[SCSI] Legacy MegaRAID: Fix READ CAPACITY

Some Legacy megaraid cards can't actually cope with the scatter/gather
version of the READ CAPACITY command (which is what we now send them
since altering all SCSI internal I/O to go via the block layer).  Fix
this (and a few other broken megaraid driver assumptions) by sending
the non-sg version of the command if the sg list only has a single
element.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index 6f308eb..61a6fd8 100644 (file)
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -621,8 +621,6 @@ mega_build_cmd(adapter_t *adapter, Scsi_Cmnd *cmd, int *busy)
        if(islogical) {
                switch (cmd->cmnd[0]) {
                case TEST_UNIT_READY:
-                       memset(cmd->request_buffer, 0, cmd->request_bufflen);
-
 #if MEGA_HAVE_CLUSTERING
                        /*
                         * Do we support clustering and is the support enabled
@@ -652,11 +650,28 @@ mega_build_cmd(adapter_t *adapter, Scsi_Cmnd *cmd, int *busy)
                        return NULL;
 #endif
 
-               case MODE_SENSE:
+               case MODE_SENSE: {
+                       char *buf;
+
+                       if (cmd->use_sg) {
+                               struct scatterlist *sg;
+
+                               sg = (struct scatterlist *)cmd->request_buffer;
+                               buf = kmap_atomic(sg->page, KM_IRQ0) +
+                                       sg->offset;
+                       } else
+                               buf = cmd->request_buffer;
                        memset(cmd->request_buffer, 0, cmd->cmnd[4]);
+                       if (cmd->use_sg) {
+                               struct scatterlist *sg;
+
+                               sg = (struct scatterlist *)cmd->request_buffer;
+                               kunmap_atomic(buf - sg->offset, KM_IRQ0);
+                       }
                        cmd->result = (DID_OK << 16);
                        cmd->scsi_done(cmd);
                        return NULL;
+               }
 
                case READ_CAPACITY:
                case INQUIRY:
@@ -1685,14 +1700,23 @@ mega_rundoneq (adapter_t *adapter)
 static void
 mega_free_scb(adapter_t *adapter, scb_t *scb)
 {
+       unsigned long length;
+
        switch( scb->dma_type ) {
 
        case MEGA_DMA_TYPE_NONE:
                break;
 
        case MEGA_BULK_DATA:
+               if (scb->cmd->use_sg == 0)
+                       length = scb->cmd->request_bufflen;
+               else {
+                       struct scatterlist *sgl =
+                               (struct scatterlist *)scb->cmd->request_buffer;
+                       length = sgl->length;
+               }
                pci_unmap_page(adapter->dev, scb->dma_h_bulkdata,
-                       scb->cmd->request_bufflen, scb->dma_direction);
+                              length, scb->dma_direction);
                break;
 
        case MEGA_SGLIST:
@@ -1741,6 +1765,7 @@ mega_build_sglist(adapter_t *adapter, scb_t *scb, u32 *buf, u32 *len)
        struct scatterlist      *sgl;
        struct page     *page;
        unsigned long   offset;
+       unsigned int    length;
        Scsi_Cmnd       *cmd;
        int     sgcnt;
        int     idx;
@@ -1748,14 +1773,23 @@ mega_build_sglist(adapter_t *adapter, scb_t *scb, u32 *buf, u32 *len)
        cmd = scb->cmd;
 
        /* Scatter-gather not used */
-       if( !cmd->use_sg ) {
-
-               page = virt_to_page(cmd->request_buffer);
-               offset = offset_in_page(cmd->request_buffer);
+       if( cmd->use_sg == 0 || (cmd->use_sg == 1 && 
+                                !adapter->has_64bit_addr)) {
+
+               if (cmd->use_sg == 0) {
+                       page = virt_to_page(cmd->request_buffer);
+                       offset = offset_in_page(cmd->request_buffer);
+                       length = cmd->request_bufflen;
+               } else {
+                       sgl = (struct scatterlist *)cmd->request_buffer;
+                       page = sgl->page;
+                       offset = sgl->offset;
+                       length = sgl->length;
+               }
 
                scb->dma_h_bulkdata = pci_map_page(adapter->dev,
                                                  page, offset,
-                                                 cmd->request_bufflen,
+                                                 length,
                                                  scb->dma_direction);
                scb->dma_type = MEGA_BULK_DATA;
 
@@ -1765,14 +1799,14 @@ mega_build_sglist(adapter_t *adapter, scb_t *scb, u32 *buf, u32 *len)
                 */
                if( adapter->has_64bit_addr ) {
                        scb->sgl64[0].address = scb->dma_h_bulkdata;
-                       scb->sgl64[0].length = cmd->request_bufflen;
+                       scb->sgl64[0].length = length;
                        *buf = (u32)scb->sgl_dma_addr;
-                       *len = (u32)cmd->request_bufflen;
+                       *len = (u32)length;
                        return 1;
                }
                else {
                        *buf = (u32)scb->dma_h_bulkdata;
-                       *len = (u32)cmd->request_bufflen;
+                       *len = (u32)length;
                }
                return 0;
        }
@@ -1791,27 +1825,23 @@ mega_build_sglist(adapter_t *adapter, scb_t *scb, u32 *buf, u32 *len)
 
        if( sgcnt > adapter->sglen ) BUG();
 
+       *len = 0;
+
        for( idx = 0; idx < sgcnt; idx++, sgl++ ) {
 
                if( adapter->has_64bit_addr ) {
                        scb->sgl64[idx].address = sg_dma_address(sgl);
-                       scb->sgl64[idx].length = sg_dma_len(sgl);
+                       *len += scb->sgl64[idx].length = sg_dma_len(sgl);
                }
                else {
                        scb->sgl[idx].address = sg_dma_address(sgl);
-                       scb->sgl[idx].length = sg_dma_len(sgl);
+                       *len += scb->sgl[idx].length = sg_dma_len(sgl);
                }
        }
 
        /* Reset pointer and length fields */
        *buf = scb->sgl_dma_addr;
 
-       /*
-        * For passthru command, dataxferlen must be set, even for commands
-        * with a sg list
-        */
-       *len = (u32)cmd->request_bufflen;
-
        /* Return count of SG requests */
        return sgcnt;
 }