From 4bce9f6ee8f84fdf333d0fd7fcf7f0d8c7cce7fa Mon Sep 17 00:00:00 2001 From: Al Viro Date: Sat, 17 Sep 2016 18:02:44 -0400 Subject: [PATCH] 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: Al Viro --- drivers/gpu/drm/armada/armada_gem.c | 2 +- drivers/gpu/drm/i915/i915_gem.c | 6 +-- drivers/gpu/drm/i915/i915_gem_execbuffer.c | 2 +- fs/ntfs/file.c | 2 +- include/linux/pagemap.h | 54 +--------------------- include/linux/uio.h | 1 - lib/iov_iter.c | 3 +- 7 files changed, 9 insertions(+), 61 deletions(-) diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c index cb8f0347b934..ff843160c600 100644 --- a/drivers/gpu/drm/armada/armada_gem.c +++ b/drivers/gpu/drm/armada/armada_gem.c @@ -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; diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index a77ce9983f69..ccf56c60e6e8 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -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; diff --git a/drivers/gpu/drm/i915/i915_gem_execbuffer.c b/drivers/gpu/drm/i915/i915_gem_execbuffer.c index b35e5b6475b2..72628edda376 100644 --- a/drivers/gpu/drm/i915/i915_gem_execbuffer.c +++ b/drivers/gpu/drm/i915/i915_gem_execbuffer.c @@ -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; } } diff --git a/fs/ntfs/file.c b/fs/ntfs/file.c index f548629dfaac..bf72a2c58b75 100644 --- a/fs/ntfs/file.c +++ b/fs/ntfs/file.c @@ -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; } diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 01e84436cddf..cb2e1d06d2e9 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -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; diff --git a/include/linux/uio.h b/include/linux/uio.h index 75b4aaf31a9d..7709f8d4a9cb 100644 --- a/include/linux/uio.h +++ b/include/linux/uio.h @@ -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); diff --git a/lib/iov_iter.c b/lib/iov_iter.c index 7e3138cfc8c9..ce4632002611 100644 --- a/lib/iov_iter.c +++ b/lib/iov_iter.c @@ -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;}))