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scsi: ips: Replace kmap_atomic() with kmap_local_page()

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kmap_atomic() is deprecated in favor of kmap_local_page(). Therefore,
replace kmap_atomic() with kmap_local_page() in ips_is_passthru(). In the
meantime remove an unnecessary comment, align code, and remove spaces.

kmap_atomic() is implemented like a kmap_local_page() which also disables
page-faults and preemption (the latter only for !PREEMPT_RT kernels).  The
code within the mapping/unmapping in ips_is_passthru() is already in atomic
context because of a call to local_irq_save() and kmap_local_page() can be
called in atomic context too (including interrupts).

Therefore, a mere replacement of the old API with the new one is all it is
required (i.e., there is no need to explicitly add any calls to
pagefault_disable() and/or preempt_disable()).

Suggested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/r/20230103173131.21259-1-fmdefrancesco@gmail.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
This commit is contained in:
Fabio M. De Francesco 2023-01-03 18:31:31 +01:00 committed by Martin K. Petersen
parent 1eeedfad9a
commit 7edd053b33
1 changed files with 5 additions and 6 deletions
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11
drivers/scsi/ips.c
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@ -1499,17 +1499,16 @@ static int ips_is_passthru(struct scsi_cmnd *SC)
struct scatterlist *sg = scsi_sglist(SC);
char *buffer;
/* kmap_atomic() ensures addressability of the user buffer.*/
/* local_irq_save() protects the KM_IRQ0 address slot. */
local_irq_save(flags);
buffer = kmap_atomic(sg_page(sg)) + sg->offset;
if (buffer && buffer[0] == 'C' && buffer[1] == 'O' &&
buffer[2] == 'P' && buffer[3] == 'P') {
kunmap_atomic(buffer - sg->offset);
buffer = kmap_local_page(sg_page(sg)) + sg->offset;
if (buffer && buffer[0] == 'C' && buffer[1] == 'O' &&
buffer[2] == 'P' && buffer[3] == 'P') {
kunmap_local(buffer);
local_irq_restore(flags);
return 1;
}
kunmap_atomic(buffer - sg->offset);
kunmap_local(buffer);
local_irq_restore(flags);
}
return 0;