ide: call ide_build_sglist() prior to ->dma_setup (v2)

* Re-map sg table if needed in ide_build_sglist().

* Move ide_build_sglist() call from ->dma_setup to its users.

* Un-export ide_build_sglist().

v2:
* Build fix for CONFIG_BLK_DEV_IDEDMA=n (noticed by Randy Dunlap).

There should be no functional changes caused by this patch.

Cc: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

9 files changed, 22 insertions, 41 deletions

diff --git a/drivers/ide/au1xxx-ide.c b/drivers/ide/au1xxx-ide.c
index 82f153810eb9..3fc3ced8192c 100644
--- a/drivers/ide/au1xxx-ide.c
+++ b/drivers/ide/au1xxx-ide.c
@@ -211,21 +211,16 @@ static void auide_set_dma_mode(ide_drive_t *drive, const u8 speed)
 #ifdef CONFIG_BLK_DEV_IDE_AU1XXX_MDMA2_DBDMA
 static int auide_build_dmatable(ide_drive_t *drive)
 {
-        int i, iswrite, count = 0;
         ide_hwif_t *hwif = drive->hwif;
         struct request *rq = hwif->rq;
         _auide_hwif *ahwif = &auide_hwif;
         struct scatterlist *sg;
+        int i = hwif->sg_nents, iswrite, count = 0;
 
         iswrite = (rq_data_dir(rq) == WRITE);
         /* Save for interrupt context */
         ahwif->drive = drive;
 
-        hwif->sg_nents = i = ide_build_sglist(drive, rq);
-
-        if (!i)
-                return 0;
-
         /* fill the descriptors */
         sg = hwif->sg_table;
         while (i && sg_dma_len(sg)) {
diff --git a/drivers/ide/icside.c b/drivers/ide/icside.c
index cf0522f937c1..78fc36f98d29 100644
--- a/drivers/ide/icside.c
+++ b/drivers/ide/icside.c
@@ -325,12 +325,6 @@ static int icside_dma_setup(ide_drive_t *drive)
          */
         BUG_ON(dma_channel_active(ec->dma));
 
-        hwif->sg_nents = ide_build_sglist(drive, rq);
-        if (hwif->sg_nents == 0) {
-                ide_map_sg(drive, rq);
-                return 1;
-        }
-
         /*
          * Ensure that we have the right interrupt routed.
          */
diff --git a/drivers/ide/ide-atapi.c b/drivers/ide/ide-atapi.c
index f72b5a675435..2b9ac2106674 100644
--- a/drivers/ide/ide-atapi.c
+++ b/drivers/ide/ide-atapi.c
@@ -631,18 +631,23 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive)
         struct ide_atapi_pc *pc;
         ide_hwif_t *hwif = drive->hwif;
         ide_expiry_t *expiry = NULL;
+        struct request *rq = hwif->rq;
         unsigned int timeout;
         u32 tf_flags;
         u16 bcount;
 
         if (dev_is_idecd(drive)) {
                 tf_flags = IDE_TFLAG_OUT_NSECT | IDE_TFLAG_OUT_LBAL;
-                bcount = ide_cd_get_xferlen(hwif->rq);
+                bcount = ide_cd_get_xferlen(rq);
                 expiry = ide_cd_expiry;
                 timeout = ATAPI_WAIT_PC;
 
-                if (drive->dma)
-                        drive->dma = !hwif->dma_ops->dma_setup(drive);
+                if (drive->dma) {
+                        if (ide_build_sglist(drive, rq))
+                                drive->dma = !hwif->dma_ops->dma_setup(drive);
+                        else
+                                drive->dma = 0;
+                }
         } else {
                 pc = drive->pc;
 
@@ -661,8 +666,12 @@ ide_startstop_t ide_issue_pc(ide_drive_t *drive)
                 }
 
                 if ((pc->flags & PC_FLAG_DMA_OK) &&
-                     (drive->dev_flags & IDE_DFLAG_USING_DMA))
-                        drive->dma = !hwif->dma_ops->dma_setup(drive);
+                     (drive->dev_flags & IDE_DFLAG_USING_DMA)) {
+                        if (ide_build_sglist(drive, rq))
+                                drive->dma = !hwif->dma_ops->dma_setup(drive);
+                        else
+                                drive->dma = 0;
+                }
 
                 if (!drive->dma)
                         pc->flags &= ~PC_FLAG_DMA_OK;
diff --git a/drivers/ide/ide-dma-sff.c b/drivers/ide/ide-dma-sff.c
index 123d393658af..22b3e751d19b 100644
--- a/drivers/ide/ide-dma-sff.c
+++ b/drivers/ide/ide-dma-sff.c
@@ -120,10 +120,6 @@ int ide_build_dmatable(ide_drive_t *drive, struct request *rq)
         struct scatterlist *sg;
         u8 is_trm290 = !!(hwif->host_flags & IDE_HFLAG_TRM290);
 
