Add code that allows smb_send_rqst to send an array of pages after the
initial kvec array has been sent. For now, we simply kmap the page
array and send it using the standard smb_send_kvec function. Eventually,
we may want to convert this code to use kernel_sendpage under the hood
and avoid the kmap altogether for the page data.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
---
fs/cifs/transport.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 54 insertions(+), 2 deletions(-)
diff --git a/fs/cifs/transport.c b/fs/cifs/transport.c
index af56e91..006c3fb 100644
--- a/fs/cifs/transport.c
+++ b/fs/cifs/transport.c
@@ -28,6 +28,7 @@
#include <linux/delay.h>
#include <linux/freezer.h>
#include <linux/tcp.h>
+#include <linux/highmem.h>
#include <asm/uaccess.h>
#include <asm/processor.h>
#include <linux/mempool.h>
@@ -241,6 +242,38 @@ smb_send_kvec(struct TCP_Server_Info *server, struct kvec *iov, size_t n_vec,
return rc;
}
+/**
+ * rqst_page_to_kvec - Turn a slot in the smb_rqst page array into a kvec
+ * @rqst: pointer to smb_rqst
+ * @idx: index into the array of the page
+ * @iov: pointer to struct kvec that will hold the result
+ *
+ * Helper function to convert a slot in the rqst->rq_pages array into a kvec.
+ * The page will be kmapped and the address placed into iov_base. The length
+ * will then be adjusted according to the ptailoff.
+ */
+static void
+cifs_rqst_page_to_kvec(struct smb_rqst *rqst, unsigned int idx,
+ struct kvec *iov)
+{
+ /*
+ * FIXME: We could avoid this kmap altogether if we used
+ * kernel_sendpage instead of kernel_sendmsg. That will only
+ * work if signing is disabled though as sendpage inlines the
+ * page directly into the fraglist. If userspace modifies the
+ * page after we calculate the signature, then the server will
+ * reject it and may break the connection. kernel_sendmsg does
+ * an extra copy of the data and avoids that issue.
+ */
+ iov->iov_base = kmap(rqst->rq_pages[idx]);
+
+ /* if last page, don't send beyond this offset into page */
+ if (idx == (rqst->rq_npages - 1))
+ iov->iov_len = rqst->rq_tailsz;
+ else
+ iov->iov_len = rqst->rq_pagesz;
+}
+
static int
smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
{
@@ -248,7 +281,8 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
struct kvec *iov = rqst->rq_iov;
int n_vec = rqst->rq_nvec;
unsigned int smb_buf_length = get_rfc1002_length(iov[0].iov_base);
- size_t total_len;
+ unsigned int i;
+ size_t total_len = 0, sent;
struct socket *ssocket = server->ssocket;
int val = 1;
@@ -259,8 +293,26 @@ smb_send_rqst(struct TCP_Server_Info *server, struct smb_rqst *rqst)
kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
(char *)&val, sizeof(val));
- rc = smb_send_kvec(server, iov, n_vec, &total_len);
+ rc = smb_send_kvec(server, iov, n_vec, &sent);
+ if (rc < 0)
+ goto uncork;
+
+ total_len += sent;
+
+ /* now walk the page array and send each page in it */
+ for (i = 0; i < rqst->rq_npages; i++) {
+ struct kvec p_iov;
+
+ cifs_rqst_page_to_kvec(rqst, i, &p_iov);
+ rc = smb_send_kvec(server, &p_iov, 1, &sent);
+ kunmap(rqst->rq_pages[i]);
+ if (rc < 0)
+ break;
+
+ total_len += sent;
+ }
+uncork:
/* uncork it */
val = 0;
kernel_setsockopt(ssocket, SOL_TCP, TCP_CORK,
--
1.7.10.4
--
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