Evolution-X-Devices/kernel_realme_sm7125
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Revert "BACKPORT: ANDROID: userfaultfd: add MMAP_TRYLOCK mode for COPY/ZEROPAGE"

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This reverts commit fa49c6bf49.
This commit is contained in:
theshaenix
2025-09-05 09:08:20 +05:30
parent c122238ddd
commit 8879c4efa1
4 changed files with 10 additions and 22 deletions
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9
fs/userfaultfd.c
View File

@@ -1759,9 +1759,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
ret = -EINVAL;
if (uffdio_copy.src + uffdio_copy.len <= uffdio_copy.src)
goto out;
if (uffdio_copy.mode & ~(UFFDIO_COPY_MODE_DONTWAKE|
UFFDIO_COPY_MODE_WP|
UFFDIO_COPY_MODE_MMAP_TRYLOCK))
if (uffdio_copy.mode & ~(UFFDIO_COPY_MODE_DONTWAKE|UFFDIO_COPY_MODE_WP))
goto out;
if (mmget_not_zero(ctx->mm)) {
ret = mcopy_atomic(ctx->mm, uffdio_copy.dst, uffdio_copy.src,
@@ -1812,14 +1810,13 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
if (ret)
goto out;
ret = -EINVAL;
if (uffdio_zeropage.mode & ~(UFFDIO_ZEROPAGE_MODE_DONTWAKE|
UFFDIO_ZEROPAGE_MODE_MMAP_TRYLOCK))
if (uffdio_zeropage.mode & ~UFFDIO_ZEROPAGE_MODE_DONTWAKE)
goto out;
if (mmget_not_zero(ctx->mm)) {
ret = mfill_zeropage(ctx->mm, uffdio_zeropage.range.start,
uffdio_zeropage.range.len,
&ctx->mmap_changing, uffdio_zeropage.mode);
&ctx->mmap_changing);
mmput(ctx->mm);
} else {
return -ESRCH;

8
include/linux/userfaultfd_k.h
View File

@@ -32,9 +32,6 @@
#define UFFD_SHARED_FCNTL_FLAGS (O_CLOEXEC | O_NONBLOCK)
#define UFFD_FLAGS_SET (EFD_SHARED_FCNTL_FLAGS)
static_assert(UFFDIO_ZEROPAGE_MODE_MMAP_TRYLOCK == UFFDIO_COPY_MODE_MMAP_TRYLOCK);
#define UFFDIO_MODE_MMAP_TRYLOCK UFFDIO_COPY_MODE_MMAP_TRYLOCK
extern int sysctl_unprivileged_userfaultfd;
extern int handle_userfault(struct vm_fault *vmf, unsigned long reason);
@@ -64,8 +61,9 @@ extern ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
unsigned long src_start, unsigned long len,
bool *mmap_changing, __u64 mode);
extern ssize_t mfill_zeropage(struct mm_struct *dst_mm,
unsigned long dst_start, unsigned long len,
bool *mmap_changing, __u64 mode);
unsigned long dst_start,
unsigned long len,
bool *mmap_changing);
extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start,
unsigned long len, bool *mmap_changing);

2
include/uapi/linux/userfaultfd.h
View File

@@ -232,7 +232,6 @@ struct uffdio_copy {
* according to the uffdio_register.ioctls.
*/
#define UFFDIO_COPY_MODE_WP ((__u64)1<<1)
#define UFFDIO_COPY_MODE_MMAP_TRYLOCK ((__u64)1<<63)
__u64 mode;
/*
@@ -245,7 +244,6 @@ struct uffdio_copy {
struct uffdio_zeropage {
struct uffdio_range range;
#define UFFDIO_ZEROPAGE_MODE_DONTWAKE ((__u64)1<<0)
#define UFFDIO_ZEROPAGE_MODE_MMAP_TRYLOCK ((__u64)1<<63)
__u64 mode;
/*

13
mm/userfaultfd.c
View File

@@ -553,19 +553,14 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
copied = 0;
page = NULL;
retry:
err = -EAGAIN;
if (mode & UFFDIO_MODE_MMAP_TRYLOCK) {
if (!down_read_trylock(&dst_mm->mmap_sem))
goto out;
} else {
down_read(&dst_mm->mmap_sem);
}
down_read(&dst_mm->mmap_sem);
/*
* If memory mappings are changing because of non-cooperative
* operation (e.g. mremap) running in parallel, bail out and
* request the user to retry later
*/
err = -EAGAIN;
if (mmap_changing && READ_ONCE(*mmap_changing))
goto out_unlock;
@@ -731,10 +726,10 @@ ssize_t mcopy_atomic(struct mm_struct *dst_mm, unsigned long dst_start,
}
ssize_t mfill_zeropage(struct mm_struct *dst_mm, unsigned long start,
unsigned long len, bool *mmap_changing, __u64 mode)
unsigned long len, bool *mmap_changing)
{
return __mcopy_atomic(dst_mm, start, 0, len, MCOPY_ATOMIC_ZEROPAGE,
mmap_changing, mode);
mmap_changing, 0);
}
ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long start,