Currently vb2 core acquires mmap_sem just around call to
__qbuf_userptr(). However since commit f035eb4e (videobuf2: fix
lockdep warning) it isn't necessary to acquire it so early as we no
longer have to drop queue mutex before acquiring mmap_sem. So push
acquisition of mmap_sem down into .get_userptr memop so that the
semaphore is acquired for a shorter time and it is clearer what it is
needed for.

Note that we also need mmap_sem in .put_userptr memop since that ends up
calling vb2_put_vma() which calls vma->vm_ops->close() which should be
called with mmap_sem held. However we didn't hold mmap_sem in some code
paths anyway (e.g. when called via vb2_ioctl_reqbufs() ->
__vb2_queue_free() -> vb2_dma_sg_put_userptr()) and getting mmap_sem in
put_userptr() introduces a lock inversion with queue->mmap_lock in the
above mentioned call path.

Luckily this whole locking mess will get resolved once we convert
videobuf2 core to the new mm helper which avoids the need for mmap_sem
in .put_userptr memop altogether.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

This reverts commit 48b25a3a.

That commit caused two regressions. The first is a BUG:

Jun 14 18:42:15 test-media kernel: [  115.972299] BUG: unable to handle kernel NULL pointer dereference at 0000000000000100
Jun 14 18:42:15 test-media kernel: [  115.972307] IP: [<ffffffff810d5cd0>] __lock_acquire+0x2f0/0x2070
Jun 14 18:42:15 test-media kernel: [  115.972316] PGD 0
Jun 14 18:42:15 test-media kernel: [  115.972318] Oops: 0000 [#1] PREEMPT SMP
Jun 14 18:42:15 test-media kernel: [  115.972321] Modules linked in: vivid v4l2_dv_timings videobuf2_vmalloc videobuf2_memops videobuf2_core v4l2_common videodev media vmw_balloon vmw_vmci acpi_cpufreq processor button
Jun 14 18:42:15 test-media kernel: [  115.972333] CPU: 0 PID: 1542 Comm: v4l2-ctl Not tainted 4.1.0-rc3-test-media #1190
Jun 14 18:42:15 test-media kernel: [  115.972336] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/20/2014
Jun 14 18:42:15 test-media kernel: [  115.972337] task: ffff880220ce4200 ti: ffff88021d16c000 task.ti: ffff88021d16c000
Jun 14 18:42:15 test-media kernel: [  115.972339] RIP: 0010:[<ffffffff810d5cd0>]  [<ffffffff810d5cd0>] __lock_acquire+0x2f0/0x2070
Jun 14 18:42:15 test-media kernel: [  115.972342] RSP: 0018:ffff88021d16f9b8  EFLAGS: 00010002
Jun 14 18:42:15 test-media kernel: [  115.972343] RAX: 0000000000000046 RBX: 0000000000000292 RCX: 0000000000000001
Jun 14 18:42:15 test-media kernel: [  115.972345] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000100
Jun 14 18:42:15 test-media kernel: [  115.972346] RBP: ffff88021d16fa88 R08: 0000000000000001 R09: 0000000000000000
Jun 14 18:42:15 test-media kernel: [  115.972347] R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000001
Jun 14 18:42:15 test-media kernel: [  115.972348] R13: ffff880220ce4200 R14: 0000000000000100 R15: 0000000000000000
Jun 14 18:42:15 test-media kernel: [  115.972350] FS:  00007f2441e7f740(0000) GS:ffff880236e00000(0000) knlGS:0000000000000000
Jun 14 18:42:15 test-media kernel: [  115.972351] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
Jun 14 18:42:15 test-media kernel: [  115.972353] CR2: 0000000000000100 CR3: 0000000001e0b000 CR4: 00000000001406f0
Jun 14 18:42:15 test-media kernel: [  115.972424] Stack:
Jun 14 18:42:15 test-media kernel: [  115.972427]  ffff88021d16fa98 ffffffff810d6543 0000000000000006 0000000000000246
Jun 14 18:42:15 test-media kernel: [  115.972431]  ffff88021d16fa08 ffffffff810d532d ffff880220ce4a78 ffff880200000000
Jun 14 18:42:15 test-media kernel: [  115.972433]  ffff880200000001 0000000000000000 0000000000000001 000000000093a4a0
Jun 14 18:42:15 test-media kernel: [  115.972436] Call Trace:
Jun 14 18:42:15 test-media kernel: [  115.972440]  [<ffffffff810d6543>] ? __lock_acquire+0xb63/0x2070
