1 files changed, 27 insertions, 50 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 9398e6cd48cb..17d3799d04bd 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1462,13 +1462,25 @@ shmem_write_end(struct file *file, struct address_space *mapping,
         return copied;
 }
 
-static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_t *desc)
+static ssize_t shmem_file_aio_read(struct kiocb *iocb,
+                const struct iovec *iov, unsigned long nr_segs, loff_t pos)
 {
-        struct inode *inode = file_inode(filp);
+        struct file *file = iocb->ki_filp;
+        struct inode *inode = file_inode(file);
         struct address_space *mapping = inode->i_mapping;
         pgoff_t index;
         unsigned long offset;
         enum sgp_type sgp = SGP_READ;
+        int error;
+        ssize_t retval;
+        size_t count;
+        loff_t *ppos = &iocb->ki_pos;
+        struct iov_iter iter;
+
+        retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
+        if (retval)
+                return retval;
+        iov_iter_init(&iter, iov, nr_segs, count, 0);
 
         /*
          * Might this read be for a stacking filesystem?  Then when reading
@@ -1496,10 +1508,10 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
                                 break;
                 }
 
-                desc->error = shmem_getpage(inode, index, &page, sgp, NULL);
-                if (desc->error) {
-                        if (desc->error == -EINVAL)
-                                desc->error = 0;
+                error = shmem_getpage(inode, index, &page, sgp, NULL);
+                if (error) {
+                        if (error == -EINVAL)
+                                error = 0;
                         break;
                 }
                 if (page)
@@ -1543,61 +1555,26 @@ static void do_shmem_file_read(struct file *filp, loff_t *ppos, read_descriptor_
                 /*
                  * Ok, we have the page, and it's up-to-date, so
                  * now we can copy it to user space...
-                 *
-                 * The actor routine returns how many bytes were actually used..
-                 * NOTE! This may not be the same as how much of a user buffer
-                 * we filled up (we may be padding etc), so we can only update
-                 * "pos" here (the actor routine has to update the user buffer
-                 * pointers and the remaining count).
                  */
-                ret = file_read_actor(desc, page, offset, nr);
+                ret = copy_page_to_iter(page, offset, nr, &iter);
+                retval += ret;
                 offset += ret;
                 index += offset >> PAGE_CACHE_SHIFT;
                 offset &= ~PAGE_CACHE_MASK;
 
                 page_cache_release(page);
-                if (ret != nr || !desc->count)
+                if (!iov_iter_count(&iter))
                         break;
-
+                if (ret < nr) {
+                        error = -EFAULT;
+                        break;
+                }
                 cond_resched();
         }
 
         *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset;
-        file_accessed(filp);
-}
-
-static ssize_t shmem_file_aio_read(struct kiocb *iocb,
-                const struct iovec *iov, unsigned long nr_segs, loff_t pos)
-{
-        struct file *filp = iocb->ki_filp;
-        ssize_t retval;
-        unsigned long seg;
-        size_t count;
-        loff_t *ppos = &iocb->ki_pos;
-
-        retval = generic_segment_checks(iov, &nr_segs, &count, VERIFY_WRITE);
-        if (retval)
-                return retval;
-
-        for (seg = 0; seg < nr_segs; seg++) {
-                read_descriptor_t desc;
-
-                desc.written = 0;
-                desc.arg.buf = iov[seg].iov_base;
-                desc.count = iov[seg].iov_len;
-                if (desc.count == 0)
-                        continue;
-                desc.error = 0;
-                do_shmem_file_read(filp, ppos, &desc);
-                retval += desc.written;
-                if (desc.error) {
-                        retval = retval ?: desc.error;
-                        break;
-                }
-                if (desc.count > 0)
-                        break;
-        }
-        return retval;
+        file_accessed(file);
+        return retval ? retval : error;
 }
 
 static ssize_t shmem_file_splice_read(struct file *in, loff_t *ppos,