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XArray: Unify xa_cmpxchg and __xa_cmpxchg

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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
2018-10-31 14:39:28 -04:00
parent 4c0608f4a0
commit c5beb07e7a
2 changed files with 69 additions and 85 deletions
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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)
}
EXPORT_SYMBOL(__xa_store);
/**
* 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: Process 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.
*/
void *xa_cmpxchg(struct xarray *xa, unsigned long index,
void *old, void *entry, gfp_t gfp)
{
XA_STATE(xas, xa, index);
void *curr;
if (WARN_ON_ONCE(xa_is_internal(entry)))
return XA_ERROR(-EINVAL);
do {
xas_lock(&xas);
curr = xas_load(&xas);
if (curr == XA_ZERO_ENTRY)
curr = NULL;
if (curr == old) {
xas_store(&xas, entry);
if (xa_track_free(xa) && entry)
xas_clear_mark(&xas, XA_FREE_MARK);
}
xas_unlock(&xas);
} while (xas_nomem(&xas, gfp));
return xas_result(&xas, curr);
}
EXPORT_SYMBOL(xa_cmpxchg);
/**
* __xa_cmpxchg() - Store this entry in the XArray.
* @xa: XArray.