Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> wrote: > /** > - * set_page_fscache - Set PG_fscache on a page and take a ref > - * @page: The page. > + * folio_start_fscache - Start an fscache operation on a folio. > + * @folio: The folio. > * > - * Set the PG_fscache (PG_private_2) flag on a page and take the reference > - * needed for the VM to handle its lifetime correctly. This sets the flag and > - * takes the reference unconditionally, so care must be taken not to set the > - * flag again if it's already set. > + * Call this function before an fscache operation starts on a folio. > + * Starting a second fscache operation before the first one finishes is > + * not allowed. That's not correct. It's only used for operations that write from the page to disk. Operations that read into the page are covered by the page lock. > + * folio_end_fscache - End an fscache operation on a folio. > ... > + * Call this function after an fscache operation has finished. This will > + * wake any sleepers waiting on this folio. Ditto. > + * folio_wait_fscache - Wait for an fscache operation on this folio to end. > + * @folio: The folio. > * > + * If an fscache operation is in progress on this folio, wait for it to > + * finish. Another fscache operation may start after this one finishes, > + * unless the caller holds the folio lock. Ditto. Apart from that, it looks okay. David
