1d475c634SMatthew Wilcox /* 2d475c634SMatthew Wilcox * fs/dax.c - Direct Access filesystem code 3d475c634SMatthew Wilcox * Copyright (c) 2013-2014 Intel Corporation 4d475c634SMatthew Wilcox * Author: Matthew Wilcox <matthew.r.wilcox@intel.com> 5d475c634SMatthew Wilcox * Author: Ross Zwisler <ross.zwisler@linux.intel.com> 6d475c634SMatthew Wilcox * 7d475c634SMatthew Wilcox * This program is free software; you can redistribute it and/or modify it 8d475c634SMatthew Wilcox * under the terms and conditions of the GNU General Public License, 9d475c634SMatthew Wilcox * version 2, as published by the Free Software Foundation. 10d475c634SMatthew Wilcox * 11d475c634SMatthew Wilcox * This program is distributed in the hope it will be useful, but WITHOUT 12d475c634SMatthew Wilcox * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13d475c634SMatthew Wilcox * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 14d475c634SMatthew Wilcox * more details. 15d475c634SMatthew Wilcox */ 16d475c634SMatthew Wilcox 17d475c634SMatthew Wilcox #include <linux/atomic.h> 18d475c634SMatthew Wilcox #include <linux/blkdev.h> 19d475c634SMatthew Wilcox #include <linux/buffer_head.h> 20d77e92e2SRoss Zwisler #include <linux/dax.h> 21d475c634SMatthew Wilcox #include <linux/fs.h> 22d475c634SMatthew Wilcox #include <linux/genhd.h> 23f7ca90b1SMatthew Wilcox #include <linux/highmem.h> 24f7ca90b1SMatthew Wilcox #include <linux/memcontrol.h> 25f7ca90b1SMatthew Wilcox #include <linux/mm.h> 26d475c634SMatthew Wilcox #include <linux/mutex.h> 279973c98eSRoss Zwisler #include <linux/pagevec.h> 28289c6aedSMatthew Wilcox #include <linux/sched.h> 29f361bf4aSIngo Molnar #include <linux/sched/signal.h> 30d475c634SMatthew Wilcox #include <linux/uio.h> 31f7ca90b1SMatthew Wilcox #include <linux/vmstat.h> 3234c0fd54SDan Williams #include <linux/pfn_t.h> 330e749e54SDan Williams #include <linux/sizes.h> 344b4bb46dSJan Kara #include <linux/mmu_notifier.h> 35a254e568SChristoph Hellwig #include <linux/iomap.h> 36a254e568SChristoph Hellwig #include "internal.h" 37d475c634SMatthew Wilcox 38282a8e03SRoss Zwisler #define CREATE_TRACE_POINTS 39282a8e03SRoss Zwisler #include <trace/events/fs_dax.h> 40282a8e03SRoss Zwisler 41ac401cc7SJan Kara /* We choose 4096 entries - same as per-zone page wait tables */ 42ac401cc7SJan Kara #define DAX_WAIT_TABLE_BITS 12 43ac401cc7SJan Kara #define DAX_WAIT_TABLE_ENTRIES (1 << DAX_WAIT_TABLE_BITS) 44ac401cc7SJan Kara 45917f3452SRoss Zwisler /* The 'colour' (ie low bits) within a PMD of a page offset. */ 46917f3452SRoss Zwisler #define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) 47977fbdcdSMatthew Wilcox #define PG_PMD_NR (PMD_SIZE >> PAGE_SHIFT) 48917f3452SRoss Zwisler 49ce95ab0fSRoss Zwisler static wait_queue_head_t wait_table[DAX_WAIT_TABLE_ENTRIES]; 50ac401cc7SJan Kara 51ac401cc7SJan Kara static int __init init_dax_wait_table(void) 52ac401cc7SJan Kara { 53ac401cc7SJan Kara int i; 54ac401cc7SJan Kara 55ac401cc7SJan Kara for (i = 0; i < DAX_WAIT_TABLE_ENTRIES; i++) 56ac401cc7SJan Kara init_waitqueue_head(wait_table + i); 57ac401cc7SJan Kara return 0; 58ac401cc7SJan Kara } 59ac401cc7SJan Kara fs_initcall(init_dax_wait_table); 60ac401cc7SJan Kara 61527b19d0SRoss Zwisler /* 62527b19d0SRoss Zwisler * We use lowest available bit in exceptional entry for locking, one bit for 63527b19d0SRoss Zwisler * the entry size (PMD) and two more to tell us if the entry is a zero page or 64527b19d0SRoss Zwisler * an empty entry that is just used for locking. In total four special bits. 65527b19d0SRoss Zwisler * 66527b19d0SRoss Zwisler * If the PMD bit isn't set the entry has size PAGE_SIZE, and if the ZERO_PAGE 67527b19d0SRoss Zwisler * and EMPTY bits aren't set the entry is a normal DAX entry with a filesystem 68527b19d0SRoss Zwisler * block allocation. 69527b19d0SRoss Zwisler */ 70527b19d0SRoss Zwisler #define RADIX_DAX_SHIFT (RADIX_TREE_EXCEPTIONAL_SHIFT + 4) 71527b19d0SRoss Zwisler #define RADIX_DAX_ENTRY_LOCK (1 << RADIX_TREE_EXCEPTIONAL_SHIFT) 72527b19d0SRoss Zwisler #define RADIX_DAX_PMD (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 1)) 73527b19d0SRoss Zwisler #define RADIX_DAX_ZERO_PAGE (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 2)) 74527b19d0SRoss Zwisler #define RADIX_DAX_EMPTY (1 << (RADIX_TREE_EXCEPTIONAL_SHIFT + 3)) 75527b19d0SRoss Zwisler 76527b19d0SRoss Zwisler static unsigned long dax_radix_sector(void *entry) 77527b19d0SRoss Zwisler { 78527b19d0SRoss Zwisler return (unsigned long)entry >> RADIX_DAX_SHIFT; 79527b19d0SRoss Zwisler } 80527b19d0SRoss Zwisler 81527b19d0SRoss Zwisler static void *dax_radix_locked_entry(sector_t sector, unsigned long flags) 82527b19d0SRoss Zwisler { 83527b19d0SRoss Zwisler return (void *)(RADIX_TREE_EXCEPTIONAL_ENTRY | flags | 84527b19d0SRoss Zwisler ((unsigned long)sector << RADIX_DAX_SHIFT) | 85527b19d0SRoss Zwisler RADIX_DAX_ENTRY_LOCK); 86527b19d0SRoss Zwisler } 87527b19d0SRoss Zwisler 88527b19d0SRoss Zwisler static unsigned int dax_radix_order(void *entry) 89527b19d0SRoss Zwisler { 90527b19d0SRoss Zwisler if ((unsigned long)entry & RADIX_DAX_PMD) 91527b19d0SRoss Zwisler return PMD_SHIFT - PAGE_SHIFT; 92527b19d0SRoss Zwisler return 0; 93527b19d0SRoss Zwisler } 94527b19d0SRoss Zwisler 95642261acSRoss Zwisler static int dax_is_pmd_entry(void *entry) 96642261acSRoss Zwisler { 97642261acSRoss Zwisler return (unsigned long)entry & RADIX_DAX_PMD; 98642261acSRoss Zwisler } 99642261acSRoss Zwisler 100642261acSRoss Zwisler static int dax_is_pte_entry(void *entry) 101642261acSRoss Zwisler { 102642261acSRoss Zwisler return !((unsigned long)entry & RADIX_DAX_PMD); 103642261acSRoss Zwisler } 104642261acSRoss Zwisler 105642261acSRoss Zwisler static int dax_is_zero_entry(void *entry) 106642261acSRoss Zwisler { 10791d25ba8SRoss Zwisler return (unsigned long)entry & RADIX_DAX_ZERO_PAGE; 108642261acSRoss Zwisler } 109642261acSRoss Zwisler 110642261acSRoss Zwisler static int dax_is_empty_entry(void *entry) 111642261acSRoss Zwisler { 112642261acSRoss Zwisler return (unsigned long)entry & RADIX_DAX_EMPTY; 113642261acSRoss Zwisler } 114642261acSRoss Zwisler 115f7ca90b1SMatthew Wilcox /* 116ac401cc7SJan Kara * DAX radix tree locking 117ac401cc7SJan Kara */ 118ac401cc7SJan Kara struct exceptional_entry_key { 119ac401cc7SJan Kara struct address_space *mapping; 12063e95b5cSRoss Zwisler pgoff_t entry_start; 121ac401cc7SJan Kara }; 122ac401cc7SJan Kara 123ac401cc7SJan Kara struct wait_exceptional_entry_queue { 124ac6424b9SIngo Molnar wait_queue_entry_t wait; 125ac401cc7SJan Kara struct exceptional_entry_key key; 126ac401cc7SJan Kara }; 127ac401cc7SJan Kara 12863e95b5cSRoss Zwisler static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, 12963e95b5cSRoss Zwisler pgoff_t index, void *entry, struct exceptional_entry_key *key) 13063e95b5cSRoss Zwisler { 13163e95b5cSRoss Zwisler unsigned long hash; 13263e95b5cSRoss Zwisler 13363e95b5cSRoss Zwisler /* 13463e95b5cSRoss Zwisler * If 'entry' is a PMD, align the 'index' that we use for the wait 13563e95b5cSRoss Zwisler * queue to the start of that PMD. This ensures that all offsets in 13663e95b5cSRoss Zwisler * the range covered by the PMD map to the same bit lock. 13763e95b5cSRoss Zwisler */ 138642261acSRoss Zwisler if (dax_is_pmd_entry(entry)) 139917f3452SRoss Zwisler index &= ~PG_PMD_COLOUR; 14063e95b5cSRoss Zwisler 14163e95b5cSRoss Zwisler key->mapping = mapping; 14263e95b5cSRoss Zwisler key->entry_start = index; 14363e95b5cSRoss Zwisler 14463e95b5cSRoss Zwisler hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); 14563e95b5cSRoss Zwisler return wait_table + hash; 14663e95b5cSRoss Zwisler } 14763e95b5cSRoss Zwisler 148ac6424b9SIngo Molnar static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mode, 149ac401cc7SJan Kara int sync, void *keyp) 150ac401cc7SJan Kara { 151ac401cc7SJan Kara struct exceptional_entry_key *key = keyp; 152ac401cc7SJan Kara struct wait_exceptional_entry_queue *ewait = 153ac401cc7SJan Kara container_of(wait, struct wait_exceptional_entry_queue, wait); 154ac401cc7SJan Kara 155ac401cc7SJan Kara if (key->mapping != ewait->key.mapping || 15663e95b5cSRoss Zwisler key->entry_start != ewait->key.entry_start) 157ac401cc7SJan Kara return 0; 158ac401cc7SJan Kara return autoremove_wake_function(wait, mode, sync, NULL); 159ac401cc7SJan Kara } 160ac401cc7SJan Kara 161ac401cc7SJan Kara /* 162e30331ffSRoss Zwisler * We do not necessarily hold the mapping->tree_lock when we call this 163e30331ffSRoss Zwisler * function so it is possible that 'entry' is no longer a valid item in the 164e30331ffSRoss Zwisler * radix tree. This is okay because all we really need to do is to find the 165e30331ffSRoss Zwisler * correct waitqueue where tasks might be waiting for that old 'entry' and 166e30331ffSRoss Zwisler * wake them. 167e30331ffSRoss Zwisler */ 168d01ad197SRoss Zwisler static void dax_wake_mapping_entry_waiter(struct address_space *mapping, 169e30331ffSRoss Zwisler pgoff_t index, void *entry, bool wake_all) 170e30331ffSRoss Zwisler { 171e30331ffSRoss Zwisler struct exceptional_entry_key key; 172e30331ffSRoss Zwisler wait_queue_head_t *wq; 173e30331ffSRoss Zwisler 174e30331ffSRoss Zwisler wq = dax_entry_waitqueue(mapping, index, entry, &key); 175e30331ffSRoss Zwisler 176e30331ffSRoss Zwisler /* 177e30331ffSRoss Zwisler * Checking for locked entry and prepare_to_wait_exclusive() happens 178e30331ffSRoss Zwisler * under mapping->tree_lock, ditto for entry handling in our callers. 