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Michael Ellerman
09fe2bfa6b
The pata_macio driver advertises a max_segment_size of 0xff00, because
the hardware doesn't cope with requests >= 64K.
However the SCSI core requires max_segment_size to be at least
PAGE_SIZE, which is a problem for pata_macio when the kernel is built
with 64K pages.
In older kernels the SCSI core would just increase the segment size to
be equal to PAGE_SIZE, however since the commit tagged below it causes a
warning and the device fails to probe:
WARNING: CPU: 0 PID: 26 at block/blk-settings.c:202 .blk_validate_limits+0x2f8/0x35c
CPU: 0 PID: 26 Comm: kworker/u4:1 Not tainted 6.10.0-rc1 #1
Hardware name: PowerMac7,2 PPC970 0x390202 PowerMac
...
NIP .blk_validate_limits+0x2f8/0x35c
LR .blk_alloc_queue+0xc0/0x2f8
Call Trace:
.blk_alloc_queue+0xc0/0x2f8
.blk_mq_alloc_queue+0x60/0xf8
.scsi_alloc_sdev+0x208/0x3c0
.scsi_probe_and_add_lun+0x314/0x52c
.__scsi_add_device+0x170/0x1a4
.ata_scsi_scan_host+0x2bc/0x3e4
.async_port_probe+0x6c/0xa0
.async_run_entry_fn+0x60/0x1bc
.process_one_work+0x228/0x510
.worker_thread+0x360/0x530
.kthread+0x134/0x13c
.start_kernel_thread+0x10/0x14
...
scsi_alloc_sdev: Allocation failure during SCSI scanning, some SCSI devices might not be configured
Although the hardware can't cope with a 64K segment, the driver
already deals with that internally by splitting large requests in
pata_macio_qc_prep(). That is how the driver has managed to function
until now on 64K kernels.
So fix the driver to advertise a max_segment_size of 64K, which avoids
the warning and keeps the SCSI core happy.
Fixes: afd53a3d85 ("scsi: core: Initialize scsi midlayer limits before allocating the queue")
Reported-by: Guenter Roeck <linux@roeck-us.net>
Closes: https://lore.kernel.org/all/ce2bf6af-4382-4fe1-b392-cc6829f5ceb2@roeck-us.net/
Reported-by: Doru Iorgulescu <doru.iorgulescu1@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218858
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Signed-off-by: Niklas Cassel <cassel@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.