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From: alison.schofield@intel.com
To: Ben Widawsky <ben.widawsky@intel.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Ira Weiny <ira.weiny@intel.com>,
	Vishal Verma <vishal.l.verma@intel.com>
Cc: Alison Schofield <alison.schofield@intel.com>, linux-cxl@vger.kernel.org
Subject: [PATCH v2 4/4] cxl/pmem: Remove CXL SET_PARTITION_INFO from exclusive_cmds list
Date: Fri, 25 Feb 2022 12:31:01 -0800	[thread overview]
Message-ID: <b5161bb8ad908510e2af36a837e43e3662a357b5.1645817416.git.alison.schofield@intel.com> (raw)
In-Reply-To: <cover.1645817416.git.alison.schofield@intel.com>

From: Alison Schofield <alison.schofield@intel.com>

With SET_PARTITION_INFO on the exclusive_cmds list for the CXL_PMEM
driver, userspace cannot execute a set-partition command without
first unbinding the pmem driver from the device.

When userspace requests a partition change to take effect on the
next reboot this unbind requirement is unnecessarily restrictive.
The driver does not need to enforce quiescing of the device before
setting up the 'next' partitions. Of course, userspace still needs
to be aware that changing the size of persistent capacity on the
next reboot will result in the loss of data stored. That can
happen regardless of whether it is presently bound/unbound at the
time of issuing the set-partition command.

When userspace requests a partition change to take effect immediately,
restrictions are needed. The CXL_MEM driver currently blocks the usage
of immediate mode, making the presence of SET_PARTITION_INFO on this
exclusive commands list redundant.

In the future, when the CXL_MEM driver adds support for immediate
changes to device partitions it will ensure that the partition change
will not affect any active decode. That means the work will not fall
right back here, onto the CXL_PMEM driver.

Signed-off-by: Alison Schofield <alison.schofield@intel.com>
---
 drivers/cxl/pmem.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/cxl/pmem.c b/drivers/cxl/pmem.c
index fabdb0c6dbf2..73a2868b5f95 100644
--- a/drivers/cxl/pmem.c
+++ b/drivers/cxl/pmem.c
@@ -344,7 +344,6 @@ static __init int cxl_pmem_init(void)
 {
 	int rc;
 
-	set_bit(CXL_MEM_COMMAND_ID_SET_PARTITION_INFO, exclusive_cmds);
 	set_bit(CXL_MEM_COMMAND_ID_SET_SHUTDOWN_STATE, exclusive_cmds);
 	set_bit(CXL_MEM_COMMAND_ID_SET_LSA, exclusive_cmds);
 
-- 
2.31.1


      parent reply	other threads:[~2022-02-25 20:27 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-25 20:30 [PATCH v2 0/4] Do not allow set-partition immediate mode alison.schofield
2022-02-25 20:30 ` [PATCH v2 1/4] cxl/mbox: Move cxl_mem_command construction to helper funcs alison.schofield
2022-02-25 21:31   ` Dan Williams
2022-02-25 20:30 ` [PATCH v2 2/4] cxl/mbox: Centralize the validation of user commands alison.schofield
2022-02-25 20:31 ` [PATCH v2 3/4] cxl/mbox: Block immediate mode in SET_PARTITION_INFO command alison.schofield
2022-02-25 20:31 ` alison.schofield [this message]

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