diff options
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/filemap.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 8c88e186a773..870971e20967 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1917,9 +1917,8 @@ static void shrink_readahead_size_eio(struct file *filp, } /** - * do_generic_file_read - generic file read routine - * @filp: the file to read - * @ppos: current file position + * generic_file_buffered_read - generic file read routine + * @iocb: the iocb to read * @iter: data destination * @written: already copied * @@ -1929,12 +1928,14 @@ static void shrink_readahead_size_eio(struct file *filp, * This is really ugly. But the goto's actually try to clarify some * of the logic when it comes to error handling etc. */ -static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, +static ssize_t generic_file_buffered_read(struct kiocb *iocb, struct iov_iter *iter, ssize_t written) { + struct file *filp = iocb->ki_filp; struct address_space *mapping = filp->f_mapping; struct inode *inode = mapping->host; struct file_ra_state *ra = &filp->f_ra; + loff_t *ppos = &iocb->ki_pos; pgoff_t index; pgoff_t last_index; pgoff_t prev_index; @@ -1967,6 +1968,8 @@ find_page: page = find_get_page(mapping, index); if (!page) { + if (iocb->ki_flags & IOCB_NOWAIT) + goto would_block; page_cache_sync_readahead(mapping, ra, filp, index, last_index - index); @@ -1980,6 +1983,11 @@ find_page: index, last_index - index); } if (!PageUptodate(page)) { + if (iocb->ki_flags & IOCB_NOWAIT) { + put_page(page); + goto would_block; + } + /* * See comment in do_read_cache_page on why * wait_on_page_locked is used to avoid unnecessarily @@ -2161,6 +2169,8 @@ no_cached_page: goto readpage; } +would_block: + error = -EAGAIN; out: ra->prev_pos = prev_index; ra->prev_pos <<= PAGE_SHIFT; @@ -2182,14 +2192,14 @@ out: ssize_t generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) { - struct file *file = iocb->ki_filp; - ssize_t retval = 0; size_t count = iov_iter_count(iter); + ssize_t retval = 0; if (!count) goto out; /* skip atime */ if (iocb->ki_flags & IOCB_DIRECT) { + struct file *file = iocb->ki_filp; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; loff_t size; @@ -2230,7 +2240,7 @@ generic_file_read_iter(struct kiocb *iocb, struct iov_iter *iter) goto out; } - retval = do_generic_file_read(file, &iocb->ki_pos, iter, retval); + retval = generic_file_buffered_read(iocb, iter, retval); out: return retval; } |