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| author | Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com> | 2023-11-20 15:24:05 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-12-10 16:51:49 -0800 |
| commit | 24d2613a6356f9c4a0b1b8e17f125562f6c8e11b (patch) | |
| tree | 02a8712af8bceb229f1b7a31b3e15b9d7eea0b95 /mm/memory.c | |
| parent | b33519896664f66358cec60f6b308d80a60d1c96 (diff) | |
| download | lwn-24d2613a6356f9c4a0b1b8e17f125562f6c8e11b.tar.gz lwn-24d2613a6356f9c4a0b1b8e17f125562f6c8e11b.zip | |
mm/memory: use kmap_local_page() in __wp_page_copy_user()
kmap_atomic() has been deprecated in favor of kmap_local_{folio,page}.
Therefore, replace kmap_atomic() with kmap_local_page in
__wp_page_copy_user().
kmap_atomic() disables preemption in !PREEMPT_RT kernels and
unconditionally disables also page-faults. My limited knowledge of the
implementation of __wp_page_copy_user() makes me think that the latter
side effect is still needed here, but kmap_local_page() is implemented not
to disable page-faults.
So, in addition to the conversion to local mapping, add explicit
pagefault_disable() / pagefault_enable() between mapping and un-mapping.
Link: https://lkml.kernel.org/r/20231120142418.6977-1-fmdefrancesco@gmail.com
Signed-off-by: Fabio M. De Francesco <fabio.maria.de.francesco@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/mm/memory.c b/mm/memory.c index e27e2e5beb3f..a8ff3489211b 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -2841,7 +2841,8 @@ static inline int __wp_page_copy_user(struct page *dst, struct page *src, * just copying from the original user address. If that * fails, we just zero-fill it. Live with it. */ - kaddr = kmap_atomic(dst); + kaddr = kmap_local_page(dst); + pagefault_disable(); uaddr = (void __user *)(addr & PAGE_MASK); /* @@ -2909,7 +2910,8 @@ warn: pte_unlock: if (vmf->pte) pte_unmap_unlock(vmf->pte, vmf->ptl); - kunmap_atomic(kaddr); + pagefault_enable(); + kunmap_local(kaddr); flush_dcache_page(dst); return ret; |