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untangling process_vm_..., part 1

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we want to massage it to use of iov_iter.  This one is an equivalent
transformation - just introduce a local variable mirroring
lvec + *lvec_current.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2014-02-05 10:14:01 -05:00
parent ec69557982
commit 480402e18d
1 changed files with 9 additions and 5 deletions
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14
mm/process_vm_access.c
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@ -60,6 +60,7 @@ static int process_vm_rw_pages(struct task_struct *task,
int ret;
ssize_t bytes_to_copy;
ssize_t rc = 0;
const struct iovec *iov = lvec + *lvec_current;
*bytes_copied = 0;
@ -81,8 +82,10 @@ static int process_vm_rw_pages(struct task_struct *task,
pgs_copied++) {
/* Make sure we have a non zero length iovec */
while (*lvec_current < lvec_cnt
&& lvec[*lvec_current].iov_len == 0)
&& iov->iov_len == 0) {
iov++;
(*lvec_current)++;
}
if (*lvec_current == lvec_cnt)
break;
@ -94,18 +97,18 @@ static int process_vm_rw_pages(struct task_struct *task,
bytes_to_copy = min_t(ssize_t, PAGE_SIZE - start_offset,
len - *bytes_copied);
bytes_to_copy = min_t(ssize_t, bytes_to_copy,
lvec[*lvec_current].iov_len
iov->iov_len
- *lvec_offset);
target_kaddr = kmap(process_pages[pgs_copied]) + start_offset;
if (vm_write)
ret = copy_from_user(target_kaddr,
lvec[*lvec_current].iov_base
iov->iov_base
+ *lvec_offset,
bytes_to_copy);
else
ret = copy_to_user(lvec[*lvec_current].iov_base
ret = copy_to_user(iov->iov_base
+ *lvec_offset,
target_kaddr, bytes_to_copy);
kunmap(process_pages[pgs_copied]);
@ -117,12 +120,13 @@ static int process_vm_rw_pages(struct task_struct *task,
}
*bytes_copied += bytes_to_copy;
*lvec_offset += bytes_to_copy;
if (*lvec_offset == lvec[*lvec_current].iov_len) {
if (*lvec_offset == iov->iov_len) {
/*
* Need to copy remaining part of page into the
* next iovec if there are any bytes left in page
*/
(*lvec_current)++;
iov++;
*lvec_offset = 0;
start_offset = (start_offset + bytes_to_copy)
% PAGE_SIZE;