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frontswap: simplify frontswap_register_ops

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Given that frontswap_register_ops must be called from built-in code,
there is no need to handle the case of swapfiles coming online before or
during it, so delete the code that deals with that case.

Link: https://lkml.kernel.org/r/20211224062246.1258487-11-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Konrad Rzeszutek Wilk <Konrad.wilk@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Christoph Hellwig 2022-01-21 22:15:04 -08:00 committed by Linus Torvalds
parent bd9cd52149
commit f328c1d16e
1 changed files with 0 additions and 41 deletions
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41
mm/frontswap.c
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@ -99,25 +99,6 @@ static inline void inc_frontswap_invalidates(void) { }
*/
void frontswap_register_ops(struct frontswap_ops *ops)
{
DECLARE_BITMAP(a, MAX_SWAPFILES);
DECLARE_BITMAP(b, MAX_SWAPFILES);
struct swap_info_struct *si;
unsigned int i;
bitmap_zero(a, MAX_SWAPFILES);
bitmap_zero(b, MAX_SWAPFILES);
spin_lock(&swap_lock);
plist_for_each_entry(si, &swap_active_head, list) {
if (!WARN_ON(!si->frontswap_map))
__set_bit(si->type, a);
}
spin_unlock(&swap_lock);
/* the new ops needs to know the currently active swap devices */
for_each_set_bit(i, a, MAX_SWAPFILES)
ops->init(i);
/*
* Setting frontswap_ops must happen after the ops->init() calls
* above; cmpxchg implies smp_mb() which will ensure the init is
@ -128,28 +109,6 @@ void frontswap_register_ops(struct frontswap_ops *ops)
} while (cmpxchg(&frontswap_ops, ops->next, ops) != ops->next);
static_branch_inc(&frontswap_enabled_key);
spin_lock(&swap_lock);
plist_for_each_entry(si, &swap_active_head, list) {
if (si->frontswap_map)
__set_bit(si->type, b);
}
spin_unlock(&swap_lock);
/*
* On the very unlikely chance that a swap device was added or
* removed between setting the "a" list bits and the ops init
* calls, we re-check and do init or invalidate for any changed
* bits.
*/
if (unlikely(!bitmap_equal(a, b, MAX_SWAPFILES))) {
for (i = 0; i < MAX_SWAPFILES; i++) {
if (!test_bit(i, a) && test_bit(i, b))
ops->init(i);
else if (test_bit(i, a) && !test_bit(i, b))
ops->invalidate_area(i);
}
}
}
/*