Re: [PATCH 1/6] iomap: convert iomap_dio_rw() to an args structure

Damien Le Moal
2021-01-12T01:23:55Z

On 2021/01/12 10:08, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
>
> Adding yet another parameter to the iomap_dio_rw() interface means
> changing lots of filesystems to add the parameter. Convert this
> interface to an args structure so in future we don't need to modify
> every caller to add a new parameter.
>
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
> fs/btrfs/file.c | 21 ++++++++++++++++-----
> fs/ext4/file.c | 24 ++++++++++++++++++------
> fs/gfs2/file.c | 19 ++++++++++++++-----
> fs/iomap/direct-io.c | 30 ++++++++++++++----------------
> fs/xfs/xfs_file.c | 30 +++++++++++++++++++++---------
> fs/zonefs/super.c | 21 +++++++++++++++++----
> include/linux/iomap.h | 16 ++++++++++------
> 7 files changed, 110 insertions(+), 51 deletions(-)
>
> diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
> index 0e41459b8de6..a49d9fa918d1 100644
> --- a/fs/btrfs/file.c
> +++ b/fs/btrfs/file.c
> @@ -1907,6 +1907,13 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
> ssize_t err;
> unsigned int ilock_flags = 0;
> struct iomap_dio *dio = NULL;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = from,
> + .ops = &btrfs_dio_iomap_ops,
> + .dops = &btrfs_dio_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> if (iocb->ki_flags & IOCB_NOWAIT)
> ilock_flags |= BTRFS_ILOCK_TRY;
> @@ -1949,9 +1956,7 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
> goto buffered;
> }
>
> - dio = __iomap_dio_rw(iocb, from, &btrfs_dio_iomap_ops,
> - &btrfs_dio_ops, is_sync_kiocb(iocb));
> -
> + dio = __iomap_dio_rw(&args);
> btrfs_inode_unlock(inode, ilock_flags);
>
> if (IS_ERR_OR_NULL(dio)) {
> @@ -3617,13 +3622,19 @@ static ssize_t btrfs_direct_read(struct kiocb *iocb, struct iov_iter *to)
> {
> struct inode *inode = file_inode(iocb->ki_filp);
> ssize_t ret;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = to,
> + .ops = &btrfs_dio_iomap_ops,
> + .dops = &btrfs_dio_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> if (check_direct_read(btrfs_sb(inode->i_sb), to, iocb->ki_pos))
> return 0;
>
> btrfs_inode_lock(inode, BTRFS_ILOCK_SHARED);
> - ret = iomap_dio_rw(iocb, to, &btrfs_dio_iomap_ops, &btrfs_dio_ops,
> - is_sync_kiocb(iocb));
> + ret = iomap_dio_rw(&args);
> btrfs_inode_unlock(inode, BTRFS_ILOCK_SHARED);
> return ret;
> }
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 3ed8c048fb12..436508be6d88 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -53,6 +53,12 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
> {
> ssize_t ret;
> struct inode *inode = file_inode(iocb->ki_filp);
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = to,
> + .ops = &ext4_iomap_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> if (iocb->ki_flags & IOCB_NOWAIT) {
> if (!inode_trylock_shared(inode))
> @@ -74,8 +80,7 @@ static ssize_t ext4_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
> return generic_file_read_iter(iocb, to);
> }
>
> - ret = iomap_dio_rw(iocb, to, &ext4_iomap_ops, NULL,
> - is_sync_kiocb(iocb));
> + ret = iomap_dio_rw(&args);
> inode_unlock_shared(inode);
>
> file_accessed(iocb->ki_filp);
> @@ -459,9 +464,15 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
> struct inode *inode = file_inode(iocb->ki_filp);
> loff_t offset = iocb->ki_pos;
> size_t count = iov_iter_count(from);
> - const struct iomap_ops *iomap_ops = &ext4_iomap_ops;
> bool extend = false, unaligned_io = false;
> bool ilock_shared = true;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = from,
> + .ops = &ext4_iomap_ops,
> + .dops = &ext4_dio_write_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> /*
> * We initially start with shared inode lock unless it is
