From 02669b17a433c242a40f01f14b691c9c9d1f8a13 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 5 Dec 2018 16:37:03 -0500 Subject: XArray: Turn xa_init_flags into a static inline A regular xa_init_flags() put all dynamically-initialised XArrays into the same locking class. That leads to lockdep believing that taking one XArray lock while holding another is a deadlock. It's possible to work around some of these situations with separate locking classes for irq/bh/regular XArrays, and SINGLE_DEPTH_NESTING, but that's ugly, and it doesn't work for all situations (where we have completely unrelated XArrays). Signed-off-by: Matthew Wilcox --- lib/xarray.c | 29 ----------------------------- 1 file changed, 29 deletions(-) (limited to 'lib/xarray.c') diff --git a/lib/xarray.c b/lib/xarray.c index 5f3f9311de89..dda6026d202e 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1250,35 +1250,6 @@ void *xas_find_conflict(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_find_conflict); -/** - * xa_init_flags() - Initialise an empty XArray with flags. - * @xa: XArray. - * @flags: XA_FLAG values. - * - * If you need to initialise an XArray with special flags (eg you need - * to take the lock from interrupt context), use this function instead - * of xa_init(). - * - * Context: Any context. - */ -void xa_init_flags(struct xarray *xa, gfp_t flags) -{ - unsigned int lock_type; - static struct lock_class_key xa_lock_irq; - static struct lock_class_key xa_lock_bh; - - spin_lock_init(&xa->xa_lock); - xa->xa_flags = flags; - xa->xa_head = NULL; - - lock_type = xa_lock_type(xa); - if (lock_type == XA_LOCK_IRQ) - lockdep_set_class(&xa->xa_lock, &xa_lock_irq); - else if (lock_type == XA_LOCK_BH) - lockdep_set_class(&xa->xa_lock, &xa_lock_bh); -} -EXPORT_SYMBOL(xa_init_flags); - /** * xa_load() - Load an entry from an XArray. * @xa: XArray. -- cgit From 76b4e52995654af260f14558e0e07b5b039ae202 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 28 Dec 2018 23:20:44 -0500 Subject: XArray: Permit storing 2-byte-aligned pointers On m68k, statically allocated pointers may only be two-byte aligned. This clashes with the XArray's method for tagging internal pointers. Permit storing these pointers in single slots (ie not in multislots). Signed-off-by: Matthew Wilcox --- lib/xarray.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-) (limited to 'lib/xarray.c') diff --git a/lib/xarray.c b/lib/xarray.c index dda6026d202e..bffa26b1f0d6 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -232,6 +232,8 @@ void *xas_load(struct xa_state *xas) if (xas->xa_shift > node->shift) break; entry = xas_descend(xas, node); + if (node->shift == 0) + break; } return entry; } @@ -506,7 +508,7 @@ static void xas_free_nodes(struct xa_state *xas, struct xa_node *top) for (;;) { void *entry = xa_entry_locked(xas->xa, node, offset); - if (xa_is_node(entry)) { + if (node->shift && xa_is_node(entry)) { node = xa_to_node(entry); offset = 0; continue; @@ -604,6 +606,7 @@ static int xas_expand(struct xa_state *xas, void *head) /* * xas_create() - Create a slot to store an entry in. * @xas: XArray operation state. + * @allow_root: %true if we can store the entry in the root directly * * Most users will not need to call this function directly, as it is called * by xas_store(). It is useful for doing conditional store operations @@ -613,7 +616,7 @@ static int xas_expand(struct xa_state *xas, void *head) * If the slot was newly created, returns %NULL. If it failed to create the * slot, returns %NULL and indicates the error in @xas. */ -static void *xas_create(struct xa_state *xas) +static void *xas_create(struct xa_state *xas, bool allow_root) { struct xarray *xa = xas->xa; void *entry; @@ -628,6 +631,8 @@ static void *xas_create(struct xa_state *xas) shift = xas_expand(xas, entry); if (shift < 0) return NULL; + if (!shift && !allow_root) + shift = XA_CHUNK_SHIFT; entry = xa_head_locked(xa); slot = &xa->xa_head; } else if (xas_error(xas)) { @@ -687,7 +692,7 @@ void xas_create_range(struct xa_state *xas) xas->xa_sibs = 0; for (;;) { - xas_create(xas); + xas_create(xas, true); if (xas_error(xas)) goto restore; if (xas->xa_index <= (index | XA_CHUNK_MASK)) @@ -754,7 +759,7 @@ void *xas_store(struct xa_state *xas, void *entry) bool value = xa_is_value(entry); if (entry) - first = xas_create(xas); + first = xas_create(xas, !xa_is_node(entry)); else first = xas_load(xas); @@ -1279,7 +1284,6 @@ static void *xas_result(struct xa_state *xas, void *curr) { if (xa_is_zero(curr)) return NULL; - XA_NODE_BUG_ON(xas->xa_node, xa_is_internal(curr)); if (xas_error(xas)) curr = xas->xa_node; return curr; @@ -1349,7 +1353,7 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) XA_STATE(xas, xa, index); void *curr; - if (WARN_ON_ONCE(xa_is_internal(entry))) + if (WARN_ON_ONCE(xa_is_advanced(entry))) return XA_ERROR(-EINVAL); if (xa_track_free(xa) && !entry) entry = XA_ZERO_ENTRY; @@ -1415,7 +1419,7 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, XA_STATE(xas, xa, index); void *curr; - if (WARN_ON_ONCE(xa_is_internal(entry))) + if (WARN_ON_ONCE(xa_is_advanced(entry))) return XA_ERROR(-EINVAL); if (xa_track_free(xa) && !entry) entry = XA_ZERO_ENTRY; @@ -1538,7 +1542,7 @@ void *xa_store_range(struct xarray *xa, unsigned long first, if (last + 1) order = __ffs(last + 1); xas_set_order(&xas, last, order); - xas_create(&xas); + xas_create(&xas, true); if (xas_error(&xas)) goto unlock; } @@ -1580,7 +1584,7 @@ int __xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry, gfp_t gfp) XA_STATE(xas, xa, 0); int err; - if (WARN_ON_ONCE(xa_is_internal(entry))) + if (WARN_ON_ONCE(xa_is_advanced(entry))) return -EINVAL; if (WARN_ON_ONCE(!xa_track_free(xa))) return -EINVAL; -- cgit From b0606fed6eece16a421034eca0bbea9a08b90e91 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Wed, 2 Jan 2019 13:57:03 -0500 Subject: XArray: Honour reserved entries in xa_insert xa_insert() should treat reserved entries as occupied, not as available. Also, it should treat requests to insert a NULL pointer as a request to reserve the slot. Add xa_insert_bh() and xa_insert_irq() for completeness. Signed-off-by: Matthew Wilcox --- lib/xarray.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) (limited to 'lib/xarray.c') diff --git a/lib/xarray.c b/lib/xarray.c index bffa26b1f0d6..81c3171ddde9 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -1439,6 +1439,47 @@ void *__xa_cmpxchg(struct xarray *xa, unsigned long index, } EXPORT_SYMBOL(__xa_cmpxchg); +/** + * __xa_insert() - Store this entry in the XArray if no entry is present. + * @xa: XArray. + * @index: Index into array. + * @entry: New entry. + * @gfp: Memory allocation flags. + * + * Inserting a NULL entry will store a reserved entry (like xa_reserve()) + * if no entry is present. Inserting will fail if a reserved entry is + * present, even though loading from this index will return NULL. + * + * Context: Any context. Expects xa_lock to be held on entry. May + * release and reacquire xa_lock if @gfp flags permit. + * Return: 0 if the store succeeded. -EEXIST if another entry was present. + * -ENOMEM if memory could not be allocated. + */ +int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp) +{ + XA_STATE(xas, xa, index); + void *curr; + + if (WARN_ON_ONCE(xa_is_advanced(entry))) + return -EINVAL; + if (!entry) + entry = XA_ZERO_ENTRY; + + do { + curr = xas_load(&xas); + if (!curr) { + xas_store(&xas, entry); + if (xa_track_free(xa)) + xas_clear_mark(&xas, XA_FREE_MARK); + } else { + xas_set_err(&xas, -EEXIST); + } + } while (__xas_nomem(&xas, gfp)); + + return xas_error(&xas); +} +EXPORT_SYMBOL(__xa_insert); + /** * __xa_reserve() - Reserve this index in the XArray. * @xa: XArray. -- cgit