add blk_rq_map_kern_iov() which takes a iovec of buffers then
maps them into bios and a request. It can make them into multiple
bios to support sg and st's large requests and avoid the BIO_MAX_PAGES
limit.
Signed-off-by: Mike Christie <michaelc@xxxxxxxxxxx>
diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -28,6 +28,7 @@
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/writeback.h>
+#include <linux/uio.h>
#include <linux/blkdev.h>
/*
@@ -2278,6 +2279,70 @@ int blk_rq_map_kern(request_queue_t *q,
EXPORT_SYMBOL(blk_rq_map_kern);
/**
+ * blk_rq_map_kern_iov - map kernel data to a request, for REQ_BLOCK_PC usage
+ * @q: request queue where request should be inserted
+ * @rq: request to fill
+ * @vec: pointer to kvec
+ * @vec_count: number of elements in kvec
+ * @gfp_mask: memory allocation flags
+ *
+ * blk_rq_map_kern_iov maps a kvec into a multiple bio request so that
+ * it can create very large requests.
+ *
+ * For now we assume that each element will fit in one bio
+ */
+int blk_rq_map_kern_iov(request_queue_t *q, struct request *rq,
+ struct kvec *vec, int vec_count, unsigned int gfp)
+{
+ struct bio *bio;
+ unsigned int len = 0;
+ int i, err = 0;
+
+ for (i = 0; i < vec_count; i++) {
+ bio = bio_map_kern(q, vec[i].iov_base, vec[i].iov_len, gfp);
+ if (IS_ERR(bio)) {
+ err = PTR_ERR(bio);
+ goto free_bios;
+ }
+
+ bio->bi_flags &= ~(1 << BIO_SEG_VALID);
+ blk_queue_bounce(q, &bio);
+ len += vec[i].iov_len;
+
+ if (rq_data_dir(rq) == WRITE)
+ bio->bi_rw |= (1 << BIO_RW);
+
+ if (i == 0)
+ blk_rq_bio_prep(q, rq, bio);
+ else if (!q->back_merge_fn(q, rq, bio)) {
+ goto free_bios;
+ } else {
+ rq->biotail->bi_next = bio;
+ rq->biotail = bio;
+ }
+
+ rq->nr_sectors = rq->hard_nr_sectors += bio_sectors(bio);
+ }
+
+ rq->buffer = rq->data = NULL;
+ rq->data_len = len;
+ return 0;
+
+free_bios:
+ while ((bio = rq->bio) != NULL) {
+ rq->bio = bio->bi_next;
+ /*
+ * call endio instead of bio_put incase it was bounced
+ */
+ bio_endio(bio, bio->bi_size, 0);
+ }
+
+ return err;
+}
+
+EXPORT_SYMBOL(blk_rq_map_kern_iov);
+
+/**
* blk_execute_rq_nowait - insert a request into queue for execution
* @q: queue to insert the request in
* @bd_disk: matching gendisk
@@ -2302,6 +2367,8 @@ void blk_execute_rq_nowait(request_queue
generic_unplug_device(q);
}
+EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
+
/**
* blk_execute_rq - insert a request into queue for execution
* @q: queue to insert the request in
@@ -2483,7 +2550,7 @@ void disk_round_stats(struct gendisk *di
/*
* queue lock must be held
*/
-static void __blk_put_request(request_queue_t *q, struct request *req)
+void __blk_put_request(request_queue_t *q, struct request *req)
{
struct request_list *rl = req->rl;
@@ -2511,6 +2578,8 @@ static void __blk_put_request(request_qu
}
}
+EXPORT_SYMBOL_GPL(__blk_put_request);
+
void blk_put_request(struct request *req)
{
/*
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -22,6 +22,7 @@ typedef struct request_queue request_que
struct elevator_queue;
typedef struct elevator_queue elevator_t;
struct request_pm_state;
+struct kvec;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
@@ -548,6 +549,7 @@ extern void blk_unregister_queue(struct
extern void register_disk(struct gendisk *dev);
extern void generic_make_request(struct bio *bio);
extern void blk_put_request(struct request *);
+extern void __blk_put_request(request_queue_t *, struct request *);
extern void blk_end_sync_rq(struct request *rq);
extern void blk_attempt_remerge(request_queue_t *, struct request *);
extern struct request *blk_get_request(request_queue_t *, int, int);
@@ -566,9 +568,15 @@ extern void blk_queue_activity_fn(reques
extern int blk_rq_map_user(request_queue_t *, struct request *, void __user *, unsigned int);
extern int blk_rq_unmap_user(struct bio *, unsigned int);
extern int blk_rq_map_kern(request_queue_t *, struct request *, void *, unsigned int, unsigned int);
+extern int blk_rq_map_kern_iov(request_queue_t *, struct request *,
+ struct kvec *, int, unsigned int);
extern int blk_rq_map_user_iov(request_queue_t *, struct request *, struct sg_iovec *, int);
extern int blk_execute_rq(request_queue_t *, struct gendisk *,
struct request *, int);
+extern void blk_execute_rq_nowait(request_queue_t *, struct gendisk *,
+ struct request *, int,
+ void (*done)(struct request *));
+
static inline request_queue_t *bdev_get_queue(struct block_device *bdev)
{
return bdev->bd_disk->queue;
-
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