diff options
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 75 |
1 files changed, 33 insertions, 42 deletions
@@ -229,8 +229,8 @@ static void put_unlocked_mapping_entry(struct address_space *mapping, * * Must be called with the i_pages lock held. */ -static void *__get_unlocked_mapping_entry(struct address_space *mapping, - pgoff_t index, void ***slotp, bool (*wait_fn)(void)) +static void *get_unlocked_mapping_entry(struct address_space *mapping, + pgoff_t index, void ***slotp) { void *entry, **slot; struct wait_exceptional_entry_queue ewait; @@ -240,8 +240,6 @@ static void *__get_unlocked_mapping_entry(struct address_space *mapping, ewait.wait.func = wake_exceptional_entry_func; for (;;) { - bool revalidate; - entry = __radix_tree_lookup(&mapping->i_pages, index, NULL, &slot); if (!entry || @@ -256,30 +254,37 @@ static void *__get_unlocked_mapping_entry(struct address_space *mapping, prepare_to_wait_exclusive(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); xa_unlock_irq(&mapping->i_pages); - revalidate = wait_fn(); + schedule(); finish_wait(wq, &ewait.wait); xa_lock_irq(&mapping->i_pages); - if (revalidate) { - put_unlocked_mapping_entry(mapping, index, entry); - return ERR_PTR(-EAGAIN); - } } } -static bool entry_wait(void) +/* + * 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. + */ +static void wait_entry_unlocked(struct address_space *mapping, pgoff_t index, + void ***slotp, void *entry) { - schedule(); + struct wait_exceptional_entry_queue ewait; + wait_queue_head_t *wq; + + init_wait(&ewait.wait); + ewait.wait.func = wake_exceptional_entry_func; + + wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); /* - * Never return an ERR_PTR() from - * __get_unlocked_mapping_entry(), just keep looping. + * Unlike get_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. */ - return false; -} - -static void *get_unlocked_mapping_entry(struct address_space *mapping, - pgoff_t index, void ***slotp) -{ - return __get_unlocked_mapping_entry(mapping, index, slotp, entry_wait); + prepare_to_wait(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); + xa_unlock_irq(&mapping->i_pages); + schedule(); + finish_wait(wq, &ewait.wait); } static void unlock_mapping_entry(struct address_space *mapping, pgoff_t index) @@ -398,19 +403,6 @@ static struct page *dax_busy_page(void *entry) return NULL; } -static bool entry_wait_revalidate(void) -{ - rcu_read_unlock(); - schedule(); - rcu_read_lock(); - - /* - * Tell __get_unlocked_mapping_entry() to take a break, we need - * to revalidate page->mapping after dropping locks - */ - return true; -} - bool dax_lock_mapping_entry(struct page *page) { pgoff_t index; @@ -446,14 +438,15 @@ bool dax_lock_mapping_entry(struct page *page) } index = page->index; - entry = __get_unlocked_mapping_entry(mapping, index, &slot, - entry_wait_revalidate); + entry = __radix_tree_lookup(&mapping->i_pages, index, + NULL, &slot); if (!entry) { xa_unlock_irq(&mapping->i_pages); break; - } else if (IS_ERR(entry)) { - xa_unlock_irq(&mapping->i_pages); - WARN_ON_ONCE(PTR_ERR(entry) != -EAGAIN); + } else if (slot_locked(mapping, slot)) { + rcu_read_unlock(); + wait_entry_unlocked(mapping, index, &slot, entry); + rcu_read_lock(); continue; } lock_slot(mapping, slot); @@ -1667,8 +1660,7 @@ static vm_fault_t dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, } trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); - result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, - write); + result = vmf_insert_pfn_pmd(vmf, pfn, write); break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: @@ -1782,8 +1774,7 @@ static vm_fault_t dax_insert_pfn_mkwrite(struct vm_fault *vmf, break; #ifdef CONFIG_FS_DAX_PMD case PE_SIZE_PMD: - ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, - pfn, true); + ret = vmf_insert_pfn_pmd(vmf, pfn, FAULT_FLAG_WRITE); break; #endif default: |