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target/pr: Use atomic bitop for se_dev_entry->deve_flags reservation check

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This patch converts the core_scsi3_pr_seq_non_holder() check for non
reservation holding registrations to use an atomic bitop in ->deve_flags
to determine if a registration is currently active.

It also includes associated a set_bit() in __core_scsi3_add_registration()
and clear_bit() in __core_scsi3_free_registration(), if se_dev_entry still
exists, and has not already been released via se_dev_entry shutdown path
in core_disable_device_list_for_node().

Also, clear_bit in core_disable_device_list_for_node as well to ensure
the read-critical path in core_scsi3_pr_seq_non_holder() picks up the
new state, preceeding the final kfree_rcu() call.

Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Cc: Sagi Grimberg <sagig@mellanox.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
Nicholas Bellinger
2015-03-25 01:02:57 -07:00
parent 29a05deebf
commit 80bfdfa924
3 changed files with 42 additions and 20 deletions
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3
include/target/target_core_base.h
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@@ -638,7 +638,6 @@ struct se_lun_acl {
};
struct se_dev_entry {
bool def_pr_registered;
/* See transport_lunflags_table */
u32 lun_flags;
u32 mapped_lun;
@@ -655,6 +654,8 @@ struct se_dev_entry {
struct se_lun_acl __rcu *se_lun_acl;
spinlock_t ua_lock;
struct se_lun __rcu *se_lun;
#define DEF_PR_REG_ACTIVE 1
unsigned long deve_flags;
struct list_head alua_port_list;
struct list_head ua_list;
struct hlist_node link;