Jun 14 18:42:15 test-media kernel: [  115.972443]  [<ffffffff810d532d>] ? mark_held_locks+0x6d/0xa0
Jun 14 18:42:15 test-media kernel: [  115.972445]  [<ffffffff810d37a8>] ? __lock_is_held+0x58/0x80
Jun 14 18:42:15 test-media kernel: [  115.972447]  [<ffffffff810d852c>] lock_acquire+0x6c/0xa0
Jun 14 18:42:15 test-media kernel: [  115.972452]  [<ffffffffa039f1f6>] ? vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:42:15 test-media kernel: [  115.972458]  [<ffffffff819b1a92>] down_read+0x42/0x60
Jun 14 18:42:15 test-media kernel: [  115.972460]  [<ffffffffa039f1f6>] ? vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:42:15 test-media kernel: [  115.972463]  [<ffffffff819af1b1>] ? mutex_lock_nested+0x2b1/0x560
Jun 14 18:42:15 test-media kernel: [  115.972467]  [<ffffffffa038fdc5>] ? vb2_queue_release+0x25/0x40 [videobuf2_core]
Jun 14 18:42:15 test-media kernel: [  115.972469]  [<ffffffffa039f1f6>] vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:42:15 test-media kernel: [  115.972472]  [<ffffffffa038b626>] __vb2_queue_free+0x146/0x5e0 [videobuf2_core]
Jun 14 18:42:15 test-media kernel: [  115.972475]  [<ffffffffa038fdd3>] vb2_queue_release+0x33/0x40 [videobuf2_core]
Jun 14 18:42:15 test-media kernel: [  115.972478]  [<ffffffffa038fe75>] _vb2_fop_release+0x95/0xb0 [videobuf2_core]
Jun 14 18:42:15 test-media kernel: [  115.972481]  [<ffffffffa038feb9>] vb2_fop_release+0x29/0x50 [videobuf2_core]
Jun 14 18:42:15 test-media kernel: [  115.972485]  [<ffffffffa03ad372>] vivid_fop_release+0x92/0x230 [vivid]
Jun 14 18:42:15 test-media kernel: [  115.972491]  [<ffffffffa0358460>] v4l2_release+0x30/0x80 [videodev]
Jun 14 18:42:15 test-media kernel: [  115.972496]  [<ffffffff811a51d5>] __fput+0xe5/0x200
Jun 14 18:42:15 test-media kernel: [  115.972498]  [<ffffffff811a5339>] ____fput+0x9/0x10
Jun 14 18:42:15 test-media kernel: [  115.972501]  [<ffffffff810a9fa4>] task_work_run+0xc4/0xf0
Jun 14 18:42:15 test-media kernel: [  115.972504]  [<ffffffff8108c670>] do_exit+0x3a0/0xaf0
Jun 14 18:42:15 test-media kernel: [  115.972507]  [<ffffffff819b3a9b>] ? _raw_spin_unlock_irq+0x2b/0x60
Jun 14 18:42:15 test-media kernel: [  115.972509]  [<ffffffff8108e0ff>] do_group_exit+0x4f/0xe0
Jun 14 18:42:15 test-media kernel: [  115.972511]  [<ffffffff8109a170>] get_signal+0x200/0x8c0
Jun 14 18:42:15 test-media kernel: [  115.972514]  [<ffffffff819b14b5>] ? __mutex_unlock_slowpath+0xf5/0x240
Jun 14 18:42:15 test-media kernel: [  115.972518]  [<ffffffff81002593>] do_signal+0x23/0x820
Jun 14 18:42:15 test-media kernel: [  115.972521]  [<ffffffff819b1609>] ? mutex_unlock+0x9/0x10
Jun 14 18:42:15 test-media kernel: [  115.972524]  [<ffffffffa0358648>] ? v4l2_ioctl+0x78/0xf0 [videodev]
Jun 14 18:42:15 test-media kernel: [  115.972526]  [<ffffffff819b4653>] ? int_very_careful+0x5/0x46
Jun 14 18:42:15 test-media kernel: [  115.972529]  [<ffffffff810d54bd>] ? trace_hardirqs_on_caller+0x15d/0x200
Jun 14 18:42:15 test-media kernel: [  115.972531]  [<ffffffff81002de0>] do_notify_resume+0x50/0x60
Jun 14 18:42:15 test-media kernel: [  115.972533]  [<ffffffff819b46a6>] int_signal+0x12/0x17
Jun 14 18:42:15 test-media kernel: [  115.972534] Code: ca 81 31 c0 e8 7a e2 8c 00 e8 aa 1d 8d 00 0f 1f 44 00 00 31 db 48 81 c4 a8 00 00 00 89 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 66 90 <49> 81 3e 40 4e 02 82 b8 00 00 00 00 44 0f 44 e0 41 83 ff 01 0f
Jun 14 18:42:15 test-media kernel: [  115.972567] RIP  [<ffffffff810d5cd0>] __lock_acquire+0x2f0/0x2070
Jun 14 18:42:15 test-media kernel: [  115.972569]  RSP <ffff88021d16f9b8>
Jun 14 18:42:15 test-media kernel: [  115.972570] CR2: 0000000000000100
Jun 14 18:42:15 test-media kernel: [  115.972573] ---[ end trace 25595c2b8560cb57 ]---
Jun 14 18:42:15 test-media kernel: [  115.972575] Fixing recursive fault but reboot is needed!

