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authorBoaz Harrosh <bharrosh@panasas.com>2009-05-17 18:57:15 +0300
committerJens Axboe <jens.axboe@oracle.com>2009-05-19 12:14:56 +0200
commit79eb63e9e5875b84341a3a05f8e6ae9cdb4bb6f6 (patch)
treebdadc2037c1d0f24c6c73b71ae82fdd7b907e610 /block
parentbc38bf106c967389a465d926be22c7371abba69d (diff)
downloadlinux-79eb63e9e5875b84341a3a05f8e6ae9cdb4bb6f6.tar.bz2
block: Add blk_make_request(), takes bio, returns a request
New block API: given a struct bio allocates a new request. This is the parallel of generic_make_request for BLOCK_PC commands users. The passed bio may be a chained-bio. The bio is bounced if needed inside the call to this member. This is in the effort of un-exporting blk_rq_append_bio(). Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> CC: Jeff Garzik <jeff@garzik.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-core.c45
1 files changed, 45 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c
index e3f7e6a3a095..bec1d69952d0 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -891,6 +891,51 @@ struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
EXPORT_SYMBOL(blk_get_request);
/**
+ * blk_make_request - given a bio, allocate a corresponding struct request.
+ *
+ * @bio: The bio describing the memory mappings that will be submitted for IO.
+ * It may be a chained-bio properly constructed by block/bio layer.
+ *
+ * blk_make_request is the parallel of generic_make_request for BLOCK_PC
+ * type commands. Where the struct request needs to be farther initialized by
+ * the caller. It is passed a &struct bio, which describes the memory info of
+ * the I/O transfer.
+ *
+ * The caller of blk_make_request must make sure that bi_io_vec
+ * are set to describe the memory buffers. That bio_data_dir() will return
+ * the needed direction of the request. (And all bio's in the passed bio-chain
+ * are properly set accordingly)
+ *
+ * If called under none-sleepable conditions, mapped bio buffers must not
+ * need bouncing, by calling the appropriate masked or flagged allocator,
+ * suitable for the target device. Otherwise the call to blk_queue_bounce will
+ * BUG.
+ */
+struct request *blk_make_request(struct request_queue *q, struct bio *bio,
+ gfp_t gfp_mask)
+{
+ struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);
+
+ if (unlikely(!rq))
+ return ERR_PTR(-ENOMEM);
+
+ for_each_bio(bio) {
+ struct bio *bounce_bio = bio;
+ int ret;
+
+ blk_queue_bounce(q, &bounce_bio);
+ ret = blk_rq_append_bio(q, rq, bounce_bio);
+ if (unlikely(ret)) {
+ blk_put_request(rq);
+ return ERR_PTR(ret);
+ }
+ }
+
+ return rq;
+}
+EXPORT_SYMBOL(blk_make_request);
+
+/**
* blk_requeue_request - put a request back on queue
* @q: request queue where request should be inserted
* @rq: request to be inserted