diff options
author | Fabio M. De Francesco <fmdefrancesco@gmail.com> | 2022-04-13 23:55:31 +0100 |
---|---|---|
committer | Mauro Carvalho Chehab <mchehab@kernel.org> | 2022-07-08 17:35:42 +0100 |
commit | ce2203e7d6de90d0d94ca3c98dde4eff3a0accd0 (patch) | |
tree | 0262454c8152489a8fbd18d69996104a7442901c /drivers/staging/media/atomisp | |
parent | aab1c42a9d77fb3f243aaab7f9f7ca14a6ffa7d2 (diff) | |
download | linux-ce2203e7d6de90d0d94ca3c98dde4eff3a0accd0.tar.bz2 |
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 <fmdefrancesco@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>
Diffstat (limited to 'drivers/staging/media/atomisp')
-rw-r--r-- | drivers/staging/media/atomisp/pci/hmm/hmm.c | 14 |
1 files 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 2b015de56823..fc6cfe9f7744 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; |