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authorLinus Torvalds <torvalds@linux-foundation.org>2018-11-25 05:44:01 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-11-25 05:44:01 +0300
commite2125dac22f2c9c66c412cd8e049a7305af59f73 (patch)
tree8584af248ee592622bd6e8a7f9cee0b041b784cc /include
parente195ca6cb6f21633e56322d5aa11ed59cdb22fb2 (diff)
parentfffc9a260e38acec3187515738122a3ecb24ac90 (diff)
downloadlinux-e2125dac22f2c9c66c412cd8e049a7305af59f73.tar.xz
Merge tag 'xarray-4.20-rc4' of git://git.infradead.org/users/willy/linux-dax
Pull XArray updates from Matthew Wilcox: "We found some bugs in the DAX conversion to XArray (and one bug which predated the XArray conversion). There were a couple of bugs in some of the higher-level functions, which aren't actually being called in today's kernel, but surfaced as a result of converting existing radix tree & IDR users over to the XArray. Some of the other changes to how the higher-level APIs work were also motivated by converting various users; again, they're not in use in today's kernel, so changing them has a low probability of introducing a bug. Dan can still trigger a bug in the DAX code with hot-offline/online, and we're working on tracking that down" * tag 'xarray-4.20-rc4' of git://git.infradead.org/users/willy/linux-dax: XArray tests: Add missing locking dax: Avoid losing wakeup in dax_lock_mapping_entry dax: Fix huge page faults dax: Fix dax_unlock_mapping_entry for PMD pages dax: Reinstate RCU protection of inode dax: Make sure the unlocking entry isn't locked dax: Remove optimisation from dax_lock_mapping_entry XArray tests: Correct some 64-bit assumptions XArray: Correct xa_store_range XArray: Fix Documentation XArray: Handle NULL pointers differently for allocation XArray: Unify xa_store and __xa_store XArray: Add xa_store_bh() and xa_store_irq() XArray: Turn xa_erase into an exported function XArray: Unify xa_cmpxchg and __xa_cmpxchg XArray: Regularise xa_reserve nilfs2: Use xa_erase_irq XArray: Export __xa_foo to non-GPL modules XArray: Fix xa_for_each with a single element at 0
Diffstat (limited to 'include')
-rw-r--r--include/linux/xarray.h267
1 files changed, 203 insertions, 64 deletions
diff --git a/include/linux/xarray.h b/include/linux/xarray.h
index d9514928ddac..564892e19f8c 100644
--- a/include/linux/xarray.h
+++ b/include/linux/xarray.h
@@ -289,9 +289,7 @@ struct xarray {
void xa_init_flags(struct xarray *, gfp_t flags);
void *xa_load(struct xarray *, unsigned long index);
void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
-void *xa_cmpxchg(struct xarray *, unsigned long index,
- void *old, void *entry, gfp_t);
-int xa_reserve(struct xarray *, unsigned long index, gfp_t);
+void *xa_erase(struct xarray *, unsigned long index);
void *xa_store_range(struct xarray *, unsigned long first, unsigned long last,
void *entry, gfp_t);
bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t);
@@ -344,65 +342,6 @@ static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark)
}
/**
- * xa_erase() - Erase this entry from the XArray.
- * @xa: XArray.
- * @index: Index of entry.
- *
- * This function is the equivalent of calling xa_store() with %NULL as
- * the third argument. The XArray does not need to allocate memory, so
- * the user does not need to provide GFP flags.
- *
- * Context: Process context. Takes and releases the xa_lock.
- * Return: The entry which used to be at this index.
- */
-static inline void *xa_erase(struct xarray *xa, unsigned long index)
-{
- return xa_store(xa, index, NULL, 0);
-}
-
-/**
- * xa_insert() - Store this entry in the XArray unless another entry is
- * already present.
- * @xa: XArray.
- * @index: Index into array.
- * @entry: New entry.
- * @gfp: Memory allocation flags.
- *
- * If you would rather see the existing entry in the array, use xa_cmpxchg().
- * This function is for users who don't care what the entry is, only that
- * one is present.
- *
- * Context: Process context. Takes and releases the xa_lock.
- * May sleep if the @gfp flags permit.
