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035e9f4716
All sbitmap code uses implied preemption protection to update
sb->alloc_hint except sbitmap_put(). Using implied preemption protection is
safe since the value of sb->alloc_hint only affects performance of sbitmap
allocations but not their correctness. Change this_cpu_ptr() in
sbitmap_put() into raw_cpu_ptr() to suppress the following kernel warning
that appears with preemption debugging enabled (CONFIG_DEBUG_PREEMPT):
BUG: using smp_processor_id() in preemptible [00000000] code: scsi_eh_0/152
caller is debug_smp_processor_id+0x17/0x20
CPU: 1 PID: 152 Comm: scsi_eh_0 Tainted: G W 5.12.0-rc1-dbg+ #6
Call Trace:
show_stack+0x52/0x58
dump_stack+0xaf/0xf3
check_preemption_disabled+0xce/0xd0
debug_smp_processor_id+0x17/0x20
scsi_device_unbusy+0x13a/0x1c0 [scsi_mod]
scsi_finish_command+0x4d/0x290 [scsi_mod]
scsi_eh_flush_done_q+0x1e7/0x280 [scsi_mod]
ata_scsi_port_error_handler+0x592/0x750 [libata]
ata_scsi_error+0x1a0/0x1f0 [libata]
scsi_error_handler+0x19e/0x330 [scsi_mod]
kthread+0x222/0x250
ret_from_fork+0x1f/0x30
Link: https://lore.kernel.org/r/20210317032648.9080-1-bvanassche@acm.org
Fixes: c548e62bcf ("scsi: sbitmap: Move allocation hint into sbitmap")
Cc: Hannes Reinecke <hare@suse.de>
Cc: Omar Sandoval <osandov@fb.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
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 Restructured Text 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.