From ce2203e7d6de90d0d94ca3c98dde4eff3a0accd0 Mon Sep 17 00:00:00 2001 From: "Fabio M. De Francesco" Date: Wed, 13 Apr 2022 23:55:31 +0100 Subject: [PATCH] media: staging: media: atomisp: Use kmap_local_page() in hmm_store() The use of kmap() is being deprecated in favor of kmap_local_page() where it is feasible. The same is true for kmap_atomic(). In file pci/hmm/hmm.c, function hmm_store() test if we are in atomic context and, if so, it calls kmap_atomic(), if not, it calls kmap(). First of all, in_atomic() shouldn't be used in drivers. This macro cannot always detect atomic context; in particular, it cannot know about held spinlocks in non-preemptible kernels. Notwithstanding what it is said above, this code doesn't need to care whether or not it is executing in atomic context. It can simply use kmap_local_page() / kunmap_local() that can instead do the mapping / unmapping regardless of the context. With kmap_local_page(), the mapping is per thread, CPU local and not globally visible. Therefore, hmm_store()() is a function where the use of kmap_local_page() in place of both kmap() and kmap_atomic() is correctly suited. Convert the calls of kmap() / kunmap() and kmap_atomic() / kunmap_atomic() to kmap_local_page() / kunmap_local() and drop the unnecessary tests which test if the code is in atomic context. Link: https://lore.kernel.org/linux-media/20220413225531.9425-1-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco Reviewed-by: Ira Weiny Tested-by: Hans de Goede Signed-off-by: Mauro Carvalho Chehab --- drivers/staging/media/atomisp/pci/hmm/hmm.c | 14 ++------------ 1 file changed, 2 insertions(+), 12 deletions(-) diff --git a/drivers/staging/media/atomisp/pci/hmm/hmm.c b/drivers/staging/media/atomisp/pci/hmm/hmm.c index 2b015de..fc6cfe9 100644 --- a/drivers/staging/media/atomisp/pci/hmm/hmm.c +++ b/drivers/staging/media/atomisp/pci/hmm/hmm.c @@ -427,10 +427,7 @@ int hmm_store(ia_css_ptr virt, const void *data, unsigned int bytes) idx = (virt - bo->start) >> PAGE_SHIFT; offset = (virt - bo->start) - (idx << PAGE_SHIFT); - if (in_atomic()) - des = (char *)kmap_atomic(bo->pages[idx]); - else - des = (char *)kmap(bo->pages[idx]); + des = (char *)kmap_local_page(bo->pages[idx]); if (!des) { dev_err(atomisp_dev, @@ -457,14 +454,7 @@ int hmm_store(ia_css_ptr virt, const void *data, unsigned int bytes) clflush_cache_range(des, len); - if (in_atomic()) - /* - * Note: kunmap_atomic requires return addr from - * kmap_atomic, not the page. See linux/highmem.h - */ - kunmap_atomic(des - offset); - else - kunmap(bo->pages[idx]); + kunmap_local(des); } return 0; -- 2.7.4