mmc: hsmmc: Fix NULL pointer dereference on unload when booted with device tree

When booting with device tree, we don't have any pdata, and will get the following when trying to unload omap_hsmmc:

Unable to handle kernel NULL pointer dereference at virtual address 00000044
pgd = edafc000
*pgd=adbbd831, *pte=00000000, *ppte=00000000
SMP ARM
Modules linked in: omap_hsmmc(-) omap_serial pinctrl_single
CPU: 1    Not tainted  (3.7.0-rc4-00044-g8ca5f6a-dirty #245)
PC is at omap_hsmmc_gpio_free+0x8/0x3c [omap_hsmmc]
LR is at omap_hsmmc_remove+0xf0/0x174 [omap_hsmmc]
   psr: 60000113

sp : ee887ef0 ip : 00000040 fp : be83cc14
r10: 00000000 r9 : ee886000 r8 : c0014348
r7 : ee886000 r6 : eea1d010 r5 : eea1d000 r4 : 00000000 r3 : 00000000 r2 : 00000000 r1 : 00000000 r0 : 00000000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 10c53c7d Table: adafc04a DAC: 00000015 Process rmmod (pid: 1758, stack limit = 0xee886240)

Stack: (0xee887ef0 to 0xee888000)

7ee0: edbe1400 bf01250c eea1d018 eea1d010
7f00: bf0138ac c0331c64 ee886000 c0330528 eea1d010 bf0138ac eea1d044 c033063c 7f20: 00000000 bf0138ac c079f250 c032f618 00000000 00000880 bf013980 c00a42d0 7f40: c02ce9b4 70616d6f 6d73685f 0000636d c04ef560 c0014348 ee886000 ee886000 7f60: eeb21600 00000001 c00142a0 60000110 00000000 ef000000 be83cc14 00095f40 7f80: bf013980 00000880 ee887f8c 00000000 00000081 be83cba8 00000000 00000000 7fa0: 00000081 c00141a0 be83cba8 00000000 be83cba8 00000880 00000880 be83cba8 7fc0: be83cba8 00000000 00000000 00000081 00000000 00000000 b6f42000 be83cc14 7fe0: 00000000 be83cba0 000091cc b6eb48bc 60000110 be83cba8 aaaaaaaa aabaaaaa (omap_hsmmc_remove+0xf0/0x174 [omap_hsmmc]) (platform_drv_remove+0x1c/0x24) (__device_release_driver+0x90/0xf0)
(driver_detach+0xb4/0xb8)
(bus_remove_driver+0x88/0xdc)
(sys_delete_module+0x144/0x220)
(ret_fast_syscall+0x0/0x3c)

Code: eaffffbe c073a1f0 e92d4010 e1a04000 (e5900044)

---

This is against v3.7-rc4, would be nice to get in during the -rc cycle.

@@ -377,6 +377,9 @@ static int omap_hsmmc_gpio_init(struct omap_mmc_platform_data *pdata)
 {
 	int ret;
 
+	if (!pdata)
+		return 0;
+
 	if (gpio_is_valid(pdata->slots[0].switch_pin)) {
 		if (pdata->slots[0].cover)
 			pdata->slots[0].get_cover_state =

@@ -418,6 +421,9 @@ err_free_sp:
 
 static void omap_hsmmc_gpio_free(struct omap_mmc_platform_data *pdata)
 {
+	if (!pdata)
+		return;
+
 	if (gpio_is_valid(pdata->slots[0].gpio_wp))
 		gpio_free(pdata->slots[0].gpio_wp);
 	if (gpio_is_valid(pdata->slots[0].switch_pin))

<snip>

Hi Tony,

Got fixed by below commit, merged in rc5

http://git.kernel.org/?p=linux/kernel/git/cjb/mmc.git;a=commit;h=9ea28ecbeb090159a3383ff60b29dee00c489774

OK thanks!

Tony