> @@ -548,9 +559,10 @@ static ssize_t ext4_dio_write_iter(struct kiocb *iocb, struct iov_iter *from)
> }
>
> if (ilock_shared)
> - iomap_ops = &ext4_iomap_overwrite_ops;
> - ret = iomap_dio_rw(iocb, from, iomap_ops, &ext4_dio_write_ops,
> - is_sync_kiocb(iocb) || unaligned_io || extend);
> + args.ops = &ext4_iomap_overwrite_ops;
> + if (unaligned_io || extend)
> + args.wait_for_completion = true;
> + ret = iomap_dio_rw(&args);
> if (ret == -ENOTBLK)
> ret = 0;
>
> diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
> index b39b339feddc..d44a5f9c5f34 100644
> --- a/fs/gfs2/file.c
> +++ b/fs/gfs2/file.c
> @@ -788,6 +788,12 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
> struct gfs2_inode *ip = GFS2_I(file->f_mapping->host);
> size_t count = iov_iter_count(to);
> ssize_t ret;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = to,
> + .ops = &gfs2_iomap_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> if (!count)
> return 0; /* skip atime */
> @@ -797,9 +803,7 @@ static ssize_t gfs2_file_direct_read(struct kiocb *iocb, struct iov_iter *to,
> if (ret)
> goto out_uninit;
>
> - ret = iomap_dio_rw(iocb, to, &gfs2_iomap_ops, NULL,
> - is_sync_kiocb(iocb));
> -
> + ret = iomap_dio_rw(&args);
> gfs2_glock_dq(gh);
> out_uninit:
> gfs2_holder_uninit(gh);
> @@ -815,6 +819,12 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
> size_t len = iov_iter_count(from);
> loff_t offset = iocb->ki_pos;
> ssize_t ret;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = from,
> + .ops = &gfs2_iomap_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> /*
> * Deferred lock, even if its a write, since we do no allocation on
> @@ -833,8 +843,7 @@ static ssize_t gfs2_file_direct_write(struct kiocb *iocb, struct iov_iter *from,
> if (offset + len > i_size_read(&ip->i_inode))
> goto out;
>
> - ret = iomap_dio_rw(iocb, from, &gfs2_iomap_ops, NULL,
> - is_sync_kiocb(iocb));
> + ret = iomap_dio_rw(&args);
> if (ret == -ENOTBLK)
> ret = 0;
> out:
> diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
> index 933f234d5bec..05cacc27578c 100644
> --- a/fs/iomap/direct-io.c
> +++ b/fs/iomap/direct-io.c
> @@ -418,13 +418,13 @@ iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length,
> * writes. The callers needs to fall back to buffered I/O in this case.
> */
> struct iomap_dio *
> -__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> - const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> - bool wait_for_completion)
> +__iomap_dio_rw(struct iomap_dio_rw_args *args)
> {
> + struct kiocb *iocb = args->iocb;
> + struct iov_iter *iter = args->iter;
> struct address_space *mapping = iocb->ki_filp->f_mapping;
> struct inode *inode = file_inode(iocb->ki_filp);
> - size_t count = iov_iter_count(iter);
> + size_t count = iov_iter_count(args->iter);
> loff_t pos = iocb->ki_pos;
> loff_t end = iocb->ki_pos + count - 1, ret = 0;
> unsigned int flags = IOMAP_DIRECT;
> @@ -434,7 +434,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> if (!count)
> return NULL;
>
> - if (WARN_ON(is_sync_kiocb(iocb) && !wait_for_completion))
> + if (WARN_ON(is_sync_kiocb(iocb) && !args->wait_for_completion))
> return ERR_PTR(-EIO);
>
> dio = kmalloc(sizeof(*dio), GFP_KERNEL);
> @@ -445,7 +445,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> atomic_set(&dio->ref, 1);
> dio->size = 0;
> dio->i_size = i_size_read(inode);
> - dio->dops = dops;
> + dio->dops = args->dops;
> dio->error = 0;
> dio->flags = 0;
>
> @@ -490,7 +490,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> if (ret)
> goto out_free_dio;
>
> - if (iov_iter_rw(iter) == WRITE) {
> + if (iov_iter_rw(args->iter) == WRITE) {
> /*
> * Try to invalidate cache pages for the range we are writing.
