On Tue, Feb 11, 2020 at 11:42:15PM -0800, Christoph Hellwig wrote: > On Tue, Feb 11, 2020 at 08:18:25PM -0800, Matthew Wilcox wrote: > > - * @fgp_flags: PCG flags > > + * @fgp_flags: FGP flags > > * @gfp_mask: gfp mask to use for the page cache data page allocation > > * > > * Looks up the page cache slot at @mapping & @offset. > > * > > - * PCG flags modify how the page is returned. > > + * FGP flags modify how the page is returned. > > This still looks weird. Why not just a single line: > > * @fgp_flags: FGP_* flags that control how the page is returned. Well, now you got me reading the entire comment for this function, and looking at the html output, so I ended up rewriting it entirely. +++ b/mm/filemap.c @@ -1574,37 +1574,34 @@ struct page *find_lock_entry(struct address_space *mapping, pgoff_t offset) 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: FGP 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. + * @offset: 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. * - * FGP flags modify how the page is returned. + * Looks up the page cache entry at @mapping & @offset. * - * @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) + int fgp_flags, gfp_t gfp_mask) {