179e30331ffSRoss Zwisler * So at this point all tasks that could have seen our entry locked 180e30331ffSRoss Zwisler * must be in the waitqueue and the following check will see them. 181e30331ffSRoss Zwisler */ 182e30331ffSRoss Zwisler if (waitqueue_active(wq)) 183e30331ffSRoss Zwisler __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); 184e30331ffSRoss Zwisler } 185e30331ffSRoss Zwisler 186e30331ffSRoss Zwisler /* 187ac401cc7SJan Kara * Check whether the given slot is locked. The function must be called with 188ac401cc7SJan Kara * mapping->tree_lock held 189ac401cc7SJan Kara */ 190ac401cc7SJan Kara static inline int slot_locked(struct address_space *mapping, void **slot) 191ac401cc7SJan Kara { 192ac401cc7SJan Kara unsigned long entry = (unsigned long) 193ac401cc7SJan Kara radix_tree_deref_slot_protected(slot, &mapping->tree_lock); 194ac401cc7SJan Kara return entry & RADIX_DAX_ENTRY_LOCK; 195ac401cc7SJan Kara } 196ac401cc7SJan Kara 197ac401cc7SJan Kara /* 198ac401cc7SJan Kara * Mark the given slot is locked. The function must be called with 199ac401cc7SJan Kara * mapping->tree_lock held 200ac401cc7SJan Kara */ 201ac401cc7SJan Kara static inline void *lock_slot(struct address_space *mapping, void **slot) 202ac401cc7SJan Kara { 203ac401cc7SJan Kara unsigned long entry = (unsigned long) 204ac401cc7SJan Kara radix_tree_deref_slot_protected(slot, &mapping->tree_lock); 205ac401cc7SJan Kara 206ac401cc7SJan Kara entry |= RADIX_DAX_ENTRY_LOCK; 2076d75f366SJohannes Weiner radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry); 208ac401cc7SJan Kara return (void *)entry; 209ac401cc7SJan Kara } 210ac401cc7SJan Kara 211ac401cc7SJan Kara /* 212ac401cc7SJan Kara * Mark the given slot is unlocked. The function must be called with 213ac401cc7SJan Kara * mapping->tree_lock held 214ac401cc7SJan Kara */ 215ac401cc7SJan Kara static inline void *unlock_slot(struct address_space *mapping, void **slot) 216ac401cc7SJan Kara { 217ac401cc7SJan Kara unsigned long entry = (unsigned long) 218ac401cc7SJan Kara radix_tree_deref_slot_protected(slot, &mapping->tree_lock); 219ac401cc7SJan Kara 220ac401cc7SJan Kara entry &= ~(unsigned long)RADIX_DAX_ENTRY_LOCK; 2216d75f366SJohannes Weiner radix_tree_replace_slot(&mapping->page_tree, slot, (void *)entry); 222ac401cc7SJan Kara return (void *)entry; 223ac401cc7SJan Kara } 224ac401cc7SJan Kara 225ac401cc7SJan Kara /* 226ac401cc7SJan Kara * Lookup entry in radix tree, wait for it to become unlocked if it is 227ac401cc7SJan Kara * exceptional entry and return it. The caller must call 228ac401cc7SJan Kara * put_unlocked_mapping_entry() when he decided not to lock the entry or 229ac401cc7SJan Kara * put_locked_mapping_entry() when he locked the entry and now wants to 230ac401cc7SJan Kara * unlock it. 231ac401cc7SJan Kara * 232ac401cc7SJan Kara * The function must be called with mapping->tree_lock held. 233ac401cc7SJan Kara */ 234ac401cc7SJan Kara static void *get_unlocked_mapping_entry(struct address_space *mapping, 235ac401cc7SJan Kara pgoff_t index, void ***slotp) 236ac401cc7SJan Kara { 237e3ad61c6SRoss Zwisler void *entry, **slot; 238ac401cc7SJan Kara struct wait_exceptional_entry_queue ewait; 23963e95b5cSRoss Zwisler wait_queue_head_t *wq; 240ac401cc7SJan Kara 241ac401cc7SJan Kara init_wait(&ewait.wait); 242ac401cc7SJan Kara ewait.wait.func = wake_exceptional_entry_func; 243ac401cc7SJan Kara 244ac401cc7SJan Kara for (;;) { 245e3ad61c6SRoss Zwisler entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, 246ac401cc7SJan Kara &slot); 24791d25ba8SRoss Zwisler if (!entry || 24891d25ba8SRoss Zwisler WARN_ON_ONCE(!radix_tree_exceptional_entry(entry)) || 249ac401cc7SJan Kara !slot_locked(mapping, slot)) { 250ac401cc7SJan Kara if (slotp) 251ac401cc7SJan Kara *slotp = slot; 252e3ad61c6SRoss Zwisler return entry; 253ac401cc7SJan Kara } 25463e95b5cSRoss Zwisler 25563e95b5cSRoss Zwisler wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); 256ac401cc7SJan Kara prepare_to_wait_exclusive(wq, &ewait.wait, 257ac401cc7SJan Kara TASK_UNINTERRUPTIBLE); 258ac401cc7SJan Kara spin_unlock_irq(&mapping->tree_lock); 259ac401cc7SJan Kara schedule(); 260ac401cc7SJan Kara finish_wait(wq, &ewait.wait); 261ac401cc7SJan Kara spin_lock_irq(&mapping->tree_lock); 262ac401cc7SJan Kara } 263ac401cc7SJan Kara } 264ac401cc7SJan Kara 265b1aa812bSJan Kara static void dax_unlock_mapping_entry(struct address_space *mapping, 266b1aa812bSJan Kara pgoff_t index) 267b1aa812bSJan Kara { 268b1aa812bSJan Kara void *entry, **slot; 269b1aa812bSJan Kara 270b1aa812bSJan Kara spin_lock_irq(&mapping->tree_lock); 271b1aa812bSJan Kara entry = __radix_tree_lookup(&mapping->page_tree, index, NULL, &slot); 272b1aa812bSJan Kara if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry) || 273b1aa812bSJan Kara !slot_locked(mapping, slot))) { 274b1aa812bSJan Kara spin_unlock_irq(&mapping->tree_lock); 275b1aa812bSJan Kara return; 276b1aa812bSJan Kara } 277b1aa812bSJan Kara unlock_slot(mapping, slot); 278b1aa812bSJan Kara spin_unlock_irq(&mapping->tree_lock); 279b1aa812bSJan Kara dax_wake_mapping_entry_waiter(mapping, index, entry, false); 280b1aa812bSJan Kara } 281b1aa812bSJan Kara 282ac401cc7SJan Kara static void put_locked_mapping_entry(struct address_space *mapping, 28391d25ba8SRoss Zwisler pgoff_t index) 284ac401cc7SJan Kara { 285bc2466e4SJan Kara dax_unlock_mapping_entry(mapping, index); 286ac401cc7SJan Kara } 287ac401cc7SJan Kara 288ac401cc7SJan Kara /* 289ac401cc7SJan Kara * Called when we are done with radix tree entry we looked up via 290ac401cc7SJan Kara * get_unlocked_mapping_entry() and which we didn't lock in the end. 291ac401cc7SJan Kara */ 292ac401cc7SJan Kara static void put_unlocked_mapping_entry(struct address_space *mapping, 293ac401cc7SJan Kara pgoff_t index, void *entry) 294ac401cc7SJan Kara { 29591d25ba8SRoss Zwisler if (!entry) 296ac401cc7SJan Kara return; 297ac401cc7SJan Kara 298ac401cc7SJan Kara /* We have to wake up next waiter for the radix tree entry lock */ 299422476c4SRoss Zwisler dax_wake_mapping_entry_waiter(mapping, index, entry, false); 300422476c4SRoss Zwisler } 301422476c4SRoss Zwisler 302ac401cc7SJan Kara /* 30391d25ba8SRoss Zwisler * Find radix tree entry at given index. If it points to an exceptional entry, 30491d25ba8SRoss Zwisler * return it with the radix tree entry locked. If the radix tree doesn't 30591d25ba8SRoss Zwisler * contain given index, create an empty exceptional entry for the index and 30691d25ba8SRoss Zwisler * return with it locked. 307ac401cc7SJan Kara * 308642261acSRoss Zwisler * When requesting an entry with size RADIX_DAX_PMD, grab_mapping_entry() will 309642261acSRoss Zwisler * either return that locked entry or will return an error. This error will 31091d25ba8SRoss Zwisler * happen if there are any 4k entries within the 2MiB range that we are 31191d25ba8SRoss Zwisler * requesting. 312642261acSRoss Zwisler * 313642261acSRoss Zwisler * We always favor 4k entries over 2MiB entries. There isn't a flow where we 314642261acSRoss Zwisler * evict 4k entries in order to 'upgrade' them to a 2MiB entry. A 2MiB 315642261acSRoss Zwisler * insertion will fail if it finds any 4k entries already in the tree, and a 316642261acSRoss Zwisler * 4k insertion will cause an existing 2MiB entry to be unmapped and 317642261acSRoss Zwisler * downgraded to 4k entries. This happens for both 2MiB huge zero pages as 318642261acSRoss Zwisler * well as 2MiB empty entries. 319642261acSRoss Zwisler * 320642261acSRoss Zwisler * The exception to this downgrade path is for 2MiB DAX PMD entries that have 321642261acSRoss Zwisler * real storage backing them. We will leave these real 2MiB DAX entries in 322642261acSRoss Zwisler * the tree, and PTE writes will simply dirty the entire 2MiB DAX entry. 323642261acSRoss Zwisler * 324ac401cc7SJan Kara * Note: Unlike filemap_fault() we don't honor FAULT_FLAG_RETRY flags. For 325ac401cc7SJan Kara * persistent memory the benefit is doubtful. We can add that later if we can 326ac401cc7SJan Kara * show it helps. 327ac401cc7SJan Kara */ 328642261acSRoss Zwisler static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, 329642261acSRoss Zwisler unsigned long size_flag) 330ac401cc7SJan Kara { 331642261acSRoss Zwisler bool pmd_downgrade = false; /* splitting 2MiB entry into 4k entries? */ 332e3ad61c6SRoss Zwisler void *entry, **slot; 333ac401cc7SJan Kara 334ac401cc7SJan Kara restart: 335ac401cc7SJan Kara spin_lock_irq(&mapping->tree_lock); 336e3ad61c6SRoss Zwisler entry = get_unlocked_mapping_entry(mapping, index, &slot); 337642261acSRoss Zwisler 33891d25ba8SRoss Zwisler if (WARN_ON_ONCE(entry && !radix_tree_exceptional_entry(entry))) { 33991d25ba8SRoss Zwisler entry = ERR_PTR(-EIO); 34091d25ba8SRoss Zwisler goto out_unlock; 34191d25ba8SRoss Zwisler } 34291d25ba8SRoss Zwisler 343642261acSRoss Zwisler if (entry) { 344642261acSRoss Zwisler if (size_flag & RADIX_DAX_PMD) { 34591d25ba8SRoss Zwisler if (dax_is_pte_entry(entry)) { 346642261acSRoss Zwisler put_unlocked_mapping_entry(mapping, index, 347642261acSRoss Zwisler entry); 348642261acSRoss Zwisler entry = ERR_PTR(-EEXIST); 349642261acSRoss Zwisler goto out_unlock; 350642261acSRoss Zwisler } 351642261acSRoss Zwisler } else { /* trying to grab a PTE entry */ 35291d25ba8SRoss Zwisler if (dax_is_pmd_entry(entry) && 353642261acSRoss Zwisler (dax_is_zero_entry(entry) || 354642261acSRoss Zwisler dax_is_empty_entry(entry))) { 355642261acSRoss Zwisler pmd_downgrade = true; 356642261acSRoss Zwisler } 357642261acSRoss Zwisler } 358642261acSRoss Zwisler } 359642261acSRoss Zwisler 360ac401cc7SJan Kara /* No entry for given index? Make sure radix tree is big enough. */ 361642261acSRoss Zwisler if (!entry || pmd_downgrade) { 362ac401cc7SJan Kara int err; 363ac401cc7SJan Kara 364642261acSRoss Zwisler if (pmd_downgrade) { 365642261acSRoss Zwisler /* 366642261acSRoss Zwisler * Make sure 'entry' remains valid while we drop 367642261acSRoss Zwisler * mapping->tree_lock. 368642261acSRoss Zwisler */ 369642261acSRoss Zwisler entry = lock_slot(mapping, slot); 370642261acSRoss Zwisler } 371642261acSRoss Zwisler 372ac401cc7SJan Kara spin_unlock_irq(&mapping->tree_lock); 373642261acSRoss Zwisler /* 374642261acSRoss Zwisler * Besides huge zero pages the only other thing that gets 375642261acSRoss Zwisler * downgraded are empty entries which don't need to be 376642261acSRoss Zwisler * unmapped. 