From: David Howells <dhowells@xxxxxxxxxx> Subject: mm/readahead: make ondemand_readahead take a readahead_control Make ondemand_readahead() take a readahead_control struct in preparation for making do_sync_mmap_readahead() pass down an RAC struct. Link: https://lkml.kernel.org/r/20200903140844.14194-6-willy@xxxxxxxxxxxxx Signed-off-by: David Howells <dhowells@xxxxxxxxxx> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/readahead.c | 29 +++++++++++++++++------------ 1 file changed, 17 insertions(+), 12 deletions(-) --- a/mm/readahead.c~mm-readahead-make-ondemand_readahead-take-a-readahead_control +++ a/mm/readahead.c @@ -431,15 +431,14 @@ static int try_context_readahead(struct /* * A minimal readahead algorithm for trivial sequential/random reads. */ -static void ondemand_readahead(struct address_space *mapping, - struct file_ra_state *ra, struct file *file, - bool hit_readahead_marker, pgoff_t index, +static void ondemand_readahead(struct readahead_control *ractl, + struct file_ra_state *ra, bool hit_readahead_marker, unsigned long req_size) { - DEFINE_READAHEAD(ractl, file, mapping, index); - struct backing_dev_info *bdi = inode_to_bdi(mapping->host); + struct backing_dev_info *bdi = inode_to_bdi(ractl->mapping->host); unsigned long max_pages = ra->ra_pages; unsigned long add_pages; + unsigned long index = readahead_index(ractl); pgoff_t prev_index; /* @@ -477,7 +476,8 @@ static void ondemand_readahead(struct ad pgoff_t start; rcu_read_lock(); - start = page_cache_next_miss(mapping, index + 1, max_pages); + start = page_cache_next_miss(ractl->mapping, index + 1, + max_pages); rcu_read_unlock(); if (!start || start - index > max_pages) @@ -510,14 +510,15 @@ static void ondemand_readahead(struct ad * Query the page cache and look for the traces(cached history pages) * that a sequential stream would leave behind. */ - if (try_context_readahead(mapping, ra, index, req_size, max_pages)) + if (try_context_readahead(ractl->mapping, ra, index, req_size, + max_pages)) goto readit; /* * standalone, small random read * Read as is, and do not pollute the readahead state. */ - do_page_cache_ra(&ractl, req_size, 0); + do_page_cache_ra(ractl, req_size, 0); return; initial_readahead: @@ -543,8 +544,8 @@ readit: } } - ractl._index = ra->start; - do_page_cache_ra(&ractl, ra->size, ra->async_size); + ractl->_index = ra->start; + do_page_cache_ra(ractl, ra->size, ra->async_size); } /** @@ -564,6 +565,8 @@ void page_cache_sync_readahead(struct ad struct file_ra_state *ra, struct file *filp, pgoff_t index, unsigned long req_count) { + DEFINE_READAHEAD(ractl, filp, mapping, index); + /* no read-ahead */ if (!ra->ra_pages) return; @@ -578,7 +581,7 @@ void page_cache_sync_readahead(struct ad } /* do read-ahead */ - ondemand_readahead(mapping, ra, filp, false, index, req_count); + ondemand_readahead(&ractl, ra, false, req_count); } EXPORT_SYMBOL_GPL(page_cache_sync_readahead); @@ -602,6 +605,8 @@ page_cache_async_readahead(struct addres struct page *page, pgoff_t index, unsigned long req_count) { + DEFINE_READAHEAD(ractl, filp, mapping, index); + /* no read-ahead */ if (!ra->ra_pages) return; @@ -624,7 +629,7 @@ page_cache_async_readahead(struct addres return; /* do read-ahead */ - ondemand_readahead(mapping, ra, filp, true, index, req_count); + ondemand_readahead(&ractl, ra, true, req_count); } EXPORT_SYMBOL_GPL(page_cache_async_readahead); _
