Commit d406d267 authored by Paulo Alcantara's avatar Paulo Alcantara Committed by Steve French
Browse files

cifs: skip alloc when request has no pages 



When smb3_init_transform_rq() was being called with requests (@old_rq)
which had no pages, it was unnecessarily allocating a single page for
every request in @new_rq.

Fix this by skipping page array allocation when requests have no pages
(e.g. !smb_rqst::rq_npages).

Also get rid of deprecated kmap() and use kmap_local_page() instead
while we're at it.

Signed-off-by: default avatarPaulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: default avatarSteve French <stfrench@microsoft.com>
parent ebaad77c

fs/cifs/smb2ops.c

+21 −15
Original line number Diff line number Diff line
@@ -4445,21 +4445,27 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst, 
	int rc = -ENOMEM;



	for (i = 1; i < num_rqst; i++) {

		npages = old_rq[i - 1].rq_npages;

		struct smb_rqst *old = &old_rq[i - 1];

		struct smb_rqst *new = &new_rq[i];



		orig_len += smb_rqst_len(server, old);

		new->rq_iov = old->rq_iov;

		new->rq_nvec = old->rq_nvec;



		npages = old->rq_npages;

		if (!npages)

			continue;



		pages = kmalloc_array(npages, sizeof(struct page *),

				      GFP_KERNEL);

		if (!pages)

			goto err_free;



		new_rq[i].rq_pages = pages;

		new_rq[i].rq_npages = npages;

		new_rq[i].rq_offset = old_rq[i - 1].rq_offset;

		new_rq[i].rq_pagesz = old_rq[i - 1].rq_pagesz;

		new_rq[i].rq_tailsz = old_rq[i - 1].rq_tailsz;

		new_rq[i].rq_iov = old_rq[i - 1].rq_iov;

		new_rq[i].rq_nvec = old_rq[i - 1].rq_nvec;



		orig_len += smb_rqst_len(server, &old_rq[i - 1]);

		new->rq_pages = pages;

		new->rq_npages = npages;

		new->rq_offset = old->rq_offset;

		new->rq_pagesz = old->rq_pagesz;

		new->rq_tailsz = old->rq_tailsz;



		for (j = 0; j < npages; j++) {

			pages[j] = alloc_page(GFP_KERNEL|__GFP_HIGHMEM);
@@ -4472,14 +4478,14 @@ smb3_init_transform_rq(struct TCP_Server_Info *server, int num_rqst, 
			char *dst, *src;

			unsigned int offset, len;



			rqst_page_get_length(&new_rq[i], j, &len, &offset);

			rqst_page_get_length(new, j, &len, &offset);



			dst = (char *) kmap(new_rq[i].rq_pages[j]) + offset;

			src = (char *) kmap(old_rq[i - 1].rq_pages[j]) + offset;

			dst = kmap_local_page(new->rq_pages[j]) + offset;

			src = kmap_local_page(old->rq_pages[j]) + offset;



			memcpy(dst, src, len);

			kunmap(new_rq[i].rq_pages[j]);

			kunmap(old_rq[i - 1].rq_pages[j]);

			kunmap(new->rq_pages[j]);

			kunmap(old->rq_pages[j]);

		}

	}