media: atomisp: isp_mmu: don't use kmem_cache

Instead of using it only if system memory is below 2GB,
don't use it at all. The problem is that the code there is not
compatible anymore with modern Kernels:

[  179.552797] virt_to_cache: Object is not a Slab page!
[  179.552821] WARNING: CPU: 0 PID: 1414 at mm/slab.h:475 cache_from_obj+0xab/0xf0
[  179.552824] Modules linked in: ccm(E) nft_fib_inet(E) nft_fib_ipv4(E) nft_fib_ipv6(E) nft_fib(E) nft_reject_inet(E) nf_reject_ipv4(E) nf_reject_ipv6(E) nft_reject(E) nft_ct(E) nft_chain_nat(E) ip6table_nat(E) ip6table_mangle(E) ip6table_raw(E) ip6table_security(E) iptable_nat(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) libcrc32c(E) nf_defrag_ipv4(E) iptable_mangle(E) iptable_raw(E) iptable_security(E) ip_set(E) nf_tables(E) nfnetlink(E) ip6table_filter(E) ip6_tables(E) iptable_filter(E) cmac(E) bnep(E) sunrpc(E) vfat(E) fat(E) mei_hdcp(E) snd_soc_sst_cht_bsw_rt5645(E) gpio_keys(E) intel_rapl_msr(E) intel_powerclamp(E) coretemp(E) kvm_intel(E) kvm(E) irqbypass(E) crct10dif_pclmul(E) crc32_pclmul(E) asus_nb_wmi(E) ath10k_pci(E) ghash_clmulni_intel(E) ath10k_core(E) intel_cstate(E) wdat_wdt(E) pcspkr(E) ath(E) mac80211(E) intel_chtdc_ti_pwrbtn(E) joydev(E) btusb(E) btrtl(E) btbcm(E) btintel(E) libarc4(E) bluetooth(E) cfg80211(E) ecdh_generic(E) ecc(E) mei_txe(E) mei(E) lpc_ich(E)
[  179.552887]  hid_sensor_accel_3d(E) hid_sensor_gyro_3d(E) hid_sensor_trigger(E) hid_sensor_iio_common(E) industrialio_triggered_buffer(E) kfifo_buf(E) industrialio(E) atomisp_ov2680(CE) snd_soc_rt5645(E) snd_intel_sst_acpi(E) snd_soc_rl6231(E) snd_intel_sst_core(E) snd_soc_sst_atom_hifi2_platform(E) intel_hid(E) snd_soc_acpi_intel_match(E) spi_pxa2xx_platform(E) snd_soc_acpi(E) snd_soc_core(E) snd_compress(E) dw_dmac(E) snd_hdmi_lpe_audio(E) int3400_thermal(E) int3406_thermal(E) snd_seq(E) acpi_thermal_rel(E) int3403_thermal(E) atomisp(CE) snd_seq_device(E) snd_pcm(E) intel_int0002_vgpio(E) soc_button_array(E) acpi_pad(E) intel_xhci_usb_role_switch(E) snd_timer(E) videobuf_vmalloc(E) videobuf_core(E) snd(E) atomisp_gmin_platform(CE) soundcore(E) videodev(E) processor_thermal_device(E) intel_soc_dts_iosf(E) mc(E) intel_rapl_common(E) int340x_thermal_zone(E) ip_tables(E) hid_sensor_hub(E) intel_ishtp_loader(E) intel_ishtp_hid(E) mmc_block(E) hid_multitouch(E) crc32c_intel(E) i915(E)
[  179.552936]  hid_asus(E) i2c_algo_bit(E) asus_wmi(E) sparse_keymap(E) rfkill(E) drm_kms_helper(E) intel_ish_ipc(E) intel_ishtp(E) drm(E) wmi(E) video(E) i2c_hid(E) pwm_lpss_platform(E) pwm_lpss(E) sdhci_acpi(E) sdhci(E) mmc_core(E) fuse(E)
[  179.552961] CPU: 0 PID: 1414 Comm: v4l2grab Tainted: G         C  EL    5.7.0-rc2+ #42
[  179.552963] Hardware name: ASUSTeK COMPUTER INC. T101HA/T101HA, BIOS T101HA.306 04/23/2019
[  179.552968] RIP: 0010:cache_from_obj+0xab/0xf0
[  179.552973] Code: c3 31 c0 80 3d 1c 38 72 01 00 75 f0 48 c7 c6 20 12 06 9f 48 c7 c7 10 f3 37 9f 48 89 04 24 c6 05 01 38 72 01 01 e8 2c 99 e0 ff <0f> 0b 48 8b 04 24 eb ca 48 8b 57 58 48 8b 48 58 48 c7 c6 30 12 06
[  179.552976] RSP: 0018:ffffaf1f00c3fae0 EFLAGS: 00010282
[  179.552980] RAX: 0000000000000029 RBX: 00000000000003ff RCX: 0000000000000007
[  179.552983] RDX: 00000000fffffff8 RSI: 0000000000000082 RDI: ffff9cb6bbc19cc0
[  179.552985] RBP: 0000000001000000 R08: 00000000000005a4 R09: ffffaf1f00c3f970
[  179.552988] R10: 0000000000000005 R11: 0000000000000000 R12: ffffffffc0713da0
[  179.552991] R13: ffff9cb5a7bb1000 R14: 0000000001000000 R15: ffff9cb5a7bb1000
[  179.552995] FS:  0000000000000000(0000) GS:ffff9cb6bbc00000(0000) knlGS:0000000000000000
[  179.552998] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  179.553000] CR2: 00007fe780544400 CR3: 000000002480a000 CR4: 00000000001006f0
[  179.553003] Call Trace:
[  179.553015]  kmem_cache_free+0x19/0x180
[  179.553070]  mmu_l2_unmap+0xd1/0x100 [atomisp]
[  179.553113]  ? __bo_merge+0x8f/0xa0 [atomisp]
[  179.553155]  mmu_unmap+0xd0/0xf0 [atomisp]
[  179.553198]  hmm_bo_unbind+0x62/0xb0 [atomisp]
[  179.553240]  hmm_free+0x44/0x60 [atomisp]
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

