[SCSI] seperate max_sectors from max_hw_sectors
[linux-3.10.git] / block / ll_rw_blk.c
index c525b5a2b59849d7af6fb3fe45e8a8699711e085..d4beb9a89ee0b08b0b681ca5a09e5cda59b7e99f 100644 (file)
@@ -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;