From: Joe Jin Date: Mon, 6 Jun 2016 05:22:30 +0000 (+0800) Subject: block/sd: Fix device-imposed transfer length limits X-Git-Tag: v4.1.12-92~105^2~5 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7075419a056c3ee43f5f724fc4647769fb068045;p=users%2Fjedix%2Flinux-maple.git block/sd: Fix device-imposed transfer length limits Orabug: 23615929 (commit ca369d51b3e1649be4a72addd6d6a168cfb3f537 of upstream) Commit 4f258a46346c ("sd: Fix maximum I/O size for BLOCK_PC requests") had the unfortunate side-effect of removing an implicit clamp to BLK_DEF_MAX_SECTORS for REQ_TYPE_FS requests in the block layer code. This caused problems for some SMR drives. Debugging this issue revealed a few problems with the existing infrastructure since the block layer didn't know how to deal with device-imposed limits, only limits set by the I/O controller. - Introduce a new queue limit, max_dev_sectors, which is used by the ULD to signal the maximum sectors for a REQ_TYPE_FS request. - Ensure that max_dev_sectors is correctly stacked and taken into account when overriding max_sectors through sysfs. - Rework sd_read_block_limits() so it saves the max_xfer and opt_xfer values for later processing. - In sd_revalidate() set the queue's max_dev_sectors based on the MAXIMUM TRANSFER LENGTH value in the Block Limits VPD. If this value is not reported, fall back to a cap based on the CDB TRANSFER LENGTH field size. - In sd_revalidate(), use OPTIMAL TRANSFER LENGTH from the Block Limits VPD--if reported and sane--to signal the preferred device transfer size for FS requests. Otherwise use BLK_DEF_MAX_SECTORS. - blk_limits_max_hw_sectors() is no longer used and can be removed. Signed-off-by: Martin K. Petersen Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=93581 Reviewed-by: Christoph Hellwig Tested-by: sweeneygj@gmx.com Tested-by: Arzeets Tested-by: David Eisner Tested-by: Mario Kicherer Signed-off-by: Martin K. Petersen Signed-off-by: Joe Jin Conflicts: drivers/scsi/sd.h include/linux/blkdev.h Adding opt_xfer_blocks and max_dev_sectors breaks kABI. They will be added using by UEK_KABI_USE2() in a fix-up commit. Signed-off-by: Chuck Anderson --- diff --git a/block/blk-settings.c b/block/blk-settings.c index e0057d035200c..dc2e66e32b661 100644 --- a/block/blk-settings.c +++ b/block/blk-settings.c @@ -112,7 +112,8 @@ void blk_set_default_limits(struct queue_limits *lim) lim->max_integrity_segments = 0; lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; lim->max_segment_size = BLK_MAX_SEGMENT_SIZE; - lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS; + lim->max_sectors = lim->max_dev_sectors = lim->max_hw_sectors = + BLK_SAFE_MAX_SECTORS; lim->chunk_sectors = 0; lim->max_write_same_sectors = 0; lim->max_discard_sectors = 0; @@ -147,6 +148,7 @@ void blk_set_stacking_limits(struct queue_limits *lim) lim->max_hw_sectors = UINT_MAX; lim->max_segment_size = UINT_MAX; lim->max_sectors = UINT_MAX; + lim->max_dev_sectors = UINT_MAX; lim->max_write_same_sectors = UINT_MAX; } EXPORT_SYMBOL(blk_set_stacking_limits); @@ -232,7 +234,6 @@ void blk_queue_bounce_limit(struct request_queue *q, u64 max_addr) } } EXPORT_SYMBOL(blk_queue_bounce_limit); - /** * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request * @limits: the queue limits @@ -267,11 +268,34 @@ EXPORT_SYMBOL(blk_limits_max_hw_sectors); * @max_hw_sectors: max hardware sectors in the usual 512b unit * * Description: - * See description for blk_limits_max_hw_sectors(). + * Enables a low level driver to set a hard upper limit, + * max_hw_sectors, on the size of requests. max_hw_sectors is set by + * the device driver based upon the capabilities of the I/O + * controller. + * + * max_dev_sectors is a hard limit imposed by the storage device for + * READ/WRITE requests. It is set by the disk driver. + * + * max_sectors is a soft limit imposed by the block layer for + * filesystem type requests. This value can be overridden on a + * per-device basis in /sys/block//queue/max_sectors_kb. + * The soft limit can not exceed max_hw_sectors. **/ void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) { - blk_limits_max_hw_sectors(&q->limits, max_hw_sectors); + struct queue_limits *limits = &q->limits; + unsigned int