This can be reproduced by loading the vivid driver and running:

v4l2-ctl --stream-user

and pressing Ctrl-C. You may have to try a few times, but in my experience this BUG
is triggered quite quickly.

The second is a possible deadlock:

Jun 14 18:44:07 test-media kernel: [   49.376650] ======================================================
Jun 14 18:44:07 test-media kernel: [   49.376651] [ INFO: possible circular locking dependency detected ]
Jun 14 18:44:07 test-media kernel: [   49.376653] 4.1.0-rc3-test-media #1190 Not tainted
Jun 14 18:44:07 test-media kernel: [   49.376654] -------------------------------------------------------
Jun 14 18:44:07 test-media kernel: [   49.376655] v4l2-compliance/1468 is trying to acquire lock:
Jun 14 18:44:07 test-media kernel: [   49.376657]  (&mm->mmap_sem){++++++}, at: [<ffffffffa03a81f6>] vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:44:07 test-media kernel: [   49.376665]
Jun 14 18:44:07 test-media kernel: [   49.376665] but task is already holding lock:
Jun 14 18:44:07 test-media kernel: [   49.376666]  (&q->mmap_lock){+.+...}, at: [<ffffffffa0398dc5>] vb2_queue_release+0x25/0x40 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376670]
Jun 14 18:44:07 test-media kernel: [   49.376670] which lock already depends on the new lock.
Jun 14 18:44:07 test-media kernel: [   49.376670]
Jun 14 18:44:07 test-media kernel: [   49.376671]
Jun 14 18:44:07 test-media kernel: [   49.376671] the existing dependency chain (in reverse order) is:
Jun 14 18:44:07 test-media kernel: [   49.376672]
Jun 14 18:44:07 test-media kernel: [   49.376672] -> #1 (&q->mmap_lock){+.+...}:
Jun 14 18:44:07 test-media kernel: [   49.376675]        [<ffffffff810d852c>] lock_acquire+0x6c/0xa0
Jun 14 18:44:07 test-media kernel: [   49.376682]        [<ffffffff819aef5e>] mutex_lock_nested+0x5e/0x560
Jun 14 18:44:07 test-media kernel: [   49.376689]        [<ffffffffa03934a2>] vb2_mmap+0x232/0x350 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376691]        [<ffffffffa0395a60>] vb2_fop_mmap+0x20/0x30 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376694]        [<ffffffffa0361102>] v4l2_mmap+0x52/0x90 [videodev]
Jun 14 18:44:07 test-media kernel: [   49.376698]        [<ffffffff81177e33>] mmap_region+0x3b3/0x5e0
Jun 14 18:44:07 test-media kernel: [   49.376701]        [<ffffffff81178377>] do_mmap_pgoff+0x317/0x400
Jun 14 18:44:07 test-media kernel: [   49.376703]        [<ffffffff81165320>] vm_mmap_pgoff+0x90/0xc0
Jun 14 18:44:07 test-media kernel: [   49.376708]        [<ffffffff81176867>] SyS_mmap_pgoff+0x1d7/0x280
Jun 14 18:44:07 test-media kernel: [   49.376709]        [<ffffffff81007f8d>] SyS_mmap+0x1d/0x20
Jun 14 18:44:07 test-media kernel: [   49.376714]        [<ffffffff819b44ae>] system_call_fastpath+0x12/0x76
Jun 14 18:44:07 test-media kernel: [   49.376716]
Jun 14 18:44:07 test-media kernel: [   49.376716] -> #0 (&mm->mmap_sem){++++++}:
Jun 14 18:44:07 test-media kernel: [   49.376718]        [<ffffffff810d79b3>] __lock_acquire+0x1fd3/0x2070
Jun 14 18:44:07 test-media kernel: [   49.376720]        [<ffffffff810d852c>] lock_acquire+0x6c/0xa0
