pagevecs of more than PAGEVEC_SIZE pages

From: Steve French
Date: Thu May 22 2008 - 15:13:27 EST

Now that various servers support processing larger than 64K file
writes, it would be helpful to have pagevecs that are larger than 14
pages (PAGEVEC_SIZE).so an array of more pages could be passed to
kernel_sendmsg (thus allowing writes larger than 56K, depending on
wsize - the server limit is currently 8MB)

pagevec_lookup_tag (and the inline function pagevec_space which I
don't use) is the main place that cifs needs a pagevec instead of
simply an array of pages and PAGEVEC_SIZE does not seem to matter
there (it works if I malloc a structure with more pages and request
more than 14 pages out of pagevec_lookup_tag). Is there another
better alternative other than defining a larger pagevec (pagevec2 or
cifs_pagevec)? Should I simply kmalloc something larger than a
pagevec and cast a (struct pagevec *) to it?

static int cifs_writepages(struct address_space *mapping,
struct writeback_control *wbc)
@@ -1209,7 +1216,7 @@ static int cifs_writepages(struct address_space *mapping,
__u64 offset = 0;
struct cifsFileInfo *open_file;
struct page *page;
- struct pagevec pvec;
+ struct pagevec2 pvec;
int rc = 0;
int scanned = 0;
int xid;
@@ -1229,7 +1236,7 @@ static int cifs_writepages(struct address_space *mapping,
if (!experimEnabled)
return generic_writepages(mapping, wbc);

- iov = kmalloc(32 * sizeof(struct kvec), GFP_KERNEL);
+ iov = kmalloc(maximum_pages_to_write_based_on_wsize *
sizeof(struct kvec), GFP_KERNEL);
if (iov == NULL)
return generic_writepages(mapping, wbc);

@@ -1261,7 +1268,7 @@ retry:
while (!done && (index <= end) &&
(nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
- min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
+ min(end - index,
(pgoff_t)maximum_pages_to_write_based_on_wsize - 1) + 1))) {
int first;
unsigned int i;


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