lkml.org 
[lkml]   [2018]   [Jun]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [Patch v2 11/15] CIFS: Pass page offset for calculating signature
From
Date
On 5/30/2018 3:48 PM, Long Li wrote:
> From: Long Li <longli@microsoft.com>
>
> When calculating signature for the packet, it needs to read into the
> correct page offset for the data.
>
> Signed-off-by: Long Li <longli@microsoft.com>
> ---
> fs/cifs/cifsencrypt.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/fs/cifs/cifsencrypt.c b/fs/cifs/cifsencrypt.c
> index a6ef088..e88303c 100644
> --- a/fs/cifs/cifsencrypt.c
> +++ b/fs/cifs/cifsencrypt.c
> @@ -68,11 +68,12 @@ int __cifs_calc_signature(struct smb_rqst *rqst,
>
> /* now hash over the rq_pages array */
> for (i = 0; i < rqst->rq_npages; i++) {
> - void *kaddr = kmap(rqst->rq_pages[i]);
> - size_t len = rqst->rq_pagesz;
> + void *kaddr;
> + unsigned int len, offset;
>
> - if (i == rqst->rq_npages - 1)
> - len = rqst->rq_tailsz;
> + rqst_page_get_length(rqst, i, &len, &offset);
> +
> + kaddr = (char *) kmap(rqst->rq_pages[i]) + offset;

I suppose it's more robust to map a page at a time, but it's pretty
expensive. Is this the only way to iterate over a potentially very
large block of data? For example, a 1MB segment means 256 kmap/kunmaps.

Tom.

>
> crypto_shash_update(shash, kaddr, len);
>
>

\
 
 \ /
  Last update: 2018-06-24 04:27    [W:0.255 / U:1.160 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site