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authorYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 12:17:53 -0700
committerYunhong Jiang <yunhong.jiang@intel.com>2015-08-04 15:44:42 -0700
commit9ca8dbcc65cfc63d6f5ef3312a33184e1d726e00 (patch)
tree1c9cafbcd35f783a87880a10f85d1a060db1a563 /kernel/block/blk-map.c
parent98260f3884f4a202f9ca5eabed40b1354c489b29 (diff)
Add the rt linux 4.1.3-rt3 as base
Import the rt linux 4.1.3-rt3 as OPNFV kvm base. It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and the base is: commit 0917f823c59692d751951bf5ea699a2d1e2f26a2 Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Sat Jul 25 12:13:34 2015 +0200 Prepare v4.1.3-rt3 Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> We lose all the git history this way and it's not good. We should apply another opnfv project repo in future. Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423 Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>
Diffstat (limited to 'kernel/block/blk-map.c')
-rw-r--r--kernel/block/blk-map.c220
1 files changed, 220 insertions, 0 deletions
diff --git a/kernel/block/blk-map.c b/kernel/block/blk-map.c
new file mode 100644
index 000000000..da310a105
--- /dev/null
+++ b/kernel/block/blk-map.c
@@ -0,0 +1,220 @@
+/*
+ * Functions related to mapping data to requests
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/uio.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_iter.bi_size;
+ }
+ return 0;
+}
+
+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;
+}
+
+/**
+ * blk_rq_map_user_iov - map user data to a request, for REQ_TYPE_BLOCK_PC usage
+ * @q: request queue where request should be inserted
+ * @rq: request to map data to
+ * @map_data: pointer to the rq_map_data holding pages (if necessary)
+ * @iter: iovec iterator
+ * @gfp_mask: memory allocation flags
+ *
+ * Description:
+ * Data will be mapped directly for zero copy I/O, if possible. Otherwise
+ * a kernel bounce buffer is used.
+ *
+ * A matching blk_rq_unmap_user() must be issued at the end of I/O, 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 rq_map_data *map_data,
+ const struct iov_iter *iter, gfp_t gfp_mask)
+{
+ struct bio *bio;
+ int unaligned = 0;
+ struct iov_iter i;
+ struct iovec iov;
+
+ if (!iter || !iter->count)
+ return -EINVAL;
+
+ iov_for_each(iov, i, *iter) {
+ unsigned long uaddr = (unsigned long) iov.iov_base;
+
+ if (!iov.iov_len)
+ return -EINVAL;
+
+ /*
+ * Keep going so we check length of all segments
+ */
+ if (uaddr & queue_dma_alignment(q))
+ unaligned = 1;
+ }
+
+ if (unaligned || (q->dma_pad_mask & iter->count) || map_data)
+ bio = bio_copy_user_iov(q, map_data, iter, gfp_mask);
+ else
+ bio = bio_map_user_iov(q, iter, gfp_mask);
+
+ if (IS_ERR(bio))
+ return PTR_ERR(bio);
+
+ if (map_data && map_data->null_mapped)
+ bio->bi_flags |= (1 << BIO_NULL_MAPPED);
+
+ if (bio->bi_iter.bi_size != iter->count) {
+ /*
+ * Grab an extra reference to this bio, as bio_unmap_user()
+ * expects to be able to drop it twice as it happens on the
+ * normal IO completion path
+ */
+ bio_get(bio);
+ bio_endio(bio, 0);
+ __blk_rq_unmap_user(bio);
+ return -EINVAL;
+ }
+
+ if (!bio_flagged(bio, BIO_USER_MAPPED))
+ rq->cmd_flags |= REQ_COPY_USER;
+
+ blk_queue_bounce(q, &bio);
+ bio_get(bio);
+ blk_rq_bio_prep(q, rq, bio);
+ return 0;
+}
+EXPORT_SYMBOL(blk_rq_map_user_iov);
+
+int blk_rq_map_user(struct request_queue *q, struct request *rq,
+ struct rq_map_data *map_data, void __user *ubuf,
+ unsigned long len, gfp_t gfp_mask)
+{
+ struct iovec iov;
+ struct iov_iter i;
+ int ret = import_single_range(rq_data_dir(rq), ubuf, len, &iov, &i);
+
+ if (unlikely(ret < 0))
+ return ret;
+
+ return blk_rq_map_user_iov(q, rq, map_data, &i, gfp_mask);
+}
+EXPORT_SYMBOL(blk_rq_map_user);
+
+/**
+ * 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 I/O 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_TYPE_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
+ *
+ * Description:
+ * Data will be mapped directly if possible. Otherwise a bounce
+ * buffer is used. Can be called multiple times to append multiple
+ * buffers.
+ */
+int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
+ unsigned int len, gfp_t gfp_mask)
+{
+ int reading = rq_data_dir(rq) == READ;
+ unsigned long addr = (unsigned long) kbuf;
+ int do_copy = 0;
+ struct bio *bio;
+ int ret;
+
+ if (len > (queue_max_hw_sectors(q) << 9))
+ return -EINVAL;
+ if (!len || !kbuf)
+ return -EINVAL;
+
+ do_copy = !blk_rq_aligned(q, addr, len) || object_is_on_stack(kbuf);
+ if (do_copy)
+ bio = bio_copy_kern(q, kbuf, len, gfp_mask, reading);
+ else
+ bio = bio_map_kern(q, kbuf, len, gfp_mask);
+
+ if (IS_ERR(bio))
+ return PTR_ERR(bio);
+
+ if (!reading)
+ bio->bi_rw |= REQ_WRITE;
+
+ if (do_copy)
+ rq->cmd_flags |= REQ_COPY_USER;
+
+ ret = blk_rq_append_bio(q, rq, bio);
+ if (unlikely(ret)) {
+ /* request is too big */
+ bio_put(bio);
+ return ret;
+ }
+
+ blk_queue_bounce(q, &rq->bio);
+ return 0;
+}
+EXPORT_SYMBOL(blk_rq_map_kern);