377642261acSRoss Zwisler */ 378642261acSRoss Zwisler if (pmd_downgrade && dax_is_zero_entry(entry)) 379977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, 380977fbdcdSMatthew Wilcox PG_PMD_NR, false); 381642261acSRoss Zwisler 3820cb80b48SJan Kara err = radix_tree_preload( 3830cb80b48SJan Kara mapping_gfp_mask(mapping) & ~__GFP_HIGHMEM); 3840cb80b48SJan Kara if (err) { 3850cb80b48SJan Kara if (pmd_downgrade) 38691d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, index); 3870cb80b48SJan Kara return ERR_PTR(err); 3880cb80b48SJan Kara } 389ac401cc7SJan Kara spin_lock_irq(&mapping->tree_lock); 390642261acSRoss Zwisler 391e11f8b7bSRoss Zwisler if (!entry) { 392e11f8b7bSRoss Zwisler /* 393e11f8b7bSRoss Zwisler * We needed to drop the page_tree lock while calling 394e11f8b7bSRoss Zwisler * radix_tree_preload() and we didn't have an entry to 395e11f8b7bSRoss Zwisler * lock. See if another thread inserted an entry at 396e11f8b7bSRoss Zwisler * our index during this time. 397e11f8b7bSRoss Zwisler */ 398e11f8b7bSRoss Zwisler entry = __radix_tree_lookup(&mapping->page_tree, index, 399e11f8b7bSRoss Zwisler NULL, &slot); 400e11f8b7bSRoss Zwisler if (entry) { 401e11f8b7bSRoss Zwisler radix_tree_preload_end(); 402e11f8b7bSRoss Zwisler spin_unlock_irq(&mapping->tree_lock); 403e11f8b7bSRoss Zwisler goto restart; 404e11f8b7bSRoss Zwisler } 405e11f8b7bSRoss Zwisler } 406e11f8b7bSRoss Zwisler 407642261acSRoss Zwisler if (pmd_downgrade) { 408642261acSRoss Zwisler radix_tree_delete(&mapping->page_tree, index); 409642261acSRoss Zwisler mapping->nrexceptional--; 410642261acSRoss Zwisler dax_wake_mapping_entry_waiter(mapping, index, entry, 411642261acSRoss Zwisler true); 412642261acSRoss Zwisler } 413642261acSRoss Zwisler 414642261acSRoss Zwisler entry = dax_radix_locked_entry(0, size_flag | RADIX_DAX_EMPTY); 415642261acSRoss Zwisler 416642261acSRoss Zwisler err = __radix_tree_insert(&mapping->page_tree, index, 417642261acSRoss Zwisler dax_radix_order(entry), entry); 418ac401cc7SJan Kara radix_tree_preload_end(); 419ac401cc7SJan Kara if (err) { 420ac401cc7SJan Kara spin_unlock_irq(&mapping->tree_lock); 421642261acSRoss Zwisler /* 422e11f8b7bSRoss Zwisler * Our insertion of a DAX entry failed, most likely 423e11f8b7bSRoss Zwisler * because we were inserting a PMD entry and it 424e11f8b7bSRoss Zwisler * collided with a PTE sized entry at a different 425e11f8b7bSRoss Zwisler * index in the PMD range. We haven't inserted 426e11f8b7bSRoss Zwisler * anything into the radix tree and have no waiters to 427e11f8b7bSRoss Zwisler * wake. 428642261acSRoss Zwisler */ 429ac401cc7SJan Kara return ERR_PTR(err); 430ac401cc7SJan Kara } 431ac401cc7SJan Kara /* Good, we have inserted empty locked entry into the tree. */ 432ac401cc7SJan Kara mapping->nrexceptional++; 433ac401cc7SJan Kara spin_unlock_irq(&mapping->tree_lock); 434e3ad61c6SRoss Zwisler return entry; 435ac401cc7SJan Kara } 436e3ad61c6SRoss Zwisler entry = lock_slot(mapping, slot); 437642261acSRoss Zwisler out_unlock: 438ac401cc7SJan Kara spin_unlock_irq(&mapping->tree_lock); 439e3ad61c6SRoss Zwisler return entry; 440ac401cc7SJan Kara } 441ac401cc7SJan Kara 442c6dcf52cSJan Kara static int __dax_invalidate_mapping_entry(struct address_space *mapping, 443c6dcf52cSJan Kara pgoff_t index, bool trunc) 444c6dcf52cSJan Kara { 445c6dcf52cSJan Kara int ret = 0; 446c6dcf52cSJan Kara void *entry; 447c6dcf52cSJan Kara struct radix_tree_root *page_tree = &mapping->page_tree; 448c6dcf52cSJan Kara 449c6dcf52cSJan Kara spin_lock_irq(&mapping->tree_lock); 450c6dcf52cSJan Kara entry = get_unlocked_mapping_entry(mapping, index, NULL); 45191d25ba8SRoss Zwisler if (!entry || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry))) 452c6dcf52cSJan Kara goto out; 453c6dcf52cSJan Kara if (!trunc && 454c6dcf52cSJan Kara (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) || 455c6dcf52cSJan Kara radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))) 456c6dcf52cSJan Kara goto out; 457c6dcf52cSJan Kara radix_tree_delete(page_tree, index); 458c6dcf52cSJan Kara mapping->nrexceptional--; 459c6dcf52cSJan Kara ret = 1; 460c6dcf52cSJan Kara out: 461c6dcf52cSJan Kara put_unlocked_mapping_entry(mapping, index, entry); 462c6dcf52cSJan Kara spin_unlock_irq(&mapping->tree_lock); 463c6dcf52cSJan Kara return ret; 464c6dcf52cSJan Kara } 465ac401cc7SJan Kara /* 466ac401cc7SJan Kara * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree 467ac401cc7SJan Kara * entry to get unlocked before deleting it. 468ac401cc7SJan Kara */ 469ac401cc7SJan Kara int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) 470ac401cc7SJan Kara { 471c6dcf52cSJan Kara int ret = __dax_invalidate_mapping_entry(mapping, index, true); 472ac401cc7SJan Kara 473ac401cc7SJan Kara /* 474ac401cc7SJan Kara * This gets called from truncate / punch_hole path. As such, the caller 475ac401cc7SJan Kara * must hold locks protecting against concurrent modifications of the 476ac401cc7SJan Kara * radix tree (usually fs-private i_mmap_sem for writing). Since the 477ac401cc7SJan Kara * caller has seen exceptional entry for this index, we better find it 478ac401cc7SJan Kara * at that index as well... 479ac401cc7SJan Kara */ 480c6dcf52cSJan Kara WARN_ON_ONCE(!ret); 481c6dcf52cSJan Kara return ret; 482ac401cc7SJan Kara } 483ac401cc7SJan Kara 484c6dcf52cSJan Kara /* 485c6dcf52cSJan Kara * Invalidate exceptional DAX entry if it is clean. 486c6dcf52cSJan Kara */ 487c6dcf52cSJan Kara int dax_invalidate_mapping_entry_sync(struct address_space *mapping, 488c6dcf52cSJan Kara pgoff_t index) 489c6dcf52cSJan Kara { 490c6dcf52cSJan Kara return __dax_invalidate_mapping_entry(mapping, index, false); 491ac401cc7SJan Kara } 492ac401cc7SJan Kara 493cccbce67SDan Williams static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, 494cccbce67SDan Williams sector_t sector, size_t size, struct page *to, 495cccbce67SDan Williams unsigned long vaddr) 496f7ca90b1SMatthew Wilcox { 497cccbce67SDan Williams void *vto, *kaddr; 498cccbce67SDan Williams pgoff_t pgoff; 499cccbce67SDan Williams pfn_t pfn; 500cccbce67SDan Williams long rc; 501cccbce67SDan Williams int id; 502e2e05394SRoss Zwisler 503cccbce67SDan Williams rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); 504cccbce67SDan Williams if (rc) 505cccbce67SDan Williams return rc; 506cccbce67SDan Williams 507cccbce67SDan Williams id = dax_read_lock(); 508cccbce67SDan Williams rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); 509cccbce67SDan Williams if (rc < 0) { 510cccbce67SDan Williams dax_read_unlock(id); 511cccbce67SDan Williams return rc; 512cccbce67SDan Williams } 513f7ca90b1SMatthew Wilcox vto = kmap_atomic(to); 514cccbce67SDan Williams copy_user_page(vto, (void __force *)kaddr, vaddr, to); 515f7ca90b1SMatthew Wilcox kunmap_atomic(vto); 516cccbce67SDan Williams dax_read_unlock(id); 517f7ca90b1SMatthew Wilcox return 0; 518f7ca90b1SMatthew Wilcox } 519f7ca90b1SMatthew Wilcox 520642261acSRoss Zwisler /* 521642261acSRoss Zwisler * By this point grab_mapping_entry() has ensured that we have a locked entry 522642261acSRoss Zwisler * of the appropriate size so we don't have to worry about downgrading PMDs to 523642261acSRoss Zwisler * PTEs. If we happen to be trying to insert a PTE and there is a PMD 524642261acSRoss Zwisler * already in the tree, we will skip the insertion and just dirty the PMD as 525642261acSRoss Zwisler * appropriate. 526642261acSRoss Zwisler */ 527ac401cc7SJan Kara static void *dax_insert_mapping_entry(struct address_space *mapping, 528ac401cc7SJan Kara struct vm_fault *vmf, 529642261acSRoss Zwisler void *entry, sector_t sector, 530f5b7b748SJan Kara unsigned long flags, bool dirty) 5319973c98eSRoss Zwisler { 5329973c98eSRoss Zwisler struct radix_tree_root *page_tree = &mapping->page_tree; 533ac401cc7SJan Kara void *new_entry; 534ac401cc7SJan Kara pgoff_t index = vmf->pgoff; 5359973c98eSRoss Zwisler 536f5b7b748SJan Kara if (dirty) 5379973c98eSRoss Zwisler __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); 5389973c98eSRoss Zwisler 53991d25ba8SRoss Zwisler if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_ZERO_PAGE)) { 54091d25ba8SRoss Zwisler /* we are replacing a zero page with block mapping */ 54191d25ba8SRoss Zwisler if (dax_is_pmd_entry(entry)) 542977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, index & ~PG_PMD_COLOUR, 543977fbdcdSMatthew Wilcox PG_PMD_NR, false); 54491d25ba8SRoss Zwisler else /* pte entry */ 545977fbdcdSMatthew Wilcox unmap_mapping_pages(mapping, vmf->pgoff, 1, false); 546ac401cc7SJan Kara } 5479973c98eSRoss Zwisler 548ac401cc7SJan Kara spin_lock_irq(&mapping->tree_lock); 549642261acSRoss Zwisler new_entry = dax_radix_locked_entry(sector, flags); 550642261acSRoss Zwisler 55191d25ba8SRoss Zwisler if (dax_is_zero_entry(entry) || dax_is_empty_entry(entry)) { 552642261acSRoss Zwisler /* 553642261acSRoss Zwisler * Only swap our new entry into the radix tree if the current 554642261acSRoss Zwisler * entry is a zero page or an empty entry. If a normal PTE or 555642261acSRoss Zwisler * PMD entry is already in the tree, we leave it alone. This 556642261acSRoss Zwisler * means that if we are trying to insert a PTE and the 557642261acSRoss Zwisler * existing entry is a PMD, we will just leave the PMD in the 558642261acSRoss Zwisler * tree and dirty it if necessary. 559642261acSRoss Zwisler */ 560f7942430SJohannes Weiner struct radix_tree_node *node; 561ac401cc7SJan Kara void **slot; 562ac401cc7SJan Kara void *ret; 563ac401cc7SJan Kara 564f7942430SJohannes Weiner ret = __radix_tree_lookup(page_tree, index, &node, &slot); 565ac401cc7SJan Kara WARN_ON_ONCE(ret != entry); 5664d693d08SJohannes Weiner __radix_tree_replace(page_tree, node, slot, 567c7df8ad2SMel Gorman new_entry, NULL); 56891d25ba8SRoss Zwisler entry = new_entry; 569ac401cc7SJan Kara } 57091d25ba8SRoss Zwisler 571f5b7b748SJan Kara if (dirty) 5729973c98eSRoss Zwisler radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY); 57391d25ba8SRoss Zwisler 5749973c98eSRoss Zwisler spin_unlock_irq(&mapping->tree_lock); 57591d25ba8SRoss Zwisler return entry; 5769973c98eSRoss Zwisler } 5779973c98eSRoss Zwisler 5784b4bb46dSJan Kara static inline unsigned long 5794b4bb46dSJan Kara pgoff_address(pgoff_t pgoff, struct vm_area_struct *vma) 5804b4bb46dSJan Kara { 5814b4bb46dSJan Kara unsigned long address; 5824b4bb46dSJan Kara 5834b4bb46dSJan Kara address = vma->vm_start + ((pgoff - vma->vm_pgoff) << PAGE_SHIFT); 5844b4bb46dSJan Kara VM_BUG_ON_VMA(address < vma->vm_start || address >= vma->vm_end, vma); 5854b4bb46dSJan Kara return address; 5864b4bb46dSJan Kara } 5874b4bb46dSJan Kara 5884b4bb46dSJan Kara /* Walk all mappings of a given index of a file and writeprotect them */ 5894b4bb46dSJan Kara static void dax_mapping_entry_mkclean(struct address_space *mapping, 5904b4bb46dSJan Kara pgoff_t index, unsigned long pfn) 5914b4bb46dSJan Kara { 5924b4bb46dSJan Kara struct vm_area_struct *vma; 593f729c8c9SRoss Zwisler pte_t pte, *ptep = NULL; 594f729c8c9SRoss Zwisler pmd_t *pmdp = NULL; 5954b4bb46dSJan Kara spinlock_t *ptl; 5964b4bb46dSJan Kara 5974b4bb46dSJan Kara i_mmap_lock_read(mapping); 5984b4bb46dSJan Kara vma_interval_tree_foreach(vma, &mapping->i_mmap, index, index) { 599a4d1a885SJérôme Glisse unsigned long address, start, end; 6004b4bb46dSJan Kara 6014b4bb46dSJan Kara cond_resched(); 6024b4bb46dSJan Kara 6034b4bb46dSJan Kara if (!