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Commit 69f4eb9f authored by Keith Busch's avatar Keith Busch Committed by Jens Axboe
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nvme-pci: make CMB SQ mod-param read-only 



A controller reset after a run time change of the CMB module parameter
breaks the driver. An 'on -> off' will have the driver use NULL for the
host memory queue, and 'off -> on' will use mismatched queue depth between
the device and the host.

We could fix both, but there isn't really a good reason to change this
at run time anyway, compared to at module load time, so this patch makes
parameter read-only after after modprobe.

Signed-off-by: default avatarKeith Busch <keith.busch@intel.com>
Reviewed-by: default avatarSagi Grimberg <sagi@grimberg.me>
Reviewed-by: default avatarJohannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 1d39e692

drivers/nvme/host/pci.c

+1 −1
Original line number Diff line number Diff line
@@ -42,7 +42,7 @@ static int use_threaded_interrupts; 
module_param(use_threaded_interrupts, int, 0);



static bool use_cmb_sqes = true;

module_param(use_cmb_sqes, bool, 0644);

module_param(use_cmb_sqes, bool, 0444);

MODULE_PARM_DESC(use_cmb_sqes, "use controller's memory buffer for I/O SQes");



static unsigned int max_host_mem_size_mb = 128;