Changeset 77710 in vbox for trunk/src/VBox/Additions/linux/sharedfolders

Timestamp:

Mar 15, 2019 2:18:34 AM (6 years ago)

Author:

vboxsync

svn:sync-xref-src-repo-rev:

129353

Message:

linux/vboxsf: More linux 3.16 fixes, this time for skipping empty iov segments. bugref:9172

File:

• trunk/src/VBox/Additions/linux/sharedfolders/regops.c (modified) (3 diffs)

trunk/src/VBox/Additions/linux/sharedfolders/regops.c

@@ -1116 +1116 @@
         while (cbToCopy > 0) {
             size_t cbThisCopy = iov_iter_single_seg_count(pSrcIter);
-            if (cbThisCopy > cbToCopy)
-                cbThisCopy = cbToCopy;
-            if (pSrcIter->type & ITER_KVEC)
-                memcpy(pbDst, (void *)pSrcIter->iov->iov_base + pSrcIter->iov_offset, cbThisCopy);
-            else if (!copy_from_user(pbDst, pSrcIter->iov->iov_base + pSrcIter->iov_offset, cbThisCopy))
-                break;
-            pbDst    += cbThisCopy;
-            cbToCopy -= cbThisCopy;
+            if (cbThisCopy > 0) {
+                if (cbThisCopy > cbToCopy)
+                    cbThisCopy = cbToCopy;
+                if (pSrcIter->type & ITER_KVEC)
+                    memcpy(pbDst, (void *)pSrcIter->iov->iov_base + pSrcIter->iov_offset, cbThisCopy);
+                else if (!copy_from_user(pbDst, pSrcIter->iov->iov_base + pSrcIter->iov_offset, cbThisCopy))
+                    break;
+                pbDst    += cbThisCopy;
+                cbToCopy -= cbThisCopy;
+            }
             iov_iter_advance(pSrcIter, cbThisCopy);
         }
@@ -1149 +1151 @@
         while (cbToCopy > 0) {
             size_t cbThisCopy = iov_iter_single_seg_count(pDstIter);
-            if (cbThisCopy > cbToCopy)
-                cbThisCopy = cbToCopy;
-            if (pDstIter->type & ITER_KVEC)
-                memcpy((void *)pDstIter->iov->iov_base + pDstIter->iov_offset, pbSrc, cbThisCopy);
-            else if (!copy_to_user(pDstIter->iov->iov_base + pDstIter->iov_offset, pbSrc, cbThisCopy))
-                break;
-            pbSrc    += cbThisCopy;
-            cbToCopy -= cbThisCopy;
+            if (cbThisCopy > 0) {
+                if (cbThisCopy > cbToCopy)
+                    cbThisCopy = cbToCopy;
+                if (pDstIter->type & ITER_KVEC)
+                    memcpy((void *)pDstIter->iov->iov_base + pDstIter->iov_offset, pbSrc, cbThisCopy);
+                else if (!copy_to_user(pDstIter->iov->iov_base + pDstIter->iov_offset, pbSrc, cbThisCopy)) {
+                    break;
+                }
+                pbSrc    += cbThisCopy;
+                cbToCopy -= cbThisCopy;
+            }
             iov_iter_advance(pDstIter, cbThisCopy);
         }
@@ -1251 +1256 @@
             ssize_t cbSegRet;
             if (cPages == 0) {
+# if LINUX_VERSION_CODE < KERNEL_VERSION(3, 19, 0)
+                while (!iov_iter_single_seg_count(iter)) /* Old code didn't skip empty segments which caused EFAULTs. */
+                    iov_iter_advance(iter, 0);
+# endif
                 cbSegRet = iov_iter_get_pages(iter, papPages, iov_iter_count(iter), cMaxPages, &offPage0);
                 if (cbSegRet > 0) {