(vma->vm_flags & VM_SHARED)) 6044b4bb46dSJan Kara continue; 6054b4bb46dSJan Kara 6064b4bb46dSJan Kara address = pgoff_address(index, vma); 607a4d1a885SJérôme Glisse 608a4d1a885SJérôme Glisse /* 609a4d1a885SJérôme Glisse * Note because we provide start/end to follow_pte_pmd it will 610a4d1a885SJérôme Glisse * call mmu_notifier_invalidate_range_start() on our behalf 611a4d1a885SJérôme Glisse * before taking any lock. 612a4d1a885SJérôme Glisse */ 613a4d1a885SJérôme Glisse if (follow_pte_pmd(vma->vm_mm, address, &start, &end, &ptep, &pmdp, &ptl)) 6144b4bb46dSJan Kara continue; 615f729c8c9SRoss Zwisler 6160f10851eSJérôme Glisse /* 6170f10851eSJérôme Glisse * No need to call mmu_notifier_invalidate_range() as we are 6180f10851eSJérôme Glisse * downgrading page table protection not changing it to point 6190f10851eSJérôme Glisse * to a new page. 6200f10851eSJérôme Glisse * 6210f10851eSJérôme Glisse * See Documentation/vm/mmu_notifier.txt 6220f10851eSJérôme Glisse */ 623f729c8c9SRoss Zwisler if (pmdp) { 624f729c8c9SRoss Zwisler #ifdef CONFIG_FS_DAX_PMD 625f729c8c9SRoss Zwisler pmd_t pmd; 626f729c8c9SRoss Zwisler 627f729c8c9SRoss Zwisler if (pfn != pmd_pfn(*pmdp)) 628f729c8c9SRoss Zwisler goto unlock_pmd; 629f6f37321SLinus Torvalds if (!pmd_dirty(*pmdp) && !pmd_write(*pmdp)) 630f729c8c9SRoss Zwisler goto unlock_pmd; 631f729c8c9SRoss Zwisler 632f729c8c9SRoss Zwisler flush_cache_page(vma, address, pfn); 633f729c8c9SRoss Zwisler pmd = pmdp_huge_clear_flush(vma, address, pmdp); 634f729c8c9SRoss Zwisler pmd = pmd_wrprotect(pmd); 635f729c8c9SRoss Zwisler pmd = pmd_mkclean(pmd); 636f729c8c9SRoss Zwisler set_pmd_at(vma->vm_mm, address, pmdp, pmd); 637f729c8c9SRoss Zwisler unlock_pmd: 638f729c8c9SRoss Zwisler #endif 639ee190ca6SJan H. Schönherr spin_unlock(ptl); 640f729c8c9SRoss Zwisler } else { 6414b4bb46dSJan Kara if (pfn != pte_pfn(*ptep)) 642f729c8c9SRoss Zwisler goto unlock_pte; 6434b4bb46dSJan Kara if (!pte_dirty(*ptep) && !pte_write(*ptep)) 644f729c8c9SRoss Zwisler goto unlock_pte; 6454b4bb46dSJan Kara 6464b4bb46dSJan Kara flush_cache_page(vma, address, pfn); 6474b4bb46dSJan Kara pte = ptep_clear_flush(vma, address, ptep); 6484b4bb46dSJan Kara pte = pte_wrprotect(pte); 6494b4bb46dSJan Kara pte = pte_mkclean(pte); 6504b4bb46dSJan Kara set_pte_at(vma->vm_mm, address, ptep, pte); 651f729c8c9SRoss Zwisler unlock_pte: 6524b4bb46dSJan Kara pte_unmap_unlock(ptep, ptl); 653f729c8c9SRoss Zwisler } 6544b4bb46dSJan Kara 655a4d1a885SJérôme Glisse mmu_notifier_invalidate_range_end(vma->vm_mm, start, end); 6564b4bb46dSJan Kara } 6574b4bb46dSJan Kara i_mmap_unlock_read(mapping); 6584b4bb46dSJan Kara } 6594b4bb46dSJan Kara 6609973c98eSRoss Zwisler static int dax_writeback_one(struct block_device *bdev, 661cccbce67SDan Williams struct dax_device *dax_dev, struct address_space *mapping, 662cccbce67SDan Williams pgoff_t index, void *entry) 6639973c98eSRoss Zwisler { 6649973c98eSRoss Zwisler struct radix_tree_root *page_tree = &mapping->page_tree; 665cccbce67SDan Williams void *entry2, **slot, *kaddr; 666cccbce67SDan Williams long ret = 0, id; 667cccbce67SDan Williams sector_t sector; 668cccbce67SDan Williams pgoff_t pgoff; 669cccbce67SDan Williams size_t size; 670cccbce67SDan Williams pfn_t pfn; 6719973c98eSRoss Zwisler 6729973c98eSRoss Zwisler /* 673a6abc2c0SJan Kara * A page got tagged dirty in DAX mapping? Something is seriously 674a6abc2c0SJan Kara * wrong. 6759973c98eSRoss Zwisler */ 676a6abc2c0SJan Kara if (WARN_ON(!radix_tree_exceptional_entry(entry))) 677a6abc2c0SJan Kara return -EIO; 6789973c98eSRoss Zwisler 679a6abc2c0SJan Kara spin_lock_irq(&mapping->tree_lock); 680a6abc2c0SJan Kara entry2 = get_unlocked_mapping_entry(mapping, index, &slot); 681a6abc2c0SJan Kara /* Entry got punched out / reallocated? */ 68291d25ba8SRoss Zwisler if (!entry2 || WARN_ON_ONCE(!radix_tree_exceptional_entry(entry2))) 683a6abc2c0SJan Kara goto put_unlocked; 684a6abc2c0SJan Kara /* 685a6abc2c0SJan Kara * Entry got reallocated elsewhere? No need to writeback. We have to 686a6abc2c0SJan Kara * compare sectors as we must not bail out due to difference in lockbit 687a6abc2c0SJan Kara * or entry type. 688a6abc2c0SJan Kara */ 689a6abc2c0SJan Kara if (dax_radix_sector(entry2) != dax_radix_sector(entry)) 690a6abc2c0SJan Kara goto put_unlocked; 691642261acSRoss Zwisler if (WARN_ON_ONCE(dax_is_empty_entry(entry) || 692642261acSRoss Zwisler dax_is_zero_entry(entry))) { 6939973c98eSRoss Zwisler ret = -EIO; 694a6abc2c0SJan Kara goto put_unlocked; 6959973c98eSRoss Zwisler } 6969973c98eSRoss Zwisler 697a6abc2c0SJan Kara /* Another fsync thread may have already written back this entry */ 698a6abc2c0SJan Kara if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) 699a6abc2c0SJan Kara goto put_unlocked; 700a6abc2c0SJan Kara /* Lock the entry to serialize with page faults */ 701a6abc2c0SJan Kara entry = lock_slot(mapping, slot); 702a6abc2c0SJan Kara /* 703a6abc2c0SJan Kara * We can clear the tag now but we have to be careful so that concurrent 704a6abc2c0SJan Kara * dax_writeback_one() calls for the same index cannot finish before we 705a6abc2c0SJan Kara * actually flush the caches. This is achieved as the calls will look 706a6abc2c0SJan Kara * at the entry only under tree_lock and once they do that they will 707a6abc2c0SJan Kara * see the entry locked and wait for it to unlock. 708a6abc2c0SJan Kara */ 709a6abc2c0SJan Kara radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE); 710a6abc2c0SJan Kara spin_unlock_irq(&mapping->tree_lock); 711a6abc2c0SJan Kara 712642261acSRoss Zwisler /* 713642261acSRoss Zwisler * Even if dax_writeback_mapping_range() was given a wbc->range_start 714642261acSRoss Zwisler * in the middle of a PMD, the 'index' we are given will be aligned to 715642261acSRoss Zwisler * the start index of the PMD, as will the sector we pull from 716642261acSRoss Zwisler * 'entry'. This allows us to flush for PMD_SIZE and not have to 717642261acSRoss Zwisler * worry about partial PMD writebacks. 718642261acSRoss Zwisler */ 719cccbce67SDan Williams sector = dax_radix_sector(entry); 720cccbce67SDan Williams size = PAGE_SIZE << dax_radix_order(entry); 721cccbce67SDan Williams 722cccbce67SDan Williams id = dax_read_lock(); 723cccbce67SDan Williams ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); 724cccbce67SDan Williams if (ret) 725cccbce67SDan Williams goto dax_unlock; 7269973c98eSRoss Zwisler 7279973c98eSRoss Zwisler /* 728cccbce67SDan Williams * dax_direct_access() may sleep, so cannot hold tree_lock over 729cccbce67SDan Williams * its invocation. 7309973c98eSRoss Zwisler */ 731cccbce67SDan Williams ret = dax_direct_access(dax_dev, pgoff, size / PAGE_SIZE, &kaddr, &pfn); 732cccbce67SDan Williams if (ret < 0) 733cccbce67SDan Williams goto dax_unlock; 7349973c98eSRoss Zwisler 735cccbce67SDan Williams if (WARN_ON_ONCE(ret < size / PAGE_SIZE)) { 7369973c98eSRoss Zwisler ret = -EIO; 737cccbce67SDan Williams goto dax_unlock; 7389973c98eSRoss Zwisler } 7399973c98eSRoss Zwisler 740cccbce67SDan Williams dax_mapping_entry_mkclean(mapping, index, pfn_t_to_pfn(pfn)); 741c3ca015fSMikulas Patocka dax_flush(dax_dev, kaddr, size); 7424b4bb46dSJan Kara /* 7434b4bb46dSJan Kara * After we have flushed the cache, we can clear the dirty tag. There 7444b4bb46dSJan Kara * cannot be new dirty data in the pfn after the flush has completed as 7454b4bb46dSJan Kara * the pfn mappings are writeprotected and fault waits for mapping 7464b4bb46dSJan Kara * entry lock. 7474b4bb46dSJan Kara */ 7484b4bb46dSJan Kara spin_lock_irq(&mapping->tree_lock); 7494b4bb46dSJan Kara radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_DIRTY); 7504b4bb46dSJan Kara spin_unlock_irq(&mapping->tree_lock); 751f9bc3a07SRoss Zwisler trace_dax_writeback_one(mapping->host, index, size >> PAGE_SHIFT); 752cccbce67SDan Williams dax_unlock: 753cccbce67SDan Williams dax_read_unlock(id); 75491d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, index); 7559973c98eSRoss Zwisler return ret; 7569973c98eSRoss Zwisler 757a6abc2c0SJan Kara put_unlocked: 758a6abc2c0SJan Kara put_unlocked_mapping_entry(mapping, index, entry2); 7599973c98eSRoss Zwisler spin_unlock_irq(&mapping->tree_lock); 7609973c98eSRoss Zwisler return ret; 7619973c98eSRoss Zwisler } 7629973c98eSRoss Zwisler 7639973c98eSRoss Zwisler /* 7649973c98eSRoss Zwisler * Flush the mapping to the persistent domain within the byte range of [start, 7659973c98eSRoss Zwisler * end]. This is required by data integrity operations to ensure file data is 7669973c98eSRoss Zwisler * on persistent storage prior to completion of the operation. 