XArray: Use xa_cmpxchg to implement xa_reserve

Jason feels this is clearer, and it saves a function and an exported
symbol.

Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
This commit is contained in:
Matthew Wilcox 2019-02-20 11:51:22 -05:00
parent b38f6c5027
commit 962033d55d
3 changed files with 3 additions and 59 deletions

View file

@ -1484,42 +1484,6 @@ int __xa_insert(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
}
EXPORT_SYMBOL(__xa_insert);
/**
* __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. Expects the xa_lock to be held on entry. May
* release the lock, sleep and reacquire the lock if the @gfp flags permit.
* Return: 0 if the reservation succeeded or -ENOMEM if it failed.
*/
int __xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp)
{
XA_STATE(xas, xa, index);
void *curr;
do {
curr = xas_load(&xas);
if (!curr) {
xas_store(&xas, XA_ZERO_ENTRY);
if (xa_track_free(xa))
xas_clear_mark(&xas, XA_FREE_MARK);
}
} while (__xas_nomem(&xas, gfp));
return xas_error(&xas);
}
EXPORT_SYMBOL(__xa_reserve);
#ifdef CONFIG_XARRAY_MULTI
static void xas_set_range(struct xa_state *xas, unsigned long first,
unsigned long last)