linux.git/drivers/video/fbdev/hyperv_fb.c, branch v6.18.21 Clone of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git fbdev/hyperv_fb: deprecate this in favor of Hyper-V DRM driver 2025-10-02T21:15:29+00:00 Prasanna Kumar T S M ptsm@linux.microsoft.com 2025-10-02T21:10:36+00:00 34b4620349fe4776babf9c735e1c68e620784763 The Hyper-V DRM driver is available since kernel version 5.14 and it provides full KMS support and fbdev emulation via the DRM fbdev helpers. Deprecate this driver in favor of Hyper-V DRM driver. Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com> Acked-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com> Signed-off-by: Wei Liu <wei.liu@kernel.org> 
The Hyper-V DRM driver is available since kernel version 5.14 and it
provides full KMS support and fbdev emulation via the DRM fbdev helpers.
Deprecate this driver in favor of Hyper-V DRM driver.

Signed-off-by: Prasanna Kumar T S M <ptsm@linux.microsoft.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
fbdev: hyperv_fb: Allow graceful removal of framebuffer 2025-03-09T23:56:29+00:00 Saurabh Sengar ssengar@linux.microsoft.com 2025-03-01T16:16:31+00:00 ea2f45ab0e53b255f72c85ccd99e2b394fc5fceb When a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to release the framebuffer forcefully. If this framebuffer is in use it produce the following WARN and hence this framebuffer is never released. [ 44.111220] WARNING: CPU: 35 PID: 1882 at drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40 < snip > [ 44.111289] Call Trace: [ 44.111290] <TASK> [ 44.111291] ? show_regs+0x6c/0x80 [ 44.111295] ? __warn+0x8d/0x150 [ 44.111298] ? framebuffer_release+0x2c/0x40 [ 44.111300] ? report_bug+0x182/0x1b0 [ 44.111303] ? handle_bug+0x6e/0xb0 [ 44.111306] ? exc_invalid_op+0x18/0x80 [ 44.111308] ? asm_exc_invalid_op+0x1b/0x20 [ 44.111311] ? framebuffer_release+0x2c/0x40 [ 44.111313] ? hvfb_remove+0x86/0xa0 [hyperv_fb] [ 44.111315] vmbus_remove+0x24/0x40 [hv_vmbus] [ 44.111323] device_remove+0x40/0x80 [ 44.111325] device_release_driver_internal+0x20b/0x270 [ 44.111327] ? bus_find_device+0xb3/0xf0 Fix this by moving the release of framebuffer and assosiated memory to fb_ops.fb_destroy function, so that framebuffer framework handles it gracefully. While we fix this, also replace manual registrations/unregistration of framebuffer with devm_register_framebuffer. Fixes: 68a2d20b79b1 ("drivers/video: add Hyper-V Synthetic Video Frame Buffer Driver") Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Tested-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/1740845791-19977-3-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <1740845791-19977-3-git-send-email-ssengar@linux.microsoft.com> 
When a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to
release the framebuffer forcefully. If this framebuffer is in use it
produce the following WARN and hence this framebuffer is never released.

[   44.111220] WARNING: CPU: 35 PID: 1882 at drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40
< snip >
[   44.111289] Call Trace:
[   44.111290]  <TASK>
[   44.111291]  ? show_regs+0x6c/0x80
[   44.111295]  ? __warn+0x8d/0x150
[   44.111298]  ? framebuffer_release+0x2c/0x40
[   44.111300]  ? report_bug+0x182/0x1b0
[   44.111303]  ? handle_bug+0x6e/0xb0
[   44.111306]  ? exc_invalid_op+0x18/0x80
[   44.111308]  ? asm_exc_invalid_op+0x1b/0x20
[   44.111311]  ? framebuffer_release+0x2c/0x40
[   44.111313]  ? hvfb_remove+0x86/0xa0 [hyperv_fb]
[   44.111315]  vmbus_remove+0x24/0x40 [hv_vmbus]
[   44.111323]  device_remove+0x40/0x80
[   44.111325]  device_release_driver_internal+0x20b/0x270
[   44.111327]  ? bus_find_device+0xb3/0xf0

Fix this by moving the release of framebuffer and assosiated memory
to fb_ops.fb_destroy function, so that framebuffer framework handles
it gracefully.

While we fix this, also replace manual registrations/unregistration of
framebuffer with devm_register_framebuffer.

