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authorMing Lei <ming.lei@canonical.com>2016-06-09 19:00:58 +0300
committerJens Axboe <axboe@fb.com>2016-06-09 19:00:58 +0300
commit8fc554552c9d89e7bf76cd4cbc0085648bf3125b (patch)
tree1fe45de8fea776f50a7bbfa970c17973a79f40da /include/linux/bvec.h
parent52b9c330c6a8a4b5a1819bdaddf4ec76ab571e81 (diff)
downloadlinux-8fc554552c9d89e7bf76cd4cbc0085648bf3125b.tar.xz
block: move bvec iterator into include/linux/bvec.h
bvec iterator helpers should be used to implement by iterate_bvec():lib/iov_iter.c too, and move them into one header, so that we can keep bvec iterator header out of CONFIG_BLOCK. Then we can remove the reinventing of wheel in iterate_bvec(). Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lei <ming.lei@canonical.com> Tested-by: Hannes Reinecke <hare@suse.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'include/linux/bvec.h')
-rw-r--r--include/linux/bvec.h74
1 files changed, 74 insertions, 0 deletions
diff --git a/include/linux/bvec.h b/include/linux/bvec.h
new file mode 100644
index 000000000000..29c459da277e
--- /dev/null
+++ b/include/linux/bvec.h
@@ -0,0 +1,74 @@
+/*
+ * bvec iterator
+ *
+ * Copyright (C) 2001 Ming Lei <ming.lei@canonical.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public Licens
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
+ */
+#ifndef __LINUX_BVEC_ITER_H
+#define __LINUX_BVEC_ITER_H
+
+#include <linux/blk_types.h>
+
+/*
+ * various member access, note that bio_data should of course not be used
+ * on highmem page vectors
+ */
+#define __bvec_iter_bvec(bvec, iter) (&(bvec)[(iter).bi_idx])
+
+#define bvec_iter_page(bvec, iter) \
+ (__bvec_iter_bvec((bvec), (iter))->bv_page)
+
+#define bvec_iter_len(bvec, iter) \
+ min((iter).bi_size, \
+ __bvec_iter_bvec((bvec), (iter))->bv_len - (iter).bi_bvec_done)
+
+#define bvec_iter_offset(bvec, iter) \
+ (__bvec_iter_bvec((bvec), (iter))->bv_offset + (iter).bi_bvec_done)
+
+#define bvec_iter_bvec(bvec, iter) \
+((struct bio_vec) { \
+ .bv_page = bvec_iter_page((bvec), (iter)), \
+ .bv_len = bvec_iter_len((bvec), (iter)), \
+ .bv_offset = bvec_iter_offset((bvec), (iter)), \
+})
+
+static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
+ unsigned bytes)
+{
+ WARN_ONCE(bytes > iter->bi_size,
+ "Attempted to advance past end of bvec iter\n");
+
+ while (bytes) {
+ unsigned len = min(bytes, bvec_iter_len(bv, *iter));
+
+ bytes -= len;
+ iter->bi_size -= len;
+ iter->bi_bvec_done += len;
+
+ if (iter->bi_bvec_done == __bvec_iter_bvec(bv, *iter)->bv_len) {
+ iter->bi_bvec_done = 0;
+ iter->bi_idx++;
+ }
+ }
+}
+
+#define for_each_bvec(bvl, bio_vec, iter, start) \
+ for (iter = (start); \
+ (iter).bi_size && \
+ ((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
+ bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))
+
+#endif /* __LINUX_BVEC_ITER_H */