Jun 14 18:44:07 test-media kernel: [   49.376721]        [<ffffffff819b1a92>] down_read+0x42/0x60
Jun 14 18:44:07 test-media kernel: [   49.376723]        [<ffffffffa03a81f6>] vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:44:07 test-media kernel: [   49.376725]        [<ffffffffa0394626>] __vb2_queue_free+0x146/0x5e0 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376727]        [<ffffffffa0398dd3>] vb2_queue_release+0x33/0x40 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376729]        [<ffffffffa0398e75>] _vb2_fop_release+0x95/0xb0 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376731]        [<ffffffffa0398eb9>] vb2_fop_release+0x29/0x50 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376733]        [<ffffffffa03b6372>] vivid_fop_release+0x92/0x230 [vivid]
Jun 14 18:44:07 test-media kernel: [   49.376737]        [<ffffffffa0361460>] v4l2_release+0x30/0x80 [videodev]
Jun 14 18:44:07 test-media kernel: [   49.376739]        [<ffffffff811a51d5>] __fput+0xe5/0x200
Jun 14 18:44:07 test-media kernel: [   49.376744]        [<ffffffff811a5339>] ____fput+0x9/0x10
Jun 14 18:44:07 test-media kernel: [   49.376746]        [<ffffffff810a9fa4>] task_work_run+0xc4/0xf0
Jun 14 18:44:07 test-media kernel: [   49.376749]        [<ffffffff81002dd1>] do_notify_resume+0x41/0x60
Jun 14 18:44:07 test-media kernel: [   49.376752]        [<ffffffff819b46a6>] int_signal+0x12/0x17
Jun 14 18:44:07 test-media kernel: [   49.376754]
Jun 14 18:44:07 test-media kernel: [   49.376754] other info that might help us debug this:
Jun 14 18:44:07 test-media kernel: [   49.376754]
Jun 14 18:44:07 test-media kernel: [   49.376755]  Possible unsafe locking scenario:
Jun 14 18:44:07 test-media kernel: [   49.376755]
Jun 14 18:44:07 test-media kernel: [   49.376756]        CPU0                    CPU1
Jun 14 18:44:07 test-media kernel: [   49.376757]        ----                    ----
Jun 14 18:44:07 test-media kernel: [   49.376758]   lock(&q->mmap_lock);
Jun 14 18:44:07 test-media kernel: [   49.376759]                                lock(&mm->mmap_sem);
Jun 14 18:44:07 test-media kernel: [   49.376760]                                lock(&q->mmap_lock);
Jun 14 18:44:07 test-media kernel: [   49.376761]   lock(&mm->mmap_sem);
Jun 14 18:44:07 test-media kernel: [   49.376763]
Jun 14 18:44:07 test-media kernel: [   49.376763]  *** DEADLOCK ***
Jun 14 18:44:07 test-media kernel: [   49.376763]
Jun 14 18:44:07 test-media kernel: [   49.376764] 2 locks held by v4l2-compliance/1468:
Jun 14 18:44:07 test-media kernel: [   49.376765]  #0:  (&dev->mutex#3){+.+.+.}, at: [<ffffffffa0398e0a>] _vb2_fop_release+0x2a/0xb0 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376770]  #1:  (&q->mmap_lock){+.+...}, at: [<ffffffffa0398dc5>] vb2_queue_release+0x25/0x40 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376773]
Jun 14 18:44:07 test-media kernel: [   49.376773] stack backtrace:
Jun 14 18:44:07 test-media kernel: [   49.376776] CPU: 2 PID: 1468 Comm: v4l2-compliance Not tainted 4.1.0-rc3-test-media #1190
