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authorMatthew Wilcox (Oracle) <willy@infradead.org>2020-04-01 21:05:07 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-04-02 09:35:27 -0700
commit2294b32e068f0a8941f5e6f022a35375365bf2ee (patch)
tree4f9a0ba00ff0e501bb351a17730b0cc52d8cb9ac /mm/filemap.c
parent83daf837884cc44c3cc0e4f8a096c5d1461cbcc2 (diff)
downloadlinux-2294b32e068f0a8941f5e6f022a35375365bf2ee.tar.bz2
mm/filemap.c: rewrite pagecache_get_page documentation
- These were never called PCG flags; they've been called FGP flags since their introduction in 2014. - The FGP_FOR_MMAP flag was misleadingly documented as if it was an alternative to FGP_CREAT instead of an option to it. - Rename the 'offset' parameter to 'index'. - Capitalisation, formatting, rewording. Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Link: http://lkml.kernel.org/r/20200318140253.6141-9-willy@infradead.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c49
1 files changed, 23 insertions, 26 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 09c1cdec924a..1a58dd6d0ca0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1574,42 +1574,39 @@ repeat:
EXPORT_SYMBOL(find_lock_entry);
/**
- * pagecache_get_page - find and get a page reference
- * @mapping: the address_space to search
- * @offset: the page index
- * @fgp_flags: PCG flags
- * @gfp_mask: gfp mask to use for the page cache data page allocation
- *
- * Looks up the page cache slot at @mapping & @offset.
+ * pagecache_get_page - Find and get a reference to a page.
+ * @mapping: The address_space to search.
+ * @index: The page index.
+ * @fgp_flags: %FGP flags modify how the page is returned.
+ * @gfp_mask: Memory allocation flags to use if %FGP_CREAT is specified.
*
- * PCG flags modify how the page is returned.
+ * Looks up the page cache entry at @mapping & @index.
*
- * @fgp_flags can be:
+ * @fgp_flags can be zero or more of these flags:
*
- * - FGP_ACCESSED: the page will be marked accessed
- * - FGP_LOCK: Page is return locked
- * - FGP_CREAT: If page is not present then a new page is allocated using
- * @gfp_mask and added to the page cache and the VM's LRU
- * list. The page is returned locked and with an increased
- * refcount.
- * - FGP_FOR_MMAP: Similar to FGP_CREAT, only we want to allow the caller to do
- * its own locking dance if the page is already in cache, or unlock the page
- * before returning if we had to add the page to pagecache.
+ * * %FGP_ACCESSED - The page will be marked accessed.
+ * * %FGP_LOCK - The page is returned locked.
+ * * %FGP_CREAT - If no page is present then a new page is allocated using
+ * @gfp_mask and added to the page cache and the VM's LRU list.
+ * The page is returned locked and with an increased refcount.
+ * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the
+ * page is already in cache. If the page was allocated, unlock it before
+ * returning so the caller can do the same dance.
*
- * If FGP_LOCK or FGP_CREAT are specified then the function may sleep even
- * if the GFP flags specified for FGP_CREAT are atomic.
+ * If %FGP_LOCK or %FGP_CREAT are specified then the function may sleep even
+ * if the %GFP flags specified for %FGP_CREAT are atomic.
*
* If there is a page cache page, it is returned with an increased refcount.
*
- * Return: the found page or %NULL otherwise.
+ * Return: The found page or %NULL otherwise.
*/
-struct page *pagecache_get_page(struct address_space *mapping, pgoff_t offset,
- int fgp_flags, gfp_t gfp_mask)
+struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
+ int fgp_flags, gfp_t gfp_mask)
{
struct page *page;
repeat:
- page = find_get_entry(mapping, offset);
+ page = find_get_entry(mapping, index);
if (xa_is_value(page))
page = NULL;
if (!page)
@@ -1631,7 +1628,7 @@ repeat:
put_page(page);
goto repeat;
}
- VM_BUG_ON_PAGE(page->index != offset, page);
+ VM_BUG_ON_PAGE(page->index != index, page);
}
if (fgp_flags & FGP_ACCESSED)
@@ -1656,7 +1653,7 @@ no_page:
if (fgp_flags & FGP_ACCESSED)
__SetPageReferenced(page);
- err = add_to_page_cache_lru(page, mapping, offset, gfp_mask);
+ err = add_to_page_cache_lru(page, mapping, index, gfp_mask);
if (unlikely(err)) {
put_page(page);
page = NULL;