diff options
author | Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com> | 2023-11-27 18:55:21 +0300 |
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committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-11 03:51:53 +0300 |
commit | 003ae2fb0b36803112f9b66cce8041afa5d46a83 (patch) | |
tree | e385d3e46982ac6c5b0fb012697ba692b9b86e6e | |
parent | 27873192ac5938bfa9d27348d79b931e5b438ba6 (diff) | |
download | linux-003ae2fb0b36803112f9b66cce8041afa5d46a83.tar.xz |
mm/zswap: replace kmap_atomic() with kmap_local_page()
kmap_atomic() has been deprecated in favor of kmap_local_page().
Therefore, replace kmap_atomic() with kmap_local_page() in
zswap.c.
kmap_atomic() is implemented like a kmap_local_page() which also disables
page-faults and preemption (the latter only in !PREEMPT_RT kernels). The
kernel virtual addresses returned by these two API are only valid in the
context of the callers (i.e., they cannot be handed to other threads).
With kmap_local_page() the mappings are per thread and CPU local like in
kmap_atomic(); however, they can handle page-faults and can be called from
any context (including interrupts). The tasks that call kmap_local_page()
can be preempted and, when they are scheduled to run again, the kernel
virtual addresses are restored and are still valid.
In mm/zswap.c, the blocks of code between the mappings and un-mappings do
not depend on the above-mentioned side effects of kmap_atomic(), so that
the mere replacements of the old API with the new one is all that is
required (i.e., there is no need to explicitly call pagefault_disable()
and/or preempt_disable()).
Link: https://lkml.kernel.org/r/20231127160058.586446-1-fabio.maria.de.francesco@linux.intel.com
Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Chris Li <chrisl@kernel.org> (Google)
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
-rw-r--r-- | mm/zswap.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/mm/zswap.c b/mm/zswap.c index 74411dfdad92..699c6ee11222 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -1267,16 +1267,16 @@ bool zswap_store(struct folio *folio) } if (zswap_same_filled_pages_enabled) { - src = kmap_atomic(page); + src = kmap_local_page(page); if (zswap_is_page_same_filled(src, &value)) { - kunmap_atomic(src); + kunmap_local(src); entry->swpentry = swp_entry(type, offset); entry->length = 0; entry->value = value; atomic_inc(&zswap_same_filled_pages); goto insert_entry; } - kunmap_atomic(src); + kunmap_local(src); } if (!zswap_non_same_filled_pages_enabled) @@ -1422,9 +1422,9 @@ bool zswap_load(struct folio *folio) spin_unlock(&tree->lock); if (!entry->length) { - dst = kmap_atomic(page); + dst = kmap_local_page(page); zswap_fill_page(dst, entry->value); - kunmap_atomic(dst); + kunmap_local(dst); ret = true; goto stats; } |