Jun 14 18:44:07 test-media kernel: [   49.376777] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/20/2014
Jun 14 18:44:07 test-media kernel: [   49.376779]  ffffffff8279e0b0 ffff88021d6f7ba8 ffffffff819a7aac 0000000000000011
Jun 14 18:44:07 test-media kernel: [   49.376781]  ffffffff8279e0b0 ffff88021d6f7bf8 ffffffff819a3964 ffff88021d6f7bd8
Jun 14 18:44:07 test-media kernel: [   49.376783]  ffff8800ac8aa100 0000000000000002 ffff8800ac8aa9a0 0000000000000002
Jun 14 18:44:07 test-media kernel: [   49.376785] Call Trace:
Jun 14 18:44:07 test-media kernel: [   49.376788]  [<ffffffff819a7aac>] dump_stack+0x4f/0x7b
Jun 14 18:44:07 test-media kernel: [   49.376792]  [<ffffffff819a3964>] print_circular_bug+0x20f/0x251
Jun 14 18:44:07 test-media kernel: [   49.376793]  [<ffffffff810d79b3>] __lock_acquire+0x1fd3/0x2070
Jun 14 18:44:07 test-media kernel: [   49.376795]  [<ffffffff810d6543>] ? __lock_acquire+0xb63/0x2070
Jun 14 18:44:07 test-media kernel: [   49.376797]  [<ffffffff810d37a8>] ? __lock_is_held+0x58/0x80
Jun 14 18:44:07 test-media kernel: [   49.376798]  [<ffffffff810d852c>] lock_acquire+0x6c/0xa0
Jun 14 18:44:07 test-media kernel: [   49.376800]  [<ffffffffa03a81f6>] ? vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:44:07 test-media kernel: [   49.376802]  [<ffffffff819b1a92>] down_read+0x42/0x60
Jun 14 18:44:07 test-media kernel: [   49.376803]  [<ffffffffa03a81f6>] ? vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:44:07 test-media kernel: [   49.376805]  [<ffffffff819af1b1>] ? mutex_lock_nested+0x2b1/0x560
Jun 14 18:44:07 test-media kernel: [   49.376807]  [<ffffffffa0398dc5>] ? vb2_queue_release+0x25/0x40 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376808]  [<ffffffffa03a81f6>] vb2_vmalloc_put_userptr+0x36/0x110 [videobuf2_vmalloc]
Jun 14 18:44:07 test-media kernel: [   49.376810]  [<ffffffffa0398e0a>] ? _vb2_fop_release+0x2a/0xb0 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376812]  [<ffffffffa0394626>] __vb2_queue_free+0x146/0x5e0 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376814]  [<ffffffffa0398dd3>] vb2_queue_release+0x33/0x40 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376816]  [<ffffffffa0398e75>] _vb2_fop_release+0x95/0xb0 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376818]  [<ffffffffa0398eb9>] vb2_fop_release+0x29/0x50 [videobuf2_core]
Jun 14 18:44:07 test-media kernel: [   49.376820]  [<ffffffffa03b6372>] vivid_fop_release+0x92/0x230 [vivid]
Jun 14 18:44:07 test-media kernel: [   49.376822]  [<ffffffffa0361460>] v4l2_release+0x30/0x80 [videodev]
Jun 14 18:44:07 test-media kernel: [   49.376824]  [<ffffffff811a51d5>] __fput+0xe5/0x200
Jun 14 18:44:07 test-media kernel: [   49.376825]  [<ffffffff819b4653>] ? int_very_careful+0x5/0x46
Jun 14 18:44:07 test-media kernel: [   49.376827]  [<ffffffff811a5339>] ____fput+0x9/0x10
Jun 14 18:44:07 test-media kernel: [   49.376828]  [<ffffffff810a9fa4>] task_work_run+0xc4/0xf0
Jun 14 18:44:07 test-media kernel: [   49.376830]  [<ffffffff81002dd1>] do_notify_resume+0x41/0x60
Jun 14 18:44:07 test-media kernel: [   49.376832]  [<ffffffff819b46a6>] int_signal+0x12/0x17

