[SCSI] seperate max_sectors from max_hw_sectors
- export __blk_put_request and blk_execute_rq_nowait
needed for async REQ_BLOCK_PC requests
- seperate max_hw_sectors and max_sectors for block/scsi_ioctl.c and
SG_IO bio.c helpers per Jens's last comments. Since block/scsi_ioctl.c SG_IO was
already testing against max_sectors and SCSI-ml was setting max_sectors and
max_hw_sectors to the same value this does not change any scsi SG_IO behavior. It only
prepares ll_rw_blk.c, scsi_ioctl.c and bio.c for when SCSI-ml begins to set
a valid max_hw_sectors for all LLDs. Today if a LLD does not set it
SCSI-ml sets it to a safe default and some LLDs set it to a artificial low
value to overcome memory and feedback issues.
Note: Since we now cap max_sectors to BLK_DEF_MAX_SECTORS, which is 1024,
drivers that used to call blk_queue_max_sectors with a large value of
max_sectors will now see the fs requests capped to BLK_DEF_MAX_SECTORS.
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index c525b5a..d4beb9a 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -239,7 +239,7 @@
q->backing_dev_info.ra_pages = (VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
q->backing_dev_info.state = 0;
q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
- blk_queue_max_sectors(q, MAX_SECTORS);
+ blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
blk_queue_hardsect_size(q, 512);
blk_queue_dma_alignment(q, 511);
blk_queue_congestion_threshold(q);
@@ -555,7 +555,12 @@
printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
}
- q->max_sectors = q->max_hw_sectors = max_sectors;
+ if (BLK_DEF_MAX_SECTORS > max_sectors)
+ q->max_hw_sectors = q->max_sectors = max_sectors;
+ else {
+ q->max_sectors = BLK_DEF_MAX_SECTORS;
+ q->max_hw_sectors = max_sectors;
+ }
}
EXPORT_SYMBOL(blk_queue_max_sectors);
@@ -657,8 +662,8 @@
void blk_queue_stack_limits(request_queue_t *t, request_queue_t *b)
{
/* zero is "infinity" */
- t->max_sectors = t->max_hw_sectors =
- min_not_zero(t->max_sectors,b->max_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_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
@@ -1293,9 +1298,15 @@
static int ll_back_merge_fn(request_queue_t *q, struct request *req,
struct bio *bio)
{
+ unsigned short max_sectors;
int len;
- if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
+ if (unlikely(blk_pc_request(req)))
+ max_sectors = q->max_hw_sectors;
+ else
+ max_sectors = q->max_sectors;
+
+ if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
req->flags |= REQ_NOMERGE;
if (req == q->last_merge)
q->last_merge = NULL;
@@ -1325,9 +1336,16 @@
static int ll_front_merge_fn(request_queue_t *q, struct request *req,
struct bio *bio)
{
+ unsigned short max_sectors;
int len;
- if (req->nr_sectors + bio_sectors(bio) > q->max_sectors) {
+ if (unlikely(blk_pc_request(req)))
+ max_sectors = q->max_hw_sectors;
+ else
+ max_sectors = q->max_sectors;
+
+
+ if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
req->flags |= REQ_NOMERGE;
if (req == q->last_merge)
q->last_merge = NULL;
@@ -2144,7 +2162,7 @@
struct bio *bio;
int reading;
- if (len > (q->max_sectors << 9))
+ if (len > (q->max_hw_sectors << 9))
return -EINVAL;
if (!len || !ubuf)
return -EINVAL;
@@ -2259,7 +2277,7 @@
{
struct bio *bio;
- if (len > (q->max_sectors << 9))
+ if (len > (q->max_hw_sectors << 9))
return -EINVAL;