> * If this invalidation fails, let the caller fall back to
> @@ -503,7 +503,7 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> goto out_free_dio;
> }
>
> - if (!wait_for_completion && !inode->i_sb->s_dio_done_wq) {
> + if (!args->wait_for_completion && !inode->i_sb->s_dio_done_wq) {
> ret = sb_init_dio_done_wq(inode->i_sb);
> if (ret < 0)
> goto out_free_dio;
> @@ -514,12 +514,12 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
>
> blk_start_plug(&plug);
> do {
> - ret = iomap_apply(inode, pos, count, flags, ops, dio,
> + ret = iomap_apply(inode, pos, count, flags, args->ops, dio,
> iomap_dio_actor);
> if (ret <= 0) {
> /* magic error code to fall back to buffered I/O */
> if (ret == -ENOTBLK) {
> - wait_for_completion = true;
> + args->wait_for_completion = true;
> ret = 0;
> }
> break;
> @@ -566,9 +566,9 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> * of the final reference, and we will complete and free it here
> * after we got woken by the I/O completion handler.
> */
> - dio->wait_for_completion = wait_for_completion;
> + dio->wait_for_completion = args->wait_for_completion;
> if (!atomic_dec_and_test(&dio->ref)) {
> - if (!wait_for_completion)
> + if (!args->wait_for_completion)
> return ERR_PTR(-EIOCBQUEUED);
>
> for (;;) {
> @@ -596,13 +596,11 @@ __iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> EXPORT_SYMBOL_GPL(__iomap_dio_rw);
>
> ssize_t
> -iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> - const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> - bool wait_for_completion)
> +iomap_dio_rw(struct iomap_dio_rw_args *args)
> {
> struct iomap_dio *dio;
>
> - dio = __iomap_dio_rw(iocb, iter, ops, dops, wait_for_completion);
> + dio = __iomap_dio_rw(args);
> if (IS_ERR_OR_NULL(dio))
> return PTR_ERR_OR_ZERO(dio);
> return iomap_dio_complete(dio);
> diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
> index 5b0f93f73837..29f4204e551f 100644
> --- a/fs/xfs/xfs_file.c
> +++ b/fs/xfs/xfs_file.c
> @@ -205,6 +205,12 @@ xfs_file_dio_aio_read(
> struct xfs_inode *ip = XFS_I(file_inode(iocb->ki_filp));
> size_t count = iov_iter_count(to);
> ssize_t ret;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = to,
> + .ops = &xfs_read_iomap_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> trace_xfs_file_direct_read(ip, count, iocb->ki_pos);
>
> @@ -219,8 +225,7 @@ xfs_file_dio_aio_read(
> } else {
> xfs_ilock(ip, XFS_IOLOCK_SHARED);
> }
> - ret = iomap_dio_rw(iocb, to, &xfs_read_iomap_ops, NULL,
> - is_sync_kiocb(iocb));
> + ret = iomap_dio_rw(&args);
> xfs_iunlock(ip, XFS_IOLOCK_SHARED);
>
> return ret;
> @@ -519,6 +524,13 @@ xfs_file_dio_aio_write(
> int iolock;
> size_t count = iov_iter_count(from);
> struct xfs_buftarg *target = xfs_inode_buftarg(ip);
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = from,
> + .ops = &xfs_direct_write_iomap_ops,
> + .dops = &xfs_dio_write_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
>
> /* DIO must be aligned to device logical sector size */
> if ((iocb->ki_pos | count) & target->bt_logical_sectormask)
> @@ -535,6 +547,12 @@ xfs_file_dio_aio_write(
> ((iocb->ki_pos + count) & mp->m_blockmask)) {
> unaligned_io = 1;
>
> + /*
> + * This must be the only IO in-flight. Wait on it before we
> + * release the iolock to prevent subsequent overlapping IO.
> + */
> + args.wait_for_completion = true;
> +
> /*
> * We can't properly handle unaligned direct I/O to reflink
> * files yet, as we can't unshare a partial block.
