mtd: maps/physmap: fix oops in suspend/resume/shutdown ops

# reboot
...
[   42.351266] Flash device refused suspend due to active operation (state 0)
[   42.358195] Unable to handle kernel NULL pointer dereference at virtual address 00000078
[   42.360060] pgd = c7d9c000
[   42.362769] [00000078] *pgd=a7d8d031, *pte=00000000, *ppte=00000000
[   42.372902] Internal error: Oops: 17 [#1]
[   42.376911] Modules linked in:
[   42.379980] CPU: 0    Not tainted  (2.6.25-rc2-10642-ge8f2594-dirty #73)
[   42.380000] PC is at physmap_flash_shutdown+0x28/0x54
...
[   42.380000] Backtrace:
[   42.380000] [<c0130c1c>] (physmap_flash_shutdown+0x0/0x54) from [<c01207c0>] (platform_drv_shutdown+0x20/0x24)
[   42.380000]  r5:28121969 r4:c0229e08
[   42.380000] [<c01207a0>] (platform_drv_shutdown+0x0/0x24) from [<c011cd40>] (device_shutdown+0x60/0x88)
[   42.380000] [<c011cce0>] (device_shutdown+0x0/0x88) from [<c003e8a4>] (kernel_restart_prepare+0x2c/0x3c)
[   42.380000]  r4:00000000
[   42.380000] [<c003e878>] (kernel_restart_prepare+0x0/0x3c) from [<c003ea00>] (kernel_restart+0x14/0x48)
[   42.380000] [<c003e9ec>] (kernel_restart+0x0/0x48) from [<c003fdc0>] (sys_reboot+0xe8/0x1f8)
[   42.380000]  r4:01234567
[   42.380000] [<c003fcd8>] (sys_reboot+0x0/0x1f8) from [<c001aa00>] (ret_fast_syscall+0x0/0x2c)
[   42.380000]  r7:00000058 r6:00000004 r5:00000001 r4:00000000
[   42.380000] Code: 0a000009 e7953004 e1a00003 e1a0e00f (e593f078)
[   42.650051] ---[ end trace 6d6c26a0fc3141de ]---
Segmentation fault
INIT: no more processes left in this runlevel

While looping for mtd[i]s, we should stop at the mtd[i] == NULL.

This patch also removes unnecessary "if (info)" checks:
suspend/resume/shutdown ops are executed only if probe() is succeeded, so info
is guaranteed to be !NULL.

Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Cc: David Brownell <david-b@pacbell.net>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 8 deletions

diff --git a/drivers/mtd/maps/physmap.c b/drivers/mtd/maps/physmap.c
index f00e04efbe28..bc4649a17b9d 100644
--- a/drivers/mtd/maps/physmap.c
+++ b/drivers/mtd/maps/physmap.c
@@ -202,9 +202,8 @@ static int physmap_flash_suspend(struct platform_device *dev, pm_message_t state
         int ret = 0;
         int i;
 
-        if (info)
-                for (i = 0; i < MAX_RESOURCES; i++)
-                        ret |= info->mtd[i]->suspend(info->mtd[i]);
+        for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
+                ret |= info->mtd[i]->suspend(info->mtd[i]);
 
         return ret;
 }
@@ -214,9 +213,9 @@ static int physmap_flash_resume(struct platform_device *dev)
         struct physmap_flash_info *info = platform_get_drvdata(dev);
         int i;
 
-        if (info)
-                for (i = 0; i < MAX_RESOURCES; i++)
-                        info->mtd[i]->resume(info->mtd[i]);
+        for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
+                info->mtd[i]->resume(info->mtd[i]);
+
         return 0;
 }
 
@@ -225,8 +224,8 @@ static void physmap_flash_shutdown(struct platform_device *dev)
         struct physmap_flash_info *info = platform_get_drvdata(dev);
         int i;
 
-        for (i = 0; i < MAX_RESOURCES; i++)
-                if (info && info->mtd[i]->suspend(info->mtd[i]) == 0)
+        for (i = 0; i < MAX_RESOURCES && info->mtd[i]; i++)
+                if (info->mtd[i]->suspend(info->mtd[i]) == 0)
                         info->mtd[i]->resume(info->mtd[i]);
 }
 #else