On 11/28/25 2:23 PM, Davidlohr Bueso wrote:
> Replace the now deprecated kmap_atomic() with kmap_local_page().
>
> Optimizing nvdimm/pmem for highmem makes no sense as this is always
> 64bit, and the mapped regions for both btt and pmem do not require
> disabling preemption and pagefaults. Specifically, kmap does not care
> about the caller's atomic context (such as reads holding the btt arena
> spinlock) or NVDIMM_IO_ATOMIC semantics to avoid error handling when
> accessing the btt arena in general. Same for the memcpy cases. kmap
> local temporary mappings will hold valid across any context switches.
>
> Signed-off-by: Davidlohr Bueso <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>> ---
> drivers/nvdimm/btt.c | 12 ++++++------
> drivers/nvdimm/pmem.c | 8 ++++----
> 2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
> index a933db961ed7..237edfa1c624 100644
> --- a/drivers/nvdimm/btt.c
> +++ b/drivers/nvdimm/btt.c
> @@ -1104,10 +1104,10 @@ static int btt_data_read(struct arena_info *arena,
> struct page *page,
> {
> int ret;
> u64 nsoff = to_namespace_offset(arena, lba);
> - void *mem = kmap_atomic(page);
> + void *mem = kmap_local_page(page);
>
> ret = arena_read_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);
> - kunmap_atomic(mem);
> + kunmap_local(mem);
>
> return ret;
> }
> @@ -1117,20 +1117,20 @@ static int btt_data_write(struct arena_info *arena,
> u32 lba,
> {
> int ret;
> u64 nsoff = to_namespace_offset(arena, lba);
> - void *mem = kmap_atomic(page);
> + void *mem = kmap_local_page(page);
>
> ret = arena_write_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);
> - kunmap_atomic(mem);
> + kunmap_local(mem);
>
> return ret;
> }
>
> static void zero_fill_data(struct page *page, unsigned int off, u32 len)
> {
> - void *mem = kmap_atomic(page);
> + void *mem = kmap_local_page(page);
>
> memset(mem + off, 0, len);
> - kunmap_atomic(mem);
> + kunmap_local(mem);
> }
>
> #ifdef CONFIG_BLK_DEV_INTEGRITY
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 05785ff21a8b..92c67fbbc1c8 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -128,10 +128,10 @@ static void write_pmem(void *pmem_addr, struct page
> *page,
> void *mem;
>
> while (len) {
> - mem = kmap_atomic(page);
> + mem = kmap_local_page(page);
> chunk = min_t(unsigned int, len, PAGE_SIZE - off);
> memcpy_flushcache(pmem_addr, mem + off, chunk);
> - kunmap_atomic(mem);
> + kunmap_local(mem);
> len -= chunk;
> off = 0;
> page++;
> @@ -147,10 +147,10 @@ static blk_status_t read_pmem(struct page *page,
> unsigned int off,
> void *mem;
>
> while (len) {
> - mem = kmap_atomic(page);
> + mem = kmap_local_page(page);
> chunk = min_t(unsigned int, len, PAGE_SIZE - off);
> rem = copy_mc_to_kernel(mem + off, pmem_addr, chunk);
> - kunmap_atomic(mem);
> + kunmap_local(mem);
> if (rem)
> return BLK_STS_IOERR;
> len -= chunk;
