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path: root/drivers/scsi/sd.c
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Diffstat (limited to 'drivers/scsi/sd.c')
-rw-r--r--drivers/scsi/sd.c46
1 files changed, 30 insertions, 16 deletions
diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c
index e868d39c39bb..7af47ed10d90 100644
--- a/drivers/scsi/sd.c
+++ b/drivers/scsi/sd.c
@@ -2238,11 +2238,8 @@ 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)
@@ -2559,7 +2556,6 @@ 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 ||
@@ -2567,14 +2563,11 @@ 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;
@@ -2723,6 +2716,11 @@ 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.
@@ -2732,8 +2730,9 @@ 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"));
@@ -2781,11 +2780,26 @@ 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);