Fixes: 68a2d20b79b1 ("drivers/video: add Hyper-V Synthetic Video Frame Buffer Driver")

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1740845791-19977-3-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1740845791-19977-3-git-send-email-ssengar@linux.microsoft.com>
fbdev: hyperv_fb: Simplify hvfb_putmem 2025-03-09T23:56:29+00:00 Saurabh Sengar ssengar@linux.microsoft.com 2025-03-01T16:16:30+00:00 f5e728a50bb17336a20803dde488515b833ecd1d The device object required in 'hvfb_release_phymem' function for 'dma_free_coherent' can also be obtained from the 'info' pointer, making 'hdev' parameter in 'hvfb_putmem' redundant. Remove the unnecessary 'hdev' argument from 'hvfb_putmem'. Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Tested-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com> 
The device object required in 'hvfb_release_phymem' function
for 'dma_free_coherent' can also be obtained from the 'info'
pointer, making 'hdev' parameter in 'hvfb_putmem' redundant.
Remove the unnecessary 'hdev' argument from 'hvfb_putmem'.

Signed-off-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Reviewed-by: Michael Kelley <mhklinux@outlook.com>
Tested-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <1740845791-19977-2-git-send-email-ssengar@linux.microsoft.com>
fbdev: hyperv_fb: Fix hang in kdump kernel when on Hyper-V Gen 2 VMs 2025-03-09T23:54:10+00:00 Michael Kelley mhklinux@outlook.com 2025-02-18T23:01:30+00:00 304386373007aaca9236a3f36afac0bbedcd2bf0 Gen 2 Hyper-V VMs boot via EFI and have a standard EFI framebuffer device. When the kdump kernel runs in such a VM, loading the efifb driver may hang because of accessing the framebuffer at the wrong memory address. The scenario occurs when the hyperv_fb driver in the original kernel moves the framebuffer to a different MMIO address because of conflicts with an already-running efifb or simplefb driver. The hyperv_fb driver then informs Hyper-V of the change, which is allowed by the Hyper-V FB VMBus device protocol. However, when the kexec command loads the kdump kernel into crash memory via the kexec_file_load() system call, the system call doesn't know the framebuffer has moved, and it sets up the kdump screen_info using the original framebuffer address. The transition to the kdump kernel does not go through the Hyper-V host, so Hyper-V does not reset the framebuffer address like it would do on a reboot. When efifb tries to run, it accesses a non-existent framebuffer address, which traps to the Hyper-V host. After many such accesses, the Hyper-V host thinks the guest is being malicious, and throttles the guest to the point that it runs very slowly or appears to have hung. When the kdump kernel is loaded into crash memory via the kexec_load() system call, the problem does not occur. In this case, the kexec command builds the screen_info table itself in user space from data returned by the FBIOGET_FSCREENINFO ioctl against /dev/fb0, which gives it the new framebuffer location. This problem was originally reported in 2020 [1], resulting in commit 3cb73bc3fa2a ("hyperv_fb: Update screen_info after removing old framebuffer"). This commit solved the problem by setting orig_video_isVGA to 0, so the kdump kernel was unaware of the EFI framebuffer. The efifb driver did not try to load, and no hang occurred. But in 2024, commit c25a19afb81c ("fbdev/hyperv_fb: Do not clear global screen_info") effectively reverted 3cb73bc3fa2a. Commit c25a19afb81c has no reference to 3cb73bc3fa2a, so perhaps it was done without knowing the implications that were reported with 3cb73bc3fa2a. In any case, as of commit c25a19afb81c, the original problem came back again. Interestingly, the hyperv_drm driver does not have this problem because it never moves the framebuffer. The difference is that the hyperv_drm driver removes any conflicting framebuffers *before* allocating an MMIO address, while the hyperv_fb drivers removes conflicting framebuffers *after* allocating an MMIO address. With the "after" ordering, hyperv_fb may encounter a conflict and move the framebuffer to a different MMIO address. But the conflict is essentially bogus because it is removed a few lines of code later. Rather than fix the problem with the approach from 2020 in commit 3cb73bc3fa2a, instead slightly reorder the steps in hyperv_fb so conflicting framebuffers are removed before allocating an MMIO address. Then the default framebuffer MMIO address should always be available, and there's never any confusion about which framebuffer address the kdump kernel should use -- it's always the original address provided by the Hyper-V host. This approach is already used by the hyperv_drm driver, and is consistent with the usage guidelines at the head of the module with the function aperture_remove_conflicting_devices(). This approach also solves a related minor problem when kexec_load() is used to load the kdump kernel. With current code, unbinding and rebinding the hyperv_fb driver could result in the framebuffer moving back to the default framebuffer address, because on the rebind there are no conflicts. If such a move is done after the kdump kernel is loaded with the new framebuffer address, at kdump time it could again have the wrong address. This problem and fix are described in terms of the kdump kernel, but it can also occur with any kernel started via kexec. See extensive discussion of the problem and solution at [2]. [1] https://lore.kernel.org/linux-hyperv/20201014092429.1415040-1-kasong@redhat.com/ [2] https://lore.kernel.org/linux-hyperv/BLAPR10MB521793485093FDB448F7B2E5FDE92@BLAPR10MB5217.namprd10.prod.outlook.com/ Reported-by: Thomas Tai <thomas.tai@oracle.com> Fixes: c25a19afb81c ("fbdev/hyperv_fb: Do not clear global screen_info") Signed-off-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/20250218230130.3207-1-mhklinux@outlook.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20250218230130.3207-1-mhklinux@outlook.com> 
Gen 2 Hyper-V VMs boot via EFI and have a standard EFI framebuffer
device. When the kdump kernel runs in such a VM, loading the efifb
driver may hang because of accessing the framebuffer at the wrong
memory address.

