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

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

drivers/gpu/drm/armada/armada_gem.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/i915/i915_gem.c

+3 −3
Original line number Diff line number Diff line
@@ -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;

drivers/gpu/drm/i915/i915_gem_execbuffer.c

+1 −1
Original line number Diff line number Diff line
@@ -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;

		}

	}

fs/ntfs/file.c

+1 −1
Original line number Diff line number Diff line
@@ -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

		 * 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;

		}

include/linux/pagemap.h

+2 −52
Original line number Diff line number Diff line
@@ -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;