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>

1 files changed, 13 insertions, 16 deletions

diff --git a/mm/process_vm_access.c b/mm/process_vm_access.c
index 40dfb396e8ab..4bbd495fcedd 100644
--- 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) {