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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: Paulo Alcantara (SUSE) <pc@cjr.nz>
Signed-off-by: Steve French <stfrench@microsoft.com>
This commit is contained in:
Paulo Alcantara 2022-12-05 23:31:53 -03:00 committed by Steve French
parent ebaad77c89
commit d406d26745
1 changed files with 21 additions and 15 deletions
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36
fs/cifs/smb2ops.c
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@ -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]);
}
}