The scenario occurs when the hyperv_fb driver in the original kernel
moves the framebuffer to a different MMIO address because of conflicts
with an already-running efifb or simplefb driver. The hyperv_fb driver
then informs Hyper-V of the change, which is allowed by the Hyper-V FB
VMBus device protocol. However, when the kexec command loads the kdump
kernel into crash memory via the kexec_file_load() system call, the
system call doesn't know the framebuffer has moved, and it sets up the
kdump screen_info using the original framebuffer address. The transition
to the kdump kernel does not go through the Hyper-V host, so Hyper-V
does not reset the framebuffer address like it would do on a reboot.
When efifb tries to run, it accesses a non-existent framebuffer
address, which traps to the Hyper-V host. After many such accesses,
the Hyper-V host thinks the guest is being malicious, and throttles
the guest to the point that it runs very slowly or appears to have hung.

When the kdump kernel is loaded into crash memory via the kexec_load()
system call, the problem does not occur. In this case, the kexec command
builds the screen_info table itself in user space from data returned
by the FBIOGET_FSCREENINFO ioctl against /dev/fb0, which gives it the
new framebuffer location.

This problem was originally reported in 2020 [1], resulting in commit
3cb73bc3fa2a ("hyperv_fb: Update screen_info after removing old
framebuffer"). This commit solved the problem by setting orig_video_isVGA
to 0, so the kdump kernel was unaware of the EFI framebuffer. The efifb
driver did not try to load, and no hang occurred. But in 2024, commit
c25a19afb81c ("fbdev/hyperv_fb: Do not clear global screen_info")
effectively reverted 3cb73bc3fa2a. Commit c25a19afb81c has no reference
to 3cb73bc3fa2a, so perhaps it was done without knowing the implications
that were reported with 3cb73bc3fa2a. In any case, as of commit
c25a19afb81c, the original problem came back again.

Interestingly, the hyperv_drm driver does not have this problem because
it never moves the framebuffer. The difference is that the hyperv_drm
driver removes any conflicting framebuffers *before* allocating an MMIO
address, while the hyperv_fb drivers removes conflicting framebuffers
*after* allocating an MMIO address. With the "after" ordering, hyperv_fb
may encounter a conflict and move the framebuffer to a different MMIO
address. But the conflict is essentially bogus because it is removed
a few lines of code later.

Rather than fix the problem with the approach from 2020 in commit
3cb73bc3fa2a, instead slightly reorder the steps in hyperv_fb so
conflicting framebuffers are removed before allocating an MMIO address.
Then the default framebuffer MMIO address should always be available, and
there's never any confusion about which framebuffer address the kdump
kernel should use -- it's always the original address provided by
the Hyper-V host. This approach is already used by the hyperv_drm
driver, and is consistent with the usage guidelines at the head of
the module with the function aperture_remove_conflicting_devices().

This approach also solves a related minor problem when kexec_load()
is used to load the kdump kernel. With current code, unbinding and
rebinding the hyperv_fb driver could result in the framebuffer moving
back to the default framebuffer address, because on the rebind there
are no conflicts. If such a move is done after the kdump kernel is
loaded with the new framebuffer address, at kdump time it could again
have the wrong address.

