Fabio M. De Francesco 21490eff12 hfs: replace kmap() with kmap_local_page() in btree.c ... kmap() is being deprecated in favor of kmap_local_page(). Two main problems with kmap(): (1) It comes with an overhead as mapping space is restricted and protected by a global lock for synchronization and (2) it also requires global TLB invalidation when the kmap's pool wraps and it might block when the mapping space is fully utilized until a slot becomes available. With kmap_local_page() the mappings are per thread, CPU local, can take page faults, and can be called from any context (including interrupts). It is faster than kmap() in kernels with HIGHMEM enabled. Furthermore, the tasks can be preempted and, when they are scheduled to run again, the kernel virtual addresses are restored and still valid. Since its use in btree.c is safe everywhere, it should be preferred. Therefore, replace kmap() with kmap_local_page() in btree.c. Where possible, use the suited standard helpers (memzero_page(), memcpy_page()) instead of open coding kmap_local_page() plus memset() or memcpy(). Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with HIGHMEM64GB enabled. Link: https://lkml.kernel.org/r/20220821180400.8198-4-fmdefrancesco@gmail.com Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com> Suggested-by: Ira Weiny <ira.weiny@intel.com> Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Chaitanya Kulkarni <kch@nvidia.com> Cc: Christian Brauner (Microsoft) <brauner@kernel.org> Cc: Damien Le Moal <damien.lemoal@opensource.wdc.com> Cc: Jeff Layton <jlayton@kernel.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kees Cook <keescook@chromium.org> Cc: Martin K. Petersen <martin.petersen@oracle.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Muchun Song <songmuchun@bytedance.com> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>		2022-09-11 21:55:09 -07:00
..
attr.c	acl: handle idmapped mounts	2021-01-24 14:27:17 +01:00
bfind.c	hfs: add lock nesting notation to hfs_find_init	2021-07-15 10:13:49 -07:00
bitmap.c
bnode.c	hfs: replace kmap() with kmap_local_page() in bnode.c	2022-09-11 21:55:08 -07:00
brec.c
btree.c	hfs: replace kmap() with kmap_local_page() in btree.c	2022-09-11 21:55:09 -07:00
btree.h	hfs: add lock nesting notation to hfs_find_init	2021-07-15 10:13:49 -07:00
catalog.c
dir.c	fs: make helpers idmap mount aware	2021-01-24 14:27:20 +01:00
extent.c	hfs: Call hfs_write_begin() and generic_write_end() directly	2022-05-08 14:45:56 -04:00
hfs_fs.h	hfs: Call hfs_write_begin() and generic_write_end() directly	2022-05-08 14:45:56 -04:00
hfs.h
inode.c	fs: Change try_to_free_buffers() to take a folio	2022-05-09 23:12:34 -04:00
Kconfig
Makefile
mdb.c	block: remove genhd.h	2022-02-02 07:49:59 -07:00
part_tbl.c
string.c
super.c	fs: allocate inode by using alloc_inode_sb()	2022-03-22 15:57:03 -07:00
sysdep.c
trans.c