[SCSI] iscsi: add high mem support

From Mike Christie <michaelc@cs.wisc.edu> and FUJITA Tomonori <tomof@acm.org>:

We cannot use page_address becuase some pages could be highmem.
Instead, we can use sock_no_sendpage which does kmap for us.

Signed-off-by: Alex Aizman <itn780@yahoo.com>
Signed-off-by: Dmitry Yusupov <dmitry_yus@yahoo.com>
Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/iscsi_tcp.c b/drivers/scsi/iscsi_tcp.c
index 5e8b3135574cdccdb3d1961973657451ddf8329c..0acc4b235d9b8b1c7d6d270e223a59f31ce2a9a2 100644 (file)
--- a/drivers/scsi/iscsi_tcp.c
+++ b/drivers/scsi/iscsi_tcp.c
@@ -87,35 +87,32 @@ iscsi_buf_init_virt(struct iscsi_buf *ibuf, char *vbuf, int size)
 {
        sg_init_one(&ibuf->sg, (u8 *)vbuf, size);
        ibuf->sent = 0;
+       ibuf->use_sendmsg = 0;
 }
 
 static inline void
 iscsi_buf_init_iov(struct iscsi_buf *ibuf, char *vbuf, int size)
 {
-       ibuf->sg.page = (void*)vbuf;
-       ibuf->sg.offset = (unsigned int)-1;
+       ibuf->sg.page = virt_to_page(vbuf);
+       ibuf->sg.offset = offset_in_page(vbuf);
        ibuf->sg.length = size;
        ibuf->sent = 0;
-}
-
-static inline void*
-iscsi_buf_iov_base(struct iscsi_buf *ibuf)
-{
-       return (char*)ibuf->sg.page + ibuf->sent;
+       ibuf->use_sendmsg = 1;
 }
 
 static inline void
 iscsi_buf_init_sg(struct iscsi_buf *ibuf, struct scatterlist *sg)
 {
+       ibuf->sg.page = sg->page;
+       ibuf->sg.offset = sg->offset;
+       ibuf->sg.length = sg->length;
        /*
         * Fastpath: sg element fits into single page
         */
-       if (sg->length + sg->offset <= PAGE_SIZE && page_count(sg->page) >= 2) {
-               ibuf->sg.page = sg->page;
-               ibuf->sg.offset = sg->offset;
-               ibuf->sg.length = sg->length;
-       } else
-               iscsi_buf_init_iov(ibuf, page_address(sg->page), sg->length);
+       if (sg->length + sg->offset <= PAGE_SIZE && page_count(sg->page) >= 2)
+               ibuf->use_sendmsg = 0;
+       else
+               ibuf->use_sendmsg = 1;
        ibuf->sent = 0;
 }
 
@@ -1311,35 +1308,25 @@ iscsi_conn_restore_callbacks(struct iscsi_conn *conn)
  * @buf: buffer to write from
  * @size: actual size to write
  * @flags: socket's flags
- *
- * Notes:
- *     depending on buffer will use tcp_sendpage() or tcp_sendmsg().
- *     buf->sg.offset == -1 tells us that buffer is non S/G and forces
- *     to use tcp_sendmsg().
  */
 static inline int
 iscsi_send(struct iscsi_conn *conn, struct iscsi_buf *buf, int size, int flags)
 {
        struct socket *sk = conn->sock;
-       int res;
-
-       if ((int)buf->sg.offset >= 0) {
-               int offset = buf->sg.offset + buf->sent;
-
-               res = conn->sendpage(sk, buf->sg.page, offset, size, flags);
-       } else {
-               struct msghdr msg;
-
-               buf->iov.iov_base = iscsi_buf_iov_base(buf);
-               buf->iov.iov_len = size;
-
-               memset(&msg, 0, sizeof(struct msghdr));
-
-               /* tcp_sendmsg */
-               res = kernel_sendmsg(sk, &msg, &buf->iov, 1, size);
-       }
+       int offset = buf->sg.offset + buf->sent;
 
-       return res;
+       /*
+        * if we got use_sg=0 or are sending something we kmallocd
+        * then we did not have to do kmap (kmap returns page_address)
+        *
+        * if we got use_sg > 0, but had to drop down, we do not
+        * set clustering so this should only happen for that
+        * slab case.
+        */
+       if (buf->use_sendmsg)
+               return sock_no_sendpage(sk, buf->sg.page, offset, size, flags);
+       else
+               return conn->sendpage(sk, buf->sg.page, offset, size, flags);
 }
 
 /**
@@ -1431,19 +1418,6 @@ iscsi_data_digest_init(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
        ctask->digest_count = 4;
 }
 
-static inline void
-iscsi_buf_data_digest_update(struct iscsi_conn *conn, struct iscsi_buf *buf)
-{
-       struct scatterlist sg;
-
-       if (buf->sg.offset != -1)
-               crypto_digest_update(conn->data_tx_tfm, &buf->sg, 1);
-       else {
-               sg_init_one(&sg, (char *)buf->sg.page, buf->sg.length);
-               crypto_digest_update(conn->data_tx_tfm, &sg, 1);
-       }
-}
-
 static inline int
 iscsi_digest_final_send(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
                        struct iscsi_buf *buf, uint32_t *digest, int final)
@@ -1806,7 +1780,8 @@ handle_xmstate_imm_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
                        return -EAGAIN;
                }
                if (conn->datadgst_en)
-                       iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
+                       crypto_digest_update(conn->data_tx_tfm,
+                                            &ctask->sendbuf.sg, 1);
 
                if (!ctask->imm_count)
                        break;
@@ -1891,7 +1866,8 @@ handle_xmstate_uns_data(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
                 * so pass it
                 */
                if (conn->datadgst_en && ctask->sent - start > 0)
-                       iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
+                       crypto_digest_update(conn->data_tx_tfm,
+                                            &ctask->sendbuf.sg, 1);
 
                if (!ctask->data_count)
                        break;
@@ -1969,7 +1945,7 @@ solicit_again:
 
        BUG_ON(r2t->data_count < 0);
        if (conn->datadgst_en)
-               iscsi_buf_data_digest_update(conn, &r2t->sendbuf);
+               crypto_digest_update(conn->data_tx_tfm, &r2t->sendbuf.sg, 1);
 
        if (r2t->data_count) {
                BUG_ON(ctask->sc->use_sg == 0);
@@ -2051,7 +2027,7 @@ handle_xmstate_w_pad(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
        }
 
        if (conn->datadgst_en) {
-               iscsi_buf_data_digest_update(conn, &ctask->sendbuf);
+               crypto_digest_update(conn->data_tx_tfm, &ctask->sendbuf.sg, 1);
                /* imm data? */
                if (!dtask) {
                        if (iscsi_digest_final_send(conn, ctask, &ctask->immbuf,

diff --git a/drivers/scsi/iscsi_tcp.h b/drivers/scsi/iscsi_tcp.h
index c8bb5b0bcb4b014df10f2a3a258c43338c7297ed..f95e61b76f70baf3ba5bdd45906439db5971c4ba 100644 (file)
--- a/drivers/scsi/iscsi_tcp.h
+++ b/drivers/scsi/iscsi_tcp.h
@@ -242,8 +242,8 @@ struct iscsi_session {
 
 struct iscsi_buf {
        struct scatterlist      sg;
-       struct kvec             iov;
        unsigned int            sent;
+       char                    use_sendmsg;
 };
 
 struct iscsi_data_task {