This problem and fix are described in terms of the kdump kernel, but
it can also occur with any kernel started via kexec.

See extensive discussion of the problem and solution at [2].

[1] https://lore.kernel.org/linux-hyperv/20201014092429.1415040-1-kasong@redhat.com/
[2] https://lore.kernel.org/linux-hyperv/BLAPR10MB521793485093FDB448F7B2E5FDE92@BLAPR10MB5217.namprd10.prod.outlook.com/

Reported-by: Thomas Tai <thomas.tai@oracle.com>
Fixes: c25a19afb81c ("fbdev/hyperv_fb: Do not clear global screen_info")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Link: https://lore.kernel.org/r/20250218230130.3207-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250218230130.3207-1-mhklinux@outlook.com>
fbdev: hyperv_fb: iounmap() the correct memory when removing a device 2025-02-21T19:45:02+00:00 Michael Kelley mhklinux@outlook.com 2025-02-09T23:52:52+00:00 7241c886a71797cc51efc6fadec7076fcf6435c2 When a Hyper-V framebuffer device is removed, or the driver is unbound from a device, any allocated and/or mapped memory must be released. In particular, MMIO address space that was mapped to the framebuffer must be unmapped. Current code unmaps the wrong address, resulting in an error like: [ 4093.980597] iounmap: bad address 00000000c936c05c followed by a stack dump. Commit d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver") changed the kind of address stored in info->screen_base, and the iounmap() call in hvfb_putmem() was not updated accordingly. Fix this by updating hvfb_putmem() to unmap the correct address. Fixes: d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver") Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com> Link: https://lore.kernel.org/r/20250209235252.2987-1-mhklinux@outlook.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20250209235252.2987-1-mhklinux@outlook.com> 
When a Hyper-V framebuffer device is removed, or the driver is unbound
from a device, any allocated and/or mapped memory must be released. In
particular, MMIO address space that was mapped to the framebuffer must
be unmapped. Current code unmaps the wrong address, resulting in an
error like:

[ 4093.980597] iounmap: bad address 00000000c936c05c

followed by a stack dump.

Commit d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for
Hyper-V frame buffer driver") changed the kind of address stored in
info->screen_base, and the iounmap() call in hvfb_putmem() was not
updated accordingly.

Fix this by updating hvfb_putmem() to unmap the correct address.

Fixes: d21987d709e8 ("video: hyperv: hyperv_fb: Support deferred IO for Hyper-V frame buffer driver")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Link: https://lore.kernel.org/r/20250209235252.2987-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20250209235252.2987-1-mhklinux@outlook.com>
fbdev: hyperv_fb: Convert comma to semicolon 2024-09-02T11:54:57+00:00 Chen Ni nichen@iscas.ac.cn 2024-09-02T07:44:02+00:00 27f22f897095b09df32bf689b63624d23b0c8ebc Replace a comma between expression statements by a semicolon. Fixes: d786e00d19f9 ("drivers: hv, hyperv_fb: Untangle and refactor Hyper-V panic notifiers") Signed-off-by: Chen Ni <nichen@iscas.ac.cn> Signed-off-by: Helge Deller <deller@gmx.de> 
Replace a comma between expression statements by a semicolon.

Fixes: d786e00d19f9 ("drivers: hv, hyperv_fb: Untangle and refactor Hyper-V panic notifiers")
Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Signed-off-by: Helge Deller <deller@gmx.de>
fbdev/hyperv_fb: Fix logic error for Gen2 VMs in hvfb_getmem() 2024-03-01T08:19:11+00:00 Michael Kelley mhklinux@outlook.com 2024-02-01T06:00:22+00:00 20ee2ae8c58990ca9e98954b7ac2b66c53a0310e A recent commit removing the use of screen_info introduced a logic error. The error causes hvfb_getmem() to always return -ENOMEM for Generation 2 VMs. As a result, the Hyper-V frame buffer device fails to initialize. The error was introduced by removing an "else if" clause, leaving Gen2 VMs to always take the -ENOMEM error path. Fix the problem by removing the error path "else" clause. Gen 2 VMs now always proceed through the MMIO memory allocation code, but with "base" and "size" defaulting to 0. Fixes: 0aa0838c84da ("fbdev/hyperv_fb: Remove firmware framebuffers with aperture helpers") Signed-off-by: Michael Kelley <mhklinux@outlook.com> Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com> Link: https://lore.kernel.org/r/20240201060022.233666-1-mhklinux@outlook.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20240201060022.233666-1-mhklinux@outlook.com> 
A recent commit removing the use of screen_info introduced a logic
error. The error causes hvfb_getmem() to always return -ENOMEM
for Generation 2 VMs. As a result, the Hyper-V frame buffer
device fails to initialize. The error was introduced by removing
an "else if" clause, leaving Gen2 VMs to always take the -ENOMEM
error path.

