iov_iter: add iter_iov_addr() and iter_iov_len() helpers

These just return the address and length of the current iovec segment
in the iterator. Convert existing iov_iter_iovec() users to use them
instead of getting a copy of the current vec.

Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/read_write.c b/fs/read_write.c
index 7a2ff61..a21ba3b 100644 (file)
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -749,15 +749,14 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
                return -EOPNOTSUPP;
 
        while (iov_iter_count(iter)) {
-               struct iovec iovec = iov_iter_iovec(iter);
                ssize_t nr;
 
                if (type == READ) {
-                       nr = filp->f_op->read(filp, iovec.iov_base,
-                                             iovec.iov_len, ppos);
+                       nr = filp->f_op->read(filp, iter_iov_addr(iter),
+                                               iter_iov_len(iter), ppos);
                } else {
-                       nr = filp->f_op->write(filp, iovec.iov_base,
-                                              iovec.iov_len, ppos);
+                       nr = filp->f_op->write(filp, iter_iov_addr(iter),
+                                               iter_iov_len(iter), ppos);
                }
 
                if (nr < 0) {
@@ -766,7 +765,7 @@ static ssize_t do_loop_readv_writev(struct file *filp, struct iov_iter *iter,
                        break;
                }
                ret += nr;
-               if (nr != iovec.iov_len)
+               if (nr != iter_iov_len(iter))
                        break;
                iov_iter_advance(iter, nr);
        }

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 4218624..b7fce87 100644 (file)
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -70,6 +70,8 @@ struct iov_iter {
 };
 
 #define iter_iov(iter) (iter)->__iov
+#define iter_iov_addr(iter)    (iter_iov(iter)->iov_base + (iter)->iov_offset)
+#define iter_iov_len(iter)     (iter_iov(iter)->iov_len - (iter)->iov_offset)
 
 static inline enum iter_type iov_iter_type(const struct iov_iter *i)
 {

diff --git a/io_uring/rw.c b/io_uring/rw.c
index 7573a34..f33ba6f 100644 (file)
--- a/io_uring/rw.c
+++ b/io_uring/rw.c
@@ -447,26 +447,25 @@ static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
        ppos = io_kiocb_ppos(kiocb);
 
        while (iov_iter_count(iter)) {
-               struct iovec iovec;
+               void __user *addr;
+               size_t len;
                ssize_t nr;
 
                if (iter_is_ubuf(iter)) {
-                       iovec.iov_base = iter->ubuf + iter->iov_offset;
-                       iovec.iov_len = iov_iter_count(iter);
+                       addr = iter->ubuf + iter->iov_offset;
+                       len = iov_iter_count(iter);
                } else if (!iov_iter_is_bvec(iter)) {
-                       iovec = iov_iter_iovec(iter);
+                       addr = iter_iov_addr(iter);
+                       len = iter_iov_len(iter);
                } else {
-                       iovec.iov_base = u64_to_user_ptr(rw->addr);
-                       iovec.iov_len = rw->len;
+                       addr = u64_to_user_ptr(rw->addr);
+                       len = rw->len;
                }
 
-               if (ddir == READ) {
-                       nr = file->f_op->read(file, iovec.iov_base,
-                                             iovec.iov_len, ppos);
-               } else {
-                       nr = file->f_op->write(file, iovec.iov_base,
-                                              iovec.iov_len, ppos);
-               }
+               if (ddir == READ)
+                       nr = file->f_op->read(file, addr, len, ppos);
+               else
+                       nr = file->f_op->write(file, addr, len, ppos);
 
                if (nr < 0) {
                        if (!ret)
@@ -482,7 +481,7 @@ static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter)
                        if (!rw->len)
                                break;
                }
-               if (nr != iovec.iov_len)
+               if (nr != len)
                        break;
        }
 

diff --git a/mm/madvise.c b/mm/madvise.c
index 340125d..9f389c5 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -1456,7 +1456,7 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
                size_t, vlen, int, behavior, unsigned int, flags)
 {
        ssize_t ret;
-       struct iovec iovstack[UIO_FASTIOV], iovec;
+       struct iovec iovstack[UIO_FASTIOV];
        struct iovec *iov = iovstack;
        struct iov_iter iter;
        struct task_struct *task;
@@ -1503,12 +1503,11 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
        total_len = iov_iter_count(&iter);
 
        while (iov_iter_count(&iter)) {
-               iovec = iov_iter_iovec(&iter);
-               ret = do_madvise(mm, (unsigned long)iovec.iov_base,
-                                       iovec.iov_len, behavior);
+               ret = do_madvise(mm, (unsigned long)iter_iov_addr(&iter),
+                                       iter_iov_len(&iter), behavior);
                if (ret < 0)
                        break;
-               iov_iter_advance(&iter, iovec.iov_len);
+               iov_iter_advance(&iter, iter_iov_len(&iter));
        }
 
        ret = (total_len - iov_iter_count(&iter)) ? : ret;