7679973c98eSRoss Zwisler */ 7687f6d5b52SRoss Zwisler int dax_writeback_mapping_range(struct address_space *mapping, 7697f6d5b52SRoss Zwisler struct block_device *bdev, struct writeback_control *wbc) 7709973c98eSRoss Zwisler { 7719973c98eSRoss Zwisler struct inode *inode = mapping->host; 772642261acSRoss Zwisler pgoff_t start_index, end_index; 7739973c98eSRoss Zwisler pgoff_t indices[PAGEVEC_SIZE]; 774cccbce67SDan Williams struct dax_device *dax_dev; 7759973c98eSRoss Zwisler struct pagevec pvec; 7769973c98eSRoss Zwisler bool done = false; 7779973c98eSRoss Zwisler int i, ret = 0; 7789973c98eSRoss Zwisler 7799973c98eSRoss Zwisler if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) 7809973c98eSRoss Zwisler return -EIO; 7819973c98eSRoss Zwisler 7827f6d5b52SRoss Zwisler if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) 7837f6d5b52SRoss Zwisler return 0; 7847f6d5b52SRoss Zwisler 785cccbce67SDan Williams dax_dev = dax_get_by_host(bdev->bd_disk->disk_name); 786cccbce67SDan Williams if (!dax_dev) 787cccbce67SDan Williams return -EIO; 788cccbce67SDan Williams 78909cbfeafSKirill A. Shutemov start_index = wbc->range_start >> PAGE_SHIFT; 79009cbfeafSKirill A. Shutemov end_index = wbc->range_end >> PAGE_SHIFT; 7919973c98eSRoss Zwisler 792d14a3f48SRoss Zwisler trace_dax_writeback_range(inode, start_index, end_index); 793d14a3f48SRoss Zwisler 7949973c98eSRoss Zwisler tag_pages_for_writeback(mapping, start_index, end_index); 7959973c98eSRoss Zwisler 79686679820SMel Gorman pagevec_init(&pvec); 7979973c98eSRoss Zwisler while (!done) { 7989973c98eSRoss Zwisler pvec.nr = find_get_entries_tag(mapping, start_index, 7999973c98eSRoss Zwisler PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, 8009973c98eSRoss Zwisler pvec.pages, indices); 8019973c98eSRoss Zwisler 8029973c98eSRoss Zwisler if (pvec.nr == 0) 8039973c98eSRoss Zwisler break; 8049973c98eSRoss Zwisler 8059973c98eSRoss Zwisler for (i = 0; i < pvec.nr; i++) { 8069973c98eSRoss Zwisler if (indices[i] > end_index) { 8079973c98eSRoss Zwisler done = true; 8089973c98eSRoss Zwisler break; 8099973c98eSRoss Zwisler } 8109973c98eSRoss Zwisler 811cccbce67SDan Williams ret = dax_writeback_one(bdev, dax_dev, mapping, 812cccbce67SDan Williams indices[i], pvec.pages[i]); 813819ec6b9SJeff Layton if (ret < 0) { 814819ec6b9SJeff Layton mapping_set_error(mapping, ret); 815d14a3f48SRoss Zwisler goto out; 816d14a3f48SRoss Zwisler } 817d14a3f48SRoss Zwisler } 8181eb643d0SJan Kara start_index = indices[pvec.nr - 1] + 1; 819d14a3f48SRoss Zwisler } 820d14a3f48SRoss Zwisler out: 821cccbce67SDan Williams put_dax(dax_dev); 822d14a3f48SRoss Zwisler trace_dax_writeback_range_done(inode, start_index, end_index); 823d14a3f48SRoss Zwisler return (ret < 0 ? ret : 0); 8249973c98eSRoss Zwisler } 8259973c98eSRoss Zwisler EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); 8269973c98eSRoss Zwisler 82731a6f1a6SJan Kara static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) 828f7ca90b1SMatthew Wilcox { 829a3841f94SLinus Torvalds return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; 83031a6f1a6SJan Kara } 831f7ca90b1SMatthew Wilcox 8325e161e40SJan Kara static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, 8335e161e40SJan Kara pfn_t *pfnp) 8345e161e40SJan Kara { 8355e161e40SJan Kara const sector_t sector = dax_iomap_sector(iomap, pos); 8365e161e40SJan Kara pgoff_t pgoff; 8375e161e40SJan Kara void *kaddr; 8385e161e40SJan Kara int id, rc; 8395e161e40SJan Kara long length; 8405e161e40SJan Kara 8415e161e40SJan Kara rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); 842cccbce67SDan Williams if (rc) 843cccbce67SDan Williams return rc; 844cccbce67SDan Williams id = dax_read_lock(); 8455e161e40SJan Kara length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), 8465e161e40SJan Kara &kaddr, pfnp); 8475e161e40SJan Kara if (length < 0) { 8485e161e40SJan Kara rc = length; 8495e161e40SJan Kara goto out; 8505e161e40SJan Kara } 8515e161e40SJan Kara rc = -EINVAL; 8525e161e40SJan Kara if (PFN_PHYS(length) < size) 8535e161e40SJan Kara goto out; 8545e161e40SJan Kara if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) 8555e161e40SJan Kara goto out; 8565e161e40SJan Kara /* For larger pages we need devmap */ 8575e161e40SJan Kara if (length > 1 && !pfn_t_devmap(*pfnp)) 8585e161e40SJan Kara goto out; 8595e161e40SJan Kara rc = 0; 8605e161e40SJan Kara out: 861cccbce67SDan Williams dax_read_unlock(id); 862cccbce67SDan Williams return rc; 863cccbce67SDan Williams } 864f7ca90b1SMatthew Wilcox 8652f89dc12SJan Kara /* 86691d25ba8SRoss Zwisler * The user has performed a load from a hole in the file. Allocating a new 86791d25ba8SRoss Zwisler * page in the file would cause excessive storage usage for workloads with 86891d25ba8SRoss Zwisler * sparse files. Instead we insert a read-only mapping of the 4k zero page. 86991d25ba8SRoss Zwisler * If this page is ever written to we will re-fault and change the mapping to 87091d25ba8SRoss Zwisler * point to real DAX storage instead. 8712f89dc12SJan Kara */ 87291d25ba8SRoss Zwisler static int dax_load_hole(struct address_space *mapping, void *entry, 873e30331ffSRoss Zwisler struct vm_fault *vmf) 874e30331ffSRoss Zwisler { 875e30331ffSRoss Zwisler struct inode *inode = mapping->host; 87691d25ba8SRoss Zwisler unsigned long vaddr = vmf->address; 87791d25ba8SRoss Zwisler int ret = VM_FAULT_NOPAGE; 87891d25ba8SRoss Zwisler struct page *zero_page; 87991d25ba8SRoss Zwisler void *entry2; 880e30331ffSRoss Zwisler 88191d25ba8SRoss Zwisler zero_page = ZERO_PAGE(0); 88291d25ba8SRoss Zwisler if (unlikely(!zero_page)) { 883e30331ffSRoss Zwisler ret = VM_FAULT_OOM; 884e30331ffSRoss Zwisler goto out; 885e30331ffSRoss Zwisler } 886e30331ffSRoss Zwisler 88791d25ba8SRoss Zwisler entry2 = dax_insert_mapping_entry(mapping, vmf, entry, 0, 888f5b7b748SJan Kara RADIX_DAX_ZERO_PAGE, false); 88991d25ba8SRoss Zwisler if (IS_ERR(entry2)) { 89091d25ba8SRoss Zwisler ret = VM_FAULT_SIGBUS; 89191d25ba8SRoss Zwisler goto out; 892e30331ffSRoss Zwisler } 89391d25ba8SRoss Zwisler 89491d25ba8SRoss Zwisler vm_insert_mixed(vmf->vma, vaddr, page_to_pfn_t(zero_page)); 895e30331ffSRoss Zwisler out: 896e30331ffSRoss Zwisler trace_dax_load_hole(inode, vmf, ret); 897e30331ffSRoss Zwisler return ret; 898e30331ffSRoss Zwisler } 899e30331ffSRoss Zwisler 9004b0228faSVishal Verma static bool dax_range_is_aligned(struct block_device *bdev, 9014b0228faSVishal Verma unsigned int offset, unsigned int length) 9024b0228faSVishal Verma { 9034b0228faSVishal Verma unsigned short sector_size = bdev_logical_block_size(bdev); 9044b0228faSVishal Verma 9054b0228faSVishal Verma if (!IS_ALIGNED(offset, sector_size)) 9064b0228faSVishal Verma return false; 9074b0228faSVishal Verma if (!IS_ALIGNED(length, sector_size)) 9084b0228faSVishal Verma return false; 9094b0228faSVishal Verma 9104b0228faSVishal Verma return true; 9114b0228faSVishal Verma } 9124b0228faSVishal Verma 913cccbce67SDan Williams int __dax_zero_page_range(struct block_device *bdev, 914cccbce67SDan Williams struct dax_device *dax_dev, sector_t sector, 915cccbce67SDan Williams unsigned int offset, unsigned int size) 916679c8bd3SChristoph Hellwig { 917cccbce67SDan Williams if (dax_range_is_aligned(bdev, offset, size)) { 918cccbce67SDan Williams sector_t start_sector = sector + (offset >> 9); 9194b0228faSVishal Verma 9204b0228faSVishal Verma return blkdev_issue_zeroout(bdev, start_sector, 92153ef7d0eSLinus Torvalds size >> 9, GFP_NOFS, 0); 9224b0228faSVishal Verma } else { 923cccbce67SDan Williams pgoff_t pgoff; 924cccbce67SDan Williams long rc, id; 925cccbce67SDan Williams void *kaddr; 926cccbce67SDan Williams pfn_t pfn; 927cccbce67SDan Williams 928e84b83b9SDan Williams rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff); 929cccbce67SDan Williams if (rc) 930cccbce67SDan Williams return rc; 931cccbce67SDan Williams 932cccbce67SDan Williams id = dax_read_lock(); 933e84b83b9SDan Williams rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, 934cccbce67SDan Williams &pfn); 935cccbce67SDan Williams if (rc < 0) { 936cccbce67SDan Williams dax_read_unlock(id); 937cccbce67SDan Williams return rc; 938cccbce67SDan Williams } 93981f55870SDan Williams memset(kaddr + offset, 0, size); 940c3ca015fSMikulas Patocka dax_flush(dax_dev, kaddr + offset, size); 941cccbce67SDan Williams dax_read_unlock(id); 9424b0228faSVishal Verma } 943679c8bd3SChristoph Hellwig return 0; 944679c8bd3SChristoph Hellwig } 945679c8bd3SChristoph Hellwig EXPORT_SYMBOL_GPL(__dax_zero_page_range); 946679c8bd3SChristoph Hellwig 947a254e568SChristoph Hellwig static loff_t 94811c59c92SRoss Zwisler dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, 949a254e568SChristoph Hellwig struct iomap *iomap) 950a254e568SChristoph Hellwig { 951cccbce67SDan Williams struct block_device *bdev = iomap->bdev; 952cccbce67SDan Williams struct dax_device *dax_dev = iomap->dax_dev; 953a254e568SChristoph Hellwig struct iov_iter *iter = data; 954a254e568SChristoph Hellwig loff_t end = pos + length, done = 0; 955a254e568SChristoph Hellwig ssize_t ret = 0; 956cccbce67SDan Williams int id; 957a254e568SChristoph Hellwig 958a254e568SChristoph Hellwig if (iov_iter_rw(iter) == READ) { 959a254e568SChristoph Hellwig end = min(end, i_size_read(inode)); 960a254e568SChristoph Hellwig if (pos >= end) 961a254e568SChristoph Hellwig return 0; 962a254e568SChristoph Hellwig 963a254e568SChristoph Hellwig if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) 964a254e568SChristoph Hellwig return iov_iter_zero(min(length, end - pos), iter); 965a254e568SChristoph Hellwig } 966a254e568SChristoph Hellwig 967a254e568SChristoph Hellwig if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) 968a254e568SChristoph Hellwig return -EIO; 969a254e568SChristoph Hellwig 970e3fce68cSJan Kara /* 971e3fce68cSJan Kara * Write can allocate block for an area which has a hole page mapped 972e3fce68cSJan Kara * into page tables. We have to tear down these mappings so that data 973e3fce68cSJan Kara * written by write(2) is visible in mmap. 974e3fce68cSJan Kara */ 975cd656375SJan Kara if (iomap->flags & IOMAP_F_NEW) { 976e3fce68cSJan Kara invalidate_inode_pages2_range(inode->i_mapping, 977e3fce68cSJan Kara pos >> PAGE_SHIFT, 978e3fce68cSJan Kara (end - 1) >> PAGE_SHIFT); 979e3fce68cSJan Kara } 980e3fce68cSJan Kara 981cccbce67SDan Williams id = dax_read_lock(); 982a254e568SChristoph Hellwig while (pos < end) { 983a254e568SChristoph Hellwig unsigned offset = pos & (PAGE_SIZE - 1); 984cccbce67SDan Williams const size_t size = ALIGN(length + offset, PAGE_SIZE); 985cccbce67SDan Williams const sector_t sector = dax_iomap_sector(iomap, pos); 986a254e568SChristoph Hellwig ssize_t map_len; 987cccbce67SDan Williams pgoff_t pgoff; 988cccbce67SDan Williams void *kaddr; 989cccbce67SDan Williams pfn_t pfn; 990a254e568SChristoph Hellwig 991d1908f52SMichal Hocko if (fatal_signal_pending(current)) { 992d1908f52SMichal Hocko ret = -EINTR; 993d1908f52SMichal Hocko break; 994d1908f52SMichal Hocko } 995d1908f52SMichal Hocko 996cccbce67SDan Williams ret = bdev_dax_pgoff(bdev, sector, size, &pgoff); 997cccbce67SDan Williams if (ret) 998cccbce67SDan Williams break; 999cccbce67SDan Williams 1000cccbce67SDan Williams map_len = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), 1001cccbce67SDan Williams &kaddr, &pfn); 1002a254e568SChristoph Hellwig if (map_len < 0) { 1003a254e568SChristoph Hellwig ret = map_len; 1004a254e568SChristoph Hellwig break; 1005a254e568SChristoph Hellwig } 1006a254e568SChristoph Hellwig 1007cccbce67SDan Williams map_len = PFN_PHYS(map_len); 1008cccbce67SDan Williams kaddr += offset; 1009a254e568SChristoph Hellwig map_len -= offset; 1010a254e568SChristoph Hellwig if (map_len > end - pos) 1011a254e568SChristoph Hellwig map_len = end - pos; 1012a254e568SChristoph Hellwig 1013a2e050f5SRoss Zwisler /* 1014a2e050f5SRoss Zwisler * The userspace address for the memory copy has already been 1015a2e050f5SRoss Zwisler * validated via access_ok() in either vfs_read() or 1016a2e050f5SRoss Zwisler * vfs_write(), depending on which operation we are doing. 