From c0371782500c5314741da9ccbfbf0375a0d379fc Mon Sep 17 00:00:00 2001 From: Stefano Garzarella Date: Tue, 4 Apr 2023 15:13:20 +0200 Subject: vringh: replace kmap_atomic() with kmap_local_page() kmap_atomic() is deprecated in favor of kmap_local_page() since commit f3ba3c710ac5 ("mm/highmem: Provide kmap_local*"). With kmap_local_page() the mappings are per thread, CPU local, can take page-faults, and can be called from any context (including interrupts). Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. kmap_atomic() is implemented like a kmap_local_page() which also disables page-faults and preemption (the latter only for !PREEMPT_RT kernels, otherwise it only disables migration). The code within the mappings/un-mappings in getu16_iotlb() and putu16_iotlb() don't depend on the above-mentioned side effects of kmap_atomic(), so that mere replacements of the old API with the new one is all that is required (i.e., there is no need to explicitly add calls to pagefault_disable() and/or preempt_disable()). This commit reuses a "boiler plate" commit message from Fabio, who has already did this change in several places. Cc: "Fabio M. De Francesco" Reviewed-by: Fabio M. De Francesco Acked-by: Jason Wang Signed-off-by: Stefano Garzarella Message-Id: <20230404131326.44403-4-sgarzare@redhat.com> Signed-off-by: Michael S. Tsirkin --- drivers/vhost/vringh.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'drivers/vhost/vringh.c') diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 694462ba3242..a98adc469f19 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -1220,10 +1220,10 @@ static inline int getu16_iotlb(const struct vringh *vrh, if (ret < 0) return ret; - kaddr = kmap_atomic(iov.bv_page); + kaddr = kmap_local_page(iov.bv_page); from = kaddr + iov.bv_offset; *val = vringh16_to_cpu(vrh, READ_ONCE(*(__virtio16 *)from)); - kunmap_atomic(kaddr); + kunmap_local(kaddr); return 0; } @@ -1241,10 +1241,10 @@ static inline int putu16_iotlb(const struct vringh *vrh, if (ret < 0) return ret; - kaddr = kmap_atomic(iov.bv_page); + kaddr = kmap_local_page(iov.bv_page); to = kaddr + iov.bv_offset; WRITE_ONCE(*(__virtio16 *)to, cpu_to_vringh16(vrh, val)); - kunmap_atomic(kaddr); + kunmap_local(kaddr); return 0; } -- cgit v1.2.3