if (!len || !kbuf)
return -EINVAL;
diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index 382dea7..4e390df 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -233,7 +233,7 @@
if (verify_command(file, cmd))
return -EPERM;
- if (hdr->dxfer_len > (q->max_sectors << 9))
+ if (hdr->dxfer_len > (q->max_hw_sectors << 9))
return -EIO;
if (hdr->dxfer_len)
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index a6d3baa..a6f2dc6 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -638,7 +638,7 @@
static void check_for_valid_limits(struct io_restrictions *rs)
{
if (!rs->max_sectors)
- rs->max_sectors = MAX_SECTORS;
+ rs->max_sectors = SAFE_MAX_SECTORS;
if (!rs->max_phys_segments)
rs->max_phys_segments = MAX_PHYS_SEGMENTS;
if (!rs->max_hw_segments)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 54a72f1..14ad2a7 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -462,6 +462,7 @@
req = blk_get_request(sdev->request_queue, write, gfp);
if (!req)
goto free_sense;
+ req->flags |= REQ_BLOCK_PC | REQ_QUIET;
if (use_sg)
err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp);
@@ -477,7 +478,6 @@
req->sense_len = 0;
req->timeout = timeout;
req->retries = retries;
- req->flags |= REQ_BLOCK_PC | REQ_QUIET;
req->end_io_data = sioc;
sioc->data = privdata;
diff --git a/fs/bio.c b/fs/bio.c
index 4d21ee3..38d3e80 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -313,7 +313,8 @@
}
static int __bio_add_page(request_queue_t *q, struct bio *bio, struct page
- *page, unsigned int len, unsigned int offset)
+ *page, unsigned int len, unsigned int offset,
+ unsigned short max_sectors)
{
int retried_segments = 0;
struct bio_vec *bvec;
@@ -327,7 +328,7 @@
if (bio->bi_vcnt >= bio->bi_max_vecs)
return 0;
- if (((bio->bi_size + len) >> 9) > q->max_sectors)
+ if (((bio->bi_size + len) >> 9) > max_sectors)
return 0;
/*
@@ -401,7 +402,7 @@
int bio_add_pc_page(request_queue_t *q, struct bio *bio, struct page *page,
unsigned int len, unsigned int offset)
{
- return __bio_add_page(q, bio, page, len, offset);
+ return __bio_add_page(q, bio, page, len, offset, q->max_hw_sectors);
}
/**
@@ -420,8 +421,8 @@
int bio_add_page(struct bio *bio, struct page *page, unsigned int len,
unsigned int offset)
{
- return __bio_add_page(bdev_get_queue(bio->bi_bdev), bio, page,
- len, offset);
+ struct request_queue *q = bdev_get_queue(bio->bi_bdev);
+ return __bio_add_page(q, bio, page, len, offset, q->max_sectors);
}
struct bio_map_data {
@@ -533,7 +534,7 @@
break;
}
- if (__bio_add_page(q, bio, page, bytes, 0) < bytes) {
+ if (bio_add_pc_page(q, bio, page, bytes, 0) < bytes) {
ret = -EINVAL;
break;
}
@@ -647,7 +648,8 @@
/*
* sorry...
*/
- if (__bio_add_page(q, bio, pages[j], bytes, offset) < bytes)
+ if (bio_add_pc_page(q, bio, pages[j], bytes, offset) <
+ bytes)
break;
len -= bytes;
@@ -820,8 +822,8 @@
if (bytes > len)
bytes = len;
- if (__bio_add_page(q, bio, virt_to_page(data), bytes,
- offset) < bytes)
+ if (bio_add_pc_page(q, bio, virt_to_page(data), bytes,
+ offset) < bytes)
break;
data += bytes;
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 509e9a03..a18500d 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -702,7 +702,8 @@
#define MAX_PHYS_SEGMENTS 128
#define MAX_HW_SEGMENTS 128
-#define MAX_SECTORS 255
+#define SAFE_MAX_SECTORS 255
+#define BLK_DEF_MAX_SECTORS 1024
#define MAX_SEGMENT_SIZE 65536
