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[v7,12/12] iomap: Put struct iomap_ops into struct iomap

Message ID 20180604123729.23414-13-agruenba@redhat.com (mailing list archive)
State New, archived
Headers show

Commit Message

Andreas Gruenbacher June 4, 2018, 12:37 p.m. UTC 
We need access to the struct iomap_ops in iomap_write_end to call the
(optional) page_write_end hook, so instead of passing the operators to
iomap_write_end differently depending on the code path, add an ops field
to struct iomap.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/dax.c              |  8 ++++--
 fs/gfs2/bmap.c        |  4 ++-
 fs/gfs2/file.c        |  4 ++-
 fs/iomap.c            | 58 ++++++++++++++-----------------------------
 include/linux/iomap.h |  2 ++
 5 files changed, 32 insertions(+), 44 deletions(-)

Comments

Christoph Hellwig June 4, 2018, 12:52 p.m. UTC | #1 
On Mon, Jun 04, 2018 at 02:37:29PM +0200, Andreas Gruenbacher wrote:
> We need access to the struct iomap_ops in iomap_write_end to call the
> (optional) page_write_end hook, so instead of passing the operators to
> iomap_write_end differently depending on the code path, add an ops field
> to struct iomap.

I don't really like this.  We already pass the iomap_ops to the
function we call from iomap.c, and in fact ->iomap_begin is called
through the ops.

But what we could do is to move the page_write_end callback out of
iomap_ops and just attached it to the iomap, especially given that
it isn't really as generic as the other ops.

Can't say I like the implications of this callback in general, but
the use case is real, so..
Andreas Grünbacher June 4, 2018, 5 p.m. UTC | #2 
2018-06-04 14:52 GMT+02:00 Christoph Hellwig <hch@lst.de>:
> On Mon, Jun 04, 2018 at 02:37:29PM +0200, Andreas Gruenbacher wrote:
>> We need access to the struct iomap_ops in iomap_write_end to call the
>> (optional) page_write_end hook, so instead of passing the operators to
>> iomap_write_end differently depending on the code path, add an ops field
>> to struct iomap.
>
> I don't really like this.  We already pass the iomap_ops to the
> function we call from iomap.c, and in fact ->iomap_begin is called
> through the ops.

There's no duplicate ops passing going on if that's what you mean.

> But what we could do is to move the page_write_end callback out of
> iomap_ops and just attached it to the iomap, especially given that
> it isn't really as generic as the other ops.

Given that struct iomap is allocated inside iomap_apply(), if
page_write_end is moved to struct iomap, how would the filesystem set
it?

> Can't say I like the implications of this callback in general, but
> the use case is real, so..

Yes, it's not very pretty.

Thanks,
Andreas
diff mbox

Patch

diff --git a/fs/dax.c b/fs/dax.c
index aaec72ded1b6..806bd53129aa 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1140,7 +1140,9 @@  static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	struct inode *inode = mapping->host;
 	unsigned long vaddr = vmf->address;
 	loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT;
-	struct iomap iomap = { 0 };
+	struct iomap iomap = {
+		.ops = ops
+	};
 	unsigned flags = IOMAP_FAULT;
 	int error, major = 0;
 	bool write = vmf->flags & FAULT_FLAG_WRITE;
@@ -1359,7 +1361,9 @@  static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp,
 	unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT;
 	struct inode *inode = mapping->host;
 	int result = VM_FAULT_FALLBACK;
-	struct iomap iomap = { 0 };
+	struct iomap iomap = {
+		.ops = ops
+	};
 	pgoff_t max_pgoff, pgoff;
 	void *entry;
 	loff_t pos;
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 703390824200..e4eeab7b6d52 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -1192,7 +1192,9 @@  int gfs2_block_map(struct inode *inode, sector_t lblock,
 	loff_t pos = (loff_t)lblock << inode->i_blkbits;
 	loff_t length = bh_map->b_size;
 	struct metapath mp = { .mp_aheight = 1, };
-	struct iomap iomap = { };
+	struct iomap iomap = {
+		/* no need to initialize .ops here */
+	};
 	int ret;
 
 	clear_buffer_mapped(bh_map);
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 8de92708f18b..02ccb2d49900 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -883,7 +883,9 @@  static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
 	struct gfs2_inode *ip = GFS2_I(inode);
 	loff_t end = offset + len;
 	struct buffer_head *dibh;
-	struct iomap iomap = { };
+	struct iomap iomap = {
+		/* no need to initialize .ops here */
+	};
 	int error;
 
 	error = gfs2_meta_inode_buffer(ip, &dibh);
diff --git a/fs/iomap.c b/fs/iomap.c
index 34ba1be1d600..571214a6ffaa 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -45,7 +45,9 @@  loff_t
 iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags,
 		const struct iomap_ops *ops, void *data, iomap_actor_t actor)
 {
-	struct iomap iomap = { 0 };
+	struct iomap iomap = {
+		.ops = ops
+	};
 	loff_t written = 0, ret;
 
 	/*
@@ -180,8 +182,7 @@  iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags,
 
 static int
 iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
-		unsigned copied, struct page *page, struct iomap *iomap,
-		const struct iomap_ops *ops)
+		unsigned copied, struct page *page, struct iomap *iomap)
 {
 	int ret;
 
@@ -191,8 +192,8 @@  iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
 		return copied;
 	}
 
