untangling process_vm_..., part 4

instead of passing vector size (by value) and index (by reference),
pass the number of elements remaining.  That's all we care about
in these functions by that point.

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

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 40dfb39..4bbd495 100644 (file)
--- a/mm/process_vm_access.c
+++ b/mm/process_vm_access.c
@@ -46,8 +46,7 @@ static int process_vm_rw_pages(struct task_struct *task,
                               unsigned long start_offset,
                               unsigned long len,
                               const struct iovec **iovp,
-                              unsigned long lvec_cnt,
-                              unsigned long *lvec_current,
+                              unsigned long *left,
                               size_t *lvec_offset,
                               int vm_write,
                               unsigned int nr_pages_to_copy,
@@ -78,15 +77,14 @@ static int process_vm_rw_pages(struct task_struct *task,
 
        /* Do the copy for each page */
        for (pgs_copied = 0;
-            (pgs_copied < nr_pages_to_copy) && (*lvec_current < lvec_cnt);
+            (pgs_copied < nr_pages_to_copy) && *left;
             pgs_copied++) {
                /* Make sure we have a non zero length iovec */
-               while (*lvec_current < lvec_cnt
-                      && iov->iov_len == 0) {
+               while (*left && iov->iov_len == 0) {
                        iov++;
-                       (*lvec_current)++;
+                       (*left)--;
                }
-               if (*lvec_current == lvec_cnt)
+               if (!*left)
                        break;
 
                /*
@@ -125,7 +123,7 @@ static int process_vm_rw_pages(struct task_struct *task,
                         * Need to copy remaining part of page into the
                         * next iovec if there are any bytes left in page
                         */
-                       (*lvec_current)++;
+                       (*left)--;
                        iov++;
                        *lvec_offset = 0;
                        start_offset = (start_offset + bytes_to_copy)
@@ -175,8 +173,7 @@ end:
 static int process_vm_rw_single_vec(unsigned long addr,
                                    unsigned long len,
                                    const struct iovec **iovp,
-                                   unsigned long lvec_cnt,
-                                   unsigned long *lvec_current,
+                                   unsigned long *left,
                                    size_t *lvec_offset,
                                    struct page **process_pages,
                                    struct mm_struct *mm,
@@ -201,14 +198,14 @@ static int process_vm_rw_single_vec(unsigned long addr,
                return 0;
        nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
 
-       while ((nr_pages_copied < nr_pages) && (*lvec_current < lvec_cnt)) {
+       while ((nr_pages_copied < nr_pages) && *left) {
                nr_pages_to_copy = min(nr_pages - nr_pages_copied,
                                       max_pages_per_loop);
 
                rc = process_vm_rw_pages(task, mm, process_pages, pa,
                                         start_offset, len,
-                                        iovp, lvec_cnt,
-                                        lvec_current, lvec_offset,
+                                        iovp, left,
+                                        lvec_offset,
                                         vm_write, nr_pages_to_copy,
                                         &bytes_copied_loop);
                start_offset = 0;
@@ -259,7 +256,7 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,
        ssize_t bytes_copied = 0;
        unsigned long nr_pages = 0;
        unsigned long nr_pages_iov;
-       unsigned long iov_l_curr_idx = 0;
+       unsigned long left = liovcnt;
        size_t iov_l_curr_offset = 0;
        ssize_t iov_len;
 
@@ -315,10 +312,10 @@ static ssize_t process_vm_rw_core(pid_t pid, const struct iovec *lvec,
                goto put_task_struct;
        }
 
-       for (i = 0; i < riovcnt && iov_l_curr_idx < liovcnt; i++) {
+       for (i = 0; i < riovcnt && left; i++) {
                rc = process_vm_rw_single_vec(
                        (unsigned long)rvec[i].iov_base, rvec[i].iov_len,
-                       &lvec, liovcnt, &iov_l_curr_idx, &iov_l_curr_offset,
+                       &lvec, &left, &iov_l_curr_offset,
                        process_pages, mm, task, vm_write, &bytes_copied_loop);
                bytes_copied += bytes_copied_loop;
                if (rc != 0) {