This can be triggered by loading the vivid module with the module option 'no_error_inj=1'
and running 'v4l2-compliance -s5'. Again, it may take a few attempts to trigger this
but for me it happens quite quickly.

Without this patch I cannot reproduce these two issues. So reverting is the best
solution for now.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

dma_map_sg returns the number of areas mapped by the hardware,
which could be different than the areas given as an input.
The output must be saved to nent.
Signed-off-by: NRicardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Reviewed-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Currently vb2 core acquires mmap_sem just around call to
__qbuf_userptr(). However since commit f035eb4e (videobuf2: fix
lockdep warning) it isn't necessary to acquire it so early as we no
longer have to drop queue mutex before acquiring mmap_sem. So push
acquisition of mmap_sem down into .get_userptr and .put_userptr memops
so that the semaphore is acquired for a shorter time and it is clearer
what it is needed for.
Signed-off-by: NJan Kara <jack@suse.cz>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

At present, dma_buf_export() takes a series of parameters, which
makes it difficult to add any new parameters for exporters, if required.

Make it simpler by moving all these parameters into a struct, and pass
the struct * as parameter to dma_buf_export().

While at it, unite dma_buf_export_named() with dma_buf_export(), and
change all callers accordingly.
Reviewed-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: NDaniel Thompson <daniel.thompson@linaro.org>
Acked-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: NDave Airlie <airlied@redhat.com>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>

The last argument of vb2_dc_get_user_pages() is of type enum
dma_data_direction, but the caller, vb2_dc_get_userptr() passes a value
which is the result of comparison dma_dir == DMA_FROM_DEVICE. This results
in the write parameter to get_user_pages() being zero in all cases, i.e.
that the caller has no intent to write there.

This was broken by patch "vb2: replace 'write' by 'dma_dir'".
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Cc: stable@vger.kernel.org  # for v3.19
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

By default dma_map_sg syncs the mapped buffer to the device. But
buf_prepare expects a buffer syncs for the cpu and the buffer
will be synced to the device in the prepare memop.

The reverse is true for dma_unmap_sg, buf_finish and the finish
memop.

To prevent unnecessary syncs we ask dma_(un)map_sg to skip the
sync.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NPawel Osciak <pawel@osciak.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

Don't try to free a pointer containing an ERR_PTR().
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NPawel Osciak <pawel@osciak.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

This is needed for the next patch where the dma-sg alloc memop needs
to know the dma_dir.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NPawel Osciak <pawel@osciak.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

The 'write' argument is very ambiguous. I first assumed that if it is 1,
then we're doing video output but instead it meant the reverse.

Since it is used to setup the dma_dir value anyway it is now replaced by
the correct dma_dir value which is unambiguous.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NPawel Osciak <pawel@osciak.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@osg.samsung.com>

This allows reservation objects to be used in dma-buf. it's required
for implementing polling support on the fences that belong to a dma-buf.
Signed-off-by: NMaarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: Mauro Carvalho Chehab <m.chehab@samsung.com> #drivers/media/v4l2-core/
Acked-by: Thomas Hellstrom <thellstrom@vmware.com> #drivers/gpu/drm/ttm
Acked-by: NSumit Semwal <sumit.semwal@linaro.org>
Acked-by: NDaniel Vetter <daniel@ffwll.ch>
Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net> #drivers/gpu/drm/armada/
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

This allows drivers to vmap contiguous dma buffers so they can inspect the
buffer contents with the CPU. This will be needed for the CODA driver's JPEG
handling. On CODA960, the header parsing has to be done on the CPU. The
hardware modules can only process the entropy coded segment after all
registers and tables are set up.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

dma_buf_map_attachment and dma_buf_vmap can return NULL or
ERR_PTR on a error.  This encourages a common buggy pattern in
callers:
	sgt = dma_buf_map_attachment(attach, DMA_BIDIRECTIONAL);
	if (IS_ERR_OR_NULL(sgt))
                return PTR_ERR(sgt);

This causes the caller to return 0 on an error.  IS_ERR_OR_NULL
is almost always a sign of poorly-defined error handling.

