iwl3945: fix length of dma buffers

commit bdb084b22d8aee66c87af5e9c36bd6cf7f3bccfd
Author: Stanislaw Gruszka <sgruszka@redhat.com>
Date:   Wed Feb 13 15:49:08 2013 +0100

    iwlegacy: more checks for dma mapping errors

broke il3945_tx_skb() dma buffer length settings, what results on
firmware errors like showed below and make 3945 device non usable.

iwl3945 0000:02:00.0: Microcode SW error detected. Restarting 0x82000008.
iwl3945 0000:02:00.0: Loaded firmware version: 15.32.2.9
iwl3945 0000:02:00.0: Start IWL Error Log Dump:
iwl3945 0000:02:00.0: Status: 0x000202E4, count: 1
iwl3945 0000:02:00.0: Desc 	Time	   asrtPC blink2 ilink1  nmiPC   Line
iwl3945 0000:02:00.0: SYSASSERT     (0x5) 0000208934 0x008B6 0x0035E 0x00320 0x00000 267
iwl3945 0000:02:00.0: Error Reply type 0x00000001 cmd

Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Reported-by: Krzysztof Kolasa <kkolasa@winsoft.pl>
Reported-by: Pedro Francisco <pedrogfrancisco@gmail.com>
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 12 insertions, 10 deletions

diff --git a/drivers/net/wireless/iwlegacy/3945-mac.c b/drivers/net/wireless/iwlegacy/3945-mac.c
index 3630a41df50d..c353b5f19c8c 100644
--- a/drivers/net/wireless/iwlegacy/3945-mac.c
+++ b/drivers/net/wireless/iwlegacy/3945-mac.c
@@ -475,6 +475,7 @@ il3945_tx_skb(struct il_priv *il,
         dma_addr_t txcmd_phys;
         int txq_id = skb_get_queue_mapping(skb);
         u16 len, idx, hdr_len;
+        u16 firstlen, secondlen;
         u8 id;
         u8 unicast;
         u8 sta_id;
@@ -589,21 +590,22 @@ il3945_tx_skb(struct il_priv *il,
         len =
             sizeof(struct il3945_tx_cmd) + sizeof(struct il_cmd_header) +
             hdr_len;
-        len = (len + 3) & ~3;
+        firstlen = (len + 3) & ~3;
 
         /* Physical address of this Tx command's header (not MAC header!),
          * within command buffer array. */
         txcmd_phys =
-            pci_map_single(il->pci_dev, &out_cmd->hdr, len, PCI_DMA_TODEVICE);
+            pci_map_single(il->pci_dev, &out_cmd->hdr, firstlen,
+                           PCI_DMA_TODEVICE);
         if (unlikely(pci_dma_mapping_error(il->pci_dev, txcmd_phys)))
                 goto drop_unlock;
 
         /* Set up TFD's 2nd entry to point directly to remainder of skb,
          * if any (802.11 null frames have no payload). */
-        len = skb->len - hdr_len;
-        if (len) {
+        secondlen = skb->len - hdr_len;
+        if (secondlen > 0) {
                 phys_addr =
-                    pci_map_single(il->pci_dev, skb->data + hdr_len, len,
+                    pci_map_single(il->pci_dev, skb->data + hdr_len, secondlen,
                                    PCI_DMA_TODEVICE);
                 if (unlikely(pci_dma_mapping_error(il->pci_dev, phys_addr)))
                         goto drop_unlock;
@@ -611,12 +613,12 @@ il3945_tx_skb(struct il_priv *il,
 
         /* Add buffer containing Tx command and MAC(!) header to TFD's
          * first entry */
-        il->ops->txq_attach_buf_to_tfd(il, txq, txcmd_phys, len, 1, 0);
+        il->ops->txq_attach_buf_to_tfd(il, txq, txcmd_phys, firstlen, 1, 0);
         dma_unmap_addr_set(out_meta, mapping, txcmd_phys);
-        dma_unmap_len_set(out_meta, len, len);
-        if (len)
-                il->ops->txq_attach_buf_to_tfd(il, txq, phys_addr, len, 0,
-                                               U32_PAD(len));
+        dma_unmap_len_set(out_meta, len, firstlen);
+        if (secondlen > 0)
+                il->ops->txq_attach_buf_to_tfd(il, txq, phys_addr, secondlen, 0,
+                                               U32_PAD(secondlen));
 
         if (!ieee80211_has_morefrags(hdr->frame_control)) {
                 txq->need_update = 1;