> @@ -578,13 +596,7 @@ xfs_file_dio_aio_write(
> }
>
> trace_xfs_file_direct_write(ip, count, iocb->ki_pos);
> - /*
> - * If unaligned, this is the only IO in-flight. Wait on it before we
> - * release the iolock to prevent subsequent overlapping IO.
> - */
> - ret = iomap_dio_rw(iocb, from, &xfs_direct_write_iomap_ops,
> - &xfs_dio_write_ops,
> - is_sync_kiocb(iocb) || unaligned_io);
> + ret = iomap_dio_rw(&args);
> out:
> xfs_iunlock(ip, iolock);
>
> diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c
> index bec47f2d074b..edf353ad1edc 100644
> --- a/fs/zonefs/super.c
> +++ b/fs/zonefs/super.c
> @@ -735,6 +735,13 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> bool append = false;
> size_t count;
> ssize_t ret;
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = from,
> + .ops = &zonefs_iomap_ops,
> + .dops = &zonefs_write_dio_ops,
> + .wait_for_completion = sync,
> + };
>
> /*
> * For async direct IOs to sequential zone files, refuse IOCB_NOWAIT
> @@ -779,8 +786,8 @@ static ssize_t zonefs_file_dio_write(struct kiocb *iocb, struct iov_iter *from)
> if (append)
> ret = zonefs_file_dio_append(iocb, from);
> else
> - ret = iomap_dio_rw(iocb, from, &zonefs_iomap_ops,
> - &zonefs_write_dio_ops, sync);
> + ret = iomap_dio_rw(&args);
> +
> if (zi->i_ztype == ZONEFS_ZTYPE_SEQ &&
> (ret > 0 || ret == -EIOCBQUEUED)) {
> if (ret > 0)
> @@ -909,6 +916,13 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> mutex_unlock(&zi->i_truncate_mutex);
>
> if (iocb->ki_flags & IOCB_DIRECT) {
> + struct iomap_dio_rw_args args = {
> + .iocb = iocb,
> + .iter = to,
> + .ops = &zonefs_iomap_ops,
> + .dops = &zonefs_read_dio_ops,
> + .wait_for_completion = is_sync_kiocb(iocb),
> + };
> size_t count = iov_iter_count(to);
>
> if ((iocb->ki_pos | count) & (sb->s_blocksize - 1)) {
> @@ -916,8 +930,7 @@ static ssize_t zonefs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> goto inode_unlock;
> }
> file_accessed(iocb->ki_filp);
> - ret = iomap_dio_rw(iocb, to, &zonefs_iomap_ops,
> - &zonefs_read_dio_ops, is_sync_kiocb(iocb));
> + ret = iomap_dio_rw(&args);
> } else {
> ret = generic_file_read_iter(iocb, to);
> if (ret == -EIO)
> diff --git a/include/linux/iomap.h b/include/linux/iomap.h
> index 5bd3cac4df9c..16d20c01b5bb 100644
> --- a/include/linux/iomap.h
> +++ b/include/linux/iomap.h
> @@ -256,12 +256,16 @@ struct iomap_dio_ops {
> struct bio *bio, loff_t file_offset);
> };
>
> -ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> - const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> - bool wait_for_completion);
> -struct iomap_dio *__iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
> - const struct iomap_ops *ops, const struct iomap_dio_ops *dops,
> - bool wait_for_completion);
> +struct iomap_dio_rw_args {
> + struct kiocb *iocb;
> + struct iov_iter *iter;
> + const struct iomap_ops *ops;
> + const struct iomap_dio_ops *dops;
> + bool wait_for_completion;
> +};
> +
> +ssize_t iomap_dio_rw(struct iomap_dio_rw_args *args);
> +struct iomap_dio *__iomap_dio_rw(struct iomap_dio_rw_args *args);
> ssize_t iomap_dio_complete(struct iomap_dio *dio);
> int iomap_dio_iopoll(struct kiocb *kiocb, bool spin);

Looks all good to me.

For the zonefs part:

Acked-by: Damien Le Moal <damien.lemoal@wdc.com>

--
Damien Le Moal
Western Digital Research