRITE); + blk_queue_flag_set(QUEUE_FLAG_ZONE_RESETALL, q); + blk_queue_required_elevator_features(q, ELEVATOR_F_ZBD_SEQ_WRITE); nr_zones = round_up(sdkp->capacity, zone_blocks) >> ilog2(zone_blocks); + /* + * Zone descriptors are 64 bytes. A report zone buffer size should be + * at most 64B times the number of zones of the device plus a 64B reply + * header and should be at least be SECTOR_SIZE bytes for ATA devices. + * Make sure that this maximum buffer size does not exceed the hardware + * capabilities in terms of maximum data transfer size. Furthermore, + * make sure that the allocated buffer can always be mapped by limiting + * the number of pages of the buffer to the device max segments limit. + */ + q->limits.zone_descriptor_size = 64; + q->limits.zones_report_granularity = SECTOR_SIZE; + max_zones_report_size = min(roundup((nr_zones + 1) * 64, SECTOR_SIZE), + queue_max_hw_sectors(q) << SECTOR_SHIFT); + q->limits.max_zones_report_size = + min(max_zones_report_size, + (unsigned int)queue_max_segments(q) << PAGE_SHIFT); + /* READ16/WRITE16 is mandatory for ZBC disks */ sdkp->device->use_16_for_rw = 1; sdkp->device->use_10_for_rw = 0; diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index f3ea78b0c91c..1c76d71fc232 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -338,6 +338,10 @@ struct queue_limits { unsigned int discard_granularity; unsigned int discard_alignment; + unsigned int zone_descriptor_size; + unsigned int zones_report_granularity; + unsigned int max_zones_report_size; + unsigned short logical_block_size; unsigned short max_segments; unsigned short max_integrity_segments; -- 2.21.0 -- dm-devel mailing list [email protected] https://www.redhat.com/mailman/listinfo/dm-devel
