diff options
| author | Fabio M. De Francesco <fmdefrancesco@gmail.com> | 2023-04-26 19:22:23 +0200 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2023-07-10 14:36:10 +0200 |
| commit | e2393b8f3987c5f29dca03aa71d0502f6d721c0d (patch) | |
| tree | 0f91ece830fb27032dd319f8cd8e7d8feb9ea762 /fs/ecryptfs | |
| parent | c3c6833ea8114a18d5acf5f9a4d32f864103144c (diff) | |
fs/ecryptfs: Use kmap_local_page() in copy_up_encrypted_with_header()
kmap_atomic() has been deprecated in favor of kmap_local_page().
Therefore, replace kmap_atomic() with kmap_local_page() in
ecryptfs_copy_up_encrypted_with_header().
kmap_atomic() is implemented like a kmap_local_page() which also
disables page-faults and preemption (the latter only in !PREEMPT_RT
kernels). The kernel virtual addresses returned by these two API are
only valid in the context of the callers (i.e., they cannot be handed to
other threads).
With kmap_local_page() the mappings are per thread and CPU local like
in kmap_atomic(); however, they can handle page-faults and can be called
from any context (including interrupts). The tasks that call
kmap_local_page() can be preempted and, when they are scheduled to run
again, the kernel virtual addresses are restored and are still valid.
In ecryptfs_copy_up_encrypted_with_header(), the block of code between
the mapping and un-mapping does not depend on the above-mentioned side
effects of kmap_aatomic(), so that the mere replacements of the old API
with the new one is all that is required (i.e., there is no need to
explicitly call pagefault_disable() and/or preempt_disable()).
Tested in a QEMU/KVM x86_32 VM, 6GB RAM, booting a kernel with
HIGHMEM64GB enabled.
Cc: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: "Fabio M. De Francesco" <fmdefrancesco@gmail.com>
Message-Id: <20230426172223.8896-4-fmdefrancesco@gmail.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/ecryptfs')
| -rw-r--r-- | fs/ecryptfs/mmap.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 373c3e5747e6..cb1e998ce54d 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -125,7 +125,7 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page, /* This is a header extent */ char *page_virt; - page_virt = kmap_atomic(page); + page_virt = kmap_local_page(page); memset(page_virt, 0, PAGE_SIZE); /* TODO: Support more than one header extent */ if (view_extent_num == 0) { @@ -138,7 +138,7 @@ ecryptfs_copy_up_encrypted_with_header(struct page *page, crypt_stat, &written); } - kunmap_atomic(page_virt); + kunmap_local(page_virt); flush_dcache_page(page); if (rc) { printk(KERN_ERR "%s: Error reading xattr " |