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authorMike Christie <michaelc@cs.wisc.edu>2005-12-05 02:37:06 -0600
committerJames Bottomley <jejb@mulgrave.(none)>2005-12-15 15:11:40 -0800
commitdefd94b75409b983f94548ea2f52ff5787ddb848 (patch)
tree0138b2dae748de88edaee4da23431f1a9dd347a1 /block
parent8b05b773b6030de5b1bab1cbb0bf1ff8c34cdbe0 (diff)
downloadlinux-defd94b75409b983f94548ea2f52ff5787ddb848.tar.gz
[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>
Diffstat (limited to 'block')
-rw-r--r--block/ll_rw_blk.c34
-rw-r--r--block/scsi_ioctl.c2
2 files changed, 27 insertions, 9 deletions
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index c525b5a2b59..d4beb9a89ee 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -239,7 +239,7 @@ void blk_queue_make_request(request_queue_t * q, make_request_fn * mfn)
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 @@ void blk_queue_max_sectors(request_queue_t *q, unsigned short max_sectors)
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 @@ EXPORT_SYMBOL(blk_queue_hardsect_size);
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 inline int ll_new_hw_segment(request_queue_t *q,
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_back_merge_fn(request_queue_t *q, struct request *req,
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 @@ int blk_rq_map_user(request_queue_t *q, struct request *rq, void __user *ubuf,
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 @@ int blk_rq_map_kern(request_queue_t *q, struct request *rq, void *kbuf,
{
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 382dea7b224..4e390dfd315 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -233,7 +233,7 @@ static int sg_io(struct file *file, request_queue_t *q,
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)