Fix the problem by removing the error path "else" clause. Gen 2
VMs now always proceed through the MMIO memory allocation code,
but with "base" and "size" defaulting to 0.

Fixes: 0aa0838c84da ("fbdev/hyperv_fb: Remove firmware framebuffers with aperture helpers")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Reviewed-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Saurabh Sengar <ssengar@linux.microsoft.com>
Link: https://lore.kernel.org/r/20240201060022.233666-1-mhklinux@outlook.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Message-ID: <20240201060022.233666-1-mhklinux@outlook.com>
fbdev/hyperv_fb: Do not clear global screen_info 2024-01-12T11:38:37+00:00 Thomas Zimmermann tzimmermann@suse.de 2024-01-03T10:15:12+00:00 c25a19afb81cfd73dab494ba64f9a434cf1a4499 Do not clear the global instance of screen_info. If necessary, clearing fields in screen_info should be done by architecture or firmware code that maintains the firmware framebuffer. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Signed-off-by: Helge Deller <deller@gmx.de> 
Do not clear the global instance of screen_info. If necessary, clearing
fields in screen_info should be done by architecture or firmware code
that maintains the firmware framebuffer.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Helge Deller <deller@gmx.de>
fbdev/hyperv_fb: Remove firmware framebuffers with aperture helpers 2024-01-12T11:38:37+00:00 Thomas Zimmermann tzimmermann@suse.de 2024-01-03T10:15:10+00:00 0aa0838c84da22cd50d8a92fac26637c630a3235 Replace use of screen_info state with the correct interfaces from the aperture helpers. The state is only for architecture and firmware code. It is not guaranteed to contain valid data. Drivers are thus not allowed to use it. For removing conflicting firmware framebuffers, there are aperture helpers. Hence replace screen_info with the correct functions that will remove conflicting framebuffers for the hypervfb driver. For GEN1 PCI devices, the driver reads the framebuffer base and size from the PCI BAR, and uses the range for removing the firmware framebuffer. For GEN2 VMBUS devices no range can be detected, so the driver clears all firmware framebuffers. Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Javier Martinez Canillas <javierm@redhat.com> Signed-off-by: Helge Deller <deller@gmx.de> 
Replace use of screen_info state with the correct interfaces from
the aperture helpers. The state is only for architecture and firmware
code. It is not guaranteed to contain valid data. Drivers are thus
not allowed to use it.

For removing conflicting firmware framebuffers, there are aperture
helpers. Hence replace screen_info with the correct functions that will
remove conflicting framebuffers for the hypervfb driver. For GEN1 PCI
devices, the driver reads the framebuffer base and size from the PCI
BAR, and uses the range for removing the firmware framebuffer. For
GEN2 VMBUS devices no range can be detected, so the driver clears all
firmware framebuffers.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Signed-off-by: Helge Deller <deller@gmx.de>
mm, treewide: rename MAX_ORDER to MAX_PAGE_ORDER 2024-01-08T23:27:15+00:00 Kirill A. Shutemov kirill.shutemov@linux.intel.com 2023-12-28T14:47:04+00:00 5e0a760b44417f7cadd79de2204d6247109558a0 commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has changed the definition of MAX_ORDER to be inclusive. This has caused issues with code that was not yet upstream and depended on the previous definition. To draw attention to the altered meaning of the define, rename MAX_ORDER to MAX_PAGE_ORDER. Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> 
commit 23baf831a32c ("mm, treewide: redefine MAX_ORDER sanely") has
changed the definition of MAX_ORDER to be inclusive.  This has caused
issues with code that was not yet upstream and depended on the previous
definition.

To draw attention to the altered meaning of the define, rename MAX_ORDER
to MAX_PAGE_ORDER.

Link: https://lkml.kernel.org/r/20231228144704.14033-2-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>