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NFS: Refactor nfs_readpage() and nfs_readpage_async() to use nfs_read…
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…desc

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: Dave Wysochanski <[email protected]>
Signed-off-by: Anna Schumaker <[email protected]>
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@DaveWysochanskiRH @amschuma-ntap
DaveWysochanskiRH authored and amschuma-ntap committed Feb 1, 2021
1 parent 6ddfd21 commit 1af7e7f
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Showing 2 changed files with 31 additions and 34 deletions.
62 changes: 30 additions & 32 deletions fs/nfs/read.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -114,40 +114,45 @@ 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);
}
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)
Expand Down Expand Up @@ -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;

Expand All @@ -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)
{
Expand All @@ -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;
}
Expand All @@ -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;
Expand Down Expand Up @@ -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;
Expand Down
3 changes: 1 addition & 2 deletions include/linux/nfs_fs.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down

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