-        hwif->sg_nents = ide_build_sglist(drive, rq);
-        if (hwif->sg_nents == 0)
-                return 0;
-
         for_each_sg(hwif->sg_table, sg, hwif->sg_nents, i) {
                 u32 cur_addr, cur_len, xcount, bcount;
 
diff --git a/drivers/ide/ide-dma.c b/drivers/ide/ide-dma.c
index a878f4734f81..12c11b71402e 100644
--- a/drivers/ide/ide-dma.c
+++ b/drivers/ide/ide-dma.c
@@ -138,14 +138,15 @@ int ide_build_sglist(ide_drive_t *drive, struct request *rq)
                 hwif->sg_dma_direction = DMA_TO_DEVICE;
 
         i = dma_map_sg(hwif->dev, sg, hwif->sg_nents, hwif->sg_dma_direction);
-        if (i) {
+        if (i == 0)
+                ide_map_sg(drive, rq);
+        else {
                 hwif->orig_sg_nents = hwif->sg_nents;
                 hwif->sg_nents = i;
         }
 
         return i;
 }
-EXPORT_SYMBOL_GPL(ide_build_sglist);
 
 /**
  *      ide_destroy_dmatable    -       clean up DMA mapping
diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index 15bbfc1dcd28..925fb9241893 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -103,6 +103,7 @@ ide_startstop_t do_rw_taskfile (ide_drive_t *drive, ide_task_t *task)
                 return ide_started;
         default:
                 if ((drive->dev_flags & IDE_DFLAG_USING_DMA) == 0 ||
+                    ide_build_sglist(drive, hwif->rq) == 0 ||
                     dma_ops->dma_setup(drive))
                         return ide_stopped;
                 dma_ops->dma_exec_cmd(drive, tf->command);
diff --git a/drivers/ide/pmac.c b/drivers/ide/pmac.c
index 74625e821a43..904fb54668e8 100644
--- a/drivers/ide/pmac.c
+++ b/drivers/ide/pmac.c
@@ -1429,10 +1429,10 @@ pmac_ide_build_dmatable(ide_drive_t *drive, struct request *rq)
         pmac_ide_hwif_t *pmif =
                 (pmac_ide_hwif_t *)dev_get_drvdata(hwif->gendev.parent);
         struct dbdma_cmd *table;
-        int i, count = 0;
         volatile struct dbdma_regs __iomem *dma = pmif->dma_regs;
         struct scatterlist *sg;
         int wr = (rq_data_dir(rq) == WRITE);
+        int i = hwif->sg_nents, count = 0;
 
         /* DMA table is already aligned */
         table = (struct dbdma_cmd *) pmif->dma_table_cpu;
@@ -1442,11 +1442,6 @@ pmac_ide_build_dmatable(ide_drive_t *drive, struct request *rq)
         while (readl(&dma->status) & RUN)
                 udelay(1);
 
-        hwif->sg_nents = i = ide_build_sglist(drive, rq);
-
-        if (!i)
-                return 0;
-
         /* Build DBDMA commands list */
         sg = hwif->sg_table;
         while (i && sg_dma_len(sg)) {
diff --git a/drivers/ide/sgiioc4.c b/drivers/ide/sgiioc4.c
index 1cffe70f385d..ab9433a7ad1f 100644
--- a/drivers/ide/sgiioc4.c
+++ b/drivers/ide/sgiioc4.c
@@ -429,15 +429,9 @@ sgiioc4_build_dma_table(ide_drive_t * drive, struct request *rq, int ddir)
 {
         ide_hwif_t *hwif = drive->hwif;
         unsigned int *table = hwif->dmatable_cpu;
-        unsigned int count = 0, i = 1;
-        struct scatterlist *sg;
+        unsigned int count = 0, i = hwif->sg_nents;
+        struct scatterlist *sg = hwif->sg_table;
 
-        hwif->sg_nents = i = ide_build_sglist(drive, rq);
-
-        if (!i)
-                return 0;       /* sglist of length Zero */
-
-        sg = hwif->sg_table;
         while (i && sg_dma_len(sg)) {
                 dma_addr_t cur_addr;
                 int cur_len;
diff --git a/drivers/ide/tx4939ide.c b/drivers/ide/tx4939ide.c
index f0033eb2e885..ee86688d8461 100644
--- a/drivers/ide/tx4939ide.c
+++ b/drivers/ide/tx4939ide.c
@@ -240,10 +240,6 @@ static int tx4939ide_build_dmatable(ide_drive_t *drive, struct request *rq)
         int i;
         struct scatterlist *sg;
 
-        hwif->sg_nents = ide_build_sglist(drive, rq);
-        if (hwif->sg_nents == 0)
-                return 0;
-
         for_each_sg(hwif->sg_table, sg, hwif->sg_nents, i) {
                 u32 cur_addr, cur_len, bcount;