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linux-stable/drivers/scsi/libsas
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Ahmed S. Darwish 58bdc321be scsi: libsas: Introduce a _gfp() variant of event notifiers 
[ Upstream commit c2d0f1a65a ]

sas_alloc_event() uses in_interrupt() to decide which allocation should be
used.

The usage of in_interrupt() in drivers is phased out and Linus clearly
requested that code which changes behaviour depending on context should
either be separated or the context be conveyed in an argument passed by the
caller, which usually knows the context.

The in_interrupt() check is also only partially correct, because it fails
to choose the correct code path when just preemption or interrupts are
disabled. For example, as in the following call chain:

  mvsas/mv_sas.c: mvs_work_queue() [process context]
  spin_lock_irqsave(mvs_info::lock, )
    -> libsas/sas_event.c: sas_notify_phy_event()
      -> sas_alloc_event()
        -> in_interrupt() = false
          -> invalid GFP_KERNEL allocation
    -> libsas/sas_event.c: sas_notify_port_event()
      -> sas_alloc_event()
        -> in_interrupt() = false
          -> invalid GFP_KERNEL allocation

Introduce sas_alloc_event_gfp(), sas_notify_port_event_gfp(), and
sas_notify_phy_event_gfp(), which all behave like the non _gfp() variants
but use a caller-passed GFP mask for allocations.

For bisectability, all callers will be modified first to pass GFP context,
then the non _gfp() libsas API variants will be modified to take a gfp_t by
default.

Link: https://lore.kernel.org/r/20210118100955.1761652-4-a.darwish@linutronix.de
Fixes: 1c393b970e ("scsi: libsas: Use dynamic alloced work to avoid sas event lost")
Cc: Jason Yan <yanaijie@huawei.com>
Reviewed-by: John Garry <john.garry@huawei.com>
Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-03-25 09:04:11 +01:00
..
Kconfig ata: make SATA_PMP option selectable only if any SATA host driver is enabled 2020-03-26 10:28:17 -06:00
Makefile
sas_ata.c SCSI misc on 20201013 2020-10-14 15:15:35 -07:00
sas_discover.c SCSI misc on 20201013 2020-10-14 15:15:35 -07:00
sas_event.c scsi: libsas: Introduce a _gfp() variant of event notifiers 2021-03-25 09:04:11 +01:00
sas_expander.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sas_host_smp.c
sas_init.c scsi: libsas: Introduce a _gfp() variant of event notifiers 2021-03-25 09:04:11 +01:00
sas_internal.h scsi: libsas: Introduce a _gfp() variant of event notifiers 2021-03-25 09:04:11 +01:00
sas_phy.c SCSI misc on 20190709 2019-07-11 15:14:01 -07:00
sas_port.c scsi: libsas: Tidy SAS address print format 2019-12-21 13:42:42 -05:00
sas_scsi_host.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
sas_task.c scsi: libsas: Tidy SAS address print format 2019-12-21 13:42:42 -05:00