ide: Fix pointer arithmetic in hpt3xx driver code (3rd try)

git commit 74811f355f4f69a187fa74892dcf2a684b84ce99 causes crash at
module load (or boot) time on my machine with a hpt374 controller.
The reason for this is that for initializing second controller which sets
(hwif->dev == host->dev[1]) to true (1), adds 1 to a void ptr, which
advances it by one byte instead of advancing it by sizeof(hpt_info) bytes.
Because of this, all initialization functions get corrupted data in info
variable which causes a crash at boot time.

This patch fixes that and makes my machine boot again.

The card itself is a HPT374 raid conroller: Here is the lspci -v output:
03:06.0 RAID bus controller: HighPoint Technologies, Inc. HPT374 (rev
07)
        Subsystem: HighPoint Technologies, Inc. Unknown device 0001
        Flags: bus master, 66MHz, medium devsel, latency 120, IRQ 28
        I/O ports at 8000 [size=8]
        I/O ports at 7800 [size=4]
        I/O ports at 7400 [size=8]
        I/O ports at 7000 [size=4]
        I/O ports at 6800 [size=256]
        Expansion ROM at fe8e0000 [disabled] [size=128K]
        Capabilities: [60] Power Management version 2

03:06.1 RAID bus controller: HighPoint Technologies, Inc. HPT374 (rev
07)
        Subsystem: HighPoint Technologies, Inc. Unknown device 0001
        Flags: bus master, 66MHz, medium devsel, latency 120, IRQ 28
        I/O ports at 9800 [size=8]
        I/O ports at 9400 [size=4]
        I/O ports at 9000 [size=8]
        I/O ports at 8800 [size=4]
        I/O ports at 8400 [size=256]
        Capabilities: [60] Power Management version 2

Signed-off-by: Masoud Sharbiani <masouds@google.com>
Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
[bart: use dev_get_drvdata() per Sergei's suggestion]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 15 insertions, 16 deletions

diff --git a/drivers/ide/pci/hpt366.c b/drivers/ide/pci/hpt366.c
index eb107eef0dbc..c37ab1743819 100644
--- a/drivers/ide/pci/hpt366.c
+++ b/drivers/ide/pci/hpt366.c
@@ -613,6 +613,14 @@ static int check_in_drive_list(ide_drive_t *drive, const char **list)
         return 0;
 }
 
+static struct hpt_info *hpt3xx_get_info(struct device *dev)
+{
+        struct ide_host *host   = dev_get_drvdata(dev);
+        struct hpt_info *info   = (struct hpt_info *)host->host_priv;
+
+        return dev == host->dev[1] ? info + 1 : info;
+}
+
 /*
  * The Marvell bridge chips used on the HighPoint SATA cards do not seem
  * to support the UltraDMA modes 1, 2, and 3 as well as any MWDMA modes...
@@ -621,9 +629,7 @@ static int check_in_drive_list(ide_drive_t *drive, const char **list)
 static u8 hpt3xx_udma_filter(ide_drive_t *drive)
 {
         ide_hwif_t *hwif        = HWIF(drive);
-        struct pci_dev *dev     = to_pci_dev(hwif->dev);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (hwif->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(hwif->dev);
         u8 mask                 = hwif->ultra_mask;
 
         switch (info->chip_type) {
@@ -662,9 +668,7 @@ static u8 hpt3xx_udma_filter(ide_drive_t *drive)
 static u8 hpt3xx_mdma_filter(ide_drive_t *drive)
 {
         ide_hwif_t *hwif        = HWIF(drive);
-        struct pci_dev *dev     = to_pci_dev(hwif->dev);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (hwif->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(hwif->dev);
 
         switch (info->chip_type) {
         case HPT372 :
@@ -700,8 +704,7 @@ static void hpt3xx_set_mode(ide_drive_t *drive, const u8 speed)
 {
         ide_hwif_t *hwif        = drive->hwif;
         struct pci_dev *dev     = to_pci_dev(hwif->dev);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (hwif->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(hwif->dev);
         struct hpt_timings *t   = info->timings;
         u8  itr_addr            = 0x40 + (drive->dn * 4);
         u32 old_itr             = 0;
@@ -744,8 +747,7 @@ static void hpt3xx_maskproc(ide_drive_t *drive, int mask)
 {
         ide_hwif_t *hwif        = HWIF(drive);
         struct pci_dev  *dev    = to_pci_dev(hwif->dev);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (hwif->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(hwif->dev);
 
         if (drive->quirk_list) {
                 if (info->chip_type >= HPT370) {
@@ -973,8 +975,7 @@ static int __devinit hpt37x_calibrate_dpll(struct pci_dev *dev, u16 f_low, u16 f
 static unsigned int __devinit init_chipset_hpt366(struct pci_dev *dev)
 {
         unsigned long io_base   = pci_resource_start(dev, 4);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (&dev->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(&dev->dev);
         const char *name        = DRV_NAME;
         u8 pci_clk,  dpll_clk   = 0;    /* PCI and DPLL clock in MHz */
         u8 chip_type;
@@ -1217,8 +1218,7 @@ static unsigned int __devinit init_chipset_hpt366(struct pci_dev *dev)
 static u8 hpt3xx_cable_detect(ide_hwif_t *hwif)
 {
         struct pci_dev  *dev    = to_pci_dev(hwif->dev);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (hwif->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(hwif->dev);
         u8 chip_type            = info->chip_type;
         u8 scr1 = 0, ata66      = hwif->channel ? 0x01 : 0x02;
 
@@ -1262,8 +1262,7 @@ static u8 hpt3xx_cable_detect(ide_hwif_t *hwif)
 static void __devinit init_hwif_hpt366(ide_hwif_t *hwif)
 {
         struct pci_dev *dev     = to_pci_dev(hwif->dev);
-        struct ide_host *host   = pci_get_drvdata(dev);
-        struct hpt_info *info   = host->host_priv + (hwif->dev == host->dev[1]);
+        struct hpt_info *info   = hpt3xx_get_info(hwif->dev);
         int serialize           = HPT_SERIALIZE_IO;
         u8  chip_type           = info->chip_type;
         u8  new_mcr, old_mcr    = 0;