This patch converts dma_buf_map_attachment to always return
ERR_PTR, and fixes the callers that incorrectly handled NULL.
There are a few more callers that were not checking for NULL
at all, which would have dereferenced a NULL pointer later.
There are also a few more callers that correctly handled NULL
and ERR_PTR differently, I left those alone but they could also
be modified to delete the NULL check.

This patch also converts dma_buf_vmap to always return NULL.
All the callers to dma_buf_vmap only check for NULL, and would
have dereferenced an ERR_PTR and panic'd if one was ever
returned. This is not consistent with the rest of the dma buf
APIs, but matches the expectations of all of the callers.
Signed-off-by: NColin Cross <ccross@android.com>
Reviewed-by: NRob Clark <robdclark@gmail.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Currently it is not possible for userspace to map a DMABUF exported buffer
with write permissions. This patch allows to also pass O_RDONLY/O_RDWR when
exporting the buffer, so that userspace may map it with write permissions.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

Currently it is not possible for userspace to map a DMABUF exported buffer
with write permissions. This patch allows to also pass O_RDONLY/O_RDWR when
exporting the buffer, so that userspace may map it with write permissions.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

Earlier version of dma-contig allocator in user ptr mode assumed that in
all cases DMA address equals physical address. This was just a special case.
Commit e15dab75 introduced correct support
for converting userpage to dma address, but unfortunately it broke the
support for simple dma address = physical address for the case, when given
physical frame has no struct page associated with it (this happens if one
use for example dma_declare_coherent api or other reserved memory approach).
This commit restores support for such cases.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
[s.nawrocki@samsung.com: replaced #elsif with #elif]
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <m.chehab@samsung.com>

Memory maps typically require that the buffer size to be page
aligned. Currently, two memops drivers do such alignment
internally, but videobuf-vmalloc doesn't.
Also, the buffer overflow check doesn't take it into account.
So, instead of doing it at each memops driver, enforce it at
VB2 core.
Reported-by: NPrabhakar lad <prabhakar.csengg@gmail.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Some drivers have special memory requirements for their buffers, usually
related to DMA (e.g. GFP_DMA or __GFP_DMA32). Make it possible to specify
additional GFP flags for those buffers by adding a gfp_flags field to
vb2_queue.
Note that this field will be replaced in the future with a different
mechanism, but that is still work in progress and we need this feature
now so we won't be able to convert drivers with such requirements to vb2.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NFederico Vaga <federico.vaga@gmail.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

The right solution is to remove the architecture dependency on
dma_common_get_sgtable(). Revert this patch to apply the right one.

This reverts commit 93049b93.

As reported by Stephen:

> After merging the v4l-dvb tree, today's linux-next build (x86_64
> allmodconfig) failed like this:
>
> ERROR: "dma_common_get_sgtable" [drivers/media/v4l2-core/videobuf2-dma-contig.ko] undefined!
>
> Caused by commit 9ef2cbeb ("[media] v4l: vb2-dma-contig: add support
> for DMABUF exporting").  dma_common_get_sgtable() is called from the
> inline dma_get_sgtable_attrs() and dma_get_sgtable_attrs() is "called
> from" dma_get_sgtable().  dma_common_get_sgtable() is only defined if
> ARCH_HAS_DMA_DECLARE_COHERENT_MEMORY is set which depends on
> CONFIG_HAVE_GENERIC_DMA_COHERENT being set which it isn't for this build.