max_sectors; + + if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) { + max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9); + printk(KERN_INFO "%s: set to minimum %d\n", + __func__, max_hw_sectors); + } + + limits->max_hw_sectors = max_hw_sectors; + max_sectors = min_not_zero(max_hw_sectors, limits->max_dev_sectors); + max_sectors = min_t(unsigned int, max_sectors, BLK_DEF_MAX_SECTORS); + limits->max_sectors = max_sectors; } EXPORT_SYMBOL(blk_queue_max_hw_sectors); @@ -544,6 +568,7 @@ int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); + t->max_dev_sectors = min_not_zero(t->max_dev_sectors, b->max_dev_sectors); t->max_write_same_sectors = min(t->max_write_same_sectors, b->max_write_same_sectors); t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c index 2b8fd302f677a..1b0a8afc1b3fd 100644 --- a/block/blk-sysfs.c +++ b/block/blk-sysfs.c @@ -173,6 +173,9 @@ queue_max_sectors_store(struct request_queue *q, const char *page, size_t count) if (ret < 0) return ret; + max_hw_sectors_kb = min_not_zero(max_hw_sectors_kb, (unsigned long) + q->limits.max_dev_sectors >> 1); + if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb) return -EINVAL; diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index 11ea52b2c36b3..4cd30d95ac310 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -2224,11 +2224,8 @@ got_data: } } - if (sdkp->capacity > 0xffffffff) { + if (sdkp->capacity > 0xffffffff) sdp->use_16_for_rw = 1; - sdkp->max_xfer_blocks = SD_MAX_XFER_BLOCKS; - } else - sdkp->max_xfer_blocks = SD_DEF_XFER_BLOCKS; /* Rescale capacity to 512-byte units */ if (sector_size == 4096) @@ -2545,7 +2542,6 @@ static void sd_read_block_limits(struct scsi_disk *sdkp) { unsigned int sector_sz = sdkp->device->sector_size; const int vpd_len = 64; - u32 max_xfer_length; unsigned char *buffer = kmalloc(vpd_len, GFP_KERNEL); if (!buffer || @@ -2553,14 +2549,11 @@ static void sd_read_block_limits(struct scsi_disk *sdkp) scsi_get_vpd_page(sdkp->device, 0xb0, buffer, vpd_len)) goto out; - max_xfer_length = get_unaligned_be32(&buffer[8]); - if (max_xfer_length) - sdkp->max_xfer_blocks = max_xfer_length; - blk_queue_io_min(sdkp->disk->queue, get_unaligned_be16(&buffer[6]) * sector_sz); - blk_queue_io_opt(sdkp->disk->queue, - get_unaligned_be32(&buffer[12]) * sector_sz); + + sdkp->max_xfer_blocks = get_unaligned_be32(&buffer[8]); + sdkp->opt_xfer_blocks = get_unaligned_be32(&buffer[12]); if (buffer[3] == 0x3c) { unsigned int lba_count, desc_count; @@ -2709,6 +2702,11 @@ static int sd_try_extended_inquiry(struct scsi_device *sdp) return 0; } +static inline u32 logical_to_sectors(struct scsi_device *sdev, u32 blocks) +{ + return blocks << (ilog2(sdev->sector_size) - 9); +} + /** * sd_revalidate_disk - called the first time a new disk is seen, * performs disk spin up, read_capacity, etc. @@ -2718,8 +2716,9 @@ static int sd_revalidate_disk(struct gendisk *disk) { struct scsi_disk *sdkp = scsi_disk(disk); struct scsi_device *sdp = sdkp->device; + struct request_queue *q = sdkp->disk->queue; unsigned char *buffer; - unsigned int max_xfer; + unsigned int dev_max, rw_max; SCSI_LOG_HLQUEUE(3, sd_printk(KERN_INFO, sdkp, "sd_revalidate_disk\n")); @@ -2767,11 +2766,26 @@ static int sd_revalidate_disk(struct gendisk *disk) */ sd_set_flush_flag(sdkp); - max_xfer = sdkp->max_xfer_blocks; - max_xfer <<= ilog2(sdp->sector_size) - 9; + /* Initial block count limit based on CDB TRANSFER LENGTH field size. */ + dev_max = sdp->use_16_for_rw ? SD_MAX_XFER_BLOCKS : SD_DEF_XFER_BLOCKS; + + /* Some devices report a maximum block count for READ/WRITE requests. */ + dev_max = min_not_zero(dev_max, sdkp->max_xfer_blocks); + q->limits.max_dev_sectors = logical_to_sectors(sdp, dev_max); + + /* + * Use the device's preferred I/O size for reads and writes + * unless the reported value is unreasonably large (or garbage). + */ + if (sdkp->opt_xfer_blocks && sdkp->opt_xfer_blocks <= dev_max && + sdkp->opt_xfer_blocks <= SD_DEF_XFER_BLOCKS) + rw_max = q->limits.io_opt = + logical_to_sectors(sdp, sdkp->opt_xfer_blocks); + else + rw_max = BLK_DEF_MAX_SECTORS; - sdkp->disk->queue->limits.max_sectors = - min_not_zero(queue_max_hw_sectors(sdkp->disk->queue), max_xfer); + /* Combine with controller limits */ + q->limits.max_sectors = min(rw_max, queue_max_hw_sectors(q)); set_capacity(disk, sdkp->capacity); sd_config_write_same(sdkp);