From ec4907ff69fb16161d9d9370260303a73dd5acde Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 28 Mar 2018 11:01:43 -0400 Subject: dax: Hash on XArray instead of mapping Since the XArray is embedded in the struct address_space, its address contains exactly as much entropy as the address of the mapping. This patch is purely preparatory for later patches which will simplify the wait/wake interfaces. Signed-off-by: Matthew Wilcox --- fs/dax.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) (limited to 'fs') diff --git a/fs/dax.c b/fs/dax.c index acdb996efad2..fd111ea1da3b 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -116,7 +116,7 @@ static int dax_is_empty_entry(void *entry) * DAX page cache entry locking */ struct exceptional_entry_key { - struct address_space *mapping; + struct xarray *xa; pgoff_t entry_start; }; @@ -125,7 +125,7 @@ struct wait_exceptional_entry_queue { struct exceptional_entry_key key; }; -static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, +static wait_queue_head_t *dax_entry_waitqueue(struct xarray *xa, pgoff_t index, void *entry, struct exceptional_entry_key *key) { unsigned long hash; @@ -138,21 +138,21 @@ static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, if (dax_is_pmd_entry(entry)) index &= ~PG_PMD_COLOUR; - key->mapping = mapping; + key->xa = xa; key->entry_start = index; - hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); + hash = hash_long((unsigned long)xa ^ index, DAX_WAIT_TABLE_BITS); return wait_table + hash; } -static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mode, - int sync, void *keyp) +static int wake_exceptional_entry_func(wait_queue_entry_t *wait, + unsigned int mode, int sync, void *keyp) { struct exceptional_entry_key *key = keyp; struct wait_exceptional_entry_queue *ewait = container_of(wait, struct wait_exceptional_entry_queue, wait); - if (key->mapping != ewait->key.mapping || + if (key->xa != ewait->key.xa || key->entry_start != ewait->key.entry_start) return 0; return autoremove_wake_function(wait, mode, sync, NULL); @@ -163,13 +163,13 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo * The important information it's conveying is whether the entry at * this index used to be a PMD entry. */ -static void dax_wake_mapping_entry_waiter(struct address_space *mapping, +static void dax_wake_mapping_entry_waiter(struct xarray *xa, pgoff_t index, void *entry, bool wake_all) { struct exceptional_entry_key key; wait_queue_head_t *wq; - wq = dax_entry_waitqueue(mapping, index, entry, &key); + wq = dax_entry_waitqueue(xa, index, entry, &key); /* * Checking for locked entry and prepare_to_wait_exclusive() happens @@ -248,7 +248,8 @@ static void *__get_unlocked_mapping_entry(struct address_space *mapping, return entry; } - wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); + wq = dax_entry_waitqueue(&mapping->i_pages, index, entry, + &ewait.key); prepare_to_wait_exclusive(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); xa_unlock_irq(&mapping->i_pages); @@ -289,7 +290,7 @@ static void unlock_mapping_entry(struct address_space *mapping, pgoff_t index) } unlock_slot(mapping, slot); xa_unlock_irq(&mapping->i_pages); - dax_wake_mapping_entry_waiter(mapping, index, entry, false); + dax_wake_mapping_entry_waiter(&mapping->i_pages, index, entry, false); } static void put_locked_mapping_entry(struct address_space *mapping, @@ -309,7 +310,7 @@ static void put_unlocked_mapping_entry(struct address_space *mapping, return; /* We have to wake up next waiter for the page cache entry lock */ - dax_wake_mapping_entry_waiter(mapping, index, entry, false); + dax_wake_mapping_entry_waiter(&mapping->i_pages, index, entry, false); } static unsigned long dax_entry_size(void *entry) @@ -578,8 +579,8 @@ restart: dax_disassociate_entry(entry, mapping, false); radix_tree_delete(&mapping->i_pages, index); mapping->nrexceptional--; - dax_wake_mapping_entry_waiter(mapping, index, entry, - true); + dax_wake_mapping_entry_waiter(&mapping->i_pages, + index, entry, true); } entry = dax_make_locked(0, size_flag | DAX_EMPTY); -- cgit v1.2.3-59-g8ed1b