| Message ID | 1724118791-51554-1-git-send-email-zhang.chuna@h3c.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | use might_sleep check if kmap_high is called from atomic context | expand |
On Tue, Aug 20, 2024 at 09:53:11AM +0800, zhangchun wrote: > kmap_high is defined as EXPORT_SYMBOL, and cannot be called from atomic > context. Add might_sleep check is necessary. No. Nobody should be calling kmap_high() directly. There's already a might_sleep() in kmap(). No need to add one in kmap_high().
>On Tue, Aug 20, 2024 at 09:53:11AM +0800, zhangchun wrote: >> kmap_high is defined as EXPORT_SYMBOL, and cannot be called from >> atomic context. Add might_sleep check is necessary. >No. Nobody should be calling kmap_high() directly. There's already a >might_sleep() in kmap(). No need to add one in kmap_high(). To avoid anyone calls kmap_high directly, add function description "Don't use kmap_high directly, if necessary, please use kmap" Signed-off-by: zhangchun <zhang.chuna@h3c.com>
diff --git a/mm/highmem.c b/mm/highmem.c index 07f2c67..5cfb5a9 100644 --- a/mm/highmem.c +++ b/mm/highmem.c @@ -319,6 +319,11 @@ void *kmap_high(struct page *page) unsigned long vaddr; /* + * Use might_sleep to check if kmap_high is called + * from atomic context. + */ + might_sleep(); + /* * For highmem pages, we can't trust "virtual" until * after we have the lock. */
kmap_high is defined as EXPORT_SYMBOL, and cannot be called from atomic context. Add might_sleep check is necessary. Signed-off-by: zhangchun <zhang.chuna@h3c.com> --- mm/highmem.c | 5 +++++ 1 file changed, 5 insertions(+)