Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
ublk: use rq_for_each_segment() for user copy
ublk_advance_io_iter() and ublk_copy_io_pages() currently open-code the
iteration over the request's bvecs. Switch to the rq_for_each_segment()
macro provided by blk-mq to avoid reaching into the bio internals and
simplify the code.
Suggested-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
authored by
Caleb Sander Mateos
and committed by
Jens Axboe
e87d66ab
2299ceec
+19
-51
+19
-51
drivers/block/ublk_drv.c
+19
-51
drivers/block/ublk_drv.c
···
913
913
.report_zones = ublk_report_zones,
914
914
};
915
915
916
-
struct ublk_io_iter {
917
-
struct bio *bio;
918
-
struct bvec_iter iter;
919
-
};
920
-
921
-
/* return how many bytes are copied */
922
-
static size_t ublk_copy_io_pages(struct ublk_io_iter *data,
923
-
struct iov_iter *uiter, int dir)
916
+
/*
917
+
* Copy data between request pages and io_iter, and 'offset'
918
+
* is the start point of linear offset of request.
919
+
*/
920
+
static size_t ublk_copy_user_pages(const struct request *req,
921
+
unsigned offset, struct iov_iter *uiter, int dir)
924
922
{
923
+
struct req_iterator iter;
924
+
struct bio_vec bv;
925
925
size_t done = 0;
926
926
927
-
for (;;) {
928
-
struct bio_vec bv = bio_iter_iovec(data->bio, data->iter);
929
-
void *bv_buf = bvec_kmap_local(&bv);
927
+
rq_for_each_segment(bv, req, iter) {
928
+
void *bv_buf;
930
929
size_t copied;
931
930
931
+
if (offset >= bv.bv_len) {
932
+
offset -= bv.bv_len;
933
+
continue;
934
+
}
935
+
936
+
bv.bv_offset += offset;
937
+
bv.bv_len -= offset;
938
+
bv_buf = bvec_kmap_local(&bv);
932
939
if (dir == ITER_DEST)
933
940
copied = copy_to_iter(bv_buf, bv.bv_len, uiter);
934
941
else
···
947
940
if (copied < bv.bv_len)
948
941
break;
949
942
950
-
/* advance bio */
951
-
bio_advance_iter_single(data->bio, &data->iter, copied);
952
-
if (!data->iter.bi_size) {
953
-
data->bio = data->bio->bi_next;
954
-
if (data->bio == NULL)
955
-
break;
956
-
data->iter = data->bio->bi_iter;
957
-
}
943
+
offset = 0;
958
944
}
959
945
return done;
960
-
}
961
-
962
-
static bool ublk_advance_io_iter(const struct request *req,
963
-
struct ublk_io_iter *iter, unsigned int offset)
964
-
{
965
-
struct bio *bio = req->bio;
966
-
967
-
for_each_bio(bio) {
968
-
if (bio->bi_iter.bi_size > offset) {
969
-
iter->bio = bio;
970
-
iter->iter = bio->bi_iter;
971
-
bio_advance_iter(iter->bio, &iter->iter, offset);
972
-
return true;
973
-
}
974
-
offset -= bio->bi_iter.bi_size;
975
-
}
976
-
return false;
977
-
}
978
-
979
-
/*
980
-
* Copy data between request pages and io_iter, and 'offset'
981
-
* is the start point of linear offset of request.
982
-
*/
983
-
static size_t ublk_copy_user_pages(const struct request *req,
984
-
unsigned offset, struct iov_iter *uiter, int dir)
985
-
{
986
-
struct ublk_io_iter iter;
987
-
988
-
if (!ublk_advance_io_iter(req, &iter, offset))
989
-
return 0;
990
-
991
-
return ublk_copy_io_pages(&iter, uiter, dir);
992
946
}
993
947
994
948
static inline bool ublk_need_map_req(const struct request *req)