@@ -112,7 +112,7 @@ void blk_set_default_limits(struct queue
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_rw_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
lim->chunk_sectors = 0;
lim->max_write_same_sectors = 0;
lim->max_discard_sectors = 0;
@@ -145,6 +145,7 @@ void blk_set_stacking_limits(struct queu
lim->discard_zeroes_data = 1;
lim->max_segments = USHRT_MAX;
lim->max_hw_sectors = UINT_MAX;
+ lim->max_rw_sectors = UINT_MAX;
lim->max_segment_size = UINT_MAX;
lim->max_sectors = UINT_MAX;
lim->max_write_same_sectors = UINT_MAX;
@@ -262,6 +263,48 @@ void blk_limits_max_hw_sectors(struct qu
EXPORT_SYMBOL(blk_limits_max_hw_sectors);
/**
+ * blk_limits_max_rw_sectors - set hard and soft limit of max sectors for request
+ * @limits: the queue limits
+ * @max_rw_sectors: max read/write sectors in the usual 512b unit
+ *
+ * Description:
+ * Enables a low level driver to set a hard upper limit,
+ * max_rw_sectors, on the size of requests. max_rw_sectors is set by
+ * the device driver based upon the capabilities of the storage device.
+ * This limit does not apply to REQ_TYPE_BLOCK_PC requests.
+ *
+ * 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 or max_rw_sectors
+ **/
+void blk_limits_max_rw_sectors(struct queue_limits *limits, unsigned int max_rw_sectors)
+{
+ if ((max_rw_sectors << 9) < PAGE_CACHE_SIZE) {
+ max_rw_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
+ printk(KERN_INFO "%s: set to minimum %d\n",
+ __func__, max_rw_sectors);
+ }
+
+ limits->max_sectors = limits->max_rw_sectors = max_rw_sectors;
+}
+EXPORT_SYMBOL(blk_limits_max_rw_sectors);
+
+/**
+ * blk_queue_max_rw_sectors - set max sectors for a request for this queue
+ * @q: the request queue for the device
+ * @max_rw_sectors: max read/write sectors in the usual 512b unit
+ *
+ * Description:
+ * See description for blk_limits_max_rw_sectors().
+ **/
+void blk_queue_max_rw_sectors(struct request_queue *q, unsigned int max_rw_sectors)
+{
+ blk_limits_max_rw_sectors(&q->limits, max_rw_sectors);
+}
+EXPORT_SYMBOL(blk_queue_max_rw_sectors);
+
+/**
* blk_queue_max_hw_sectors - set max sectors for a request for this queue
* @q: the request queue for the device
* @max_hw_sectors: max hardware sectors in the usual 512b unit
@@ -544,6 +587,7 @@ int blk_stack_limits(struct queue_limits
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_rw_sectors = min_not_zero(t->max_rw_sectors, b->max_rw_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);
@@ -167,13 +167,15 @@ queue_max_sectors_store(struct request_q
{
unsigned long max_sectors_kb,
max_hw_sectors_kb = queue_max_hw_sectors(q) >> 1,
+ max_rw_sectors_kb = queue_max_rw_sectors(q) >> 1,
page_kb = 1 << (PAGE_CACHE_SHIFT - 10);
ssize_t ret = queue_var_store(&max_sectors_kb, page, count);
if (ret < 0)
return ret;
- if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb)
+ if (max_sectors_kb > max_hw_sectors_kb || max_sectors_kb < page_kb ||
+ max_sectors_kb > max_rw_sectors_kb)
return -EINVAL;
spin_lock_irq(q->queue_lock);
@@ -2781,7 +2781,7 @@ static int sd_revalidate_disk(struct gen
max_xfer = min_not_zero(queue_max_hw_sectors(sdkp->disk->queue),
max_xfer);
- blk_queue_max_hw_sectors(sdkp->disk->queue, max_xfer);
+ blk_queue_max_rw_sectors(sdkp->disk->queue, max_xfer);
set_capacity(disk, sdkp->capacity);
sd_config_write_same(sdkp);
kfree(buffer);
@@ -286,6 +286,7 @@ struct queue_limits {
unsigned long seg_boundary_mask;
unsigned int max_hw_sectors;
+ unsigned int max_rw_sectors;
unsigned int chunk_sectors;
unsigned int max_sectors;
unsigned int max_segment_size;
@@ -1004,7 +1005,9 @@ extern void blk_cleanup_queue(struct req
extern void blk_queue_make_request(struct request_queue *, make_request_fn *);
extern void blk_queue_bounce_limit(struct request_queue *, u64);
extern void blk_limits_max_hw_sectors(struct queue_limits *, unsigned int);
+extern void blk_limits_max_rw_sectors(struct queue_limits *, unsigned int);
extern void blk_queue_max_hw_sectors(struct request_queue *, unsigned int);
+extern void blk_queue_max_rw_sectors(struct request_queue *, unsigned int);
extern void blk_queue_chunk_sectors(struct request_queue *, unsigned int);
extern void blk_queue_max_segments(struct request_queue *, unsigned short);
extern void blk_queue_max_segment_size(struct request_queue *, unsigned int);
@@ -1213,6 +1216,11 @@ static inline unsigned int queue_max_hw_
return q->limits.max_hw_sectors;
}
+static inline unsigned int queue_max_rw_sectors(struct request_queue *q)
+{
+ return q->limits.max_rw_sectors;
+}
+
static inline unsigned short queue_max_segments(struct request_queue *q)
{
return q->limits.max_segments;
The commit bcdb247c6b6a1f3e72b9b787b73f47dd509d17ec "sd: Limit transfer length" added support for setting max_hw_sectors based on the block limits VPD page. As defined in the transfer limit table in the block limits VPD page section of SBC4, this value is only supposed to apply to a small subset of SCSI opcodes. However, we are using that value for all SCSI commands. I ran into this with a new disk drive we are qualifying which is reporting a value here that is smaller than the size of its firmware image, which means sg_write_buffer fails when trying to update the drive code. This patch adds a new max_rw_sectors limit on the block device to reflect this max read/write transfer size for media commands that the device supports. It restricts max_sectors_kb from being set to a value larger than this and removes any policing of per target limits for BLOCK_PC requests. Signed-off-by: Brian King <brking@linux.vnet.ibm.com> --- block/blk-settings.c | 46 +++++++++++++++++++++++++++++++++++++++++++++- block/blk-sysfs.c | 4 +++- drivers/scsi/sd.c | 2 +- include/linux/blkdev.h | 8 ++++++++ 4 files changed, 57 insertions(+), 3 deletions(-)