1017a2e050f5SRoss Zwisler */ 1018a254e568SChristoph Hellwig if (iov_iter_rw(iter) == WRITE) 1019fec53774SDan Williams map_len = dax_copy_from_iter(dax_dev, pgoff, kaddr, 1020fec53774SDan Williams map_len, iter); 1021a254e568SChristoph Hellwig else 1022cccbce67SDan Williams map_len = copy_to_iter(kaddr, map_len, iter); 1023a254e568SChristoph Hellwig if (map_len <= 0) { 1024a254e568SChristoph Hellwig ret = map_len ? map_len : -EFAULT; 1025a254e568SChristoph Hellwig break; 1026a254e568SChristoph Hellwig } 1027a254e568SChristoph Hellwig 1028a254e568SChristoph Hellwig pos += map_len; 1029a254e568SChristoph Hellwig length -= map_len; 1030a254e568SChristoph Hellwig done += map_len; 1031a254e568SChristoph Hellwig } 1032cccbce67SDan Williams dax_read_unlock(id); 1033a254e568SChristoph Hellwig 1034a254e568SChristoph Hellwig return done ? done : ret; 1035a254e568SChristoph Hellwig } 1036a254e568SChristoph Hellwig 1037a254e568SChristoph Hellwig /** 103811c59c92SRoss Zwisler * dax_iomap_rw - Perform I/O to a DAX file 1039a254e568SChristoph Hellwig * @iocb: The control block for this I/O 1040a254e568SChristoph Hellwig * @iter: The addresses to do I/O from or to 1041a254e568SChristoph Hellwig * @ops: iomap ops passed from the file system 1042a254e568SChristoph Hellwig * 1043a254e568SChristoph Hellwig * This function performs read and write operations to directly mapped 1044a254e568SChristoph Hellwig * persistent memory. The callers needs to take care of read/write exclusion 1045a254e568SChristoph Hellwig * and evicting any page cache pages in the region under I/O. 1046a254e568SChristoph Hellwig */ 1047a254e568SChristoph Hellwig ssize_t 104811c59c92SRoss Zwisler dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, 10498ff6daa1SChristoph Hellwig const struct iomap_ops *ops) 1050a254e568SChristoph Hellwig { 1051a254e568SChristoph Hellwig struct address_space *mapping = iocb->ki_filp->f_mapping; 1052a254e568SChristoph Hellwig struct inode *inode = mapping->host; 1053a254e568SChristoph Hellwig loff_t pos = iocb->ki_pos, ret = 0, done = 0; 1054a254e568SChristoph Hellwig unsigned flags = 0; 1055a254e568SChristoph Hellwig 1056168316dbSChristoph Hellwig if (iov_iter_rw(iter) == WRITE) { 1057168316dbSChristoph Hellwig lockdep_assert_held_exclusive(&inode->i_rwsem); 1058a254e568SChristoph Hellwig flags |= IOMAP_WRITE; 1059168316dbSChristoph Hellwig } else { 1060168316dbSChristoph Hellwig lockdep_assert_held(&inode->i_rwsem); 1061168316dbSChristoph Hellwig } 1062a254e568SChristoph Hellwig 1063a254e568SChristoph Hellwig while (iov_iter_count(iter)) { 1064a254e568SChristoph Hellwig ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, 106511c59c92SRoss Zwisler iter, dax_iomap_actor); 1066a254e568SChristoph Hellwig if (ret <= 0) 1067a254e568SChristoph Hellwig break; 1068a254e568SChristoph Hellwig pos += ret; 1069a254e568SChristoph Hellwig done += ret; 1070a254e568SChristoph Hellwig } 1071a254e568SChristoph Hellwig 1072a254e568SChristoph Hellwig iocb->ki_pos += done; 1073a254e568SChristoph Hellwig return done ? done : ret; 1074a254e568SChristoph Hellwig } 107511c59c92SRoss Zwisler EXPORT_SYMBOL_GPL(dax_iomap_rw); 1076a7d73fe6SChristoph Hellwig 10779f141d6eSJan Kara static int dax_fault_return(int error) 10789f141d6eSJan Kara { 10799f141d6eSJan Kara if (error == 0) 10809f141d6eSJan Kara return VM_FAULT_NOPAGE; 10819f141d6eSJan Kara if (error == -ENOMEM) 10829f141d6eSJan Kara return VM_FAULT_OOM; 10839f141d6eSJan Kara return VM_FAULT_SIGBUS; 10849f141d6eSJan Kara } 10859f141d6eSJan Kara 1086aaa422c4SDan Williams /* 1087aaa422c4SDan Williams * MAP_SYNC on a dax mapping guarantees dirty metadata is 1088aaa422c4SDan Williams * flushed on write-faults (non-cow), but not read-faults. 1089aaa422c4SDan Williams */ 1090aaa422c4SDan Williams static bool dax_fault_is_synchronous(unsigned long flags, 1091aaa422c4SDan Williams struct vm_area_struct *vma, struct iomap *iomap) 1092aaa422c4SDan Williams { 1093aaa422c4SDan Williams return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) 1094aaa422c4SDan Williams && (iomap->flags & IOMAP_F_DIRTY); 1095aaa422c4SDan Williams } 1096aaa422c4SDan Williams 10979a0dd422SJan Kara static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, 1098a2d58167SDave Jiang const struct iomap_ops *ops) 1099a7d73fe6SChristoph Hellwig { 1100a0987ad5SJan Kara struct vm_area_struct *vma = vmf->vma; 1101a0987ad5SJan Kara struct address_space *mapping = vma->vm_file->f_mapping; 1102a7d73fe6SChristoph Hellwig struct inode *inode = mapping->host; 11031a29d85eSJan Kara unsigned long vaddr = vmf->address; 1104a7d73fe6SChristoph Hellwig loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; 1105a7d73fe6SChristoph Hellwig struct iomap iomap = { 0 }; 11069484ab1bSJan Kara unsigned flags = IOMAP_FAULT; 1107a7d73fe6SChristoph Hellwig int error, major = 0; 1108d2c43ef1SJan Kara bool write = vmf->flags & FAULT_FLAG_WRITE; 1109caa51d26SJan Kara bool sync; 1110b1aa812bSJan Kara int vmf_ret = 0; 1111a7d73fe6SChristoph Hellwig void *entry; 11121b5a1cb2SJan Kara pfn_t pfn; 1113a7d73fe6SChristoph Hellwig 1114a9c42b33SRoss Zwisler trace_dax_pte_fault(inode, vmf, vmf_ret); 1115a7d73fe6SChristoph Hellwig /* 1116a7d73fe6SChristoph Hellwig * Check whether offset isn't beyond end of file now. Caller is supposed 1117a7d73fe6SChristoph Hellwig * to hold locks serializing us with truncate / punch hole so this is 1118a7d73fe6SChristoph Hellwig * a reliable test. 1119a7d73fe6SChristoph Hellwig */ 1120a9c42b33SRoss Zwisler if (pos >= i_size_read(inode)) { 1121a9c42b33SRoss Zwisler vmf_ret = VM_FAULT_SIGBUS; 1122a9c42b33SRoss Zwisler goto out; 1123a9c42b33SRoss Zwisler } 1124a7d73fe6SChristoph Hellwig 1125d2c43ef1SJan Kara if (write && !vmf->cow_page) 1126a7d73fe6SChristoph Hellwig flags |= IOMAP_WRITE; 1127a7d73fe6SChristoph Hellwig 112813e451fdSJan Kara entry = grab_mapping_entry(mapping, vmf->pgoff, 0); 112913e451fdSJan Kara if (IS_ERR(entry)) { 113013e451fdSJan Kara vmf_ret = dax_fault_return(PTR_ERR(entry)); 113113e451fdSJan Kara goto out; 113213e451fdSJan Kara } 113313e451fdSJan Kara 1134a7d73fe6SChristoph Hellwig /* 1135e2093926SRoss Zwisler * It is possible, particularly with mixed reads & writes to private 1136e2093926SRoss Zwisler * mappings, that we have raced with a PMD fault that overlaps with 1137e2093926SRoss Zwisler * the PTE we need to set up. If so just return and the fault will be 1138e2093926SRoss Zwisler * retried. 1139e2093926SRoss Zwisler */ 1140e2093926SRoss Zwisler if (pmd_trans_huge(*vmf->pmd) || pmd_devmap(*vmf->pmd)) { 1141e2093926SRoss Zwisler vmf_ret = VM_FAULT_NOPAGE; 1142e2093926SRoss Zwisler goto unlock_entry; 1143e2093926SRoss Zwisler } 1144e2093926SRoss Zwisler 1145e2093926SRoss Zwisler /* 1146a7d73fe6SChristoph Hellwig * Note that we don't bother to use iomap_apply here: DAX required 1147a7d73fe6SChristoph Hellwig * the file system block size to be equal the page size, which means 1148a7d73fe6SChristoph Hellwig * that we never have to deal with more than a single extent here. 1149a7d73fe6SChristoph Hellwig */ 1150a7d73fe6SChristoph Hellwig error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); 1151a9c42b33SRoss Zwisler if (error) { 1152a9c42b33SRoss Zwisler vmf_ret = dax_fault_return(error); 115313e451fdSJan Kara goto unlock_entry; 1154a9c42b33SRoss Zwisler } 1155a7d73fe6SChristoph Hellwig if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { 115613e451fdSJan Kara error = -EIO; /* fs corruption? */ 115713e451fdSJan Kara goto error_finish_iomap; 1158a7d73fe6SChristoph Hellwig } 1159a7d73fe6SChristoph Hellwig 1160a7d73fe6SChristoph Hellwig if (vmf->cow_page) { 116131a6f1a6SJan Kara sector_t sector = dax_iomap_sector(&iomap, pos); 116231a6f1a6SJan Kara 1163a7d73fe6SChristoph Hellwig switch (iomap.type) { 1164a7d73fe6SChristoph Hellwig case IOMAP_HOLE: 1165a7d73fe6SChristoph Hellwig case IOMAP_UNWRITTEN: 1166a7d73fe6SChristoph Hellwig clear_user_highpage(vmf->cow_page, vaddr); 1167a7d73fe6SChristoph Hellwig break; 1168a7d73fe6SChristoph Hellwig case IOMAP_MAPPED: 1169cccbce67SDan Williams error = copy_user_dax(iomap.bdev, iomap.dax_dev, 1170cccbce67SDan Williams sector, PAGE_SIZE, vmf->cow_page, vaddr); 1171a7d73fe6SChristoph Hellwig break; 1172a7d73fe6SChristoph Hellwig default: 1173a7d73fe6SChristoph Hellwig WARN_ON_ONCE(1); 1174a7d73fe6SChristoph Hellwig error = -EIO; 1175a7d73fe6SChristoph Hellwig break; 1176a7d73fe6SChristoph Hellwig } 1177a7d73fe6SChristoph Hellwig 1178a7d73fe6SChristoph Hellwig if (error) 117913e451fdSJan Kara goto error_finish_iomap; 1180b1aa812bSJan Kara 1181b1aa812bSJan Kara __SetPageUptodate(vmf->cow_page); 1182b1aa812bSJan Kara vmf_ret = finish_fault(vmf); 1183b1aa812bSJan Kara if (!vmf_ret) 1184b1aa812bSJan Kara vmf_ret = VM_FAULT_DONE_COW; 118513e451fdSJan Kara goto finish_iomap; 1186a7d73fe6SChristoph Hellwig } 1187a7d73fe6SChristoph Hellwig 1188aaa422c4SDan Williams sync = dax_fault_is_synchronous(flags, vma, &iomap); 1189caa51d26SJan Kara 1190a7d73fe6SChristoph Hellwig switch (iomap.type) { 1191a7d73fe6SChristoph Hellwig case IOMAP_MAPPED: 1192a7d73fe6SChristoph Hellwig if (iomap.flags & IOMAP_F_NEW) { 1193a7d73fe6SChristoph Hellwig count_vm_event(PGMAJFAULT); 1194a0987ad5SJan Kara count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); 1195a7d73fe6SChristoph Hellwig major = VM_FAULT_MAJOR; 1196a7d73fe6SChristoph Hellwig } 11971b5a1cb2SJan Kara error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); 11981b5a1cb2SJan Kara if (error < 0) 11991b5a1cb2SJan Kara goto error_finish_iomap; 12001b5a1cb2SJan Kara 12011b5a1cb2SJan Kara entry = dax_insert_mapping_entry(mapping, vmf, entry, 12021b5a1cb2SJan Kara dax_iomap_sector(&iomap, pos), 1203caa51d26SJan Kara 0, write && !sync); 12041b5a1cb2SJan Kara if (IS_ERR(entry)) { 12051b5a1cb2SJan Kara error = PTR_ERR(entry); 12061b5a1cb2SJan Kara goto error_finish_iomap; 12071b5a1cb2SJan Kara } 12081b5a1cb2SJan Kara 1209caa51d26SJan Kara /* 1210caa51d26SJan Kara * If we are doing synchronous page fault and inode needs fsync, 1211caa51d26SJan Kara * we can insert PTE into page tables only after that happens. 