From: Paulo Alcantara <pc@cjr.nz>
Date: Mon, 5 Dec 2022 23:31:53 -0300
Subject: [PATCH] cifs: skip alloc when request has no pages
Git-commit: d406d26745aba3365ab9171b2d5cbea9c1757305
References: bsc#1193629
Patch-mainline: v6.1
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: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
Acked-by: Paulo Alcantara <palcantara@suse.de>
---
fs/cifs/smb2ops.c | 36 +++++++++++++++++++++---------------
1 file changed, 21 insertions(+), 15 deletions(-)
diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
index bfaafd02fb1f..72b22d033ed5 100644
--- a/fs/cifs/smb2ops.c
+++ b/fs/cifs/smb2ops.c
@@ -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]);
}
}
--
2.39.0