On Sat, Dec 31, 2022 at 06:44:39PM +0100, Fabio M. De Francesco wrote: > kmap_atomic() is deprecated in favor of kmap_local_page(). Therefore, > replace kmap_atomic() with kmap_local_page(). > > kmap_atomic() is implemented like a kmap_local_page() which also disables > page-faults and preemption (the latter only for !PREEMPT_RT kernels). > > However, the code within the mappings and un-mappings in ext4/inline.c > does not depend on the above-mentioned side effects. > > Therefore, a mere replacement of the old API with the new one is all it > is required (i.e., there is no need to explicitly add any calls to > pagefault_disable() and/or preempt_disable()). > > Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx> Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> > Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx> > --- > > I tried my best to understand the code within mapping and un-mapping. > However, I'm not an expert. Therefore, although I'm pretty confident, I > cannot be 100% sure that the code between the mapping and the un-mapping > does not depend on pagefault_disable() and/or preempt_disable(). > > Unfortunately, I cannot currently test this changes to check the > above-mentioned assumptions. However, if I'm required to do the tests > with (x)fstests, I have no problems with doing them in the next days. > > If so, I'll test in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with > HIGHMEM64GB enabled. > > I'd like to hear whether or not the maintainers require these tests > and/or other tests. > > fs/ext4/inline.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c > index 2b42ececa46d..bfb044425d8a 100644 > --- a/fs/ext4/inline.c > +++ b/fs/ext4/inline.c > @@ -490,10 +490,10 @@ static int ext4_read_inline_page(struct inode *inode, struct page *page) > goto out; > > len = min_t(size_t, ext4_get_inline_size(inode), i_size_read(inode)); > - kaddr = kmap_atomic(page); > + kaddr = kmap_local_page(page); > ret = ext4_read_inline_data(inode, kaddr, len, &iloc); > flush_dcache_page(page); > - kunmap_atomic(kaddr); > + kunmap_local(kaddr); > zero_user_segment(page, len, PAGE_SIZE); > SetPageUptodate(page); > brelse(iloc.bh); > @@ -763,9 +763,9 @@ int ext4_write_inline_data_end(struct inode *inode, loff_t pos, unsigned len, > */ > (void) ext4_find_inline_data_nolock(inode); > > - kaddr = kmap_atomic(page); > + kaddr = kmap_local_page(page); > ext4_write_inline_data(inode, &iloc, kaddr, pos, copied); > - kunmap_atomic(kaddr); > + kunmap_local(kaddr); > SetPageUptodate(page); > /* clear page dirty so that writepages wouldn't work for us. */ > ClearPageDirty(page); > @@ -831,9 +831,9 @@ ext4_journalled_write_inline_data(struct inode *inode, > } > > ext4_write_lock_xattr(inode, &no_expand); > - kaddr = kmap_atomic(page); > + kaddr = kmap_local_page(page); > ext4_write_inline_data(inode, &iloc, kaddr, 0, len); > - kunmap_atomic(kaddr); > + kunmap_local(kaddr); > ext4_write_unlock_xattr(inode, &no_expand); > > return iloc.bh; > -- > 2.39.0 >
