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;
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);
}
}
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
* @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/<device>/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);
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);
}
}
- 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)
{
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 ||
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;
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.
{
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"));
*/
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);