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get rid of separate multipage fault-in primitives

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* the only remaining callers of "short" fault-ins are just as happy with generic
variants (both in lib/iov_iter.c); switch them to multipage variants, kill the
"short" ones
* rename the multipage variants to now available plain ones.
* get rid of compat macro defining iov_iter_fault_in_multipage_readable by
expanding it in its only user.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2016-09-17 18:02:44 -04:00
parent 08895a8b6b
commit 4bce9f6ee8
7 changed files with 9 additions and 61 deletions
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2
drivers/gpu/drm/armada/armada_gem.c
View File

@ -387,7 +387,7 @@ int armada_gem_pwrite_ioctl(struct drm_device *dev, void *data,
if (!access_ok(VERIFY_READ, ptr, args->size))
return -EFAULT;
ret = fault_in_multipages_readable(ptr, args->size);
ret = fault_in_pages_readable(ptr, args->size);
if (ret)
return ret;

6
drivers/gpu/drm/i915/i915_gem.c
View File

@ -675,7 +675,7 @@ i915_gem_gtt_pread(struct drm_device *dev,
mutex_unlock(&dev->struct_mutex);
if (likely(!i915.prefault_disable)) {
ret = fault_in_multipages_writeable(user_data, remain);
ret = fault_in_pages_writeable(user_data, remain);
if (ret) {
mutex_lock(&dev->struct_mutex);
goto out_unpin;
@ -803,7 +803,7 @@ i915_gem_shmem_pread(struct drm_device *dev,
mutex_unlock(&dev->struct_mutex);
if (likely(!i915.prefault_disable) && !prefaulted) {
ret = fault_in_multipages_writeable(user_data, remain);
ret = fault_in_pages_writeable(user_data, remain);
/* Userspace is tricking us, but we've already clobbered
* its pages with the prefault and promised to write the
* data up to the first fault. Hence ignore any errors
@ -1267,7 +1267,7 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
return -EFAULT;
if (likely(!i915.prefault_disable)) {
ret = fault_in_multipages_readable(u64_to_user_ptr(args->data_ptr),
ret = fault_in_pages_readable(u64_to_user_ptr(args->data_ptr),
args->size);
if (ret)
return -EFAULT;

2
drivers/gpu/drm/i915/i915_gem_execbuffer.c
View File

@ -1048,7 +1048,7 @@ validate_exec_list(struct drm_device *dev,
return -EFAULT;
if (likely(!i915.prefault_disable)) {
if (fault_in_multipages_readable(ptr, length))
if (fault_in_pages_readable(ptr, length))
return -EFAULT;
}
}

2
fs/ntfs/file.c
View File

@ -1850,7 +1850,7 @@ again:
* pages being swapped out between us bringing them into memory
* and doing the actual copying.
*/
if (unlikely(iov_iter_fault_in_multipages_readable(i, bytes))) {
if (unlikely(iov_iter_fault_in_readable(i, bytes))) {
status = -EFAULT;
break;
}

54
include/linux/pagemap.h
View File

@ -518,58 +518,9 @@ void page_endio(struct page *page, bool is_write, int err);
extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter);
/*
* Fault one or two userspace pages into pagetables.
* Return -EINVAL if more than two pages would be needed.
* Return non-zero on a fault.
* Fault everything in given userspace address range in.
*/
static inline int fault_in_pages_writeable(char __user *uaddr, int size)
{
int span, ret;
if (unlikely(size == 0))
return 0;
span = offset_in_page(uaddr) + size;
if (span > 2 * PAGE_SIZE)
return -EINVAL;
/*
* Writing zeroes into userspace here is OK, because we know that if
* the zero gets there, we'll be overwriting it.
*/
ret = __put_user(0, uaddr);
if (ret == 0 && span > PAGE_SIZE)
ret = __put_user(0, uaddr + size - 1);
return ret;
}
static inline int fault_in_pages_readable(const char __user *uaddr, int size)
{
volatile char c;
int ret;
if (unlikely(size == 0))
return 0;
ret = __get_user(c, uaddr);
if (ret == 0) {
const char __user *end = uaddr + size - 1;
if (((unsigned long)uaddr & PAGE_MASK) !=
((unsigned long)end & PAGE_MASK)) {
ret = __get_user(c, end);
(void)c;
}
}
return ret;
}
/*
* Multipage variants of the above prefault helpers, useful if more than
* PAGE_SIZE of data needs to be prefaulted. These are separate from the above
* functions (which only handle up to PAGE_SIZE) to avoid clobbering the
* filemap.c hotpaths.
*/
static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
{
char __user *end = uaddr + size - 1;
@ -596,8 +547,7 @@ static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
return 0;
}
static inline int fault_in_multipages_readable(const char __user *uaddr,
int size)
static inline int fault_in_pages_readable(const char __user *uaddr, int size)
{
volatile char c;
const char __user *end = uaddr + size - 1;

1
include/linux/uio.h
View File

@ -76,7 +76,6 @@ size_t iov_iter_copy_from_user_atomic(struct page *page,
struct iov_iter *i, unsigned long offset, size_t bytes);
void iov_iter_advance(struct iov_iter *i, size_t bytes);
int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes);
#define iov_iter_fault_in_multipages_readable iov_iter_fault_in_readable
size_t iov_iter_single_seg_count(const struct iov_iter *i);
size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i);

3
lib/iov_iter.c
View File

@ -306,8 +306,7 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
iterate_iovec(i, bytes, v, iov, skip, ({
err = fault_in_multipages_readable(v.iov_base,
v.iov_len);
err = fault_in_pages_readable(v.iov_base, v.iov_len);
if (unlikely(err))
return err;
0;}))