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authorFabio M. De Francesco <fmdefrancesco@gmail.com>2023-04-26 19:22:23 +0200
committerChristian Brauner <brauner@kernel.org>2023-07-10 14:36:10 +0200
commite2393b8f3987c5f29dca03aa71d0502f6d721c0d (patch)
tree0f91ece830fb27032dd319f8cd8e7d8feb9ea762 /fs/ecryptfs/mmap.c
parentfs/ecryptfs: Use kmap_local_page() in ecryptfs_write() (diff)
downloadlinux-e2393b8f3987c5f29dca03aa71d0502f6d721c0d.tar.xz
linux-e2393b8f3987c5f29dca03aa71d0502f6d721c0d.zip
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 '')
-rw-r--r--fs/ecryptfs/mmap.c4
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 "