Commit 4bce9f6e authored by Al Viro's avatar Al Viro

get rid of separate multipage fault-in primitives

* 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: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 08895a8b
...@@ -387,7 +387,7 @@ int armada_gem_pwrite_ioctl(struct drm_device *dev, void *data, ...@@ -387,7 +387,7 @@ int armada_gem_pwrite_ioctl(struct drm_device *dev, void *data,
if (!access_ok(VERIFY_READ, ptr, args->size)) if (!access_ok(VERIFY_READ, ptr, args->size))
return -EFAULT; return -EFAULT;
ret = fault_in_multipages_readable(ptr, args->size); ret = fault_in_pages_readable(ptr, args->size);
if (ret) if (ret)
return ret; return ret;
......
...@@ -675,7 +675,7 @@ i915_gem_gtt_pread(struct drm_device *dev, ...@@ -675,7 +675,7 @@ i915_gem_gtt_pread(struct drm_device *dev,
mutex_unlock(&dev->struct_mutex); mutex_unlock(&dev->struct_mutex);
if (likely(!i915.prefault_disable)) { if (likely(!i915.prefault_disable)) {
ret = fault_in_multipages_writeable(user_data, remain); ret = fault_in_pages_writeable(user_data, remain);
if (ret) { if (ret) {
mutex_lock(&dev->struct_mutex); mutex_lock(&dev->struct_mutex);
goto out_unpin; goto out_unpin;
...@@ -803,7 +803,7 @@ i915_gem_shmem_pread(struct drm_device *dev, ...@@ -803,7 +803,7 @@ i915_gem_shmem_pread(struct drm_device *dev,
mutex_unlock(&dev->struct_mutex); mutex_unlock(&dev->struct_mutex);
if (likely(!i915.prefault_disable) && !prefaulted) { 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 /* Userspace is tricking us, but we've already clobbered
* its pages with the prefault and promised to write the * its pages with the prefault and promised to write the
* data up to the first fault. Hence ignore any errors * data up to the first fault. Hence ignore any errors
...@@ -1267,7 +1267,7 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data, ...@@ -1267,7 +1267,7 @@ i915_gem_pwrite_ioctl(struct drm_device *dev, void *data,
return -EFAULT; return -EFAULT;
if (likely(!i915.prefault_disable)) { 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); args->size);
if (ret) if (ret)
return -EFAULT; return -EFAULT;
......
...@@ -1048,7 +1048,7 @@ validate_exec_list(struct drm_device *dev, ...@@ -1048,7 +1048,7 @@ validate_exec_list(struct drm_device *dev,
return -EFAULT; return -EFAULT;
if (likely(!i915.prefault_disable)) { if (likely(!i915.prefault_disable)) {
if (fault_in_multipages_readable(ptr, length)) if (fault_in_pages_readable(ptr, length))
return -EFAULT; return -EFAULT;
} }
} }
......
...@@ -1850,7 +1850,7 @@ static ssize_t ntfs_perform_write(struct file *file, struct iov_iter *i, ...@@ -1850,7 +1850,7 @@ static ssize_t ntfs_perform_write(struct file *file, struct iov_iter *i,
* pages being swapped out between us bringing them into memory * pages being swapped out between us bringing them into memory
* and doing the actual copying. * 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; status = -EFAULT;
break; break;
} }
......
...@@ -518,58 +518,9 @@ void page_endio(struct page *page, bool is_write, int err); ...@@ -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); extern void add_page_wait_queue(struct page *page, wait_queue_t *waiter);
/* /*
* Fault one or two userspace pages into pagetables. * Fault everything in given userspace address range in.
* Return -EINVAL if more than two pages would be needed.
* Return non-zero on a fault.
*/ */
static inline int fault_in_pages_writeable(char __user *uaddr, int size) 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; char __user *end = uaddr + size - 1;
...@@ -596,8 +547,7 @@ static inline int fault_in_multipages_writeable(char __user *uaddr, int size) ...@@ -596,8 +547,7 @@ static inline int fault_in_multipages_writeable(char __user *uaddr, int size)
return 0; return 0;
} }
static inline int fault_in_multipages_readable(const char __user *uaddr, static inline int fault_in_pages_readable(const char __user *uaddr, int size)
int size)
{ {
volatile char c; volatile char c;
const char __user *end = uaddr + size - 1; const char __user *end = uaddr + size - 1;
......
...@@ -76,7 +76,6 @@ size_t iov_iter_copy_from_user_atomic(struct page *page, ...@@ -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); struct iov_iter *i, unsigned long offset, size_t bytes);
void iov_iter_advance(struct iov_iter *i, 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); 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 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, size_t copy_page_to_iter(struct page *page, size_t offset, size_t bytes,
struct iov_iter *i); struct iov_iter *i);
......
...@@ -306,8 +306,7 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes) ...@@ -306,8 +306,7 @@ int iov_iter_fault_in_readable(struct iov_iter *i, size_t bytes)
if (!(i->type & (ITER_BVEC|ITER_KVEC))) { if (!(i->type & (ITER_BVEC|ITER_KVEC))) {
iterate_iovec(i, bytes, v, iov, skip, ({ iterate_iovec(i, bytes, v, iov, skip, ({
err = fault_in_multipages_readable(v.iov_base, err = fault_in_pages_readable(v.iov_base, v.iov_len);
v.iov_len);
if (unlikely(err)) if (unlikely(err))
return err; return err;
0;})) 0;}))
......
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