kmap() has been deprecated in favor of the kmap_local_page()
due to high cost, restricted mapping space, the overhead of
a global lock for synchronization, and making the process
sleep in the absence of free slots.
kmap_local_page() is faster than kmap() and offers thread-local
and CPU-local mappings, take pagefaults in a local kmap region
and preserves preemption by saving the mappings of outgoing
tasks and restoring those of the incoming one during a context
switch.
The mappings are kept thread local in the functions
“dmirror_do_read” and “dmirror_do_write” in test_hmm.c
Therefore, replace kmap() with kmap_local_page() and use
mempcy_from/to_page() to avoid open coding kmap_local_page()
+ memcpy() + kunmap_local().
Remove the unused variable “tmp”.
Suggested-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
Signed-off-by: Sumitra Sharma <sumitraartsy@xxxxxxxxx>
---
Changes in v2:
- Change commit subject and description.
- Remove unnecessary type casting (char *).
lib/test_hmm.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/lib/test_hmm.c b/lib/test_hmm.c
index 67e6f83fe0f8..717dcb830127 100644
--- a/lib/test_hmm.c
+++ b/lib/test_hmm.c
@@ -368,16 +368,13 @@ static int dmirror_do_read(struct dmirror *dmirror, unsigned long start,
for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
void *entry;
struct page *page;
- void *tmp;
entry = xa_load(&dmirror->pt, pfn);
page = xa_untag_pointer(entry);
if (!page)
return -ENOENT;
- tmp = kmap(page);
- memcpy(ptr, tmp, PAGE_SIZE);
- kunmap(page);
+ memcpy_from_page(ptr, page, 0, PAGE_SIZE);
ptr += PAGE_SIZE;
bounce->cpages++;
@@ -437,16 +434,13 @@ static int dmirror_do_write(struct dmirror *dmirror, unsigned long start,
for (pfn = start >> PAGE_SHIFT; pfn < (end >> PAGE_SHIFT); pfn++) {
void *entry;
struct page *page;
- void *tmp;
entry = xa_load(&dmirror->pt, pfn);
page = xa_untag_pointer(entry);
if (!page || xa_pointer_tag(entry) != DPT_XA_TAG_WRITE)
return -ENOENT;
- tmp = kmap(page);
- memcpy(tmp, ptr, PAGE_SIZE);
- kunmap(page);
+ memcpy_to_page(page, 0, ptr, PAGE_SIZE);
ptr += PAGE_SIZE;
bounce->cpages++;
--
2.25.1