- * Return: 0 if the store succeeded. -EEXIST if another entry was present.
- * -ENOMEM if memory could not be allocated.
- */
-static inline int xa_insert(struct xarray *xa, unsigned long index,
- void *entry, gfp_t gfp)
-{
- void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp);
- if (!curr)
- return 0;
- if (xa_is_err(curr))
- return xa_err(curr);
- return -EEXIST;
-}
-
-/**
- * xa_release() - Release a reserved entry.
- * @xa: XArray.
- * @index: Index of entry.
- *
- * After calling xa_reserve(), you can call this function to release the
- * reservation. If the entry at @index has been stored to, this function
- * will do nothing.
- */
-static inline void xa_release(struct xarray *xa, unsigned long index)
-{
- xa_cmpxchg(xa, index, NULL, NULL, 0);
-}
-
-/**
* xa_for_each() - Iterate over a portion of an XArray.
* @xa: XArray.
* @entry: Entry retrieved from array.
@@ -455,6 +394,7 @@ void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old,
void *entry, gfp_t);
int __xa_alloc(struct xarray *, u32 *id, u32 max, void *entry, gfp_t);
+int __xa_reserve(struct xarray *, unsigned long index, gfp_t);
void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t);
void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t);
@@ -487,6 +427,58 @@ static inline int __xa_insert(struct xarray *xa, unsigned long index,
}
/**
+ * xa_store_bh() - Store this entry in the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * This function is like calling xa_store() except it disables softirqs
+ * while holding the array lock.
+ *
+ * Context: Any context. Takes and releases the xa_lock while
+ * disabling softirqs.
+ * Return: The entry which used to be at this index.
+ */
+static inline void *xa_store_bh(struct xarray *xa, unsigned long index,
+ void *entry, gfp_t gfp)
+{
+ void *curr;
+
+ xa_lock_bh(xa);
+ curr = __xa_store(xa, index, entry, gfp);
+ xa_unlock_bh(xa);
+
+ return curr;
+}
+
+/**
+ * xa_store_irq() - Erase this entry from the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * This function is like calling xa_store() except it disables interrupts
+ * while holding the array lock.
+ *
+ * Context: Process context. Takes and releases the xa_lock while
+ * disabling interrupts.
+ * Return: The entry which used to be at this index.
+ */
+static inline void *xa_store_irq(struct xarray *xa, unsigned long index,
+ void *entry, gfp_t gfp)
+{
+ void *curr;
+
+ xa_lock_irq(xa);
+ curr = __xa_store(xa, index, entry, gfp);
+ xa_unlock_irq(xa);
+
+ return curr;
+}
+
+/**
* xa_erase_bh() - Erase this entry from the XArray.
* @xa: XArray.
* @index: Index of entry.
@@ -495,7 +487,7 @@ static inline int __xa_insert(struct xarray *xa, unsigned long index,
* the third argument. The XArray does not need to allocate memory, so
* the user does not need to provide GFP flags.
*
- * Context: Process context. Takes and releases the xa_lock while
+ * Context: Any context. Takes and releases the xa_lock while
* disabling softirqs.
* Return: The entry which used to be at this index.
*/
@@ -535,6 +527,61 @@ static inline void *xa_erase_irq(struct xarray *xa, unsigned long index)
}
/**
+ * xa_cmpxchg() - Conditionally replace an entry in the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @old: Old value to test against.
+ * @entry: New value to place in array.
+ * @gfp: Memory allocation flags.
+ *
+ * If the entry at @index is the same as @old, replace it with @entry.
+ * If the return value is equal to @old, then the exchange was successful.
+ *
+ * Context: Any context. Takes and releases the xa_lock. May sleep
+ * if the @gfp flags permit.
+ * Return: The old value at this index or xa_err() if an error happened.
+ */
+static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index,
+ void *old, void *entry, gfp_t gfp)
+{
+ void *curr;
+
+ xa_lock(xa);
+ curr = __xa_cmpxchg(xa, index, old, entry, gfp);
+ xa_unlock(xa);
+
+ return curr;
+}
+
+/**
+ * xa_insert() - Store this entry in the XArray unless another entry is
+ * already present.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @entry: New entry.
+ * @gfp: Memory allocation flags.
