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Commit 66386c08 authored by Pavel Shilovsky's avatar Pavel Shilovsky Committed by Steve French
Browse files

CIFS: Separate filling pages from iovec write 



Reviewed-by: default avatarShirish Pargaonkar <spargaonkar@suse.com>
Signed-off-by: default avatarPavel Shilovsky <pshilovsky@samba.org>
Signed-off-by: default avatarSteve French <smfrench@gmail.com>
parent 7f6c5008

fs/cifs/file.c

+50 −34
Original line number Diff line number Diff line
@@ -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;