lift iov_iter into {compat_,}do_readv_writev()

get it closer to matching {compat_,}rw_copy_check_uvector().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 23 insertions, 31 deletions

diff --git a/fs/read_write.c b/fs/read_write.c
index 99a6ef946d01..11980f164432 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -695,25 +695,23 @@ unsigned long iov_shorten(struct iovec *iov, unsigned long nr_segs, size_t to)
 }
 EXPORT_SYMBOL(iov_shorten);
 
-static ssize_t do_iter_readv_writev(struct file *filp, int rw, const struct iovec *iov,
-                unsigned long nr_segs, size_t len, loff_t *ppos, iter_fn_t fn)
+static ssize_t do_iter_readv_writev(struct file *filp, struct iov_iter *iter,
+                loff_t *ppos, iter_fn_t fn)
 {
         struct kiocb kiocb;
-        struct iov_iter iter;
         ssize_t ret;
 
         init_sync_kiocb(&kiocb, filp);
         kiocb.ki_pos = *ppos;
 
-        iov_iter_init(&iter, rw, iov, nr_segs, len);
-        ret = fn(&kiocb, &iter);
+        ret = fn(&kiocb, iter);
         BUG_ON(ret == -EIOCBQUEUED);
         *ppos = kiocb.ki_pos;
         return ret;
 }
 
-static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
-                unsigned long nr_segs, size_t len, loff_t *ppos, iov_fn_t fn)
+static ssize_t do_sync_readv_writev(struct file *filp, struct iov_iter *iter,
+                loff_t *ppos, iov_fn_t fn)
 {
         struct kiocb kiocb;
         ssize_t ret;
@@ -721,30 +719,23 @@ static ssize_t do_sync_readv_writev(struct file *filp, const struct iovec *iov,
         init_sync_kiocb(&kiocb, filp);
         kiocb.ki_pos = *ppos;
 
-        ret = fn(&kiocb, iov, nr_segs, kiocb.ki_pos);
+        ret = fn(&kiocb, iter->iov, iter->nr_segs, kiocb.ki_pos);
         BUG_ON(ret == -EIOCBQUEUED);
         *ppos = kiocb.ki_pos;
         return ret;
 }
 
 /* Do it by hand, with file-ops */
-static ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
-                unsigned long nr_segs, loff_t *ppos, io_fn_t fn)
+static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
+                loff_t *ppos, io_fn_t fn)
 {
-        struct iovec *vector = iov;
         ssize_t ret = 0;
 
-        while (nr_segs > 0) {
-                void __user *base;
-                size_t len;
+        while (iov_iter_count(iter)) {
+                struct iovec iovec = iov_iter_iovec(iter);
                 ssize_t nr;
 
-                base = vector->iov_base;
-                len = vector->iov_len;
-                vector++;
-                nr_segs--;
-
-                nr = fn(filp, base, len, ppos);
+                nr = fn(filp, iovec.iov_base, iovec.iov_len, ppos);
 
                 if (nr < 0) {
                         if (!ret)
@@ -752,8 +743,9 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iovec *iov,
                         break;
                 }
                 ret += nr;
-                if (nr != len)
+                if (nr != iovec.iov_len)
                         break;
+                iov_iter_advance(iter, nr);
         }
 
         return ret;
@@ -844,6 +836,7 @@ static ssize_t do_readv_writev(int type, struct file *file,
         size_t tot_len;
         struct iovec iovstack[UIO_FASTIOV];
         struct iovec *iov = iovstack;
+        struct iov_iter iter;
         ssize_t ret;
         io_fn_t fn;
         iov_fn_t fnv;
@@ -853,6 +846,7 @@ static ssize_t do_readv_writev(int type, struct file *file,
                                     ARRAY_SIZE(iovstack), iovstack, &iov);
         if (ret <= 0)
                 goto out;
+        iov_iter_init(&iter, type, iov, nr_segs, ret);
 
         tot_len = ret;
         ret = rw_verify_area(type, file, pos, tot_len);
@@ -872,13 +866,11 @@ static ssize_t do_readv_writev(int type, struct file *file,
         }
 
         if (iter_fn)
-                ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
-                                                pos, iter_fn);
+                ret = do_iter_readv_writev(file, &iter, pos, iter_fn);
         else if (fnv)
-                ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
-                                                pos, fnv);
+                ret = do_sync_readv_writev(file, &iter, pos, fnv);
         else
-                ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
+                ret = do_loop_readv_writev(file, &iter, pos, fn);
 
         if (type != READ)
                 file_end_write(file);
@@ -1024,6 +1016,7 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,
         compat_ssize_t tot_len;
         struct iovec iovstack[UIO_FASTIOV];
         struct iovec *iov = iovstack;
+        struct iov_iter iter;
         ssize_t ret;
         io_fn_t fn;
         iov_fn_t fnv;
@@ -1033,6 +1026,7 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,
                                                UIO_FASTIOV, iovstack, &iov);
         if (ret <= 0)
                 goto out;
+        iov_iter_init(&iter, type, iov, nr_segs, ret);
 
         tot_len = ret;
         ret = rw_verify_area(type, file, pos, tot_len);
@@ -1052,13 +1046,11 @@ static ssize_t compat_do_readv_writev(int type, struct file *file,
         }
 
         if (iter_fn)
-                ret = do_iter_readv_writev(file, type, iov, nr_segs, tot_len,
-                                                pos, iter_fn);
+                ret = do_iter_readv_writev(file, &iter, pos, iter_fn);
         else if (fnv)
-                ret = do_sync_readv_writev(file, iov, nr_segs, tot_len,
-                                                pos, fnv);
+                ret = do_sync_readv_writev(file, &iter, pos, fnv);
         else
-                ret = do_loop_readv_writev(file, iov, nr_segs, pos, fn);
+                ret = do_loop_readv_writev(file, &iter, pos, fn);
 
         if (type != READ)
                 file_end_write(file);