drivers/staging/media/atomisp/include/mmu/isp_mmu.h

@@ -113,7 +113,6 @@ struct isp_mmu {
 	phys_addr_t base_address;
 
 	struct mutex pt_mutex;
-	struct kmem_cache *tbl_cache;
 };
 
 /* flags for PDE and PTE */

drivers/staging/media/atomisp/pci/mmu/isp_mmu.c

@@ -99,15 +99,8 @@ static phys_addr_t alloc_page_table(struct isp_mmu *mmu)
 	phys_addr_t page;
 	void *virt;
 
-	/*page table lock may needed here*/
-	/*
-	 * The slab allocator(kmem_cache and kmalloc family) doesn't handle
-	 * GFP_DMA32 flag, so we have to use buddy allocator.
-	 */
-	if (totalram_pages() > (unsigned long)NR_PAGES_2GB)
-		virt = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
-	else
-		virt = kmem_cache_zalloc(mmu->tbl_cache, GFP_KERNEL);
+	virt = (void *)__get_free_page(GFP_KERNEL | GFP_DMA32);
+
 	if (!virt)
 		return (phys_addr_t)NULL_PAGE;
 
@@ -142,10 +135,7 @@ static void free_page_table(struct isp_mmu *mmu, phys_addr_t page)
 	set_memory_wb((unsigned long)virt, 1);
 #endif
 
-	if (totalram_pages() > (unsigned long)NR_PAGES_2GB)
-		free_page((unsigned long)virt);
-	else
-		kmem_cache_free(mmu->tbl_cache, virt);
+	free_page((unsigned long)virt);
 }
 
 static void mmu_remap_error(struct isp_mmu *mmu,
@@ -541,12 +531,6 @@ int isp_mmu_init(struct isp_mmu *mmu, struct isp_mmu_client *driver)
 
 	mutex_init(&mmu->pt_mutex);
 
-	mmu->tbl_cache = kmem_cache_create("iopte_cache", ISP_PAGE_SIZE,
-					   ISP_PAGE_SIZE, SLAB_HWCACHE_ALIGN,
-					   NULL);
-	if (!mmu->tbl_cache)
-		return -ENOMEM;
-
 	return 0;
 }
 
@@ -579,6 +563,4 @@ void isp_mmu_exit(struct isp_mmu *mmu)
 	}
 
 	free_page_table(mmu, l1_pt);
-
-	kmem_cache_destroy(mmu->tbl_cache);
 }