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authorJens Axboe <jens.axboe@oracle.com>2008-01-29 14:53:40 +0100
committerJens Axboe <jens.axboe@oracle.com>2008-01-29 21:55:08 +0100
commit86db1e29772372155db08ff48a9ceb76e11a2ad1 (patch)
tree312f38eb3245873c476c50f816b85610fef9615a /block/blk-map.c
parent8324aa91d1e11a1fc25f209687a0b2e6c2ed47d0 (diff)
downloadkernel-86db1e29772372155db08ff48a9ceb76e11a2ad1.tar.gz
block: continue ll_rw_blk.c splitup
Adds files for barrier handling, rq execution, io context handling, mapping data to requests, and queue settings. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Diffstat (limited to 'block/blk-map.c')
-rw-r--r--block/blk-map.c264
1 files changed, 264 insertions, 0 deletions
diff --git a/block/blk-map.c b/block/blk-map.c
new file mode 100644
index 000000000000..916cfc96ffa0
--- /dev/null
+++ b/block/blk-map.c
@@ -0,0 +1,264 @@
+/*
+ * Functions related to mapping data to requests
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+
+#include "blk.h"
+
+int blk_rq_append_bio(struct request_queue *q, struct request *rq,
+ struct bio *bio)
+{
+ if (!rq->bio)
+ blk_rq_bio_prep(q, rq, bio);
+ else if (!ll_back_merge_fn(q, rq, bio))
+ return -EINVAL;
+ else {
+ rq->biotail->bi_next = bio;
+ rq->biotail = bio;
+
+ rq->data_len += bio->bi_size;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(blk_rq_append_bio);
+
+static int __blk_rq_unmap_user(struct bio *bio)
+{
+ int ret = 0;
+
+ if (bio) {
+ if (bio_flagged(bio, BIO_USER_MAPPED))
+ bio_unmap_user(bio);
+ else
+ ret = bio_uncopy_user(bio);
+ }
+
+ return ret;
+}
+
+static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
+ void __user *ubuf, unsigned int len)
+{
+ unsigned long uaddr;
+ struct bio *bio, *orig_bio;
+ int reading, ret;
+
+ reading = rq_data_dir(rq) == READ;
+
+ /*
+ * if alignment requirement is satisfied, map in user pages for
+ * direct dma. else, set up kernel bounce buffers
+ */
+ uaddr = (unsigned long) ubuf;
+ if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
+ bio = bio_map_user(q, NULL, uaddr, len, reading);
+ else
+ bio = bio_copy_user(q, uaddr, len, reading);
+
+ if (IS_ERR(bio))
+ return PTR_ERR(bio);
+
+ orig_bio = bio;
+ blk_queue_bounce(q, &bio);
+
+ /*
+ * We link the bounce buffer in and could have to traverse it
+ * later so we have to get a ref to prevent it from being freed
+ */
+ bio_get(bio);
+
+ ret = blk_rq_append_bio(q, rq, bio);
+ if (!ret)
+ return bio->bi_size;
+
+ /* if it was boucned we must call the end io function */
+ bio_endio(bio, 0);
+ __blk_rq_unmap_user(orig_bio);
+ bio_put(bio);
+ return ret;
+}
+
+/**
+ * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
+ * @q: request queue where request should be inserted
+ * @rq: request structure to fill
+ * @ubuf: the user buffer
+ * @len: length of user data
+ *
+ * Description:
+ * Data will be mapped directly for zero copy io, if possible. Otherwise
+ * a kernel bounce buffer is used.
+ *
+ * A matching blk_rq_unmap_user() must be issued at the end of io, while
+ * still in process context.
+ *
+ * Note: The mapped bio may need to be bounced through blk_queue_bounce()
+ * before being submitted to the device, as pages mapped may be out of
+ * reach. It's the callers responsibility to make sure this happens. The
+ * original bio must be passed back in to blk_rq_unmap_user() for proper
+ * unmapping.
