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CIFS: Separate filling pages from iovec write 

Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: Pavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: Steve French <smfrench@gmail.com>
This commit is contained in:
Pavel Shilovsky 2014-06-20 15:48:40 +04:00 committed by Steve French
parent 7f6c50086a
commit 66386c08be
1 changed files with 50 additions and 34 deletions
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84
fs/cifs/file.c
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@ -2423,11 +2423,53 @@ cifs_uncached_retry_writev(struct cifs_writedata *wdata)
return rc;
}
static int
wdata_fill_from_iovec(struct cifs_writedata *wdata, struct iov_iter *from,
size_t *len, unsigned long *num_pages)
{
size_t save_len, copied, bytes, cur_len = *len;
unsigned long i, nr_pages = *num_pages;
save_len = cur_len;
for (i = 0; i < nr_pages; i++) {
bytes = min_t(const size_t, cur_len, PAGE_SIZE);
copied = copy_page_from_iter(wdata->pages[i], 0, bytes, from);
cur_len -= copied;
/*
* If we didn't copy as much as we expected, then that
* may mean we trod into an unmapped area. Stop copying
* at that point. On the next pass through the big
* loop, we'll likely end up getting a zero-length
* write and bailing out of it.
*/
if (copied < bytes)
break;
}
cur_len = save_len - cur_len;
*len = cur_len;
/*
* If we have no data to send, then that probably means that
* the copy above failed altogether. That's most likely because
* the address in the iovec was bogus. Return -EFAULT and let
* the caller free anything we allocated and bail out.
*/
if (!cur_len)
return -EFAULT;
/*
* i + 1 now represents the number of pages we actually used in
* the copy phase above.
*/
*num_pages = i + 1;
return 0;
}
static ssize_t
cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
{
unsigned long nr_pages, i;
size_t bytes, copied, len, cur_len;
unsigned long nr_pages, num_pages, i;
size_t len, cur_len;
ssize_t total_written = 0;
loff_t offset;
struct cifsFileInfo *open_file;
@ -2464,8 +2506,6 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
pid = current->tgid;
do {
size_t save_len;
nr_pages = get_numpages(cifs_sb->wsize, len, &cur_len);
wdata = cifs_writedata_alloc(nr_pages,
cifs_uncached_writev_complete);
@ -2480,44 +2520,20 @@ cifs_iovec_write(struct file *file, struct iov_iter *from, loff_t *poffset)
break;
}
save_len = cur_len;
for (i = 0; i < nr_pages; i++) {
bytes = min_t(size_t, cur_len, PAGE_SIZE);
copied = copy_page_from_iter(wdata->pages[i], 0, bytes,
from);
cur_len -= copied;
/*
* If we didn't copy as much as we expected, then that
* may mean we trod into an unmapped area. Stop copying
* at that point. On the next pass through the big
* loop, we'll likely end up getting a zero-length
* write and bailing out of it.
*/
if (copied < bytes)
break;
}
cur_len = save_len - cur_len;
/*
* If we have no data to send, then that probably means that
* the copy above failed altogether. That's most likely because
* the address in the iovec was bogus. Set the rc to -EFAULT,
* free anything we allocated and bail out.
*/
if (!cur_len) {
num_pages = nr_pages;
rc = wdata_fill_from_iovec(wdata, from, &cur_len, &num_pages);
if (rc) {
for (i = 0; i < nr_pages; i++)
put_page(wdata->pages[i]);
kfree(wdata);
rc = -EFAULT;
break;
}
/*
* i + 1 now represents the number of pages we actually used in
* the copy phase above. Bring nr_pages down to that, and free
* any pages that we didn't use.
* Bring nr_pages down to the number of pages we actually used,
* and free any pages that we didn't use.
*/
for ( ; nr_pages > i + 1; nr_pages--)
for ( ; nr_pages > num_pages; nr_pages--)
put_page(wdata->pages[nr_pages - 1]);
wdata->sync_mode = WB_SYNC_ALL;