The simplest fix is to just not support DMABUF with vb2-contig, on archs
where this symbol doesn't exist. Some latter patch can rewrite it to
support this outside -arm.
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Most operations on DMA and DMABUF framework require the size of a buffer to be
page aligned. This patch guarantees the requirement is satisfied for all
vb2-dma-contig buffers.
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

The DMA transfer must be aligned to a specific value. If userptr is not aligned
to DMA requirements then unexpected corruptions of the memory may occur before
or after a buffer.  To prevent such situations, all unligned userptr buffers
are rejected at VIDIOC_QBUF.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This patch adds taking reference to the device for MMAP buffers.
Such buffers, may be exported using DMABUF mechanism. If the driver that
created a queue is unloaded then the queue is released, the device might be
released too.  However, buffers cannot be released if they are referenced by
DMABUF descriptor(s). The device pointer kept in a buffer must be valid for the
whole buffer's lifetime. Therefore MMAP buffers should take a reference to the
device to avoid risk of dangling pointers.
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This patch adds support for exporting a dma-contig buffer using
DMABUF interface.
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Let mmap method to use dma_mmap_coherent call.  Moreover, this patch removes
vb2_mmap_pfn_range from videobuf2 helpers as it was suggested by Laurent
Pinchart.  The function is no longer used in vb2 code.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This patch makes changes for adding dma-contig as a dma_buf user. It provides
function implementations for the {attach, detach, map, unmap}_dmabuf()
mem_ops of DMABUF memory type.
	[author of the original patch]
	[integration with refactored dma-contig allocator]
Signed-off-by: NSumit Semwal <sumit.semwal@ti.com>
Signed-off-by: NSumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Add prepare/finish callbacks to vb2-dma-contig allocator.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This patch introduces usage of dma_map_sg to map memory behind
a userspace pointer to a device as dma-contiguous mapping.
This patch contains some of the code kindly provided by Marek Szyprowski
<m.szyprowski@samsung.com> and Kamil Debski <k.debski@samsung.com> and Andrzej
Pietrasiewicz <andrzej.p@samsung.com>. Kind thanks for bug reports from Laurent
Pinchart <laurent.pinchart@ideasonboard.com> and Seung-Woo Kim
<sw0312.kim@samsung.com>.
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Group functions by buffer type.
Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

This patch removes a reference to alloc_ctx from an instance of a DMA
contiguous buffer. It helps to avoid a risk of a dangling pointer if the
context is released while the buffer is still valid. Moreover it removes one
dereference step while accessing a device structure.
Signed-off-by: NTomasz Stanislawski <t.stanislaws@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Signed-off-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NHans Verkuil <hans.verkuil@cisco.com>
Tested-by: NMauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Currently, the v4l2 core is mixed together with other non-core drivers.
Move them into a separate directory.
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

The function vb2_dma_contig_vaddr returns a void * not an integer.

Quiets the sparse noise:

warning: Using plain integer as NULL pointer
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Include the header to pickup the definitions of the exported symbols.

Quiets the following sparse warnings:

warning: symbol 'vb2_dma_contig_memops' was not declared. Should it be static?
warning: symbol 'vb2_dma_contig_init_ctx' was not declared. Should it be static?
warning: symbol 'vb2_dma_contig_cleanup_ctx' was not declared. Should it be static?
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Include the header to pickup the definitions of the exported symbols.

Quiets the following sparse warnings:

warning: symbol 'vb2_dma_contig_memops' was not declared. Should it be static?
warning: symbol 'vb2_dma_contig_init_ctx' was not declared. Should it be static?
warning: symbol 'vb2_dma_contig_cleanup_ctx' was not declared. Should it be static?
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

The function vb2_dma_contig_vaddr returns a void * not an integer.

Quiets the sparse noise:

warning: Using plain integer as NULL pointer
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Pawel Osciak <pawel@osciak.com>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Acked-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NSylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Use the correct 'dma_addr' name for the buffer address. 'paddr' suggested
that this is the physical address in system memory. For most ARM platforms
these two are the same, but this is not a generic rule. 'dma_addr' will
also point better to dma-mapping api.
Signed-off-by: NMarek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
CC: Pawel Osciak <pawel@osciak.com>
Acked-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

buf->size is not yet initialised in videobuf2-dma-contig at the time of
the error message, use "size."
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

dma_addr_t may not fit into void* on some architectures. To be safe, make
vb2_dma_contig_cookie() return a pointer to dma_addr_t and dereference it
in vb2_dma_contig_plane_paddr() back to dma_addr_t.
Signed-off-by: NPawel Osciak <pawel@osciak.com>
Reported-by: NHans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: NGuennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>

Signed-off-by: NPawel Osciak <pawel@osciak.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab@redhat.com>