+ */
+int blk_rq_map_user(struct request_queue *q, struct request *rq,
+ void __user *ubuf, unsigned long len)
+{
+ unsigned long bytes_read = 0;
+ struct bio *bio = NULL;
+ int ret;
+
+ if (len > (q->max_hw_sectors << 9))
+ return -EINVAL;
+ if (!len || !ubuf)
+ return -EINVAL;
+
+ while (bytes_read != len) {
+ unsigned long map_len, end, start;
+
+ map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
+ end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
+ >> PAGE_SHIFT;
+ start = (unsigned long)ubuf >> PAGE_SHIFT;
+
+ /*
+ * A bad offset could cause us to require BIO_MAX_PAGES + 1
+ * pages. If this happens we just lower the requested
+ * mapping len by a page so that we can fit
+ */
+ if (end - start > BIO_MAX_PAGES)
+ map_len -= PAGE_SIZE;
+
+ ret = __blk_rq_map_user(q, rq, ubuf, map_len);
+ if (ret < 0)
+ goto unmap_rq;
+ if (!bio)
+ bio = rq->bio;
+ bytes_read += ret;
+ ubuf += ret;
+ }
+
+ rq->buffer = rq->data = NULL;
+ return 0;
+unmap_rq:
+ blk_rq_unmap_user(bio);
+ return ret;
+}
+
+EXPORT_SYMBOL(blk_rq_map_user);
+
+/**
+ * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
+ * @q: request queue where request should be inserted
+ * @rq: request to map data to
+ * @iov: pointer to the iovec
+ * @iov_count: number of elements in the iovec
+ * @len: I/O byte count
+ *
+ * Description:
+ * Data will be mapped directly for zero copy io, if possible. Otherwise
+ * a kernel bounce buffer is used.
+ *
+ * A matching blk_rq_unmap_user() must be issued at the end of io, while
+ * still in process context.
+ *
+ * Note: The mapped bio may need to be bounced through blk_queue_bounce()
+ * before being submitted to the device, as pages mapped may be out of
+ * reach. It's the callers responsibility to make sure this happens. The
+ * original bio must be passed back in to blk_rq_unmap_user() for proper
+ * unmapping.
+ */
+int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
+ struct sg_iovec *iov, int iov_count, unsigned int len)
+{
+ struct bio *bio;
+
+ if (!iov || iov_count <= 0)
+ return -EINVAL;
+
+ /* we don't allow misaligned data like bio_map_user() does. If the
+ * user is using sg, they're expected to know the alignment constraints
+ * and respect them accordingly */
+ bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
+ if (IS_ERR(bio))
+ return PTR_ERR(bio);
+
+ if (bio->bi_size != len) {
+ bio_endio(bio, 0);
+ bio_unmap_user(bio);
+ return -EINVAL;
+ }
+
+ bio_get(bio);
+ blk_rq_bio_prep(q, rq, bio);
+ rq->buffer = rq->data = NULL;
+ return 0;
+}
+
+EXPORT_SYMBOL(blk_rq_map_user_iov);
+
+/**
+ * blk_rq_unmap_user - unmap a request with user data
+ * @bio: start of bio list
+ *
+ * Description:
+ * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
+ * supply the original rq->bio from the blk_rq_map_user() return, since
+ * the io completion may have changed rq->bio.
+ */
+int blk_rq_unmap_user(struct bio *bio)
+{
+ struct bio *mapped_bio;
+ int ret = 0, ret2;
+
+ while (bio) {
+ mapped_bio = bio;
+ if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
+ mapped_bio = bio->bi_private;
+
+ ret2 = __blk_rq_unmap_user(mapped_bio);
+ if (ret2 && !ret)
+ ret = ret2;
+
+ mapped_bio = bio;
+ bio = bio->bi_next;
+ bio_put(mapped_bio);
+ }
+
+ return ret;
+}
+
+EXPORT_SYMBOL(blk_rq_unmap_user);
+
+/**
+ * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
+ * @q: request queue where request should be inserted
+ * @rq: request to fill
+ * @kbuf: the kernel buffer
+ * @len: length of user data
+ * @gfp_mask: memory allocation flags
+ */
+int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
+ unsigned int len, gfp_t gfp_mask)
+{
+ struct bio *bio;
+
+ if (len > (q->max_hw_sectors << 9))
+ return -EINVAL;
+ if (!len || !kbuf)
+ return -EINVAL;
+
+ bio = bio_map_kern(q, kbuf, len, gfp_mask);
+ if (IS_ERR(bio))
+ return PTR_ERR(bio);
+
+ if (rq_data_dir(rq) == WRITE)
+ bio->bi_rw |= (1 << BIO_RW);
+
+ blk_rq_bio_prep(q, rq, bio);
+ blk_queue_bounce(q, &rq->bio);
+ rq->buffer = rq->data = NULL;
+ return 0;
+}
+
+EXPORT_SYMBOL(blk_rq_map_kern);