1212caa51d26SJan Kara * Skip insertion for now and return the pfn so that caller can 1213caa51d26SJan Kara * insert it after fsync is done. 1214caa51d26SJan Kara */ 1215caa51d26SJan Kara if (sync) { 1216caa51d26SJan Kara if (WARN_ON_ONCE(!pfnp)) { 1217caa51d26SJan Kara error = -EIO; 1218caa51d26SJan Kara goto error_finish_iomap; 1219caa51d26SJan Kara } 1220caa51d26SJan Kara *pfnp = pfn; 1221caa51d26SJan Kara vmf_ret = VM_FAULT_NEEDDSYNC | major; 1222caa51d26SJan Kara goto finish_iomap; 1223caa51d26SJan Kara } 12241b5a1cb2SJan Kara trace_dax_insert_mapping(inode, vmf, entry); 12251b5a1cb2SJan Kara if (write) 12261b5a1cb2SJan Kara error = vm_insert_mixed_mkwrite(vma, vaddr, pfn); 12271b5a1cb2SJan Kara else 12281b5a1cb2SJan Kara error = vm_insert_mixed(vma, vaddr, pfn); 12291b5a1cb2SJan Kara 12309f141d6eSJan Kara /* -EBUSY is fine, somebody else faulted on the same PTE */ 12319f141d6eSJan Kara if (error == -EBUSY) 12329f141d6eSJan Kara error = 0; 1233a7d73fe6SChristoph Hellwig break; 1234a7d73fe6SChristoph Hellwig case IOMAP_UNWRITTEN: 1235a7d73fe6SChristoph Hellwig case IOMAP_HOLE: 1236d2c43ef1SJan Kara if (!write) { 123791d25ba8SRoss Zwisler vmf_ret = dax_load_hole(mapping, entry, vmf); 123813e451fdSJan Kara goto finish_iomap; 12391550290bSRoss Zwisler } 1240a7d73fe6SChristoph Hellwig /*FALLTHRU*/ 1241a7d73fe6SChristoph Hellwig default: 1242a7d73fe6SChristoph Hellwig WARN_ON_ONCE(1); 1243a7d73fe6SChristoph Hellwig error = -EIO; 1244a7d73fe6SChristoph Hellwig break; 1245a7d73fe6SChristoph Hellwig } 1246a7d73fe6SChristoph Hellwig 124713e451fdSJan Kara error_finish_iomap: 12489f141d6eSJan Kara vmf_ret = dax_fault_return(error) | major; 12499f141d6eSJan Kara finish_iomap: 12509f141d6eSJan Kara if (ops->iomap_end) { 12519f141d6eSJan Kara int copied = PAGE_SIZE; 12529f141d6eSJan Kara 12539f141d6eSJan Kara if (vmf_ret & VM_FAULT_ERROR) 12549f141d6eSJan Kara copied = 0; 12559f141d6eSJan Kara /* 12569f141d6eSJan Kara * The fault is done by now and there's no way back (other 12579f141d6eSJan Kara * thread may be already happily using PTE we have installed). 12589f141d6eSJan Kara * Just ignore error from ->iomap_end since we cannot do much 12599f141d6eSJan Kara * with it. 12609f141d6eSJan Kara */ 12619f141d6eSJan Kara ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); 12621550290bSRoss Zwisler } 126313e451fdSJan Kara unlock_entry: 126491d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, vmf->pgoff); 1265a9c42b33SRoss Zwisler out: 1266a9c42b33SRoss Zwisler trace_dax_pte_fault_done(inode, vmf, vmf_ret); 12679f141d6eSJan Kara return vmf_ret; 1268a7d73fe6SChristoph Hellwig } 1269642261acSRoss Zwisler 1270642261acSRoss Zwisler #ifdef CONFIG_FS_DAX_PMD 1271f4200391SDave Jiang static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, 127291d25ba8SRoss Zwisler void *entry) 1273642261acSRoss Zwisler { 1274f4200391SDave Jiang struct address_space *mapping = vmf->vma->vm_file->f_mapping; 1275f4200391SDave Jiang unsigned long pmd_addr = vmf->address & PMD_MASK; 1276653b2ea3SRoss Zwisler struct inode *inode = mapping->host; 1277642261acSRoss Zwisler struct page *zero_page; 1278653b2ea3SRoss Zwisler void *ret = NULL; 1279642261acSRoss Zwisler spinlock_t *ptl; 1280642261acSRoss Zwisler pmd_t pmd_entry; 1281642261acSRoss Zwisler 1282f4200391SDave Jiang zero_page = mm_get_huge_zero_page(vmf->vma->vm_mm); 1283642261acSRoss Zwisler 1284642261acSRoss Zwisler if (unlikely(!zero_page)) 1285653b2ea3SRoss Zwisler goto fallback; 1286642261acSRoss Zwisler 128791d25ba8SRoss Zwisler ret = dax_insert_mapping_entry(mapping, vmf, entry, 0, 1288f5b7b748SJan Kara RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false); 1289642261acSRoss Zwisler if (IS_ERR(ret)) 1290653b2ea3SRoss Zwisler goto fallback; 1291642261acSRoss Zwisler 1292f4200391SDave Jiang ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd); 1293f4200391SDave Jiang if (!pmd_none(*(vmf->pmd))) { 1294642261acSRoss Zwisler spin_unlock(ptl); 1295653b2ea3SRoss Zwisler goto fallback; 1296642261acSRoss Zwisler } 1297642261acSRoss Zwisler 1298f4200391SDave Jiang pmd_entry = mk_pmd(zero_page, vmf->vma->vm_page_prot); 1299642261acSRoss Zwisler pmd_entry = pmd_mkhuge(pmd_entry); 1300f4200391SDave Jiang set_pmd_at(vmf->vma->vm_mm, pmd_addr, vmf->pmd, pmd_entry); 1301642261acSRoss Zwisler spin_unlock(ptl); 1302f4200391SDave Jiang trace_dax_pmd_load_hole(inode, vmf, zero_page, ret); 1303642261acSRoss Zwisler return VM_FAULT_NOPAGE; 1304653b2ea3SRoss Zwisler 1305653b2ea3SRoss Zwisler fallback: 1306f4200391SDave Jiang trace_dax_pmd_load_hole_fallback(inode, vmf, zero_page, ret); 1307642261acSRoss Zwisler return VM_FAULT_FALLBACK; 1308642261acSRoss Zwisler } 1309642261acSRoss Zwisler 13109a0dd422SJan Kara static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 1311a2d58167SDave Jiang const struct iomap_ops *ops) 1312642261acSRoss Zwisler { 1313f4200391SDave Jiang struct vm_area_struct *vma = vmf->vma; 1314642261acSRoss Zwisler struct address_space *mapping = vma->vm_file->f_mapping; 1315d8a849e1SDave Jiang unsigned long pmd_addr = vmf->address & PMD_MASK; 1316d8a849e1SDave Jiang bool write = vmf->flags & FAULT_FLAG_WRITE; 1317caa51d26SJan Kara bool sync; 13189484ab1bSJan Kara unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; 1319642261acSRoss Zwisler struct inode *inode = mapping->host; 1320642261acSRoss Zwisler int result = VM_FAULT_FALLBACK; 1321642261acSRoss Zwisler struct iomap iomap = { 0 }; 1322642261acSRoss Zwisler pgoff_t max_pgoff, pgoff; 1323642261acSRoss Zwisler void *entry; 1324642261acSRoss Zwisler loff_t pos; 1325642261acSRoss Zwisler int error; 1326302a5e31SJan Kara pfn_t pfn; 1327642261acSRoss Zwisler 1328282a8e03SRoss Zwisler /* 1329282a8e03SRoss Zwisler * Check whether offset isn't beyond end of file now. Caller is 1330282a8e03SRoss Zwisler * supposed to hold locks serializing us with truncate / punch hole so 1331282a8e03SRoss Zwisler * this is a reliable test. 1332282a8e03SRoss Zwisler */ 1333282a8e03SRoss Zwisler pgoff = linear_page_index(vma, pmd_addr); 1334957ac8c4SJeff Moyer max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); 1335282a8e03SRoss Zwisler 1336f4200391SDave Jiang trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); 1337282a8e03SRoss Zwisler 1338fffa281bSRoss Zwisler /* 1339fffa281bSRoss Zwisler * Make sure that the faulting address's PMD offset (color) matches 1340fffa281bSRoss Zwisler * the PMD offset from the start of the file. This is necessary so 1341fffa281bSRoss Zwisler * that a PMD range in the page table overlaps exactly with a PMD 1342fffa281bSRoss Zwisler * range in the radix tree. 1343fffa281bSRoss Zwisler */ 1344fffa281bSRoss Zwisler if ((vmf->pgoff & PG_PMD_COLOUR) != 1345fffa281bSRoss Zwisler ((vmf->address >> PAGE_SHIFT) & PG_PMD_COLOUR)) 1346fffa281bSRoss Zwisler goto fallback; 1347fffa281bSRoss Zwisler 1348642261acSRoss Zwisler /* Fall back to PTEs if we're going to COW */ 1349642261acSRoss Zwisler if (write && !(vma->vm_flags & VM_SHARED)) 1350642261acSRoss Zwisler goto fallback; 1351642261acSRoss Zwisler 1352642261acSRoss Zwisler /* If the PMD would extend outside the VMA */ 1353642261acSRoss Zwisler if (pmd_addr < vma->vm_start) 1354642261acSRoss Zwisler goto fallback; 1355642261acSRoss Zwisler if ((pmd_addr + PMD_SIZE) > vma->vm_end) 1356642261acSRoss Zwisler goto fallback; 1357642261acSRoss Zwisler 1358957ac8c4SJeff Moyer if (pgoff >= max_pgoff) { 1359282a8e03SRoss Zwisler result = VM_FAULT_SIGBUS; 1360282a8e03SRoss Zwisler goto out; 1361282a8e03SRoss Zwisler } 1362642261acSRoss Zwisler 1363642261acSRoss Zwisler /* If the PMD would extend beyond the file size */ 1364957ac8c4SJeff Moyer if ((pgoff | PG_PMD_COLOUR) >= max_pgoff) 1365642261acSRoss Zwisler goto fallback; 1366642261acSRoss Zwisler 1367642261acSRoss Zwisler /* 136891d25ba8SRoss Zwisler * grab_mapping_entry() will make sure we get a 2MiB empty entry, a 136991d25ba8SRoss Zwisler * 2MiB zero page entry or a DAX PMD. If it can't (because a 4k page 137091d25ba8SRoss Zwisler * is already in the tree, for instance), it will return -EEXIST and 137191d25ba8SRoss Zwisler * we just fall back to 4k entries. 13729f141d6eSJan Kara */ 13739f141d6eSJan Kara entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); 13749f141d6eSJan Kara if (IS_ERR(entry)) 1375876f2946SRoss Zwisler goto fallback; 1376876f2946SRoss Zwisler 1377876f2946SRoss Zwisler /* 1378e2093926SRoss Zwisler * It is possible, particularly with mixed reads & writes to private 1379e2093926SRoss Zwisler * mappings, that we have raced with a PTE fault that overlaps with 1380e2093926SRoss Zwisler * the PMD we need to set up. If so just return and the fault will be 1381e2093926SRoss Zwisler * retried. 