From a18037b27ebd23edf5edad8bc6ceb72e4bb5716d Mon Sep 17 00:00:00 2001
From: Mitchel Humpherys <mitchelh@codeaurora.org>
Date: Wed, 30 Jul 2014 18:58:13 +0100
Subject: [PATCH] iommu/arm-smmu: avoid calling request_irq in atomic context

request_irq shouldn't be called from atomic context since it might
sleep, but we're calling it with a spinlock held, resulting in:

    [    9.172202] BUG: sleeping function called from invalid context at kernel/mm/slub.c:926
    [    9.182989] in_atomic(): 1, irqs_disabled(): 128, pid: 1, name: swapper/0
    [    9.189762] CPU: 1 PID: 1 Comm: swapper/0 Tainted: G        W    3.10.40-gbc1b510b-38437-g55831d3bd9-dirty #97
    [    9.199757] [<c020c448>] (unwind_backtrace+0x0/0x11c) from [<c02097d0>] (show_stack+0x10/0x14)
    [    9.208346] [<c02097d0>] (show_stack+0x10/0x14) from [<c0301d74>] (kmem_cache_alloc_trace+0x3c/0x210)
    [    9.217543] [<c0301d74>] (kmem_cache_alloc_trace+0x3c/0x210) from [<c0276a48>] (request_threaded_irq+0x88/0x11c)
    [    9.227702] [<c0276a48>] (request_threaded_irq+0x88/0x11c) from [<c0931ca4>] (arm_smmu_attach_dev+0x188/0x858)
    [    9.237686] [<c0931ca4>] (arm_smmu_attach_dev+0x188/0x858) from [<c0212cd8>] (arm_iommu_attach_device+0x18/0xd0)
    [    9.247837] [<c0212cd8>] (arm_iommu_attach_device+0x18/0xd0) from [<c093314c>] (arm_smmu_test_probe+0x68/0xd4)
    [    9.257823] [<c093314c>] (arm_smmu_test_probe+0x68/0xd4) from [<c05aadd0>] (driver_probe_device+0x12c/0x330)
    [    9.267629] [<c05aadd0>] (driver_probe_device+0x12c/0x330) from [<c05ab080>] (__driver_attach+0x68/0x8c)
    [    9.277090] [<c05ab080>] (__driver_attach+0x68/0x8c) from [<c05a92d4>] (bus_for_each_dev+0x70/0x84)
    [    9.286118] [<c05a92d4>] (bus_for_each_dev+0x70/0x84) from [<c05aa3b0>] (bus_add_driver+0x100/0x244)
    [    9.295233] [<c05aa3b0>] (bus_add_driver+0x100/0x244) from [<c05ab5d0>] (driver_register+0x9c/0x124)
    [    9.304347] [<c05ab5d0>] (driver_register+0x9c/0x124) from [<c0933088>] (arm_smmu_test_init+0x14/0x38)
    [    9.313635] [<c0933088>] (arm_smmu_test_init+0x14/0x38) from [<c0200618>] (do_one_initcall+0xb8/0x160)
    [    9.322926] [<c0200618>] (do_one_initcall+0xb8/0x160) from [<c1200b7c>] (kernel_init_freeable+0x108/0x1cc)
    [    9.332564] [<c1200b7c>] (kernel_init_freeable+0x108/0x1cc) from [<c0b924b0>] (kernel_init+0xc/0xe4)
    [    9.341675] [<c0b924b0>] (kernel_init+0xc/0xe4) from [<c0205e38>] (ret_from_fork+0x14/0x3c)

Fix this by moving the request_irq out of the critical section. This
should be okay since smmu_domain->smmu is still being protected by the
critical section. Also, we still don't program the Stream Match Register
until after registering our interrupt handler so we shouldn't be missing
any interrupts.

Cc: <stable@vger.kernel.org>
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
[will: code cleanup and fixed request_irq token parameter]
Signed-off-by: Will Deacon <will.deacon@arm.com>
---
Reading git-format-patch failed