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 <viro@zeniv.linux.org.uk>

diff --git a/drivers/gpu/drm/armada/armada_gem.c b/drivers/gpu/drm/armada/armada_gem.c
index cb8f034..ff84316 100644 (file)
--- 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 a77ce99..ccf56c6 100644 (file)
--- 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 b35e5b6..72628ed 100644 (file)
--- 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 f548629..bf72a2c 100644 (file)
--- a/fs/ntfs/file.c
+++ b/fs/ntfs/file.c
@@ -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;
                }

diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 01e8443..cb2e1d0 100644 (file)
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -518,59 +518,10 @@ 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;
 
        if (unlikely(size == 0))
@@ -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 75b4aaf..7709f8d 100644 (file)
--- 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 7e3138c..ce46320 100644 (file)
--- 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;}))