+ *
+ * If you would rather see the existing entry in the array, use xa_cmpxchg().
+ * This function is for users who don't care what the entry is, only that
+ * one is present.
+ *
+ * Context: Process context. Takes and releases the xa_lock.
+ * May sleep if the @gfp flags permit.
+ * Return: 0 if the store succeeded. -EEXIST if another entry was present.
+ * -ENOMEM if memory could not be allocated.
+ */
+static inline int xa_insert(struct xarray *xa, unsigned long index,
+ void *entry, gfp_t gfp)
+{
+ void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp);
+ if (!curr)
+ return 0;
+ if (xa_is_err(curr))
+ return xa_err(curr);
+ return -EEXIST;
+}
+
+/**
* xa_alloc() - Find somewhere to store this entry in the XArray.
* @xa: XArray.
* @id: Pointer to ID.
@@ -575,7 +622,7 @@ static inline int xa_alloc(struct xarray *xa, u32 *id, u32 max, void *entry,
* Updates the @id pointer with the index, then stores the entry at that
* index. A concurrent lookup will not see an uninitialised @id.
*
- * Context: Process context. Takes and releases the xa_lock while
+ * Context: Any context. Takes and releases the xa_lock while
* disabling softirqs. May sleep if the @gfp flags permit.
* Return: 0 on success, -ENOMEM if memory allocation fails or -ENOSPC if
* there is no more space in the XArray.
@@ -621,6 +668,98 @@ static inline int xa_alloc_irq(struct xarray *xa, u32 *id, u32 max, void *entry,
return err;
}
+/**
+ * xa_reserve() - Reserve this index in the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @gfp: Memory allocation flags.
+ *
+ * Ensures there is somewhere to store an entry at @index in the array.
+ * If there is already something stored at @index, this function does
+ * nothing. If there was nothing there, the entry is marked as reserved.
+ * Loading from a reserved entry returns a %NULL pointer.
+ *
+ * If you do not use the entry that you have reserved, call xa_release()
+ * or xa_erase() to free any unnecessary memory.
+ *
+ * Context: Any context. Takes and releases the xa_lock.
+ * May sleep if the @gfp flags permit.
+ * Return: 0 if the reservation succeeded or -ENOMEM if it failed.
+ */
+static inline
+int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
+{
+ int ret;
+
+ xa_lock(xa);
+ ret = __xa_reserve(xa, index, gfp);
+ xa_unlock(xa);
+
+ return ret;
+}
+
+/**
+ * xa_reserve_bh() - Reserve this index in the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @gfp: Memory allocation flags.
+ *
+ * A softirq-disabling version of xa_reserve().
+ *
+ * Context: Any context. Takes and releases the xa_lock while
+ * disabling softirqs.
+ * Return: 0 if the reservation succeeded or -ENOMEM if it failed.
+ */
+static inline
+int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp)
+{
+ int ret;
+
+ xa_lock_bh(xa);
+ ret = __xa_reserve(xa, index, gfp);
+ xa_unlock_bh(xa);
+
+ return ret;
+}
+
+/**
+ * xa_reserve_irq() - Reserve this index in the XArray.
+ * @xa: XArray.
+ * @index: Index into array.
+ * @gfp: Memory allocation flags.
+ *
+ * An interrupt-disabling version of xa_reserve().
+ *
+ * Context: Process context. Takes and releases the xa_lock while
+ * disabling interrupts.
+ * Return: 0 if the reservation succeeded or -ENOMEM if it failed.
+ */
+static inline
+int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp)
+{
+ int ret;
+
+ xa_lock_irq(xa);
+ ret = __xa_reserve(xa, index, gfp);
+ xa_unlock_irq(xa);
+
+ return ret;
+}
+
+/**
+ * xa_release() - Release a reserved entry.
+ * @xa: XArray.
+ * @index: Index of entry.
+ *
+ * After calling xa_reserve(), you can call this function to release the
+ * reservation. If the entry at @index has been stored to, this function
+ * will do nothing.
+ */
+static inline void xa_release(struct xarray *xa, unsigned long index)
+{
+ xa_cmpxchg(xa, index, NULL, NULL, 0);
+}
+
/* Everything below here is the Advanced API. Proceed with caution. */
/*