mirror of https://gitee.com/openkylin/linux.git
XArray: Unify xa_cmpxchg and __xa_cmpxchg
xa_cmpxchg() was one of the largest functions in the xarray implementation. By turning it into a wrapper and having the callers take the lock (like several other functions), we save 160 bytes on a tinyconfig build and reduce the duplication in xarray.c. Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox
parent
4c0608f4a0
commit
c5beb07e7a
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@ -289,8 +289,6 @@ struct xarray {
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void xa_init_flags(struct xarray *, gfp_t flags);
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void *xa_load(struct xarray *, unsigned long index);
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void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t);
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void *xa_cmpxchg(struct xarray *, unsigned long index,
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void *old, void *entry, gfp_t);
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void *xa_store_range(struct xarray *, unsigned long first, unsigned long last,
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void *entry, gfp_t);
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bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t);
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@ -359,48 +357,6 @@ static inline void *xa_erase(struct xarray *xa, unsigned long index)
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return xa_store(xa, index, NULL, 0);
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}
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/**
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* xa_insert() - Store this entry in the XArray unless another entry is
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* already present.
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* @xa: XArray.
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* @index: Index into array.
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* @entry: New entry.
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* @gfp: Memory allocation flags.
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*
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* If you would rather see the existing entry in the array, use xa_cmpxchg().
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* This function is for users who don't care what the entry is, only that
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* one is present.
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*
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* Context: Process context. Takes and releases the xa_lock.
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* May sleep if the @gfp flags permit.
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* Return: 0 if the store succeeded. -EEXIST if another entry was present.
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* -ENOMEM if memory could not be allocated.
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*/
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static inline int xa_insert(struct xarray *xa, unsigned long index,
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void *entry, gfp_t gfp)
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{
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void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp);
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if (!curr)
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return 0;
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if (xa_is_err(curr))
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return xa_err(curr);
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return -EEXIST;
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}
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/**
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* xa_release() - Release a reserved entry.
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* @xa: XArray.
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* @index: Index of entry.
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*
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* After calling xa_reserve(), you can call this function to release the
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* reservation. If the entry at @index has been stored to, this function
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* will do nothing.
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*/
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static inline void xa_release(struct xarray *xa, unsigned long index)
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{
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xa_cmpxchg(xa, index, NULL, NULL, 0);
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}
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/**
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* xa_for_each() - Iterate over a portion of an XArray.
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* @xa: XArray.
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@ -534,6 +490,61 @@ static inline void *xa_erase_irq(struct xarray *xa, unsigned long index)
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return entry;
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}
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/**
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* xa_cmpxchg() - Conditionally replace an entry in the XArray.
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* @xa: XArray.
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* @index: Index into array.
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* @old: Old value to test against.
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* @entry: New value to place in array.
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* @gfp: Memory allocation flags.
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*
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* If the entry at @index is the same as @old, replace it with @entry.
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* If the return value is equal to @old, then the exchange was successful.
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*
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* Context: Any context. Takes and releases the xa_lock. May sleep
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* if the @gfp flags permit.
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* Return: The old value at this index or xa_err() if an error happened.
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*/
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static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index,
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void *old, void *entry, gfp_t gfp)
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{
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void *curr;
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xa_lock(xa);
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curr = __xa_cmpxchg(xa, index, old, entry, gfp);
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xa_unlock(xa);
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return curr;
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}
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/**
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* xa_insert() - Store this entry in the XArray unless another entry is
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* already present.
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* @xa: XArray.
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* @index: Index into array.
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* @entry: New entry.
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* @gfp: Memory allocation flags.
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*
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* If you would rather see the existing entry in the array, use xa_cmpxchg().
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* This function is for users who don't care what the entry is, only that
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* one is present.
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*
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* Context: Process context. Takes and releases the xa_lock.
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* May sleep if the @gfp flags permit.
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* Return: 0 if the store succeeded. -EEXIST if another entry was present.
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* -ENOMEM if memory could not be allocated.
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*/
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static inline int xa_insert(struct xarray *xa, unsigned long index,
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void *entry, gfp_t gfp)
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{
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void *curr = xa_cmpxchg(xa, index, NULL, entry, gfp);
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if (!curr)
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return 0;
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if (xa_is_err(curr))
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return xa_err(curr);
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return -EEXIST;
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}
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/**
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* xa_alloc() - Find somewhere to store this entry in the XArray.
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* @xa: XArray.
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@ -699,6 +710,20 @@ int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp)
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return ret;
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}
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/**
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* xa_release() - Release a reserved entry.
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* @xa: XArray.
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* @index: Index of entry.
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*
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* After calling xa_reserve(), you can call this function to release the
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* reservation. If the entry at @index has been stored to, this function
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* will do nothing.
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*/
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static inline void xa_release(struct xarray *xa, unsigned long index)
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{
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xa_cmpxchg(xa, index, NULL, NULL, 0);
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}
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/* Everything below here is the Advanced API. Proceed with caution. */
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/*
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41
lib/xarray.c
41
lib/xarray.c
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@ -1406,47 +1406,6 @@ void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
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}
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EXPORT_SYMBOL(__xa_store);
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/**
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* xa_cmpxchg() - Conditionally replace an entry in the XArray.
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* @xa: XArray.
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* @index: Index into array.
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* @old: Old value to test against.
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* @entry: New value to place in array.
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* @gfp: Memory allocation flags.
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*
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* If the entry at @index is the same as @old, replace it with @entry.
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* If the return value is equal to @old, then the exchange was successful.
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*
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* Context: Process context. Takes and releases the xa_lock. May sleep
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* if the @gfp flags permit.
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* Return: The old value at this index or xa_err() if an error happened.
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*/
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void *xa_cmpxchg(struct xarray *xa, unsigned long index,
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void *old, void *entry, gfp_t gfp)
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{
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XA_STATE(xas, xa, index);
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void *curr;
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if (WARN_ON_ONCE(xa_is_internal(entry)))
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return XA_ERROR(-EINVAL);
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do {
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xas_lock(&xas);
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curr = xas_load(&xas);
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if (curr == XA_ZERO_ENTRY)
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curr = NULL;
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if (curr == old) {
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xas_store(&xas, entry);
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if (xa_track_free(xa) && entry)
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xas_clear_mark(&xas, XA_FREE_MARK);
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}
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xas_unlock(&xas);
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} while (xas_nomem(&xas, gfp));
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return xas_result(&xas, curr);
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}
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EXPORT_SYMBOL(xa_cmpxchg);
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/**
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* __xa_cmpxchg() - Store this entry in the XArray.
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* @xa: XArray.
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