-	if (ops->page_write_end)
-		ops->page_write_end(inode, pos, copied, page);
+	if (iomap->ops->page_write_end)
+		iomap->ops->page_write_end(inode, pos, copied, page);
 
 	ret = generic_write_end(NULL, inode->i_mapping, pos, len,
 			copied, page, NULL);
@@ -201,17 +202,11 @@  iomap_write_end(struct inode *inode, loff_t pos, unsigned len,
 	return ret;
 }
 
-struct iomap_write_args {
-	const struct iomap_ops *ops;
-	struct iov_iter *iter;
-};
-
 static loff_t
 iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		struct iomap *iomap)
 {
-	struct iomap_write_args *args = data;
-	struct iov_iter *i = args->iter;
+	struct iov_iter *i = data;
 	long status = 0;
 	ssize_t written = 0;
 	unsigned int flags = AOP_FLAG_NOFS;
@@ -257,7 +252,7 @@  iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		flush_dcache_page(page);
 
 		status = iomap_write_end(inode, pos, bytes, copied, page,
-				iomap, args->ops);
+				iomap);
 		if (unlikely(status < 0))
 			break;
 		copied = status;
@@ -294,14 +289,10 @@  iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter,
 {
 	struct inode *inode = iocb->ki_filp->f_mapping->host;
 	loff_t pos = iocb->ki_pos, ret = 0, written = 0;
-	struct iomap_write_args args = {
-		.ops = ops,
-		.iter = iter,
-	};
 
 	while (iov_iter_count(iter)) {
 		ret = iomap_apply(inode, pos, iov_iter_count(iter),
-				IOMAP_WRITE, ops, &args, iomap_write_actor);
+				IOMAP_WRITE, ops, iter, iomap_write_actor);
 		if (ret <= 0)
 			break;
 		pos += ret;
@@ -332,7 +323,6 @@  static loff_t
 iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 		struct iomap *iomap)
 {
-	const struct iomap_ops *ops = data;
 	long status = 0;
 	ssize_t written = 0;
 
@@ -356,8 +346,7 @@  iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data,
 
 		WARN_ON_ONCE(!PageUptodate(page));
 
-		status = iomap_write_end(inode, pos, bytes, bytes, page, iomap,
-				ops);
+		status = iomap_write_end(inode, pos, bytes, bytes, page, iomap);
 		if (unlikely(status <= 0)) {
 			if (WARN_ON_ONCE(status == 0))
 				return -EIO;
@@ -384,7 +373,7 @@  iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
 
 	while (len) {
 		ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops,
-				(void *)ops, iomap_dirty_actor);
+				NULL, iomap_dirty_actor);
 		if (ret <= 0)
 			return ret;
 		pos += ret;
@@ -396,8 +385,7 @@  iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len,
 EXPORT_SYMBOL_GPL(iomap_file_dirty);
 
 static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
-		unsigned bytes, const struct iomap_ops *ops,
-		struct iomap *iomap)
+		unsigned bytes, struct iomap *iomap)
 {
 	struct page *page;
 	int status;
@@ -410,8 +398,7 @@  static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset,
 	zero_user(page, offset, bytes);
 	mark_page_accessed(page);
 
-	return iomap_write_end(inode, pos, bytes, bytes, page, iomap,
-			ops);
+	return iomap_write_end(inode, pos, bytes, bytes, page, iomap);
 }
 
 static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
@@ -424,16 +411,11 @@  static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes,
 			offset, bytes);
 }
 
-struct iomap_zero_range_args {
-	const struct iomap_ops *ops;
-	bool *did_zero;
-};
-
 static loff_t
 iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
 		void *data, struct iomap *iomap)
 {
-	struct iomap_zero_range_args *args = data;
+	bool *did_zero = data;
 	loff_t written = 0;
 	int status;
 
@@ -451,15 +433,15 @@  iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count,
 			status = iomap_dax_zero(pos, offset, bytes, iomap);
 		else
 			status = iomap_zero(inode, pos, offset, bytes,
-					args->ops, iomap);
+					iomap);
 		if (status < 0)
 			return status;
 
 		pos += bytes;
 		count -= bytes;
 		written += bytes;
-		if (args->did_zero)
-			*args->did_zero = true;
+		if (did_zero)
+			*did_zero = true;
 	} while (count > 0);
 
 	return written;
@@ -469,15 +451,11 @@  int
 iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero,
 		const struct iomap_ops *ops)
 {
-	struct iomap_zero_range_args args = {
-		.ops = ops,
-		.did_zero = did_zero,
-	};
 	loff_t ret;
 
 	while (len > 0) {
 		ret = iomap_apply(inode, pos, len, IOMAP_ZERO,
-				ops, &args, iomap_zero_range_actor);
+				ops, did_zero, iomap_zero_range_actor);
 		if (ret <= 0)
 			return ret;
 
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 88ea8b970a95..98426cdfcc2e 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -6,6 +6,7 @@ 
 
 struct fiemap_extent_info;
 struct inode;
+struct iomap_ops;
 struct iov_iter;
 struct kiocb;
 struct page;
@@ -43,6 +44,7 @@  struct vm_fault;
 #define IOMAP_NULL_ADDR -1ULL	/* addr is not valid */
 
 struct iomap {
+	const struct iomap_ops	*ops;
 	u64			addr; /* disk offset of mapping, bytes */
 	loff_t			offset;	/* file offset of mapping, bytes */
 	u64			length;	/* length of mapping, bytes */