From b620743077e291ae7d0debd21f50413a8c266229 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Wed, 26 Jun 2019 15:49:28 +0200 Subject: [PATCH] block: never take page references for ITER_BVEC If we pass pages through an iov_iter we always already have a reference in the caller. Thus remove the ITER_BVEC_FLAG_NO_REF and don't take reference to pages by default for bvec backed iov_iters. Reviewed-by: Minwoo Im Reviewed-by: Johannes Thumshirn Signed-off-by: Christoph Hellwig Signed-off-by: Jens Axboe --- block/bio.c | 14 +------------- drivers/block/loop.c | 16 ++++------------ fs/io_uring.c | 3 --- include/linux/uio.h | 10 +--------- 4 files changed, 6 insertions(+), 37 deletions(-) diff --git a/block/bio.c b/block/bio.c index 1cbf2a7c245e..5733b9426231 100644 --- a/block/bio.c +++ b/block/bio.c @@ -836,15 +836,6 @@ int bio_add_page(struct bio *bio, struct page *page, } EXPORT_SYMBOL(bio_add_page); -static void bio_get_pages(struct bio *bio) -{ - struct bvec_iter_all iter_all; - struct bio_vec *bvec; - - bio_for_each_segment_all(bvec, bio, iter_all) - get_page(bvec->bv_page); -} - void bio_release_pages(struct bio *bio, bool mark_dirty) { struct bvec_iter_all iter_all; @@ -960,11 +951,8 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) ret = __bio_iov_iter_get_pages(bio, iter); } while (!ret && iov_iter_count(iter) && !bio_full(bio)); - if (iov_iter_bvec_no_ref(iter)) + if (is_bvec) bio_set_flag(bio, BIO_NO_PAGE_REF); - else if (is_bvec) - bio_get_pages(bio); - return bio->bi_vcnt ? 0 : ret; } diff --git a/drivers/block/loop.c b/drivers/block/loop.c index f11b7dc16e9d..44c9985f352a 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -264,20 +264,12 @@ lo_do_transfer(struct loop_device *lo, int cmd, return ret; } -static inline void loop_iov_iter_bvec(struct iov_iter *i, - unsigned int direction, const struct bio_vec *bvec, - unsigned long nr_segs, size_t count) -{ - iov_iter_bvec(i, direction, bvec, nr_segs, count); - i->type |= ITER_BVEC_FLAG_NO_REF; -} - static int lo_write_bvec(struct file *file, struct bio_vec *bvec, loff_t *ppos) { struct iov_iter i; ssize_t bw; - loop_iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len); + iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len); file_start_write(file); bw = vfs_iter_write(file, &i, ppos, 0); @@ -355,7 +347,7 @@ static int lo_read_simple(struct loop_device *lo, struct request *rq, ssize_t len; rq_for_each_segment(bvec, rq, iter) { - loop_iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len); + iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len); len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); if (len < 0) return len; @@ -396,7 +388,7 @@ static int lo_read_transfer(struct loop_device *lo, struct request *rq, b.bv_offset = 0; b.bv_len = bvec.bv_len; - loop_iov_iter_bvec(&i, READ, &b, 1, b.bv_len); + iov_iter_bvec(&i, READ, &b, 1, b.bv_len); len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0); if (len < 0) { ret = len; @@ -563,7 +555,7 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, } atomic_set(&cmd->ref, 2); - loop_iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); + iov_iter_bvec(&iter, rw, bvec, nr_bvec, blk_rq_bytes(rq)); iter.iov_offset = offset; cmd->iocb.ki_pos = pos; diff --git a/fs/io_uring.c b/fs/io_uring.c index 86a2bd721900..eb6ab1507913 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -997,9 +997,6 @@ static int io_import_fixed(struct io_ring_ctx *ctx, int rw, iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); if (offset) iov_iter_advance(iter, offset); - - /* don't drop a reference to these pages */ - iter->type |= ITER_BVEC_FLAG_NO_REF; return 0; } diff --git a/include/linux/uio.h b/include/linux/uio.h index 2c90a0842ee8..cea1761c5672 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -19,9 +19,6 @@ struct kvec { }; enum iter_type { - /* set if ITER_BVEC doesn't hold a bv_page ref */ - ITER_BVEC_FLAG_NO_REF = 2, - /* iter types */ ITER_IOVEC = 4, ITER_KVEC = 8, @@ -56,7 +53,7 @@ struct iov_iter { static inline enum iter_type iov_iter_type(const struct iov_iter *i) { - return i->type & ~(READ | WRITE | ITER_BVEC_FLAG_NO_REF); + return i->type & ~(READ | WRITE); } static inline bool iter_is_iovec(const struct iov_iter *i) @@ -89,11 +86,6 @@ static inline unsigned char iov_iter_rw(const struct iov_iter *i) return i->type & (READ | WRITE); } -static inline bool iov_iter_bvec_no_ref(const struct iov_iter *i) -{ - return (i->type & ITER_BVEC_FLAG_NO_REF) != 0; -} - /* * Total number of bytes covered by an iovec. *