1382e2093926SRoss Zwisler */ 1383e2093926SRoss Zwisler if (!pmd_none(*vmf->pmd) && !pmd_trans_huge(*vmf->pmd) && 1384e2093926SRoss Zwisler !pmd_devmap(*vmf->pmd)) { 1385e2093926SRoss Zwisler result = 0; 1386e2093926SRoss Zwisler goto unlock_entry; 1387e2093926SRoss Zwisler } 1388e2093926SRoss Zwisler 1389e2093926SRoss Zwisler /* 1390876f2946SRoss Zwisler * Note that we don't use iomap_apply here. We aren't doing I/O, only 1391876f2946SRoss Zwisler * setting up a mapping, so really we're using iomap_begin() as a way 1392876f2946SRoss Zwisler * to look up our filesystem block. 1393876f2946SRoss Zwisler */ 1394876f2946SRoss Zwisler pos = (loff_t)pgoff << PAGE_SHIFT; 1395876f2946SRoss Zwisler error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); 1396876f2946SRoss Zwisler if (error) 1397876f2946SRoss Zwisler goto unlock_entry; 1398876f2946SRoss Zwisler 1399876f2946SRoss Zwisler if (iomap.offset + iomap.length < pos + PMD_SIZE) 14009f141d6eSJan Kara goto finish_iomap; 14019f141d6eSJan Kara 1402aaa422c4SDan Williams sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); 1403caa51d26SJan Kara 1404642261acSRoss Zwisler switch (iomap.type) { 1405642261acSRoss Zwisler case IOMAP_MAPPED: 1406302a5e31SJan Kara error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); 1407302a5e31SJan Kara if (error < 0) 1408302a5e31SJan Kara goto finish_iomap; 1409302a5e31SJan Kara 1410302a5e31SJan Kara entry = dax_insert_mapping_entry(mapping, vmf, entry, 1411302a5e31SJan Kara dax_iomap_sector(&iomap, pos), 1412caa51d26SJan Kara RADIX_DAX_PMD, write && !sync); 1413302a5e31SJan Kara if (IS_ERR(entry)) 1414302a5e31SJan Kara goto finish_iomap; 1415302a5e31SJan Kara 1416caa51d26SJan Kara /* 1417caa51d26SJan Kara * If we are doing synchronous page fault and inode needs fsync, 1418caa51d26SJan Kara * we can insert PMD into page tables only after that happens. 1419caa51d26SJan Kara * Skip insertion for now and return the pfn so that caller can 1420caa51d26SJan Kara * insert it after fsync is done. 1421caa51d26SJan Kara */ 1422caa51d26SJan Kara if (sync) { 1423caa51d26SJan Kara if (WARN_ON_ONCE(!pfnp)) 1424caa51d26SJan Kara goto finish_iomap; 1425caa51d26SJan Kara *pfnp = pfn; 1426caa51d26SJan Kara result = VM_FAULT_NEEDDSYNC; 1427caa51d26SJan Kara goto finish_iomap; 1428caa51d26SJan Kara } 1429caa51d26SJan Kara 1430302a5e31SJan Kara trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); 1431302a5e31SJan Kara result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, 1432302a5e31SJan Kara write); 1433642261acSRoss Zwisler break; 1434642261acSRoss Zwisler case IOMAP_UNWRITTEN: 1435642261acSRoss Zwisler case IOMAP_HOLE: 1436642261acSRoss Zwisler if (WARN_ON_ONCE(write)) 1437876f2946SRoss Zwisler break; 143891d25ba8SRoss Zwisler result = dax_pmd_load_hole(vmf, &iomap, entry); 1439642261acSRoss Zwisler break; 1440642261acSRoss Zwisler default: 1441642261acSRoss Zwisler WARN_ON_ONCE(1); 1442642261acSRoss Zwisler break; 1443642261acSRoss Zwisler } 1444642261acSRoss Zwisler 14459f141d6eSJan Kara finish_iomap: 14469f141d6eSJan Kara if (ops->iomap_end) { 14479f141d6eSJan Kara int copied = PMD_SIZE; 14489f141d6eSJan Kara 14499f141d6eSJan Kara if (result == VM_FAULT_FALLBACK) 14509f141d6eSJan Kara copied = 0; 14519f141d6eSJan Kara /* 14529f141d6eSJan Kara * The fault is done by now and there's no way back (other 14539f141d6eSJan Kara * thread may be already happily using PMD we have installed). 14549f141d6eSJan Kara * Just ignore error from ->iomap_end since we cannot do much 14559f141d6eSJan Kara * with it. 14569f141d6eSJan Kara */ 14579f141d6eSJan Kara ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, 14589f141d6eSJan Kara &iomap); 14599f141d6eSJan Kara } 1460876f2946SRoss Zwisler unlock_entry: 146191d25ba8SRoss Zwisler put_locked_mapping_entry(mapping, pgoff); 1462642261acSRoss Zwisler fallback: 1463642261acSRoss Zwisler if (result == VM_FAULT_FALLBACK) { 1464d8a849e1SDave Jiang split_huge_pmd(vma, vmf->pmd, vmf->address); 1465642261acSRoss Zwisler count_vm_event(THP_FAULT_FALLBACK); 1466642261acSRoss Zwisler } 1467282a8e03SRoss Zwisler out: 1468f4200391SDave Jiang trace_dax_pmd_fault_done(inode, vmf, max_pgoff, result); 1469642261acSRoss Zwisler return result; 1470642261acSRoss Zwisler } 1471a2d58167SDave Jiang #else 14729a0dd422SJan Kara static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, 147301cddfe9SArnd Bergmann const struct iomap_ops *ops) 1474a2d58167SDave Jiang { 1475a2d58167SDave Jiang return VM_FAULT_FALLBACK; 1476a2d58167SDave Jiang } 1477642261acSRoss Zwisler #endif /* CONFIG_FS_DAX_PMD */ 1478a2d58167SDave Jiang 1479a2d58167SDave Jiang /** 1480a2d58167SDave Jiang * dax_iomap_fault - handle a page fault on a DAX file 1481a2d58167SDave Jiang * @vmf: The description of the fault 1482cec04e8cSJan Kara * @pe_size: Size of the page to fault in 14839a0dd422SJan Kara * @pfnp: PFN to insert for synchronous faults if fsync is required 1484cec04e8cSJan Kara * @ops: Iomap ops passed from the file system 1485a2d58167SDave Jiang * 1486a2d58167SDave Jiang * When a page fault occurs, filesystems may call this helper in 1487a2d58167SDave Jiang * their fault handler for DAX files. dax_iomap_fault() assumes the caller 1488a2d58167SDave Jiang * has done all the necessary locking for page fault to proceed 1489a2d58167SDave Jiang * successfully. 1490a2d58167SDave Jiang */ 1491c791ace1SDave Jiang int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 14929a0dd422SJan Kara pfn_t *pfnp, const struct iomap_ops *ops) 1493a2d58167SDave Jiang { 1494c791ace1SDave Jiang switch (pe_size) { 1495c791ace1SDave Jiang case PE_SIZE_PTE: 14969a0dd422SJan Kara return dax_iomap_pte_fault(vmf, pfnp, ops); 1497c791ace1SDave Jiang case PE_SIZE_PMD: 14989a0dd422SJan Kara return dax_iomap_pmd_fault(vmf, pfnp, ops); 1499a2d58167SDave Jiang default: 1500a2d58167SDave Jiang return VM_FAULT_FALLBACK; 1501a2d58167SDave Jiang } 1502a2d58167SDave Jiang } 1503a2d58167SDave Jiang EXPORT_SYMBOL_GPL(dax_iomap_fault); 150471eab6dfSJan Kara 150571eab6dfSJan Kara /** 150671eab6dfSJan Kara * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables 150771eab6dfSJan Kara * @vmf: The description of the fault 150871eab6dfSJan Kara * @pe_size: Size of entry to be inserted 150971eab6dfSJan Kara * @pfn: PFN to insert 151071eab6dfSJan Kara * 151171eab6dfSJan Kara * This function inserts writeable PTE or PMD entry into page tables for mmaped 151271eab6dfSJan Kara * DAX file. It takes care of marking corresponding radix tree entry as dirty 151371eab6dfSJan Kara * as well. 151471eab6dfSJan Kara */ 151571eab6dfSJan Kara static int dax_insert_pfn_mkwrite(struct vm_fault *vmf, 151671eab6dfSJan Kara enum page_entry_size pe_size, 151771eab6dfSJan Kara pfn_t pfn) 151871eab6dfSJan Kara { 151971eab6dfSJan Kara struct address_space *mapping = vmf->vma->vm_file->f_mapping; 152071eab6dfSJan Kara void *entry, **slot; 152171eab6dfSJan Kara pgoff_t index = vmf->pgoff; 152271eab6dfSJan Kara int vmf_ret, error; 152371eab6dfSJan Kara 152471eab6dfSJan Kara spin_lock_irq(&mapping->tree_lock); 152571eab6dfSJan Kara entry = get_unlocked_mapping_entry(mapping, index, &slot); 152671eab6dfSJan Kara /* Did we race with someone splitting entry or so? */ 152771eab6dfSJan Kara if (!entry || 152871eab6dfSJan Kara (pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) || 152971eab6dfSJan Kara (pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) { 153071eab6dfSJan Kara put_unlocked_mapping_entry(mapping, index, entry); 153171eab6dfSJan Kara spin_unlock_irq(&mapping->tree_lock); 153271eab6dfSJan Kara trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, 153371eab6dfSJan Kara VM_FAULT_NOPAGE); 153471eab6dfSJan Kara return VM_FAULT_NOPAGE; 153571eab6dfSJan Kara } 153671eab6dfSJan Kara radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY); 153771eab6dfSJan Kara entry = lock_slot(mapping, slot); 153871eab6dfSJan Kara spin_unlock_irq(&mapping->tree_lock); 153971eab6dfSJan Kara switch (pe_size) { 154071eab6dfSJan Kara case PE_SIZE_PTE: 154171eab6dfSJan Kara error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); 154271eab6dfSJan Kara vmf_ret = dax_fault_return(error); 154371eab6dfSJan Kara break; 154471eab6dfSJan Kara #ifdef CONFIG_FS_DAX_PMD 154571eab6dfSJan Kara case PE_SIZE_PMD: 154671eab6dfSJan Kara vmf_ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, 154771eab6dfSJan Kara pfn, true); 154871eab6dfSJan Kara break; 154971eab6dfSJan Kara #endif 155071eab6dfSJan Kara default: 155171eab6dfSJan Kara vmf_ret = VM_FAULT_FALLBACK; 155271eab6dfSJan Kara } 155371eab6dfSJan Kara put_locked_mapping_entry(mapping, index); 155471eab6dfSJan Kara trace_dax_insert_pfn_mkwrite(mapping->host, vmf, vmf_ret); 155571eab6dfSJan Kara return vmf_ret; 155671eab6dfSJan Kara } 155771eab6dfSJan Kara 155871eab6dfSJan Kara /** 155971eab6dfSJan Kara * dax_finish_sync_fault - finish synchronous page fault 156071eab6dfSJan Kara * @vmf: The description of the fault 156171eab6dfSJan Kara * @pe_size: Size of entry to be inserted 156271eab6dfSJan Kara * @pfn: PFN to insert 156371eab6dfSJan Kara * 156471eab6dfSJan Kara * This function ensures that the file range touched by the page fault is 156571eab6dfSJan Kara * stored persistently on the media and handles inserting of appropriate page 156671eab6dfSJan Kara * table entry. 156771eab6dfSJan Kara */ 156871eab6dfSJan Kara int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size, 156971eab6dfSJan Kara pfn_t pfn) 157071eab6dfSJan Kara { 157171eab6dfSJan Kara int err; 157271eab6dfSJan Kara loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; 157371eab6dfSJan Kara size_t len = 0; 157471eab6dfSJan Kara 157571eab6dfSJan Kara if (pe_size == PE_SIZE_PTE) 157671eab6dfSJan Kara len = PAGE_SIZE; 157771eab6dfSJan Kara else if (pe_size == PE_SIZE_PMD) 157871eab6dfSJan Kara len = PMD_SIZE; 157971eab6dfSJan Kara else 158071eab6dfSJan Kara WARN_ON_ONCE(1); 158171eab6dfSJan Kara err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); 158271eab6dfSJan Kara if (err) 158371eab6dfSJan Kara return VM_FAULT_SIGBUS; 158471eab6dfSJan Kara return dax_insert_pfn_mkwrite(vmf, pe_size, pfn); 158571eab6dfSJan Kara } 158671eab6dfSJan Kara EXPORT_SYMBOL_GPL(dax_finish_sync_fault); 1587