diff options
| -rw-r--r-- | io_uring/rsrc.c | 75 |
1 files changed, 37 insertions, 38 deletions
diff --git a/io_uring/rsrc.c b/io_uring/rsrc.c index b36c8825550e..4d62897d1c89 100644 --- a/io_uring/rsrc.c +++ b/io_uring/rsrc.c @@ -1036,6 +1036,7 @@ static int io_import_fixed(int ddir, struct iov_iter *iter, struct io_mapped_ubuf *imu, u64 buf_addr, size_t len) { + const struct bio_vec *bvec; size_t offset; int ret; @@ -1054,47 +1055,45 @@ static int io_import_fixed(int ddir, struct iov_iter *iter, offset = buf_addr - imu->ubuf; iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); - if (offset) { - /* - * Don't use iov_iter_advance() here, as it's really slow for - * using the latter parts of a big fixed buffer - it iterates - * over each segment manually. We can cheat a bit here for user - * registered nodes, because we know that: - * - * 1) it's a BVEC iter, we set it up - * 2) all bvecs are the same in size, except potentially the - * first and last bvec - * - * So just find our index, and adjust the iterator afterwards. - * If the offset is within the first bvec (or the whole first - * bvec, just use iov_iter_advance(). This makes it easier - * since we can just skip the first segment, which may not - * be folio_size aligned. - */ - const struct bio_vec *bvec = imu->bvec; + /* + * Don't use iov_iter_advance() here, as it's really slow for + * using the latter parts of a big fixed buffer - it iterates + * over each segment manually. We can cheat a bit here for user + * registered nodes, because we know that: + * + * 1) it's a BVEC iter, we set it up + * 2) all bvecs are the same in size, except potentially the + * first and last bvec + * + * So just find our index, and adjust the iterator afterwards. + * If the offset is within the first bvec (or the whole first + * bvec, just use iov_iter_advance(). This makes it easier + * since we can just skip the first segment, which may not + * be folio_size aligned. + */ + bvec = imu->bvec; - /* - * Kernel buffer bvecs, on the other hand, don't necessarily - * have the size property of user registered ones, so we have - * to use the slow iter advance. - */ - if (offset < bvec->bv_len) { - iter->count -= offset; - iter->iov_offset = offset; - } else if (imu->is_kbuf) { - iov_iter_advance(iter, offset); - } else { - unsigned long seg_skip; + /* + * Kernel buffer bvecs, on the other hand, don't necessarily + * have the size property of user registered ones, so we have + * to use the slow iter advance. + */ + if (offset < bvec->bv_len) { + iter->count -= offset; + iter->iov_offset = offset; + } else if (imu->is_kbuf) { + iov_iter_advance(iter, offset); + } else { + unsigned long seg_skip; - /* skip first vec */ - offset -= bvec->bv_len; - seg_skip = 1 + (offset >> imu->folio_shift); + /* skip first vec */ + offset -= bvec->bv_len; + seg_skip = 1 + (offset >> imu->folio_shift); - iter->bvec += seg_skip; - iter->nr_segs -= seg_skip; - iter->count -= bvec->bv_len + offset; - iter->iov_offset = offset & ((1UL << imu->folio_shift) - 1); - } + iter->bvec += seg_skip; + iter->nr_segs -= seg_skip; + iter->count -= bvec->bv_len + offset; + iter->iov_offset = offset & ((1UL << imu->folio_shift) - 1); } return 0; |