mm: add_to_swap_cache() does not return -EEXIST
After commit 355cfa73 ("mm: modify swap_map and add SWAP_HAS_CACHE flag"), only the context which have set SWAP_HAS_CACHE flag by swapcache_prepare() or get_swap_page() would call add_to_swap_cache(). So add_to_swap_cache() doesn't return -EEXIST any more. Even though it doesn't return -EEXIST, it's not good behavior conceptually to call swapcache_prepare() in the -EEXIST case, because it means clearing SWAP_HAS_CACHE flag while the entry is on swap cache. This patch removes redundant codes and comments from callers of it, and adds VM_BUG_ON() in error path of add_to_swap_cache() and some comments. Signed-off-by:Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Reviewed-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
parent
31a56396
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