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| author | Dan Williams <dan.j.williams@intel.com> | 2019-04-22 16:08:21 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-27 09:36:39 +0200 |
| commit | 40221d56ae28eb0b3e86a482063b0e303903e397 (patch) | |
| tree | 2647c35b4df6160452d3698a90396768ece40dca /drivers/acpi | |
| parent | bc18c2593635364f0c71f76f8fc395bee33954ab (diff) | |
| download | linux-rpi3-40221d56ae28eb0b3e86a482063b0e303903e397.tar.gz linux-rpi3-40221d56ae28eb0b3e86a482063b0e303903e397.tar.bz2 linux-rpi3-40221d56ae28eb0b3e86a482063b0e303903e397.zip | |
nfit/ars: Allow root to busy-poll the ARS state machine
commit 5479b2757f26fe9908fc341d105b2097fe820b6f upstream.
The ARS implementation implements exponential back-off on the poll
interval to prevent high-frequency access to the DIMM / platform
interface. Depending on when the ARS completes the poll interval may
exceed the completion event by minutes. Allow root to reset the timeout
each time it probes the status. A one-second timeout is still enforced,
but root can otherwise can control the poll interval.
Fixes: bc6ba8085842 ("nfit, address-range-scrub: rework and simplify ARS...")
Cc: <stable@vger.kernel.org>
Reported-by: Erwin Tsaur <erwin.tsaur@oracle.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/nfit/core.c | 8 | ||||
| -rw-r--r-- | drivers/acpi/nfit/nfit.h | 1 |
2 files changed, 9 insertions, 0 deletions
diff --git a/drivers/acpi/nfit/core.c b/drivers/acpi/nfit/core.c index 6b5a3c3b4458..4b489d14a680 100644 --- a/drivers/acpi/nfit/core.c +++ b/drivers/acpi/nfit/core.c @@ -1314,6 +1314,13 @@ static ssize_t scrub_show(struct device *dev, busy = test_bit(ARS_BUSY, &acpi_desc->scrub_flags) && !test_bit(ARS_CANCEL, &acpi_desc->scrub_flags); rc = sprintf(buf, "%d%s", acpi_desc->scrub_count, busy ? "+\n" : "\n"); + /* Allow an admin to poll the busy state at a higher rate */ + if (busy && capable(CAP_SYS_RAWIO) && !test_and_set_bit(ARS_POLL, + &acpi_desc->scrub_flags)) { + acpi_desc->scrub_tmo = 1; + mod_delayed_work(nfit_wq, &acpi_desc->dwork, HZ); + } + mutex_unlock(&acpi_desc->init_mutex); device_unlock(dev); return rc; @@ -3075,6 +3082,7 @@ static void acpi_nfit_scrub(struct work_struct *work) else notify_ars_done(acpi_desc); memset(acpi_desc->ars_status, 0, acpi_desc->max_ars); + clear_bit(ARS_POLL, &acpi_desc->scrub_flags); mutex_unlock(&acpi_desc->init_mutex); } diff --git a/drivers/acpi/nfit/nfit.h b/drivers/acpi/nfit/nfit.h index 94710e579598..b5fd3522abc7 100644 --- a/drivers/acpi/nfit/nfit.h +++ b/drivers/acpi/nfit/nfit.h @@ -184,6 +184,7 @@ struct nfit_mem { enum scrub_flags { ARS_BUSY, ARS_CANCEL, + ARS_POLL, }; struct acpi_nfit_desc { |