diff options
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 50 |
1 files changed, 41 insertions, 9 deletions
@@ -206,7 +206,7 @@ static void dax_wake_entry(struct xa_state *xas, void *entry, * * Must be called with the i_pages lock held. */ -static void *get_unlocked_entry(struct xa_state *xas, unsigned int order) +static void *get_next_unlocked_entry(struct xa_state *xas, unsigned int order) { void *entry; struct wait_exceptional_entry_queue ewait; @@ -236,6 +236,37 @@ static void *get_unlocked_entry(struct xa_state *xas, unsigned int order) } /* + * Wait for the given entry to become unlocked. Caller must hold the i_pages + * lock and call either put_unlocked_entry() if it did not lock the entry or + * dax_unlock_entry() if it did. Returns an unlocked entry if still present. + */ +static void *wait_entry_unlocked_exclusive(struct xa_state *xas, void *entry) +{ + struct wait_exceptional_entry_queue ewait; + wait_queue_head_t *wq; + + init_wait(&ewait.wait); + ewait.wait.func = wake_exceptional_entry_func; + + while (unlikely(dax_is_locked(entry))) { + wq = dax_entry_waitqueue(xas, entry, &ewait.key); + prepare_to_wait_exclusive(wq, &ewait.wait, + TASK_UNINTERRUPTIBLE); + xas_pause(xas); + xas_unlock_irq(xas); + schedule(); + finish_wait(wq, &ewait.wait); + xas_lock_irq(xas); + entry = xas_load(xas); + } + + if (xa_is_internal(entry)) + return NULL; + + return entry; +} + +/* * The only thing keeping the address space around is the i_pages lock * (it's cycled in clear_inode() after removing the entries from i_pages) * After we call xas_unlock_irq(), we cannot touch xas->xa. @@ -250,7 +281,7 @@ static void wait_entry_unlocked(struct xa_state *xas, void *entry) wq = dax_entry_waitqueue(xas, entry, &ewait.key); /* - * Unlike get_unlocked_entry() there is no guarantee that this + * Unlike get_next_unlocked_entry() there is no guarantee that this * path ever successfully retrieves an unlocked entry before an * inode dies. Perform a non-exclusive wait in case this path * never successfully performs its own wake up. @@ -581,7 +612,7 @@ static void *grab_mapping_entry(struct xa_state *xas, retry: pmd_downgrade = false; xas_lock_irq(xas); - entry = get_unlocked_entry(xas, order); + entry = get_next_unlocked_entry(xas, order); if (entry) { if (dax_is_conflict(entry)) @@ -717,8 +748,7 @@ struct page *dax_layout_busy_page_range(struct address_space *mapping, xas_for_each(&xas, entry, end_idx) { if (WARN_ON_ONCE(!xa_is_value(entry))) continue; - if (unlikely(dax_is_locked(entry))) - entry = get_unlocked_entry(&xas, 0); + entry = wait_entry_unlocked_exclusive(&xas, entry); if (entry) page = dax_busy_page(entry); put_unlocked_entry(&xas, entry, WAKE_NEXT); @@ -751,7 +781,7 @@ static int __dax_invalidate_entry(struct address_space *mapping, void *entry; xas_lock_irq(&xas); - entry = get_unlocked_entry(&xas, 0); + entry = get_next_unlocked_entry(&xas, 0); if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) goto out; if (!trunc && @@ -777,7 +807,9 @@ static int __dax_clear_dirty_range(struct address_space *mapping, xas_lock_irq(&xas); xas_for_each(&xas, entry, end) { - entry = get_unlocked_entry(&xas, 0); + entry = wait_entry_unlocked_exclusive(&xas, entry); + if (!entry) + continue; xas_clear_mark(&xas, PAGECACHE_TAG_DIRTY); xas_clear_mark(&xas, PAGECACHE_TAG_TOWRITE); put_unlocked_entry(&xas, entry, WAKE_NEXT); @@ -941,7 +973,7 @@ static int dax_writeback_one(struct xa_state *xas, struct dax_device *dax_dev, if (unlikely(dax_is_locked(entry))) { void *old_entry = entry; - entry = get_unlocked_entry(xas, 0); + entry = get_next_unlocked_entry(xas, 0); /* Entry got punched out / reallocated? */ if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) @@ -1950,7 +1982,7 @@ dax_insert_pfn_mkwrite(struct vm_fault *vmf, pfn_t pfn, unsigned int order) vm_fault_t ret; xas_lock_irq(&xas); - entry = get_unlocked_entry(&xas, order); + entry = get_next_unlocked_entry(&xas, order); /* Did we race with someone splitting entry or so? */ if (!entry || dax_is_conflict(entry) || (order == 0 && !dax_is_pte_entry(entry))) { |