[PATCH 10/10] fs/dax: remove useless functions

Shiyang Ruan
2020-12-30T17:01:27Z

Since owner tarcking is triggerred by pmem device, these functions are
useless. So remove it.

Signed-off-by: Shiyang Ruan <ruansy.fnst@cn.fujitsu.com>
---
fs/dax.c | 112 --------------------------------------------
include/linux/dax.h | 2 -
2 files changed, 114 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 799210cfa687..4267de360d79 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -323,48 +323,6 @@ static unsigned long dax_end_pfn(void *entry)
for (pfn = dax_to_pfn(entry); \
pfn < dax_end_pfn(entry); pfn++)

-/*
- * TODO: for reflink+dax we need a way to associate a single page with
- * multiple address_space instances at different linear_page_index()
- * offsets.
- */
-static void dax_associate_entry(void *entry, struct address_space *mapping,
- struct vm_area_struct *vma, unsigned long address)
-{
- unsigned long size = dax_entry_size(entry), pfn, index;
- int i = 0;
-
- if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
- return;
-
- index = linear_page_index(vma, address & ~(size - 1));
- for_each_mapped_pfn(entry, pfn) {
- struct page *page = pfn_to_page(pfn);
-
- WARN_ON_ONCE(page->mapping);
- page->mapping = mapping;
- page->index = index + i++;
- }
-}
-
-static void dax_disassociate_entry(void *entry, struct address_space *mapping,
- bool trunc)
-{
- unsigned long pfn;
-
- if (IS_ENABLED(CONFIG_FS_DAX_LIMITED))
- return;
-
- for_each_mapped_pfn(entry, pfn) {
- struct page *page = pfn_to_page(pfn);
-
- WARN_ON_ONCE(trunc && page_ref_count(page) > 1);
- WARN_ON_ONCE(page->mapping && page->mapping != mapping);
- page->mapping = NULL;
- page->index = 0;
- }
-}
-
static struct page *dax_busy_page(void *entry)
{
unsigned long pfn;
@@ -399,72 +357,6 @@ unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index)
return pfn;
}

-/*
- * dax_lock_mapping_entry - Lock the DAX entry corresponding to a page
- * @page: The page whose entry we want to lock
- *
- * Context: Process context.
- * Return: A cookie to pass to dax_unlock_page() or 0 if the entry could
- * not be locked.
- */
-dax_entry_t dax_lock_page(struct page *page)
-{
- XA_STATE(xas, NULL, 0);
- void *entry;
-
- /* Ensure page->mapping isn't freed while we look at it */
- rcu_read_lock();
- for (;;) {
- struct address_space *mapping = READ_ONCE(page->mapping);
-
- entry = NULL;
- if (!mapping || !dax_mapping(mapping))
- break;
-
- /*
- * In the device-dax case there's no need to lock, a
- * struct dev_pagemap pin is sufficient to keep the
- * inode alive, and we assume we have dev_pagemap pin
- * otherwise we would not have a valid pfn_to_page()
- * translation.
- */
- entry = (void *)~0UL;
- if (S_ISCHR(mapping->host->i_mode))
- break;
-
- xas.xa = &mapping->i_pages;
- xas_lock_irq(&xas);
- if (mapping != page->mapping) {
- xas_unlock_irq(&xas);
- continue;
- }
- xas_set(&xas, page->index);
- entry = xas_load(&xas);
- if (dax_is_locked(entry)) {
- rcu_read_unlock();
- wait_entry_unlocked(&xas, entry);
- rcu_read_lock();
- continue;
- }
- dax_lock_entry(&xas, entry);
- xas_unlock_irq(&xas);
- break;
- }
- rcu_read_unlock();
- return (dax_entry_t)entry;
-}
-
-void dax_unlock_page(struct page *page, dax_entry_t cookie)
-{
- struct address_space *mapping = page->mapping;
- XA_STATE(xas, &mapping->i_pages, page->index);
-
- if (S_ISCHR(mapping->host->i_mode))
- return;
-
- dax_unlock_entry(&xas, (void *)cookie);
-}
-
/*
* Find page cache entry at given index. If it is a DAX entry, return it
* with the entry locked. If the page cache doesn't contain an entry at
@@ -543,7 +435,6 @@ static void *grab_mapping_entry(struct xa_state *xas,
xas_lock_irq(xas);
}

- dax_disassociate_entry(entry, mapping, false);
xas_store(xas, NULL); /* undo the PMD join */
dax_wake_entry(xas, entry, true);
mapping->nrexceptional--;
@@ -680,7 +571,6 @@ static int __dax_invalidate_entry(struct address_space *mapping,
(xas_get_mark(&xas, PAGECACHE_TAG_DIRTY) ||
xas_get_mark(&xas, PAGECACHE_TAG_TOWRITE)))
goto out;
- dax_disassociate_entry(entry, mapping, trunc);
xas_store(&xas, NULL);
mapping->nrexceptional--;
ret = 1;
@@ -774,8 +664,6 @@ static void *dax_insert_entry(struct xa_state *xas,
if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) {
void *old;

- dax_disassociate_entry(entry, mapping, false);
- dax_associate_entry(new_entry, mapping, vmf->vma, vmf->address);
/*
* Only swap our new entry into the page cache if the current
* entry is a zero page or an empty entry. If a normal PTE or
diff --git a/include/linux/dax.h b/include/linux/dax.h
index 89e56ceeffc7..c6b8dc094b26 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -151,8 +151,6 @@ int dax_writeback_mapping_range(struct address_space *mapping,
struct page *dax_layout_busy_page(struct address_space *mapping);
struct page *dax_layout_busy_page_range(struct address_space *mapping, loff_t start, loff_t end);
unsigned long dax_load_pfn(struct address_space *mapping, unsigned long index);
-dax_entry_t dax_lock_page(struct page *page);
-void dax_unlock_page(struct page *page, dax_entry_t cookie);
#else
static inline bool bdev_dax_supported(struct block_device *bdev,
int blocksize)
--
2.29.2