Commit 1af7e7f8 authored by Dave Wysochanski's avatar Dave Wysochanski Committed by Anna Schumaker
Browse files

NFS: Refactor nfs_readpage() and nfs_readpage_async() to use nfs_readdesc 



Both nfs_readpage() and nfs_readpages() use similar code.
This patch should be no functional change, and refactors
nfs_readpage_async() to use nfs_readdesc to enable future
merging of nfs_readpage_async() and nfs_readpage_async_filler().

Signed-off-by: default avatarDave Wysochanski <dwysocha@redhat.com>
Signed-off-by: default avatarAnna Schumaker <Anna.Schumaker@Netapp.com>
parent 6ddfd213

fs/nfs/read.c

+30 −32
Original line number Diff line number Diff line
@@ -114,18 +114,23 @@ static void nfs_readpage_release(struct nfs_page *req, int error) 
	nfs_release_request(req);

}



int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode,

struct nfs_readdesc {

	struct nfs_pageio_descriptor pgio;

	struct nfs_open_context *ctx;

};



int nfs_readpage_async(void *data, struct inode *inode,

		       struct page *page)

{

	struct nfs_readdesc *desc = data;

	struct nfs_page	*new;

	unsigned int len;

	struct nfs_pageio_descriptor pgio;

	struct nfs_pgio_mirror *pgm;



	len = nfs_page_length(page);

	if (len == 0)

		return nfs_return_empty_page(page);

	new = nfs_create_request(ctx, page, 0, len);

	new = nfs_create_request(desc->ctx, page, 0, len);

	if (IS_ERR(new)) {

		unlock_page(page);

		return PTR_ERR(new);
@@ -133,21 +138,21 @@ int nfs_readpage_async(struct nfs_open_context *ctx, struct inode *inode, 
	if (len < PAGE_SIZE)

		zero_user_segment(page, len, PAGE_SIZE);



	nfs_pageio_init_read(&pgio, inode, false,

	nfs_pageio_init_read(&desc->pgio, inode, false,

			     &nfs_async_read_completion_ops);

	if (!nfs_pageio_add_request(&pgio, new)) {

	if (!nfs_pageio_add_request(&desc->pgio, new)) {

		nfs_list_remove_request(new);

		nfs_readpage_release(new, pgio.pg_error);

		nfs_readpage_release(new, desc->pgio.pg_error);

	}

	nfs_pageio_complete(&pgio);

	nfs_pageio_complete(&desc->pgio);



	/* It doesn't make sense to do mirrored reads! */

	WARN_ON_ONCE(pgio.pg_mirror_count != 1);

	WARN_ON_ONCE(desc->pgio.pg_mirror_count != 1);



	pgm = &pgio.pg_mirrors[0];

	pgm = &desc->pgio.pg_mirrors[0];

	NFS_I(inode)->read_io += pgm->pg_bytes_written;



	return pgio.pg_error < 0 ? pgio.pg_error : 0;

	return desc->pgio.pg_error < 0 ? desc->pgio.pg_error : 0;

}



static void nfs_page_group_set_uptodate(struct nfs_page *req)
@@ -312,7 +317,7 @@ static void nfs_readpage_result(struct rpc_task *task, 
 */

int nfs_readpage(struct file *file, struct page *page)

{

	struct nfs_open_context *ctx;

	struct nfs_readdesc desc;

	struct inode *inode = page_file_mapping(page)->host;

	int ret;
@@ -339,39 +344,34 @@ int nfs_readpage(struct file *file, struct page *page) 


	if (file == NULL) {

		ret = -EBADF;

		ctx = nfs_find_open_context(inode, NULL, FMODE_READ);

		if (ctx == NULL)

		desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);

		if (desc.ctx == NULL)

			goto out_unlock;

	} else

		ctx = get_nfs_open_context(nfs_file_open_context(file));

		desc.ctx = get_nfs_open_context(nfs_file_open_context(file));



	if (!IS_SYNC(inode)) {

		ret = nfs_readpage_from_fscache(ctx, inode, page);

		ret = nfs_readpage_from_fscache(desc.ctx, inode, page);

		if (ret == 0)

			goto out;

	}



	xchg(&ctx->error, 0);

	ret = nfs_readpage_async(ctx, inode, page);

	xchg(&desc.ctx->error, 0);

	ret = nfs_readpage_async(&desc, inode, page);

	if (!ret) {

		ret = wait_on_page_locked_killable(page);

		if (!PageUptodate(page) && !ret)

			ret = xchg(&ctx->error, 0);

			ret = xchg(&desc.ctx->error, 0);

	}

	nfs_add_stats(inode, NFSIOS_READPAGES, 1);

out:

	put_nfs_open_context(ctx);

	put_nfs_open_context(desc.ctx);

	return ret;

out_unlock:

	unlock_page(page);

	return ret;

}



struct nfs_readdesc {

	struct nfs_pageio_descriptor *pgio;

	struct nfs_open_context *ctx;

};



static int

readpage_async_filler(void *data, struct page *page)

{
@@ -390,9 +390,9 @@ readpage_async_filler(void *data, struct page *page) 


	if (len < PAGE_SIZE)

		zero_user_segment(page, len, PAGE_SIZE);

	if (!nfs_pageio_add_request(desc->pgio, new)) {

	if (!nfs_pageio_add_request(&desc->pgio, new)) {

		nfs_list_remove_request(new);

		error = desc->pgio->pg_error;

		error = desc->pgio.pg_error;

		nfs_readpage_release(new, error);

		goto out;

	}
@@ -407,7 +407,6 @@ readpage_async_filler(void *data, struct page *page) 
int nfs_readpages(struct file *file, struct address_space *mapping,

		struct list_head *pages, unsigned nr_pages)

{

	struct nfs_pageio_descriptor pgio;

	struct nfs_pgio_mirror *pgm;

	struct nfs_readdesc desc;

	struct inode *inode = mapping->host;
@@ -440,17 +439,16 @@ int nfs_readpages(struct file *file, struct address_space *mapping, 
	if (ret == 0)

		goto read_complete; /* all pages were read */



	desc.pgio = &pgio;

	nfs_pageio_init_read(&pgio, inode, false,

	nfs_pageio_init_read(&desc.pgio, inode, false,

			     &nfs_async_read_completion_ops);



	ret = read_cache_pages(mapping, pages, readpage_async_filler, &desc);

	nfs_pageio_complete(&pgio);

	nfs_pageio_complete(&desc.pgio);



	/* It doesn't make sense to do mirrored reads! */

	WARN_ON_ONCE(pgio.pg_mirror_count != 1);

	WARN_ON_ONCE(desc.pgio.pg_mirror_count != 1);



	pgm = &pgio.pg_mirrors[0];

	pgm = &desc.pgio.pg_mirrors[0];

	NFS_I(inode)->read_io += pgm->pg_bytes_written;

	npages = (pgm->pg_bytes_written + PAGE_SIZE - 1) >>

		 PAGE_SHIFT;

include/linux/nfs_fs.h

+1 −2
Original line number Diff line number Diff line
@@ -570,8 +570,7 @@ nfs_have_writebacks(struct inode *inode) 
extern int  nfs_readpage(struct file *, struct page *);

extern int  nfs_readpages(struct file *, struct address_space *,

		struct list_head *, unsigned);

extern int  nfs_readpage_async(struct nfs_open_context *, struct inode *,

			       struct page *);

extern int  nfs_readpage_async(void *, struct inode *, struct page *);



/*

 * inline functions